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Silva Fennica 1926-1997
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Articles containing the keyword 'rest'.

Category: Commentary

article id 6985, category Commentary
Eshetu Yirdaw, Markku Kanninen, Mohamed Elfadl, Daniel Tsegai. (2017). Special issue: Drought and Dryland Management – a commentary. Silva Fennica vol. 51 no. 1B article id 6985. https://doi.org/10.14214/sf.6985
  • Yirdaw, Viikki Tropical Resources Institute (VITRI), Department of Forest Sciences, P.O. Box 27, FI-00014 University of Helsinki, Finland ORCID ID:E-mail: eshetu.yirdaw@helsinki.fi (email)
  • Kanninen, Viikki Tropical Resources Institute (VITRI), Department of Forest Sciences, P.O. Box 27, FI-00014 University of Helsinki, Finland ORCID ID:E-mail: markku.kanninen@helsinki.fi
  • Elfadl, Viikki Tropical Resources Institute (VITRI), Department of Forest Sciences, P.O. Box 27, FI-00014 University of Helsinki, Finland ORCID ID:E-mail: mohamed.elfadl@helsinki.fi
  • Tsegai, UNCCD Secretariat, Platz der Vereinten Nationen 1, 53113 Bonn, Germany ORCID ID:E-mail: dtsegai@unccd.int
article id 6985, category Commentary
Eshetu Yirdaw, Markku Kanninen, Mohamed Elfadl, Daniel Tsegai. (2017). Special issue: Drought and Dryland Management – a commentary. Silva Fennica vol. 51 no. 1B article id 6985. https://doi.org/10.14214/sf.6985
  • Yirdaw, Viikki Tropical Resources Institute (VITRI), Department of Forest Sciences, P.O. Box 27, FI-00014 University of Helsinki, Finland ORCID ID:E-mail: eshetu.yirdaw@helsinki.fi (email)
  • Kanninen, Viikki Tropical Resources Institute (VITRI), Department of Forest Sciences, P.O. Box 27, FI-00014 University of Helsinki, Finland ORCID ID:E-mail: markku.kanninen@helsinki.fi
  • Elfadl, Viikki Tropical Resources Institute (VITRI), Department of Forest Sciences, P.O. Box 27, FI-00014 University of Helsinki, Finland ORCID ID:E-mail: mohamed.elfadl@helsinki.fi
  • Tsegai, UNCCD Secretariat, Platz der Vereinten Nationen 1, 53113 Bonn, Germany ORCID ID:E-mail: dtsegai@unccd.int
article id 461, category Commentary
Sari Palmroth. (2009). Boreal forest and climate change – from processes and transport to trees, ecosystems and atmosphere. Silva Fennica vol. 43 no. 4 article id 461. https://doi.org/10.14214/sf.461
Book review: Hari, P. & Kulmala, L. (eds.). 2008. Boreal Forest and Climate Change. Advances in Global Change Research 34. Springer. 582 p. ISBN 978-1-4020-8717-2.
  • Palmroth, Duke University, Nicholas School of the Environment, Box 90328 Duke University, Durham, USA ORCID ID:E-mail: sari.palmroth@duke.edu (email)
article id 547, category Commentary
Timo Kuuluvainen. (2002). Introduction. Disturbance dynamics in boreal forests: defining the ecological basis of restoration and management of biodiversity. Silva Fennica vol. 36 no. 1 article id 547. https://doi.org/10.14214/sf.547
  • Kuuluvainen, Department of Forest Ecology, P.O. Box 27, FIN-00014 University of Helsinki, Finland ORCID ID:E-mail: timo.kuuluvainen@helsinki.fi (email)
article id 547, category Commentary
Timo Kuuluvainen. (2002). Introduction. Disturbance dynamics in boreal forests: defining the ecological basis of restoration and management of biodiversity. Silva Fennica vol. 36 no. 1 article id 547. https://doi.org/10.14214/sf.547
  • Kuuluvainen, Department of Forest Ecology, P.O. Box 27, FIN-00014 University of Helsinki, Finland ORCID ID:E-mail: timo.kuuluvainen@helsinki.fi (email)

Category: Research article

article id 10010, category Research article
Panu Halme, Jenna Purhonen, Emma-Liina Marjakangas, Atte Komonen, Katja Juutilainen, Nerea Abrego. (2019). Dead wood profile of a semi-natural boreal forest – implications for sampling. Silva Fennica vol. 53 no. 4 article id 10010. https://doi.org/10.14214/sf.10010
Highlights: We constructed a full dead wood profile of a semi-natural boreal forest; Abundance-diameter distributions were different among tree species; Extensive sampling is needed if focus on large dead wood and rare tree species.

Dead wood profile of a forest is a useful tool for describing forest characteristics and assessing forest disturbance history. Nevertheless, there are few studies on dead wood profiles, including both coarse and fine dead wood, and on the effect of sampling intensity on the dead wood estimates. In a semi-natural boreal forest, we measured every dead wood item over 2 cm in diameter from 80 study plots. From eight plots, we further recorded dead wood items below 2 cm in diameter. Based on these data we constructed the full dead wood profile, i.e. the overall number of dead wood items and their distribution among different tree species, volumes of different size and decay stage categories. We discovered that while the number of small dead wood items was immense, their number dropped drastically from the diameter below 1 cm to diameters 2–3 cm. Different tree species had notably different abundance-diameter distribution patterns: spruce dead wood comprised most strikingly the smallest diameter fractions, whereas aspen dead wood comprised a larger share of large-diameter items. Most of the dead wood volume constituted of large pieces (>10 cm in diameter), and 62% of volume was birch. The variation in the dead wood estimates was small for the numerically dominant tree species and smallest diameter categories, but high for the sub-dominant tree species and larger size categories. In conclusion, the more the focus is on rare tree species and large dead wood items, the more comprehensive should the sampling be.

  • Halme, Department of Biological and Environmental Science, University of Jyväskylä, P.O. Box 35, FI-40014 University of Jyväskylä, Finland; School of Resource Wisdom, University of Jyväskylä, P.O. Box 35, FI-40014 University of Jyväskylä, Finland ORCID ID:E-mail: panu.halme@jyu.fi (email)
  • Purhonen, Department of Biological and Environmental Science, University of Jyväskylä, P.O. Box 35, FI-40014 University of Jyväskylä, Finland ORCID ID:E-mail: jenna.e.i.purhonen@jyu.fi
  • Marjakangas, Centre for Biodiversity Dynamics, Department of Biology, Norwegian University of Science and Technology, N-7491 Trondheim, Norway ORCID ID:E-mail: emma-liina.marjakangas@ntnu.no
  • Komonen, Department of Biological and Environmental Science, University of Jyväskylä, P.O. Box 35, FI-40014 University of Jyväskylä, Finland; School of Resource Wisdom, University of Jyväskylä, P.O. Box 35, FI-40014 University of Jyväskylä, Finland ORCID ID:E-mail: atte.komonen@jyu.fi
  • Juutilainen, Department of Biological and Environmental Science, University of Jyväskylä, P.O. Box 35, FI-40014 University of Jyväskylä, Finland ORCID ID:E-mail: kjuutilainen@yahoo.com
  • Abrego, Department of Agricultural Sciences, University of Helsinki, P.O. Box 27, FI-00014 University of Helsinki, Finland ORCID ID:E-mail: nerea.abrego@helsinki.fi
article id 10010, category Research article
Panu Halme, Jenna Purhonen, Emma-Liina Marjakangas, Atte Komonen, Katja Juutilainen, Nerea Abrego. (2019). Dead wood profile of a semi-natural boreal forest – implications for sampling. Silva Fennica vol. 53 no. 4 article id 10010. https://doi.org/10.14214/sf.10010
Highlights: We constructed a full dead wood profile of a semi-natural boreal forest; Abundance-diameter distributions were different among tree species; Extensive sampling is needed if focus on large dead wood and rare tree species.

Dead wood profile of a forest is a useful tool for describing forest characteristics and assessing forest disturbance history. Nevertheless, there are few studies on dead wood profiles, including both coarse and fine dead wood, and on the effect of sampling intensity on the dead wood estimates. In a semi-natural boreal forest, we measured every dead wood item over 2 cm in diameter from 80 study plots. From eight plots, we further recorded dead wood items below 2 cm in diameter. Based on these data we constructed the full dead wood profile, i.e. the overall number of dead wood items and their distribution among different tree species, volumes of different size and decay stage categories. We discovered that while the number of small dead wood items was immense, their number dropped drastically from the diameter below 1 cm to diameters 2–3 cm. Different tree species had notably different abundance-diameter distribution patterns: spruce dead wood comprised most strikingly the smallest diameter fractions, whereas aspen dead wood comprised a larger share of large-diameter items. Most of the dead wood volume constituted of large pieces (>10 cm in diameter), and 62% of volume was birch. The variation in the dead wood estimates was small for the numerically dominant tree species and smallest diameter categories, but high for the sub-dominant tree species and larger size categories. In conclusion, the more the focus is on rare tree species and large dead wood items, the more comprehensive should the sampling be.

  • Halme, Department of Biological and Environmental Science, University of Jyväskylä, P.O. Box 35, FI-40014 University of Jyväskylä, Finland; School of Resource Wisdom, University of Jyväskylä, P.O. Box 35, FI-40014 University of Jyväskylä, Finland ORCID ID:E-mail: panu.halme@jyu.fi (email)
  • Purhonen, Department of Biological and Environmental Science, University of Jyväskylä, P.O. Box 35, FI-40014 University of Jyväskylä, Finland ORCID ID:E-mail: jenna.e.i.purhonen@jyu.fi
  • Marjakangas, Centre for Biodiversity Dynamics, Department of Biology, Norwegian University of Science and Technology, N-7491 Trondheim, Norway ORCID ID:E-mail: emma-liina.marjakangas@ntnu.no
  • Komonen, Department of Biological and Environmental Science, University of Jyväskylä, P.O. Box 35, FI-40014 University of Jyväskylä, Finland; School of Resource Wisdom, University of Jyväskylä, P.O. Box 35, FI-40014 University of Jyväskylä, Finland ORCID ID:E-mail: atte.komonen@jyu.fi
  • Juutilainen, Department of Biological and Environmental Science, University of Jyväskylä, P.O. Box 35, FI-40014 University of Jyväskylä, Finland ORCID ID:E-mail: kjuutilainen@yahoo.com
  • Abrego, Department of Agricultural Sciences, University of Helsinki, P.O. Box 27, FI-00014 University of Helsinki, Finland ORCID ID:E-mail: nerea.abrego@helsinki.fi
article id 10010, category Research article
Panu Halme, Jenna Purhonen, Emma-Liina Marjakangas, Atte Komonen, Katja Juutilainen, Nerea Abrego. (2019). Dead wood profile of a semi-natural boreal forest – implications for sampling. Silva Fennica vol. 53 no. 4 article id 10010. https://doi.org/10.14214/sf.10010
Highlights: We constructed a full dead wood profile of a semi-natural boreal forest; Abundance-diameter distributions were different among tree species; Extensive sampling is needed if focus on large dead wood and rare tree species.

Dead wood profile of a forest is a useful tool for describing forest characteristics and assessing forest disturbance history. Nevertheless, there are few studies on dead wood profiles, including both coarse and fine dead wood, and on the effect of sampling intensity on the dead wood estimates. In a semi-natural boreal forest, we measured every dead wood item over 2 cm in diameter from 80 study plots. From eight plots, we further recorded dead wood items below 2 cm in diameter. Based on these data we constructed the full dead wood profile, i.e. the overall number of dead wood items and their distribution among different tree species, volumes of different size and decay stage categories. We discovered that while the number of small dead wood items was immense, their number dropped drastically from the diameter below 1 cm to diameters 2–3 cm. Different tree species had notably different abundance-diameter distribution patterns: spruce dead wood comprised most strikingly the smallest diameter fractions, whereas aspen dead wood comprised a larger share of large-diameter items. Most of the dead wood volume constituted of large pieces (>10 cm in diameter), and 62% of volume was birch. The variation in the dead wood estimates was small for the numerically dominant tree species and smallest diameter categories, but high for the sub-dominant tree species and larger size categories. In conclusion, the more the focus is on rare tree species and large dead wood items, the more comprehensive should the sampling be.

  • Halme, Department of Biological and Environmental Science, University of Jyväskylä, P.O. Box 35, FI-40014 University of Jyväskylä, Finland; School of Resource Wisdom, University of Jyväskylä, P.O. Box 35, FI-40014 University of Jyväskylä, Finland ORCID ID:E-mail: panu.halme@jyu.fi (email)
  • Purhonen, Department of Biological and Environmental Science, University of Jyväskylä, P.O. Box 35, FI-40014 University of Jyväskylä, Finland ORCID ID:E-mail: jenna.e.i.purhonen@jyu.fi
  • Marjakangas, Centre for Biodiversity Dynamics, Department of Biology, Norwegian University of Science and Technology, N-7491 Trondheim, Norway ORCID ID:E-mail: emma-liina.marjakangas@ntnu.no
  • Komonen, Department of Biological and Environmental Science, University of Jyväskylä, P.O. Box 35, FI-40014 University of Jyväskylä, Finland; School of Resource Wisdom, University of Jyväskylä, P.O. Box 35, FI-40014 University of Jyväskylä, Finland ORCID ID:E-mail: atte.komonen@jyu.fi
  • Juutilainen, Department of Biological and Environmental Science, University of Jyväskylä, P.O. Box 35, FI-40014 University of Jyväskylä, Finland ORCID ID:E-mail: kjuutilainen@yahoo.com
  • Abrego, Department of Agricultural Sciences, University of Helsinki, P.O. Box 27, FI-00014 University of Helsinki, Finland ORCID ID:E-mail: nerea.abrego@helsinki.fi
article id 10187, category Research article
Timo Pukkala, Kjersti Holt Hanssen, Kjell Andreassen. (2019). Stem taper and bark functions for Norway spruce in Norway. Silva Fennica vol. 53 no. 3 article id 10187. https://doi.org/10.14214/sf.10187
Highlights: New variable-exponent stem taper and bark functions were developed for Norway spruce; Both fixed and mixed-effects models were developed; Site index and tree age had statistically significant but small effects on stem taper.

Based on data from long-term experimental fields with Norway spruce (Picea abies (L.) H. Karst.), we developed new stem taper and bark functions for Norway. Data was collected from 477 trees in stands across Norway. Three candidate functions which have shown good performance in previous studies (Kozak 02, Kozak 97 and Bi) were fitted to the data as fixed-effects models. The function with the smallest Akaike Information Criterion (AIC) was then chosen for additional analyses, fitting 1) site index-dependent and 2) age-dependent versions of the model, and 3) fitting a mixed-effects model with tree-specific random parameters. Kozak 97 was found to be the function with the smallest AIC, but all three tested taper functions resulted in fairly similar predictions of stem taper. The site index-dependent function reduced AIC and residual standard error and showed that the effect of site index on stem taper is different in small and large trees. The predictions of the age-independent and age-dependent models were very close to each other. Adding tree-specific random parameters to the model clearly reduced AIC and residual variation. However, the results suggest that the mixed-effects model should be used only when it is possible to calibrate it for each tree, otherwise the fixed-effects Kozak 97 model should be used. A model for double bark thickness was also fitted as fixed-effects Kozak 97 model. The model behaved logically, predicting larger relative but smaller absolute bark thickness for small trees.

article id 10043, category Research article
Outi Manninen, Rainer Peltola. (2019). Continuous picking may increase bilberry yields. Silva Fennica vol. 53 no. 3 article id 10043. https://doi.org/10.14214/sf.10043
Highlights: Bilberry fruit production and fruit set increased under continuous picking by rake in three-year study; Bilberry flower number and fruit mass were not affected by picking; Bilberry compensated for biomass loss; The highest relative deciduous species abundance was found in the picking treatment plots at the end of the experiment.

Accumulated knowledge about the health benefits of bilberry (Vaccinium myrtillus L.) has increased the demand and utilization of wild bilberries. Intensive berry picking by metal rakes is believed to cause damage in bilberry stands in areas under continuous picking pressure, and hence expected to hamper the production of berries in forthcoming years. We conducted an experiment to examine the effect of continuous bilberry picking by metal rake on the number of bilberry flowers and fruits, fruit mass, compensation for biomass loss after picking, and plant functional type abundance in the understorey in northern Finland. Bilberry lost less than 0.5% of its biomass annually during the three-year study period due to rake harvesting. The number of flowers was not significantly affected by damage caused by picking, while both fruit production and fruit set increased without any indication of reduced fruit mass, and biomass loss was fully compensated. Moreover, the relative abundance of plant functional types was not affected by picking during the study. We suggest that the low intensity and timing of damage act as a buffer against the adverse effects of picking on bilberry fruit production. On the basis of this study, it is reasonable to anticipate that there are no indications that current intensive berry picking would not be on a sustainable level.

  • Manninen, Natural Resources Institute Finland (Luke), Bioeconomy and environment, Paavo Havaksentie 3, FI-90014 University of Oulu, Finland ORCID ID:E-mail: outi.manninen@luke.fi (email)
  • Peltola, Natural Resources Institute Finland (Luke), Bioeconomy and environment, Ounasjoentie 6, FI-96200 Rovaniemi, Finland ORCID ID:E-mail: rainer.peltola@luke.fi
article id 10150, category Research article
Petri Forsström, Jouni Peltoniemi, Miina Rautiainen. (2019). Seasonal dynamics of lingonberry and blueberry spectra. Silva Fennica vol. 53 no. 2 article id 10150. https://doi.org/10.14214/sf.10150
Highlights: Seasonal series of multiangular spectra for lingonberry (Vaccinium vitis-idaea L.) and blueberry (Vaccinium myrtillus L.); Decidous blueberry has strong seasonal pattern while temporal variations of evergreen lingonberry were linked to phenological stages of flowering and berrying; Detection of flowers and berries from shrub spectra was possible; Collected spectral data are openly available through SPECCHIO Spectral Information System.

Accurate mapping of the spatial distribution of understory species from spectral images requires ground reference data which represent the prevailing phenological stage at the time of image acquisition. We measured the spectral bidirectional reflectance factors (BRFs, 350–2500 nm) at varying view angles for lingonberry (Vaccinium vitis-idaea L.) and blueberry (Vaccinium myrtillus L.) throughout the growing season of 2017 using Finnish Geospatial Research Institute’s FIGIFIGO field goniometer. Additionally, we measured spectra of leaves and berries of both species, and flowers of lingonberry. Both lingonberry and blueberry showed seasonality in visible and near-infrared spectral regions which was linked to occurrences of leaf growth, flowering, berrying, and leaf senescence. The seasonality of spectra differed between species due to different phenologies (evergreen vs. deciduous). Vegetation indices, normalized difference vegetation index (NDVI), moisture stress index (MSI), plant senescence reflectance index (PSRI), and red-edge inflection point (REIP2), showed characteristic seasonal trends. NDVI and PSRI were sensitive to the presence of flowers and berries of lingonberry, while with blueberry the effects were less evident. Off-nadir observations supported differentiating the dwarf shrub species from each other but showed little improvement for detection of flowers and berries. Lingonberry and blueberry can be identified by their spectral signatures if ground reference data are available over the entire growing season. The spectral data measured in this study are reposited in the publicly open SPECCHIO Spectral Information System.

  • Forsström, Aalto University, School of Engineering, Department of Built Environment, FI-00076 Aalto, Finland ORCID ID: https://orcid.org/0000-0002-2357-2517 E-mail: petri.forsstrom@aalto.fi (email)
  • Peltoniemi, Finnish Geospatial Research Institute (FGI), Department of Geodesy and Geodynamics, Geodeetinrinne 2, FI-02430 Masala, Finland ORCID ID: https://orcid.org/0000-0002-4701-128X E-mail: jouni.peltoniemi@nls.fi
  • Rautiainen, Aalto University, School of Engineering, Department of Built Environment, FI-00076 Aalto, Finland; Aalto University, Department of Electronics and Nanoengineering, FI-00076 Aalto, Finland ORCID ID: https://orcid.org/0000-0002-6568-3258 E-mail: miina.a.rautiainen@aalto.fi
article id 10089, category Research article
Arto Haara, Annika Kangas, Sakari Tuominen. (2019). Economic losses caused by tree species proportions and site type errors in forest management planning. Silva Fennica vol. 53 no. 2 article id 10089. https://doi.org/10.14214/sf.10089
Highlights: Errors in tree species proportions caused more economic losses for forest owners than site type errors; Economic losses due to sub-optimal treatments were observed from 26.5% to 31.7% of plots, depending on the remote sensing data set used; Even with the most accurate remote sensing data set, namely ALS data set, NPV losses were on average 124.4 € ha–1 with 3% interest rate.

The aim of this study was to estimate economic losses, which are caused by forest inventory errors of tree species proportions and site types. Our study data consisted of ground truth data and four sets of erroneous tree species proportions. They reflect the accuracy of tree species proportions in four remote sensing data sets, namely 1) airborne laser scanning (ALS) with 2D aerial image, 2) 2D aerial image, 3) 3D and 2D aerial image data together and 4) satellite data. Furthermore, our study data consisted of one simulated site type data set. We used the erroneous tree species proportions to optimise the timing of forest harvests and compared that to the true optimum obtained with ground truth data. According to the results, the mean losses of Net Present Value (NPV) because of erroneous tree species proportions at an interest rate of 3% varied from 124.4 € ha–1 to 167.7 € ha–1. The smallest losses were observed using tree species proportions predicted using ALS data and largest using satellite data. In those stands, respectively, in which tree species proportion errors actually caused economic losses, they were 468 € ha–1 on average with tree species proportions based on ALS data. In turn, site type errors caused only small losses. Based on this study, accurate tree species identification seems to be very important with respect to operational forest inventory.

  • Haara, Natural Resources Institute Finland (Luke), Bioeconomy and environment, P.O. Box 68, FI-80101 Joensuu, Finland ORCID ID:E-mail: arto.haara@luke.fi (email)
  • Kangas, Natural Resources Institute Finland (Luke), Bioeconomy and environment, P.O. Box 68, FI-80101 Joensuu, Finland ORCID ID: https://orcid.org/0000-0002-8637-5668 E-mail: annika.kangas@luke.fi
  • Tuominen, Natural Resources Institute Finland (Luke), Bioeconomy and environment, P.O. Box 2, FI-00791 Helsinki, Finland ORCID ID: https://orcid.org/0000-0001-5429-3433 E-mail: sakari.tuominen@luke.fi
article id 10088, category Research article
Antti-Jussi Lindroos, Kira Ryhti, Tomi Kaakkurivaara, Jori Uusitalo, Heljä-Sisko Helmisaari. (2019). Leaching of heavy metals and barium from forest roads reinforced with fly ash. Silva Fennica vol. 53 no. 2 article id 10088. https://doi.org/10.14214/sf.10088
Highlights: Heavy metal concentrations were generally low in percolation and ditch water samples of ash roads, but elevated concentrations were found in some parts of ash roads; Risk for heavy metal leaching is negligible if road parts producing high concentrations are rare.

The aim of this study was to determine the effect of leaching of heavy metals (Cr, As, Cd, Cu, Ni, Pb, Zn, Co, Mo) and earth-alkaline metal, barium (Ba), on the percolation and ditch water quality from the forest roads that contained ash in the road structures. Water quality was studied in the immediate vicinity below the ash layers as well as deeper in the road structure. Water quality was also determined in the drainage water in ditches that crossed the forest roads. A mixture of wood and peat based fly ash was used in the road structures. The treatments were: 1) no ash, 2) a 15 cm layer of ash/gravel mixture, 3) a 20 cm layer of ash/gravel mixture, 4) a 25 cm layer of ash, and 5) a 50 cm layer of ash. Large variation in the concentrations of Cr, As, Cu, Ni, Pb, Mo and Ba in the percolation water, even within the same treatment, caused difficulties to generalize the results. The concentrations of Cr, As, Ni, Pb, Mo and Ba in water samples were high in some treatment plot lysimeters containing ash compared to the control (no ash). On the other hand, many lysimeters had low and similar concentrations in water samples in the treatment plots containing ash compared to concentrations in the control plots. The ash in the roads did not affect the concentrations in the ditches. The leaching is uneven and seems to take place only from some parts of the ash layer. Risk for leaching is minimal if such parts are not widely spread.

  • Lindroos, Natural Resources Institute Finland (Luke), Latokartanonkaari 9, FI-00790 Helsinki, Finland ORCID ID:E-mail: antti.lindroos@luke.fi (email)
  • Ryhti, University of Helsinki, Department of Forest Sciences, P.O. Box 27, FI-00014 University of Helsinki, Finland ORCID ID:E-mail: kira.ryhti@helsinki.fi
  • Kaakkurivaara, Natural Resources Institute Finland (Luke), Latokartanonkaari 9, FI-00790 Helsinki, Finland ORCID ID:E-mail: tomi.kaakkurivaara@gmail.com
  • Uusitalo, Natural Resources Institute Finland (Luke), Korkeakoulunkatu 7, FI-33720 Tampere, Finland ORCID ID:E-mail: jori.uusitalo@luke.fi
  • Helmisaari, University of Helsinki, Department of Forest Sciences, P.O. Box 27, FI-00014 University of Helsinki, Finland ORCID ID:E-mail: helja-sisko.helmisaari@helsinki.fi
article id 10048, category Research article
Urszula Zajączkowska, Karina Kaczmarczyk, Janusz Liana. (2019). Birch sap exudation: influence of tree position in a forest stand on birch sap production, trunk wood anatomy and radial bending strength. Silva Fennica vol. 53 no. 2 article id 10048. https://doi.org/10.14214/sf.10048
Highlights: Birch trees along the forest edge exude more xylem sap but less concentrated than the trees from the interior; Radial bending strength of wood in birch trunk is higher in the trees from forest edge; Trees exhibit higher bending strength in western side of the trunk, where the number of vessels and the wood potential conductivity index are smaller.

It is commonly accepted that the period of early-spring xylem sap exudation marks a stage during which a positive pressure builds inside the tree trunks. This state changes when leaves appear, initiating water transport within the trunk. It is unknown, however, how the wood anatomical structure and its mechanical resistance influences the sap. We present the results of research on the relationship between exudation of sap from Betula pendula Roth trees from the interior of a forest stand and from its edge, and the anatomical structure of the trunk wood and its bending strength. During the period between March 21 and April 18, we performed five sets of measurements of sap exudation from trees at the edge of the stand and from the forest interior. The resulting radial wood samples were tested for bending strength using a fractometer. We tested the sap for electrolytic conductivity and sugars content. For the anatomical analysis of the wood, we determined the number of vessels per 1 mm2, average vessel lumen area and potential conductivity index. We found that the trees along the edge of the stand exude more sap, but it is less concentrated than the sap from the trees from the interior. Bending strength perpendicular to wood fibres is higher in the trees from the stand edge and in the western side of the trunk, where the number of vessels per 1 mm2 and conductivity index are smaller. Seemingly, this is the result of western winds, which are dominant in Poland.

  • Zajączkowska, Department of Forest Botany, Faculty of Forestry, Warsaw University of Life Sciences, 159 Nowoursynowska St., 02-776 Warsaw, Poland ORCID ID:E-mail: urszula.zajaczkowska@wl.sggw.pl (email)
  • Kaczmarczyk, Department of Forest Botany, Faculty of Forestry, Warsaw University of Life Sciences, 159 Nowoursynowska St., 02-776 Warsaw, Poland ORCID ID:E-mail: karina.kaczmarczyk@wl.sggw.pl
  • Liana, Department of Forest Botany, Faculty of Forestry, Warsaw University of Life Sciences, 159 Nowoursynowska St., 02-776 Warsaw, Poland ORCID ID:E-mail: janusz.liana@wl.sggw.pl
article id 10019, category Research article
Junyan Liu, Junfeng Tang, Si-Chong Chen, Wenbao Ma, Zheng Zheng, Tingfa Dong. (2019). Do tree cavity density and characteristics vary across topographical habitats in the tropics? A case study from Xishuangbanna, southwest China. Silva Fennica vol. 53 no. 1 article id 10019. https://doi.org/10.14214/sf.10019
Highlights: Cavities were significantly more abundant in high- and low-slope than high-plateau habitats; There are more “butt hollow” cavities in high-slope habitat and they occurred at a lower height; More “crack” cavities in low-slope habitat and they had a narrower entrance diameter; Certain types of cavities are concentrated in specific habitats, which provide opportunities for forest management and biodiversity conservation.

Despite the influence of cavities on the survival and distribution of cavity-dependent fauna, the variation in the density and characteristics of tree cavities across different habitat types in tropical forests is unknown. In this study, we surveyed 26 312 living trees from 376 species and compared cavity density and characteristics (height, size, type, and orientation) across five habitat types (valley, low-slope, high-slope, high-gully, and high-plateau) in a 20-hectare tropical rainforest in southwest China. From a total of 2047 cavities, we found that cavity density was mainly driven by habitat rather than tree species richness or diameter at breast height (DBH), and the characteristics of cavities were not uniformly distributed across habitats. Cavities were significantly more abundant in high- and low-slope than high-plateau habitats. Compared with other habitats, more “butt hollow” cavity types were found in high-slope habitat and they occurred at a lower tree height, whereas more “crack” cavities were found in low-slope habitat and they had a narrower entrance diameter. Although the mean orientation of cavities faced towards the northeast, cavity orientation varied significantly across habitat types. Our results indicate that certain types of cavities are concentrated in specific habitat types, which can provide avenues for forest management and biodiversity conservation. We highlight the importance of habitat heterogeneity in providing resources for cavity nesters.

  • Liu, Key Laboratory of Southwest China Wildlife Resources Conservation of Ministry of Education, Key Laboratory of Environmental Science and Biodiversity Conservation (Sichuan Province) and Institute of Plant Adaptation and Utilization in Southwest Mountains, China West Normal University, Nanchong, Sichuan 637009, China; Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, Yunnan 666303, China ORCID ID:E-mail: liujunyan2300@163.com
  • Tang, Key Laboratory of Southwest China Wildlife Resources Conservation of Ministry of Education, Key Laboratory of Environmental Science and Biodiversity Conservation (Sichuan Province) and Institute of Plant Adaptation and Utilization in Southwest Mountains, China West Normal University, Nanchong, Sichuan 637009, China ORCID ID:E-mail:
  • Chen, Royal Botanic Gardens, Kew, Wakehurst Place, West Sussex RH17 6TN, UK; Mitrani Department of Desert Ecology, Swiss Institute for Dryland Environmental and Energy Research, Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Midreshet Ben-Gurion, Beer-Sheva 8499000, Israel ORCID ID:E-mail: chensichong0528@gmail.com
  • Ma, Ecological Restoration and Conservation of Forests and Wetlands Key Laboratory of Sichuan Province, Sichuan Academy of Forestry, Chengdu 610081, China ORCID ID:E-mail: mawenbao_2000@126.com
  • Zheng, Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, Yunnan 666303, China ORCID ID:E-mail: dioeco@outlook.com
  • Dong, Key Laboratory of Southwest China Wildlife Resources Conservation of Ministry of Education, Key Laboratory of Environmental Science and Biodiversity Conservation (Sichuan Province) and Institute of Plant Adaptation and Utilization in Southwest Mountains, China West Normal University, Nanchong, Sichuan 637009, China ORCID ID:E-mail: dongtf@aliyun.com (email)
article id 9968, category Research article
Hubert Lachowicz, Anna Bieniasz, Rafał Wojtan. (2019). Variability in the basic density of silver birch wood in Poland. Silva Fennica vol. 53 no. 1 article id 9968. https://doi.org/10.14214/sf.9968
Highlights: Location, tree age and forest habitat type, and the interactions between those factors, have a statistically significant impact on the basic density of silver birch wood; The average basic density of silver birch wood increases with the age of the tree.

This work presents the findings of a study concerning variability in the basic density of silver birch (Betula pendula Roth) wood, depending on the geographical location of tree stands, the age and thickness of the trees, the forest habitat type, and interactions between some of these factors. The study was carried out on wood from trees aged approximately 30, 50 and 70 years in 12 forest districts located throughout Poland. In total 4777 wood samples, taken from 306 trees from 51 test plots, were measured. The location, the age of the trees, the thickness of the trees and the forest habitat type, as well as interactions between these factors, proved to have a significant influence on the basic density of silver birch wood. The highest mean values of the basic density of the birch wood were found in Sokołów forest district on the FBF habitat type (549 kg m–3) and in Giżycko forest district on the FMBF habitat type (548 kg m–3). For the entire set of examined material, the average values of the basic density of wood increase with tree age. For the examined material originating in FBF and FMBF habitats the average values of basic density showed no significant differences; however, in the cases of the forest districts of Giżycko, Łobez and Rudziniec, significant differences in the analysed property were observed.

  • Lachowicz, Department of Forest Utilization, Warsaw University of Life Sciences SGGW, Nowoursynowska 159 02-787 Warsaw, Poland ORCID ID:E-mail: hubert.lachowicz@wl.sggw.pl
  • Bieniasz, Department of Forest Utilization, Warsaw University of Life Sciences SGGW, Nowoursynowska 159 02-787 Warsaw, Poland ORCID ID:E-mail: anna.bieniasz@wl.sggw.pl (email)
  • Wojtan, Laboratory of Dendrometry and Forest Productivity, Warsaw University of Life Sciences SGGW, Nowoursynowska 159 02-787 Warsaw, Poland ORCID ID:E-mail: rwojtan@wl.sggw.pl
article id 9918, category Research article
Ari Nikula, Vesa Nivala, Juho Matala, Kari Heliövaara. (2019). Modelling the effect of habitat composition and roads on the occurrence and number of moose damage at multiple scales. Silva Fennica vol. 53 no. 1 article id 9918. https://doi.org/10.14214/sf.9918
Highlights: The occurrence and number of moose damage were modelled with a zero-inflated count model; An admixture of mature forests within plantations increased the number of damage; Vicinity of inhabited areas and roads reduced damage; Plantations in landscapes with a large amount of pine-dominated thinning forests had less damage in Lapland; Damage risk assessment should include characteristics specific to each region.

We modelled the effect of habitat composition and roads on the number and occurrence of moose (Alces alces L.) damage in Ostrobothnia and Lapland using a zero-inflated count model. Models were developed for 1 km2, 25 km2 and 100 km2 landscapes consisting of equilateral rectangular grid cells. Count models predict the number of damage, i.e. the number of plantations and zero models the probability of a landscape being without damage for a given habitat composition. The number of moose damage in neighboring grid cells was a significant predictor in all models. The proportion of mature forest was the most frequent significant variable, and an increasing admixture of mature forests among plantations increased the number and occurrence of damage. The amount of all types of plantations was the second most common significant variable predicting increasing damage along with increasing amount of plantations. An increase in thinning forests as an admixture also increased damage in 1 km2 landscapes in both areas, whereas an increase in pine-dominated thinning forests in Lapland reduced the number of damage in 25 km2 landscapes. An increasing amount of inhabited areas in Ostrobothnia and the length of connecting roads in Lapland reduced the number of damage in 1 and 25 km2 landscapes. Differences in model variables between areas suggest that models of moose damage risk should be adjusted according to characteristics that are specific to the study area.

  • Nikula, Natural Resources Institute Finland (Luke), Bioeconomy and Environment, Ounasjoentie 6, FI-96200 Rovaniemi, Finland ORCID ID:E-mail: ari.nikula@luke.fi (email)
  • Nivala, Natural Resources Institute Finland (Luke), Bioeconomy and Environment, Ounasjoentie 6, FI-96200 Rovaniemi, Finland ORCID ID:E-mail: vesa.nivala@luke.fi
  • Matala, Natural Resources Institute Finland (Luke), Natural resources, Yliopistokatu 6, FI-80100 Joensuu, Finland ORCID ID:E-mail: juho.matala@luke.fi
  • Heliövaara, University of Helsinki, Department of Forest Sciences, P.O. Box 27, FI-00014 University of Helsinki, Finland ORCID ID:E-mail: kari.heliovaara@helsinki.fi
article id 9918, category Research article
Ari Nikula, Vesa Nivala, Juho Matala, Kari Heliövaara. (2019). Modelling the effect of habitat composition and roads on the occurrence and number of moose damage at multiple scales. Silva Fennica vol. 53 no. 1 article id 9918. https://doi.org/10.14214/sf.9918
Highlights: The occurrence and number of moose damage were modelled with a zero-inflated count model; An admixture of mature forests within plantations increased the number of damage; Vicinity of inhabited areas and roads reduced damage; Plantations in landscapes with a large amount of pine-dominated thinning forests had less damage in Lapland; Damage risk assessment should include characteristics specific to each region.

We modelled the effect of habitat composition and roads on the number and occurrence of moose (Alces alces L.) damage in Ostrobothnia and Lapland using a zero-inflated count model. Models were developed for 1 km2, 25 km2 and 100 km2 landscapes consisting of equilateral rectangular grid cells. Count models predict the number of damage, i.e. the number of plantations and zero models the probability of a landscape being without damage for a given habitat composition. The number of moose damage in neighboring grid cells was a significant predictor in all models. The proportion of mature forest was the most frequent significant variable, and an increasing admixture of mature forests among plantations increased the number and occurrence of damage. The amount of all types of plantations was the second most common significant variable predicting increasing damage along with increasing amount of plantations. An increase in thinning forests as an admixture also increased damage in 1 km2 landscapes in both areas, whereas an increase in pine-dominated thinning forests in Lapland reduced the number of damage in 25 km2 landscapes. An increasing amount of inhabited areas in Ostrobothnia and the length of connecting roads in Lapland reduced the number of damage in 1 and 25 km2 landscapes. Differences in model variables between areas suggest that models of moose damage risk should be adjusted according to characteristics that are specific to the study area.

  • Nikula, Natural Resources Institute Finland (Luke), Bioeconomy and Environment, Ounasjoentie 6, FI-96200 Rovaniemi, Finland ORCID ID:E-mail: ari.nikula@luke.fi (email)
  • Nivala, Natural Resources Institute Finland (Luke), Bioeconomy and Environment, Ounasjoentie 6, FI-96200 Rovaniemi, Finland ORCID ID:E-mail: vesa.nivala@luke.fi
  • Matala, Natural Resources Institute Finland (Luke), Natural resources, Yliopistokatu 6, FI-80100 Joensuu, Finland ORCID ID:E-mail: juho.matala@luke.fi
  • Heliövaara, University of Helsinki, Department of Forest Sciences, P.O. Box 27, FI-00014 University of Helsinki, Finland ORCID ID:E-mail: kari.heliovaara@helsinki.fi
article id 9918, category Research article
Ari Nikula, Vesa Nivala, Juho Matala, Kari Heliövaara. (2019). Modelling the effect of habitat composition and roads on the occurrence and number of moose damage at multiple scales. Silva Fennica vol. 53 no. 1 article id 9918. https://doi.org/10.14214/sf.9918
Highlights: The occurrence and number of moose damage were modelled with a zero-inflated count model; An admixture of mature forests within plantations increased the number of damage; Vicinity of inhabited areas and roads reduced damage; Plantations in landscapes with a large amount of pine-dominated thinning forests had less damage in Lapland; Damage risk assessment should include characteristics specific to each region.

We modelled the effect of habitat composition and roads on the number and occurrence of moose (Alces alces L.) damage in Ostrobothnia and Lapland using a zero-inflated count model. Models were developed for 1 km2, 25 km2 and 100 km2 landscapes consisting of equilateral rectangular grid cells. Count models predict the number of damage, i.e. the number of plantations and zero models the probability of a landscape being without damage for a given habitat composition. The number of moose damage in neighboring grid cells was a significant predictor in all models. The proportion of mature forest was the most frequent significant variable, and an increasing admixture of mature forests among plantations increased the number and occurrence of damage. The amount of all types of plantations was the second most common significant variable predicting increasing damage along with increasing amount of plantations. An increase in thinning forests as an admixture also increased damage in 1 km2 landscapes in both areas, whereas an increase in pine-dominated thinning forests in Lapland reduced the number of damage in 25 km2 landscapes. An increasing amount of inhabited areas in Ostrobothnia and the length of connecting roads in Lapland reduced the number of damage in 1 and 25 km2 landscapes. Differences in model variables between areas suggest that models of moose damage risk should be adjusted according to characteristics that are specific to the study area.

  • Nikula, Natural Resources Institute Finland (Luke), Bioeconomy and Environment, Ounasjoentie 6, FI-96200 Rovaniemi, Finland ORCID ID:E-mail: ari.nikula@luke.fi (email)
  • Nivala, Natural Resources Institute Finland (Luke), Bioeconomy and Environment, Ounasjoentie 6, FI-96200 Rovaniemi, Finland ORCID ID:E-mail: vesa.nivala@luke.fi
  • Matala, Natural Resources Institute Finland (Luke), Natural resources, Yliopistokatu 6, FI-80100 Joensuu, Finland ORCID ID:E-mail: juho.matala@luke.fi
  • Heliövaara, University of Helsinki, Department of Forest Sciences, P.O. Box 27, FI-00014 University of Helsinki, Finland ORCID ID:E-mail: kari.heliovaara@helsinki.fi
article id 10055, category Research article
Jaakko Repola, Hannu Hökkä, Hannu Salminen. (2018). Models for diameter and height growth of Scots pine, Norway spruce and pubescent birch in drained peatland sites in Finland. Silva Fennica vol. 52 no. 5 article id 10055. https://doi.org/10.14214/sf.10055
Highlights: Tree growth strongly correlated with site drainage status; Between-tree competition had a higher impact on tree diameter growth than on height growth; Growth predicted by the constructed models were calibrated using NFI11 data to ensure generally applicable growth predictions level in whole country.

The aim of this study was to develop individual-tree diameter and height growth models for Scots pine, Norway spruce, and pubescent birch growing in drained peatlands in Finland. Trees growing in peatland sites have growth patterns that deviate from that of trees growing in mineral soil sites. Five-year growth was explained by tree diameter, different tree and stand level competition measures, management operations and site characteristics. The drainage status of the site was influencing growth directly or in interaction with other variables. Site quality had a direct impact but was also commonly related to current site drainage status (need for ditch maintenance). Recent thinning increased growth of all species and former PK fertilization increased growth of pine and birch. Temperature sum was a significant predictor in all models and altitude for spruce and birch. The data were a subsample of the 7th National Forest Inventory (NFI) sample plots representing northern and southern Finland and followed by repeated measurements for 15–20 yrs. Growth levels predicted by the models were calibrated using NFI11 data to remove bias originating from the sample of the modelling data. The mixed linear models technique was used in model estimation. The models will be incorporated into the MOTTI stand simulator to replace the current peatlands growth models.

  • Repola, Natural Resources Institute Finland (Luke), Natural resources, Eteläranta 55, FI-96300 Rovaniemi, Finland ORCID ID:E-mail: jaakko.repola@luke.fi (email)
  • Hökkä, Natural Resources Institute Finland (Luke), Natural resources, Paavo Havaksen tie 3, FI-90014 University OF Oulu, Finland ORCID ID:E-mail: hannu.hokka@luke.fi
  • Salminen, Natural Resources Institute Finland (Luke), Natural resources, Eteläranta 55, FI-96300 Rovaniemi, Finland ORCID ID:E-mail: hannu.salminen@luke.fi
article id 10000, category Research article
Hamed Yousefzadeh, Rasta Rajaei, Anna Jasińska, Łukasz Walas, Yann Fragnière, Gregor Kozlowski. (2018). Genetic diversity and differentiation of the riparian relict tree Pterocarya fraxinifolia (Juglandaceae) along altitudinal gradients in the Hyrcanian forest (Iran). Silva Fennica vol. 52 no. 5 article id 10000. https://doi.org/10.14214/sf.10000
Highlights: The Caucasian wingnut (Pterocarya fraxinifolia Spach) is an emblematic and relict riparian tree with limited distribution in Hyrcanian forest which investigating its genetic population structure and diversity along altitudinal gradients, and migration patterns are novel; We concluded that rivers are the main seed dispersal vector among P. fraxinifolia populations and there was no trend from upstream to downstream; The high level of gene flow and uniform genetic diversity along each river system suggest the “classical” metapopulation structure of the species.

Riparian trees, especially relict trees, are attractive and important for research to understand both past and recent biogeographical and evolutionary processes. Our work is the first study to elucidate the genetic diversity and spatial genetic structure of the canopy-dominating riparian Pterocarya fraxinifolia (Juglandaceae) along two altitudinal gradients in different river systems of the Hyrcanian forest, which is one of the most important refugium of relict trees in Western Eurasia. Altitudinal gradients were chosen along two river systems at 100, 400 and 900 m a.s.l. Leaf samples were collected from 116 trees, and the genetic diversity was evaluated with eight SSR markers. Overall, 39 alleles were identified for all of the populations studied. The observed heterozygosity (Ho) varied from 0.79 to 0.87 (with a mean of 0.83). The results of the AMOVA analysis indicated that the variation within populations was 88%, whereas the variation among populations was 12% for all of the gradients. A structure analysis indicated that 93% of the trees were grouped in the same gradient. The genetic distance based on Fst confirmed the structure result and indicated a high rate of gene flow among the investigated populations. Based on high gene flow (low differentiation of the population along the same river) and the clearly distinct genetic structure of the investigated gradients, it can be concluded that rivers are the main seed dispersal vector among P. fraxinifolia populations. The genetic diversity of P. fraxinifolia did not show any trend from upstream to downstream. The high level of gene flow and uniform genetic diversity along each river suggest the “classical” metapopulation structure of the species.

  • Yousefzadeh, Department of Environmental Science, Faculty of Natural Resources and Marine Sciences, Tarbiat Modares University, Noor, Mazandaran, Iran ORCID ID:E-mail: h.yousefzadeh@modares.ac.ir (email)
  • Rajaei, Department of Forestry, Faculty of Natural Resources and Marine Sciences, Tarbiat Modares University, Noor, Mazandaran, Iran ORCID ID:E-mail: r.rajaei@modares.ac.ir
  • Jasińska, Laboratory of Systematics and Geography, Institute of Dendrology, Polish Academy of Sciences, Parkowa 5, PL-62-035 Kornik, Poland ORCID ID:E-mail: jasiak9@wp.pl
  • Walas, Laboratory of Systematics and Geography, Institute of Dendrology, Polish Academy of Sciences, Parkowa 5, PL-62-035 Kornik, Poland ORCID ID:E-mail: lukaswalas@wp.pl
  • Fragnière, Department of Biology and Botanic Garden, University of Fribourg, Chemin du Musée 10, CH-1700 Fribourg, Switzerland ORCID ID:E-mail: yann.fragniere@unifr.ch
  • Kozlowski, Department of Biology and Botanic Garden, University of Fribourg, Chemin du Musée 10, CH-1700 Fribourg, Switzerland; Natural History Museum Fribourg, Chemin du Musée 6, CH-1700 Fribourg, Switzerland ORCID ID:E-mail: gregor.kozlowski@unifr.ch
article id 10013, category Research article
Hardo Becker, Jürgen Aosaar, Mats Varik, Gunnar Morozov, Kristiina Aun, Ülo Mander, Kaido Soosaar, Veiko Uri. (2018). Annual net nitrogen mineralization and litter flux in well-drained downy birch, Norway spruce and Scots pine forest ecosystems. Silva Fennica vol. 52 no. 4 article id 10013. https://doi.org/10.14214/sf.10013
Highlights: The net nitrogen mineralization (NNM) flux in drained peat soils depends largely on the C/N ratio and tree species; The soil NNM process is affected by trees through organic litter input into soil; Pine stand in low-fertility drained transitional bog is dominated by net ammonification; Birch and spruce stands on the fertile drained peat soil with higher pH and N content are dominated by net nitrification.

The main aim of the current study was to estimate the annual net nitrogen mineralization (NNM) flux in stands of different tree species growing on drained peatlands, as well as to clarify the effect of tree species, soil properties and litter on annual NNM dynamics. Three study sites were set up in May 2014: a downy birch (Betula pubescens Ehrh.) stand and a Norway spruce (Picea abies (L.) Karst.) stand in Oxalis full-drained swamp (ODS) and a Scots pine (Pinus sylvestris L.) stand in Myrtillus full-drained swamp (MDS). The NNM flux was estimated using the in situ method with incubated polyethylene bags. The highest value of NNM was found in stands that were growing on fertile ODS: 127.5 kg N ha–1 yr–1 and 87.7 kg N ha–1 yr–1, in the downy birch stand and in the Norway spruce stand, respectively. A significantly lower annual NNM flux (11.8 kg N ha–1 yr–1) occurred in the Scots pine stand growing in MDS. Nitrification was highest at fertile ODS sites and ammonification was the highest at the low fertility MDS site. For all study sites, positive correlation was found between soil temperature and NNM intensity. The difference in annual NNM between the downy birch stand and the Norway spruce stand growing on similar drained fertile peatlands was due to litter quality. The annual N input into the soil through leaf litter was the highest at the downy birch site where also the C/N ratio of litter was the lowest. The second highest N input into the soil was found in the spruce stand and the lowest in the pine stand.

  • Becker, Chair of Silviculture and Forest Ecology, Institute of Forestry and Rural Engineering, Estonian University of Life Sciences, Friedrich Reinhold Kreutzwaldi 1, 51014 Tartu, Estonia ORCID ID:E-mail: hardo.becker@emu.ee (email)
  • Aosaar, Chair of Silviculture and Forest Ecology, Institute of Forestry and Rural Engineering, Estonian University of Life Sciences, Friedrich Reinhold Kreutzwaldi 1, 51014 Tartu, Estonia ORCID ID:E-mail: jyrgen.aosaar@emu.ee
  • Varik, Chair of Silviculture and Forest Ecology, Institute of Forestry and Rural Engineering, Estonian University of Life Sciences, Friedrich Reinhold Kreutzwaldi 1, 51014 Tartu, Estonia ORCID ID:E-mail: mats.varik@emu.ee
  • Morozov, Chair of Silviculture and Forest Ecology, Institute of Forestry and Rural Engineering, Estonian University of Life Sciences, Friedrich Reinhold Kreutzwaldi 1, 51014 Tartu, Estonia ORCID ID:E-mail: gunnar.morozov@emu.ee
  • Aun, Chair of Silviculture and Forest Ecology, Institute of Forestry and Rural Engineering, Estonian University of Life Sciences, Friedrich Reinhold Kreutzwaldi 1, 51014 Tartu, Estonia ORCID ID:E-mail: kristiina.aun@emu.ee
  • Mander, Department of Geography, Institute of Ecology & Earth Sciences, University of Tartu, Ülikooli 18, 50090 Tartu, Estonia ORCID ID:E-mail: ulo.mander@ut.ee
  • Soosaar, Department of Geography, Institute of Ecology & Earth Sciences, University of Tartu, Ülikooli 18, 50090 Tartu, Estonia ORCID ID:E-mail: kaido.soosaar@ut.ee
  • Uri, Chair of Silviculture and Forest Ecology, Institute of Forestry and Rural Engineering, Estonian University of Life Sciences, Friedrich Reinhold Kreutzwaldi 1, 51014 Tartu, Estonia ORCID ID:E-mail: veiko.uri@emu.ee
article id 10002, category Research article
Bayasaa Tumenjargal, Futoshi Ishiguri, Haruna Aiso-Sanada, Yusuke Takahashi, Bayartsetseg Baasan, Ganbaatar Chultem, Jyunichi Ohshima, Shinso Yokota. (2018). Geographic variations of wood properties of Larix sibirica naturally grown in Mongolia. Silva Fennica vol. 52 no. 4 article id 10002. https://doi.org/10.14214/sf.10002
Highlights: Significant differences (p  < 0.01) among five stands were found in tree height, stress-wave velocity of stems, dynamic Young’s modulus of stems and logs, annual ring width, and latewood percentage, suggesting that there was geographic variation of mechanical properties of wood in Larix sibirica (Münchh.) Ledeb. grown in Mongolia; Dynamic Young’s modulus of logs in L. sibirica trees can be predicted by stress-wave velocity of stems; Stem diameter of L. sibirica naturally grown in Mongolia is closely related to radial growth at initial stage of growth, especially within the first twenty years.

Geographic variations in growth, stress-wave velocity of stem, dynamic Young’s modulus of stems and logs, annual ring width, latewood percentage and basic density were investigated for Larix sibirica (Münchh.) Ledeb. naturally grown in Mongolia. A total of 250 trees with 20 to 30 cm in stem diameter at a height of 1.3 m above ground level were selected from each natural stand in five different provenances in Mongolia. In addition, five trees in each stand were cut for measuring dynamic Young’s modulus of stems and logs, annual ring width, latewood percentage and basic density. Mean values of stress-wave velocity of stems in each stand ranged from 2.92 to 3.41 km s–1, and the mean value of five stands was 3.23 km s–1. Mean values of dynamic Young’s modulus of logs in each stand ranged from 5.17 to 9.72 GPa. A significant correlation (r = 0.798, p < 0.01) was found between stress-wave velocity of stems and dynamic Young’s modulus of logs. Among the five stands, the highest and the lowest values of average annual ring number were 193 and 44, respectively. Mean values of basic density in five trees within each stand were examined and ranged from 0.52 to 0.56 g cm–3. Significant differences among five stands were found in tree height, stress-wave velocity of stem, dynamic Young’s modulus of stems and logs, annual ring width and latewood percentage, suggesting that L. sibirica trees naturally grown in Mongolia have geographic variations in mechanical properties of wood.

  • Tumenjargal, Faculty of Agriculture, Utsunomiya University, Utsunomiya, Tochigi 321-8505, Japan; United Graduate School of Agricultural Science, Tokyo University of Agriculture and Technology, Fuchu, Tokyo 183-8509, Japan; Research and Training Institute of Forestry and Wood Industry, Mongolian University Science and Technology, Ulaanbaatar 14191, Mongolia ORCID ID:E-mail: t_bayasaa88@yahoo.com
  • Ishiguri, Faculty of Agriculture, Utsunomiya University, Utsunomiya, Tochigi 321-8505, Japan ORCID ID:E-mail: ishiguri@cc.utsunomiya-u.ac.jp (email)
  • Aiso-Sanada, Forestry and Forest Products Research Institute, Tsukuba, Ibaraki 305-8687, Japan ORCID ID:E-mail: haiso@ffpri.affrc.go.jp
  • Takahashi, Faculty of Agriculture, Utsunomiya University, Utsunomiya, Tochigi 321-8505, Japan ORCID ID:E-mail: zo.r.by0814@gmail.com
  • Baasan, Research and Training Institute of Forestry and Wood Industry, Mongolian University Science and Technology, Ulaanbaatar 14191, Mongolia ORCID ID:E-mail: bayartsetseg@must.edu.mn
  • Chultem, Research and Training Institute of Forestry and Wood Industry, Mongolian University Science and Technology, Ulaanbaatar 14191, Mongolia ORCID ID:E-mail: t_bayasaa88@yahoo.com
  • Ohshima, Faculty of Agriculture, Utsunomiya University, Utsunomiya, Tochigi 321-8505, Japan ORCID ID:E-mail: joshima@cc.utsunomiya-u.ac.jp
  • Yokota, Faculty of Agriculture, Utsunomiya University, Utsunomiya, Tochigi 321-8505, Japan ORCID ID:E-mail: yokotas@cc.utsunomiya-u.ac.jp
article id 7763, category Research article
Sergei Senko, Mikko Kurttila, Timo Karjalainen. (2018). Prospects for Nordic intensive forest management solutions in the Republic of Karelia. Silva Fennica vol. 52 no. 4 article id 7763. https://doi.org/10.14214/sf.7763
Highlights: SWOT (strengths, weaknesses, opportunities and threats) and multi-criteria decision support analysis were combined to examine the potential for Nordic intensive forest management solutions (NIFMS) in Karelia, Russia; NIFMS looks promising for Karelian forestry; Improving quality-and-value of timber and sustained yield are the highly prioritized strengths; Unprepared forestry regulations are the main threat that needs to be taken into account.

In this study, the prospects for future forest management in Republic of Karelia, Russia were analyzed. Forestry has an important role in the economy of Karelia. However, productivity and profitability in the forestry sector are extremely low, forest stand structure and quality are weak, the commercial forest land of coniferous species has declined and the wood processing industry struggles with a deficit of raw materials. The situation is typical to many forest regions in Russia with extensive forest management cited as one reason for the current situation. In contrast, the Nordic countries have significant experience in intensive and sustainable forest management and the results have been to a large extent positive. The transfer of Nordic intensive forest management solutions (NIFMS) could improve forestry in Karelia. SWOT analysis, combined with the multi-criteria decision support (MCDS) method was used to identify local operational environments and to assign priorities. Major threats included unprepared regulations, poor road infrastructure, insecure investments, low forestry productivity, forest degradation, high investment costs and a negative attitude to intensive forestry. The main opportunities are high forest resource potential in Karelia, favorable authority development programs, proven Nordic expertise, wood-based energy development and availability of new technology. Results also showed that the main weaknesses that might influence the NIFMS in Karelia are slow return on investments, low market demand for energy wood, high costs associated with young forest thinnings, high demand for skilled specialists and a lack of investment in research and development.

  • Senko, University of Eastern Finland (UEF), School of Forest Sciences, Yliopistokatu 7, FI-80111 Joensuu, Finland ORCID ID:E-mail: sergei.senko@uef.fi (email)
  • Kurttila, The Natural Resources Institute Finland (Luke), Bioeconomy and environment, Yliopistokatu 6, FI-80100 Joensuu, Finland ORCID ID:E-mail: mikko.kurttila@luke.fi
  • Karjalainen, † Deceased ORCID ID:E-mail:
article id 7763, category Research article
Sergei Senko, Mikko Kurttila, Timo Karjalainen. (2018). Prospects for Nordic intensive forest management solutions in the Republic of Karelia. Silva Fennica vol. 52 no. 4 article id 7763. https://doi.org/10.14214/sf.7763
Highlights: SWOT (strengths, weaknesses, opportunities and threats) and multi-criteria decision support analysis were combined to examine the potential for Nordic intensive forest management solutions (NIFMS) in Karelia, Russia; NIFMS looks promising for Karelian forestry; Improving quality-and-value of timber and sustained yield are the highly prioritized strengths; Unprepared forestry regulations are the main threat that needs to be taken into account.

In this study, the prospects for future forest management in Republic of Karelia, Russia were analyzed. Forestry has an important role in the economy of Karelia. However, productivity and profitability in the forestry sector are extremely low, forest stand structure and quality are weak, the commercial forest land of coniferous species has declined and the wood processing industry struggles with a deficit of raw materials. The situation is typical to many forest regions in Russia with extensive forest management cited as one reason for the current situation. In contrast, the Nordic countries have significant experience in intensive and sustainable forest management and the results have been to a large extent positive. The transfer of Nordic intensive forest management solutions (NIFMS) could improve forestry in Karelia. SWOT analysis, combined with the multi-criteria decision support (MCDS) method was used to identify local operational environments and to assign priorities. Major threats included unprepared regulations, poor road infrastructure, insecure investments, low forestry productivity, forest degradation, high investment costs and a negative attitude to intensive forestry. The main opportunities are high forest resource potential in Karelia, favorable authority development programs, proven Nordic expertise, wood-based energy development and availability of new technology. Results also showed that the main weaknesses that might influence the NIFMS in Karelia are slow return on investments, low market demand for energy wood, high costs associated with young forest thinnings, high demand for skilled specialists and a lack of investment in research and development.

  • Senko, University of Eastern Finland (UEF), School of Forest Sciences, Yliopistokatu 7, FI-80111 Joensuu, Finland ORCID ID:E-mail: sergei.senko@uef.fi (email)
  • Kurttila, The Natural Resources Institute Finland (Luke), Bioeconomy and environment, Yliopistokatu 6, FI-80100 Joensuu, Finland ORCID ID:E-mail: mikko.kurttila@luke.fi
  • Karjalainen, † Deceased ORCID ID:E-mail:
article id 10006, category Research article
Matti Maltamo, Tomi Karjalainen, Jaakko Repola, Jari Vauhkonen. (2018). Incorporating tree- and stand-level information on crown base height into multivariate forest management inventories based on airborne laser scanning. Silva Fennica vol. 52 no. 3 article id 10006. https://doi.org/10.14214/sf.10006
Highlights: The most accurate tree-level alternative is to include crown base height (CBH) to nearest neighbour imputation; Also mixed-effects models can be applied to predict CBH using tree attributes and airborne laser scanning (ALS) metrics; CBH prediction can be included with an accuracy of 1–1.5 m to forest management inventory applications.

This study examines the alternatives to include crown base height (CBH) predictions in operational forest inventories based on airborne laser scanning (ALS) data. We studied 265 field sample plots in a strongly pine-dominated area in northeastern Finland. The CBH prediction alternatives used area-based metrics of sparse ALS data to produce this attribute by means of: 1) Tree-level imputation based on the k-nearest neighbor (k-nn) method and full field-measured tree lists including CBH observations as reference data; 2) Tree-level mixed-effects model (LME) prediction based on tree diameter (DBH) and height and ALS metrics as predictors of the models; 3) Plot-level prediction based on analyzing the computational geometry and topology of the ALS point clouds; and 4) Plot-level regression analysis using average CBH observations of the plots for model fitting. The results showed that all of the methods predicted CBH with an accuracy of 1–1.5 m. The plot-level regression model was the most accurate alternative, although alternatives producing tree-level information may be more interesting for inventories aiming at forest management planning. For this purpose, k-nn approach is promising and it only requires that field measurements of CBH is added to the tree lists used as reference data. Alternatively, the LME-approach produced good results especially in the case of dominant trees.

  • Maltamo, University of Eastern Finland, School of Forest Sciences, P.O. Box 111, FI-80101 Joensuu, Finland ORCID ID:E-mail: matti.maltamo@uef.fi (email)
  • Karjalainen, University of Eastern Finland, School of Forest Sciences, P.O. Box 111, FI-80101 Joensuu, Finland ORCID ID:E-mail: tomimkarjalainen@gmail.com
  • Repola, Natural Resources Institute of Finland (Luke), Natural resources, Eteläranta 55, FI-96300 Rovaniemi, Finland ORCID ID:E-mail: jaakko.repola@luke.fi
  • Vauhkonen, Natural Resources Institute of Finland (Luke), Bioeconomy and environment, Yliopistokatu 6, 80100 Joensuu, Finland ORCID ID:E-mail: jari.vauhkonen@luke.fi
article id 10006, category Research article
Matti Maltamo, Tomi Karjalainen, Jaakko Repola, Jari Vauhkonen. (2018). Incorporating tree- and stand-level information on crown base height into multivariate forest management inventories based on airborne laser scanning. Silva Fennica vol. 52 no. 3 article id 10006. https://doi.org/10.14214/sf.10006
Highlights: The most accurate tree-level alternative is to include crown base height (CBH) to nearest neighbour imputation; Also mixed-effects models can be applied to predict CBH using tree attributes and airborne laser scanning (ALS) metrics; CBH prediction can be included with an accuracy of 1–1.5 m to forest management inventory applications.

This study examines the alternatives to include crown base height (CBH) predictions in operational forest inventories based on airborne laser scanning (ALS) data. We studied 265 field sample plots in a strongly pine-dominated area in northeastern Finland. The CBH prediction alternatives used area-based metrics of sparse ALS data to produce this attribute by means of: 1) Tree-level imputation based on the k-nearest neighbor (k-nn) method and full field-measured tree lists including CBH observations as reference data; 2) Tree-level mixed-effects model (LME) prediction based on tree diameter (DBH) and height and ALS metrics as predictors of the models; 3) Plot-level prediction based on analyzing the computational geometry and topology of the ALS point clouds; and 4) Plot-level regression analysis using average CBH observations of the plots for model fitting. The results showed that all of the methods predicted CBH with an accuracy of 1–1.5 m. The plot-level regression model was the most accurate alternative, although alternatives producing tree-level information may be more interesting for inventories aiming at forest management planning. For this purpose, k-nn approach is promising and it only requires that field measurements of CBH is added to the tree lists used as reference data. Alternatively, the LME-approach produced good results especially in the case of dominant trees.

  • Maltamo, University of Eastern Finland, School of Forest Sciences, P.O. Box 111, FI-80101 Joensuu, Finland ORCID ID:E-mail: matti.maltamo@uef.fi (email)
  • Karjalainen, University of Eastern Finland, School of Forest Sciences, P.O. Box 111, FI-80101 Joensuu, Finland ORCID ID:E-mail: tomimkarjalainen@gmail.com
  • Repola, Natural Resources Institute of Finland (Luke), Natural resources, Eteläranta 55, FI-96300 Rovaniemi, Finland ORCID ID:E-mail: jaakko.repola@luke.fi
  • Vauhkonen, Natural Resources Institute of Finland (Luke), Bioeconomy and environment, Yliopistokatu 6, 80100 Joensuu, Finland ORCID ID:E-mail: jari.vauhkonen@luke.fi
article id 9983, category Research article
Mika Rekola, Jaakko Nippala, Päivi Tynjälä, Anne Virtanen. (2018). Modelling competences and anticipating the future competence needs in the forest sector. Silva Fennica vol. 52 no. 3 article id 9983. https://doi.org/10.14214/sf.9983
Highlights: The most frequently used practices of modelling competences in Finnish forest sector organisations were superior-subordinate review discussions and quantitative surveys; Competence modelling was used for several human resources functions but surprisingly not for hiring and compensation; The experts interviewed underlined the need for generic competences in the future, especially they highlighted the importance of information processing and personal self-management skills.

This explorative study examined practices of competence modelling in the forest sector organisations and how organisations anticipate changes in competence needs in the future. Semi-structured in-depth interviews (n=10) were conducted amongst forest sector experts in Finland and data was analysed by thematic analysis. The findings showed that the practices of modelling competences were diverse, most frequently used ones being superior-subordinate review discussions and quantitative competence surveys. In addition to these formal systems, informal modelling, especially on the team level and in smaller companies was also frequent. Organisations used competence modelling for several human resources functions, such as appraisal, motivation and promotion of employees. Surprisingly hiring and compensation functions were not mentioned. Perceptions related to competence modelling were generally speaking positive. The most important challenges were the lack of further actions and sometimes the extraordinary burden to the employees. When anticipating the future, the experts interviewed mentioned several commonly recognised trends, e.g., development of information technology, fragmentation of working life and structural changes in labour markets. All these require more generic competences related to information processing and personal self-management, especially respondents highlighted the importance of self-awareness skills. It is concluded that several useful practices for competence modelling already exist and that present study provides a basis for further quantitative further study.

  • Rekola, Department of Forest Sciences, University of Helsinki, P.O. Box 27, FI-00014 University of Helsinki, Finland ORCID ID:E-mail: mika.rekola@helsinki.fi (email)
  • Nippala, Suomen Partiolaiset – Finlands Scouter ry, Töölönkatu 55, FI-00250 Helsinki, Finland ORCID ID:E-mail: jaakko.nippala@partio.fi
  • Tynjälä, Finnish Institute for Educational Research, P.O. Box 35, FI-40014 University of Jyväskylä, Finland ORCID ID:E-mail: paivi.a.tynjala@jyu.fi
  • Virtanen, Finnish Institute for Educational Research, P.O. Box 35, FI-40014 University of Jyväskylä, Finland ORCID ID:E-mail: anne.virtanen@jyu.fi
article id 9946, category Research article
Frauke Fedderwitz, Niklas Björklund, Velemir Ninkovic, Göran Nordlander. (2018). Does the pine weevil (Hylobius abietis) prefer conifer seedlings over other main food sources? Silva Fennica vol. 52 no. 3 article id 9946. https://doi.org/10.14214/sf.9946
Highlights: Adult pine weevils feed on seedlings and mature conifers, but cause economic damage only on seedlings; Their feeding preferences for branches and roots over seedlings were tested in a laboratory experiment; The only clear preference was for Norway spruce roots; Results support new approaches of seedling protection attempting to redirect pine weevils from planted seedlings to other food sources.

Adult pine weevils (Hylobius abietis (L.)) feed on the tender bark of branches and roots of mature conifer trees and on the stem bark of conifer seedlings. Their feeding on mature trees does not cause any economic damage, but their feeding on planted seedlings is so devastating that the pine weevil is considered one of the most important forest pest insects in Europe. We asked whether the pine weevil prefers seedlings over other regularly utilized food sources. This question is of particular interest because new approaches to seedling protection are based on decreasing any preference for seedlings by using less palatable plants or by enhancing their defence (by genetic selection or by methyl jasmonate treatment). In a laboratory choice experiment we tested pine weevil feeding preferences for seedlings compared with branches and roots from mature trees (separately for Norway spruce and Scots pine). Pine weevils preferred roots, but not branches, of Norway spruce over seedlings of the same species. With Scots pine there were no clear preferences, but the weevils showed a tendency to prefer roots over seedlings. These results provide support for seedling protection approaches that attempt to redirect pine feeding from planted seedlings to other food sources.

  • Fedderwitz, Department of Ecology, Swedish University of Agricultural Sciences, Box 7044, SE-750 07 Uppsala, Sweden ORCID ID:E-mail: frauke.fedderwitz@slu.se (email)
  • Björklund, Department of Ecology, Swedish University of Agricultural Sciences, Box 7044, SE-750 07 Uppsala, Sweden ORCID ID:E-mail: niklas.bjorklund@slu.se
  • Ninkovic, Department of Ecology, Swedish University of Agricultural Sciences, Box 7044, SE-750 07 Uppsala, Sweden ORCID ID:E-mail: velemir.ninkovic@slu.se
  • Nordlander, Department of Ecology, Swedish University of Agricultural Sciences, Box 7044, SE-750 07 Uppsala, Sweden ORCID ID:E-mail: goran.nordlander@slu.se
article id 9940, category Research article
Esteban Ceriani-Nakamurakare, Sergio Ramos, Carolina A. Robles, María V. Novas, María F. D´Jonsiles, Paola Gonzalez-Audino, Cecilia Carmarán. (2018). Metagenomic approach of associated fungi with Megaplatypus mutatus (Coleoptera: Platypodinae). Silva Fennica vol. 52 no. 3 article id 9940. https://doi.org/10.14214/sf.9940
Highlights: There were no significant effects of host plant and location on fungal richness; Two fungal species, belonging to Fusarium and Candida genera, were present in all the studied associations; Results suggest that host plant identity would not be crucial to determine the composition of fungal communities associated to Megaplatypus mutatus.

Megaplatypus mutatus is a major forest pest in Argentina and an emerging pest in Europe. In this study the multitrophic interactions between M. mutatus and associated fungi were assessed with a metagenomics approach (454-pyrosequencing). A total of 270 collection points from insect galleries from three locations in Argentina were pooled for pyrosequencing analyses. Two hosts, Populus deltoides and Casuarina cunninghamiana, were independently evaluated to characterize the fungal communities associated to M. mutatus; compare the culture-independent approach with previous culturing studies, in terms of data recovery related to the fungal community composition, and test the specificity of the fungal communities amongst locations and hosts. A Generalized Linear Mixed Model was performed to compare the fungal richness in each dataset, which showed no significant differences between taxa richness amongst locations. Principal Coordinates Analyses showed a separation between fungal communities within the same host, suggesting that host identity would not be crucial to determine the specificity in fungal communities. Candida insectalens and one Fusarium species, present in all hosts and locations, achieved 37.6% of the total relative frequency per taxa. These results complement the data from culturing methods previously reported, thus improving the accuracy and understanding of the fungal assemblages associated to M. mutatus.

  • Ceriani-Nakamurakare, Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Depto. Biodiversidad y Biología Experimental. Buenos Aires, Argentina; CONICET- Universidad de Buenos Aires. Instituto de Micología y Botánica (INMIBO). Buenos Aires, (C1428EHA) Argentina ORCID ID:E-mail: cerianinaka@gmail.com
  • Ramos, Instituto Nacional de Tecnología Agropecuaria. Estación Experimental Agropecuaria Concordia. Entre Ríos, (E3200) Argentina ORCID ID:E-mail: ramos.sergio@inta.gob.ar
  • Robles, Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Depto. Biodiversidad y Biología Experimental. Buenos Aires, Argentina; CONICET- Universidad de Buenos Aires. Instituto de Micología y Botánica (INMIBO). Buenos Aires, (C1428EHA) Argentina ORCID ID:E-mail: carorobles@bg.fcen.uba.ar
  • Novas, Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Depto. Biodiversidad y Biología Experimental. Buenos Aires, Argentina; CONICET- Universidad de Buenos Aires. Instituto de Micología y Botánica (INMIBO). Buenos Aires, (C1428EHA) Argentina ORCID ID:E-mail: vicnovas@bg.fcen.uba.ar
  • D´Jonsiles, Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Depto. Biodiversidad y Biología Experimental. Buenos Aires, Argentina; CONICET- Universidad de Buenos Aires. Instituto de Micología y Botánica (INMIBO). Buenos Aires, (C1428EHA) Argentina ORCID ID:E-mail: lalijonsi@gmail.com
  • Gonzalez-Audino, Centro de Investigaciones de Plagas e Insecticidas (CITEFA-CONICET). Buenos Aires, (B1603ALO) Argentina ORCID ID:E-mail: pgonzalezaudino@citedef.gob.ar
  • Carmarán, Centro de Investigaciones de Plagas e Insecticidas (CITEFA-CONICET). Buenos Aires, (B1603ALO) Argentina ORCID ID:E-mail: carmaran@bg.fcen.uba.ar (email)
article id 9933, category Research article
Timo Saksa, Jari Miina, Hilkka Haatainen, Kauko Kärkkäinen. (2018). Quality of spot mounding performed by continuously advancing mounders. Silva Fennica vol. 52 no. 2 article id 9933. https://doi.org/10.14214/sf.9933
Highlights: The number and quality of mounds varied considerably according to the operating conditions;The main factors reducing the quality of spot mounding were steep terrain, a thick humus layer, fresh logging residues, stoniness and soil texture;With careful selection of timing and conditions for mounding, the quality obtained by continuously advancing mounders can be improved.

Operating conditions affecting the quality of spot mounding by Bracke continuously advancing mounders were investigated on 66 regeneration areas (124 ha) in eastern Finland. The quality of mounds was classified as suitable (good or acceptable after additional compression) or unsuitable for planting. Models were constructed for the number of suitable planting spots obtained per hectare (good and acceptable mounds), the probability of successful mounding (≥1600 planting spots ha–1) and the probability of creating a suitable mound as a function of terrain, site and soil characteristics, as well as slash conditions (removed, fresh or dry logging residues). The average number of mounds created was 1892 ± 290 mounds ha–1, of which 1398 ± 325 mounds ha–1 (74%) were classified as suitable for planting. The quality of spot mounding was reduced by steep terrain, a thick humus layer and fresh logging residues. Stoniness and soil texture also affected the number of planting spots created. Mounding after logging residues had dried increased the number of planting spots by 191 spots ha–1 compared with mounding in the presence of fresh residues. Removing residues did not significantly increase the number of planting spots compared with mounding amongst dry residues. A thick humus layer, very stony soil, steep slopes and valley terrain decreased the number of planting spots by 150–450 spots ha–1. The number and quality of mounds varied considerably according to the operating conditions, but with careful selection of timing and sites the quality obtained by a continuously advancing mounder can be improved.

  • Saksa, Natural Resources Institute Finland (Luke), Juntintie 154, FI-77600 Suonenjoki, Finland ORCID ID:E-mail: timo.saksa@luke.fi (email)
  • Miina, Natural Resources Institute Finland (Luke), Yliopistokatu 6, FI-80100 Joensuu, Finland ORCID ID:E-mail: jari.miina@luke.fi
  • Haatainen, Faculty of Science and Forestry, School of Forest Sciences, University of Eastern Finland, P.O. Box 111, FI-80101 Joensuu, Finland ORCID ID:E-mail: hilkka.haatainen@storaenso.com
  • Kärkkäinen, Tornator Oyj, Muuntamontie 2, FI-80100 Joensuu, Finland ORCID ID:E-mail: kauko.karkkainen@tornator.fi
article id 7699, category Research article
Dalytė Matulevičiūtė, Jurga Motiejunaite, Domas Uogintas, Ričardas Taraškevičius, Mindaugas Dagys, Valerijus Rašomavičius. (2018). Decline of a protected coastal pine forest under impact of a colony of great cormorants and the rate of vegetation change under ornithogenic influence. Silva Fennica vol. 52 no. 2 article id 7699. https://doi.org/10.14214/sf.7699
Highlights: We studied vegetation and its changes in a pine forest affected by a colony of great cormorants; Vegetation in the colony varied according to the period of bird influence and the stand elevation above sea level; Considerable vegetation changes occur in several years after bird colony establishment; Pine forest ecosystem cease to exist following a decade of bird activity.

We investigated the impact of a colony of great cormorants on the vegetation of the old growth Pinus sylvestris L. forest on the Curonian Spit peninsula, Lithuania. We studied the characteristics and rates of plant cover changes under varying length and intensity of bird influence. Plant species numbers, as well as the coverage of plants with different ecological requirements, varied according to the period of bird influence, but the resulting vegetation also depended upon the stand elevation above sea level. In our study, the initial increase in plant species richness at the start of bird nesting was not obvious and was of a transient character, due to the weak invasion of non-forest species and the rapid decline of forest plants. The colony area showed obvious and rapid vegetation changes during the investigation period. According to the calculated colony expansion rates, after 6–7 years of impact from birds the tree layer decreased by about four fold; the shrub layer decreased by about two fold; the field layer decreased by about 15 fold; and the dwarf shrub and bottom layers disappeared. The coverage by oligotrophic species decreased by more than four fold, while the coverage by eutrophic species increased by more than 60 fold. After 9–10 years of ornithogenic impact, all the trees were dead, and the protected coniferous forest ecosystem, with its characteristic plant species, had ceased to exist as such.

  • Matulevičiūtė, Institute of Botany, Nature Research Centre, Žaliųjų ežerų Str. 49, LT-08406 Vilnius, Lithuania ORCID ID: http://orcid.org/0000-0001-7550-1860 E-mail: dalyte.matuleviciute@botanika.lt (email)
  • Motiejunaite, Institute of Botany, Nature Research Centre, Žaliųjų ežerų Str. 49, LT-08406 Vilnius, Lithuania ORCID ID: http://orcid.org/0000-0002-6949-1990 E-mail: jurga.motiejunaite@botanika.lt
  • Uogintas, Institute of Botany, Nature Research Centre, Žaliųjų ežerų Str. 49, LT-08406 Vilnius, Lithuania ORCID ID: http://orcid.org/0000-0002-3937-1218 E-mail: domas.uogintas@botanika.lt
  • Taraškevičius, Geology and Geography Institute, Nature Research Centre, Akademijos Str. 2, LT-08412 Vilnius, Lithuania ORCID ID: http://orcid.org/0000-0002-5110-6142 E-mail: taraskevicius@geo.lt
  • Dagys, Institute of Ecology, Nature Research Centre, Akademijos Str. 2, LT-08412 Vilnius, Lithuania ORCID ID: http://orcid.org/0000-0001-9342-3464 E-mail: dagys@ekoi.lt
  • Rašomavičius, Institute of Botany, Nature Research Centre, Žaliųjų ežerų Str. 49, LT-08406 Vilnius, Lithuania ORCID ID: http://orcid.org/0000-0003-1314-4356 E-mail: valerijus.rasomavicius@botanika.lt
article id 9923, category Research article
Annika Kangas, Terje Gobakken, Stefano Puliti, Marius Hauglin, Erik Naesset. (2018). Value of airborne laser scanning and digital aerial photogrammetry data in forest decision making. Silva Fennica vol. 52 no. 1 article id 9923. https://doi.org/10.14214/sf.9923
Highlights: Airborne laser scanning (ALS) and digital aerial photogrammetry (DAP) are nearly equally valuable for harvest scheduling decisions even though ALS data is more precise; Large underestimates of stand volume are most dangerous errors for forest owner because of missed cutting probabilities; Relative RMSE of stand volume and the mean volume in a test area explain 77% of the variation between the expected losses due to errors in the data in the published studies; Increasing the relative RMSE of volume by 1 unit, increased the losses in average by 4.4 € ha–1.

Airborne laser scanning (ALS) has been the main method for acquiring data for forest management planning in Finland and Norway in the last decade. Recently, digital aerial photogrammetry (DAP) has provided an interesting alternative, as the accuracy of stand-based estimates has been quite close to that of ALS while the costs are markedly smaller. Thus, it is important to know if the better accuracy of ALS is worth the higher costs for forest owners. In many recent studies, the value of forest inventory information in the harvest scheduling has been examined, for instance through cost-plus-loss analysis. Cost-plus-loss means that the quality of the data is accounted for in monetary terms through calculating the losses due to errors in the data in the forest management planning context. These costs are added to the inventory costs. In the current study, we compared the losses of ALS and DAP at plot level. According to the results, the data produced using DAP are as good as data produced using ALS from a decision making point of view, even though ALS is slightly more accurate. ALS is better than DAP only if the data will be used for more than 15 years before acquiring new data, and even then the difference is quite small. Thus, the increased errors in DAP do not significantly affect the results from a decision making point of view, and ALS and DAP data can be equally well recommended to the forest owners for management planning. The decision of which data to acquire, can thus be made based on the availability of the data on first hand and the costs of acquiring it on the second hand.

  • Kangas, Natural Resources Institute Finland (Luke), Bioeconomy and environment, P.O. Box 68, FI-80170 Joensuu, Finland ORCID ID:E-mail: annika.kangas@luke.fi (email)
  • Gobakken, Faculty of Environmental Sciences and Natural Resource Management, Norwegian University of Life Sciences, P.O. Box 5003, NO-1432 Ås, Norway ORCID ID:E-mail: terje.gobakken@nmbu.no
  • Puliti, Faculty of Environmental Sciences and Natural Resource Management, Norwegian University of Life Sciences, P.O. Box 5003, NO-1432 Ås, Norway ORCID ID:E-mail: stefano.puliti@nibio.no
  • Hauglin, Faculty of Environmental Sciences and Natural Resource Management, Norwegian University of Life Sciences, P.O. Box 5003, NO-1432 Ås, Norway ORCID ID:E-mail: marius.hauglin@nmbu.no
  • Naesset, Faculty of Environmental Sciences and Natural Resource Management, Norwegian University of Life Sciences, P.O. Box 5003, NO-1432 Ås, Norway ORCID ID:E-mail: erik.naesset@nmbu.no
article id 7803, category Research article
Lingbo Dong, Pete Bettinger, Huiyan Qin, Zhaogang Liu. (2018). Reflections on the number of independent solutions for forest spatial harvest scheduling problems: a case of simulated annealing. Silva Fennica vol. 52 no. 1 article id 7803. https://doi.org/10.14214/sf.7803
Highlights: No one particular neighborhood search technique of simulated annealing was found to be universally acceptable; The optimal number of independent solutions necessary for addressing the area restriction harvest scheduling model was described with a negative logarithmic function that was related with the problem size. However, optimal number of independent solutions necessary was not sensitive to the problem size for non-spatial and unit restriction harvest scheduling model problems, which should be somewhat above 250 independent runs; The types of adjacency constraints have moderate effects on the number of independent solutions, but these effects are not significant.

To assess the quality of results obtained from heuristics through statistical procedures, a number of independently generated solutions to the same problem are required, however the knowledge of how many solutions are necessary for this purpose using a specific heuristic is still not clear. Therefore, the overall aims of this paper are to quantitatively evaluate the effects of the number of independent solutions generated on the forest planning objectives and on the performance of different neighborhood search techniques of simulated annealing (SA) in three increasing difficult forest spatial harvest scheduling problems, namely non-spatial model, area restriction model (ARM) and unit restriction model (URM). The tested neighborhood search techniques included the standard version of SA using the conventional 1-opt moves, SA using the combined strategy that oscillates between the conventional 1-opt moves and the exchange version of 2-opt moves, and SA using the change version of 2-opt moves. The obtained results indicated that the number of independent solutions generated had clear effects on the conclusions of the performances of different neighborhood search techniques of SA, which indicated that no one particular neighborhood search technique of SA was universally acceptable. The optimal number of independent solutions generated for all alternative neighborhood search techniques of SA for ARM problems could be estimated using a negative logarithmic function based on the problem size, however the relationships were not sensitive (i.e., 0.13 < p < 0.78) to the problem size for non-spatial and URM harvest scheduling problems, which should be somewhat above 250 independent runs. The types of adjacency constraints did moderately affect the number of independent solutions necessary, but not significantly. Therefore, determining an optimal number of independent solutions generated is a necessary process prior to employing heuristics in forest management planning practices.

  • Dong, College of Forestry, Northeast Forestry University, Harbin 150040, China ORCID ID:E-mail: farrell0503@126.com
  • Bettinger, Warnell School of Forestry and Natural Resources, University of Georgia, Athens 30602, GA, USA ORCID ID:E-mail: pbettinger@warnell.uga.edu
  • Qin, College of Economic and Management, Northeast Forestry University, Harbin 150040, China ORCID ID:E-mail: huiyanqin@hotmail.com
  • Liu, College of Forestry, Northeast Forestry University, Harbin 150040, China ORCID ID:E-mail: lzg19700602@163.com (email)
article id 7791, category Research article
Tadeusz B. Splawinski, Sylvie Gauthier, Nicole J. Fenton, Daniel Houle, Yves Bergeron. (2018). The colonization of young fire initiated stands by the crustose lichen Trapeliopsis granulosa and its potential effect on conifer establishment and stand succession. Silva Fennica vol. 52 no. 1 article id 7791. https://doi.org/10.14214/sf.7791
Highlights: T. granulosa is a poor seedbed for jack pine establishment; The presence of extensive T. granulosa cover can limit ongoing tree recruitment, thereby maintaining open lichen woodland; Dry open conditions favor the establishment of T. granulosa; Stands with significant T. granulosa cover may be good candidates for afforestation initiatives due to lower evaporation potential and decreased water stress.

The resilience of closed-crown coniferous stands within the boreal forest of North America is highly dependent on successful re-establishment of tree species following fire. A shift from closed-crown forest to open lichen woodland is possible following poor natural regeneration during the initial establishment phase, followed by the development of extensive lichen cover, which may hinder ongoing recruitment. We examined the development of the crustose lichen Trapeliopsis granulosa (Hoffm.) 18 to 21 years following fire within six sites in the boreal forest of northwestern Quebec, and explored its potential to affect ongoing recruitment during early successional stages of stand development. Germination and survivorship trials were conducted within the laboratory to determine the establishment rate of Pinus banksiana Lamb. (jack pine) on T. granulosa, mineral soil, and burnt duff under two separate watering frequencies (observed and drought). Survival and establishment rates of jack pine were highest on burnt duff, and poor on both T. granulosa and mineral soil. Under the drought treatment, no seedlings survived on any substrates. In the field, T. granulosa cover had a positive relationship with mineral soil cover, and negative relationships with duff cover, ericaceous shrub cover, organic layer depth, other lichen cover, and Sphagnum moss cover. No discernable relationship was found between T. granulosa and tree density, rock cover, dead wood cover or other moss cover. The development of extensive T. granulosa cover in fire-initiated stands can impede ongoing recruitment of conifer species due to its poor seedbed quality, thereby maintaining open forests.

  • Splawinski, Institut de recherche sur les forêts, Université du Québec en Abitibi-Témiscamingue, 445, boul. de l’Université, Rouyn-Noranda, QC, J9X 5E4, Canada ORCID ID:E-mail: tsplawinski@gmail.com (email)
  • Gauthier, Natural Resources Canada, Canadian Forest Service, Laurentian Forestry Centre, 1055 rue du PEPS, P.O. Box 10380, Stn Sainte Foy, QC, G1V 4C7, Canada ORCID ID:E-mail: sylvie.gauthier@rncan-nrcan.gc.ca
  • Fenton, Institut de recherche sur les forêts (IRF), Université du Québec en Abitibi-Témiscamingue, 445 boul. de l’Université, Rouyn-Noranda, QC, J9X 5E4, Canada ORCID ID:E-mail: nicole.fenton@uqat.ca
  • Houle, Ministère des Forêts, de la Faune et des Parcs, Direction de la recherché forestière, Québec, QC, G1P 3W8, Canada; Ouranos Climate Change Consortium, Montréal, QC, H3A 1B9, Canada ORCID ID:E-mail: daniel.houle@mffp.gouv.qc.ca
  • Bergeron, Centre d’étude sur la forêt and Chaire industrielle en aménagement forestier durable, Université du Québec à Montréal, CP 8888 Succursale A, Montréal, QC, H3C 3P8, Canada ORCID ID:E-mail: bergeron.yves@uqam.ca
article id 1665, category Research article
Lauri Haataja, Ville Kankaanhuhta, Timo Saksa. (2018). Reliability of self-control method in the management of non-industrial private forests. Silva Fennica vol. 52 no. 1 article id 1665. https://doi.org/10.14214/sf.1665
Highlights: Self-control method was found reliable at the main stages of the forest regeneration process; Only slight overestimation was found in self-control results of soil preparation and planting and small underestimation in self-control of young stand management; Diverse utilizing of self-control data is possible in support of service providers operations.
This study seeks to determine the extent to which self-control data can be relied upon in the management of private forests. Self-control (SC) requires the forest workers to evaluate their own work quality to ensure the clients’ needs are met in terms of soil preparation, planting and young stand management. Self-control data were compared to an independent evaluation of the same worksites. Each dataset had a hierarchical structure (e.g., sample plot, regeneration area and contractor), and key quality indicators (i.e., number of prepared mounds, planted seedlings or crop trees) were measured for each plot.  Self-control and independent-assessments (IA) were analyzed by fitting a multi-level multivariate model containing explanatory variables. No significant differences were observed in terms of soil preparation (number of mounds) or young stand management (number of crop trees) between self-control and independent-assessments. However, the self-control planting data included a slight but significant overestimation of the number of planted seedlings. Discrepancies are discussed in terms of sampling error and other explanatory factors. According to overall results, self-control methods are reliable at every stage of the forest regeneration process. As such, the diverse utilizing of self-control data is possible in support of service providers operations.
  • Haataja, Natural Resources Institute Finland (Luke), Natural resources, Juntintie 154, FI-77600 Suonenjoki, Finland ORCID ID:E-mail: lauritapiohaataja@gmail.com (email)
  • Kankaanhuhta, Natural Resources Institute Finland (Luke), Natural resources, Juntintie 154, FI-77600 Suonenjoki, Finland ORCID ID:E-mail: ville.kankaanhuhta@luke.fi
  • Saksa, Natural Resources Institute Finland (Luke), Natural resources, Juntintie 154, FI-77600 Suonenjoki, Finland ORCID ID:E-mail: timo.saksa@luke.fi
article id 1665, category Research article
Lauri Haataja, Ville Kankaanhuhta, Timo Saksa. (2018). Reliability of self-control method in the management of non-industrial private forests. Silva Fennica vol. 52 no. 1 article id 1665. https://doi.org/10.14214/sf.1665
Highlights: Self-control method was found reliable at the main stages of the forest regeneration process; Only slight overestimation was found in self-control results of soil preparation and planting and small underestimation in self-control of young stand management; Diverse utilizing of self-control data is possible in support of service providers operations.
This study seeks to determine the extent to which self-control data can be relied upon in the management of private forests. Self-control (SC) requires the forest workers to evaluate their own work quality to ensure the clients’ needs are met in terms of soil preparation, planting and young stand management. Self-control data were compared to an independent evaluation of the same worksites. Each dataset had a hierarchical structure (e.g., sample plot, regeneration area and contractor), and key quality indicators (i.e., number of prepared mounds, planted seedlings or crop trees) were measured for each plot.  Self-control and independent-assessments (IA) were analyzed by fitting a multi-level multivariate model containing explanatory variables. No significant differences were observed in terms of soil preparation (number of mounds) or young stand management (number of crop trees) between self-control and independent-assessments. However, the self-control planting data included a slight but significant overestimation of the number of planted seedlings. Discrepancies are discussed in terms of sampling error and other explanatory factors. According to overall results, self-control methods are reliable at every stage of the forest regeneration process. As such, the diverse utilizing of self-control data is possible in support of service providers operations.
  • Haataja, Natural Resources Institute Finland (Luke), Natural resources, Juntintie 154, FI-77600 Suonenjoki, Finland ORCID ID:E-mail: lauritapiohaataja@gmail.com (email)
  • Kankaanhuhta, Natural Resources Institute Finland (Luke), Natural resources, Juntintie 154, FI-77600 Suonenjoki, Finland ORCID ID:E-mail: ville.kankaanhuhta@luke.fi
  • Saksa, Natural Resources Institute Finland (Luke), Natural resources, Juntintie 154, FI-77600 Suonenjoki, Finland ORCID ID:E-mail: timo.saksa@luke.fi
article id 1665, category Research article
Lauri Haataja, Ville Kankaanhuhta, Timo Saksa. (2018). Reliability of self-control method in the management of non-industrial private forests. Silva Fennica vol. 52 no. 1 article id 1665. https://doi.org/10.14214/sf.1665
Highlights: Self-control method was found reliable at the main stages of the forest regeneration process; Only slight overestimation was found in self-control results of soil preparation and planting and small underestimation in self-control of young stand management; Diverse utilizing of self-control data is possible in support of service providers operations.
This study seeks to determine the extent to which self-control data can be relied upon in the management of private forests. Self-control (SC) requires the forest workers to evaluate their own work quality to ensure the clients’ needs are met in terms of soil preparation, planting and young stand management. Self-control data were compared to an independent evaluation of the same worksites. Each dataset had a hierarchical structure (e.g., sample plot, regeneration area and contractor), and key quality indicators (i.e., number of prepared mounds, planted seedlings or crop trees) were measured for each plot.  Self-control and independent-assessments (IA) were analyzed by fitting a multi-level multivariate model containing explanatory variables. No significant differences were observed in terms of soil preparation (number of mounds) or young stand management (number of crop trees) between self-control and independent-assessments. However, the self-control planting data included a slight but significant overestimation of the number of planted seedlings. Discrepancies are discussed in terms of sampling error and other explanatory factors. According to overall results, self-control methods are reliable at every stage of the forest regeneration process. As such, the diverse utilizing of self-control data is possible in support of service providers operations.
  • Haataja, Natural Resources Institute Finland (Luke), Natural resources, Juntintie 154, FI-77600 Suonenjoki, Finland ORCID ID:E-mail: lauritapiohaataja@gmail.com (email)
  • Kankaanhuhta, Natural Resources Institute Finland (Luke), Natural resources, Juntintie 154, FI-77600 Suonenjoki, Finland ORCID ID:E-mail: ville.kankaanhuhta@luke.fi
  • Saksa, Natural Resources Institute Finland (Luke), Natural resources, Juntintie 154, FI-77600 Suonenjoki, Finland ORCID ID:E-mail: timo.saksa@luke.fi
article id 7751, category Research article
Göran Nordlander, Euan G. Mason, Karin Hjelm, Henrik Nordenhem, Claes Hellqvist. (2017). Influence of climate and forest management on damage risk by the pine weevil Hylobius abietis in northern Sweden. Silva Fennica vol. 51 no. 5 article id 7751. https://doi.org/10.14214/sf.7751
Highlights: Analysis of survey data from 292 reforestation areas in northern Sweden show that the probability of pine weevil damage can be predicted with a standard error of 0.12; Three variables are important in the optimal model: proportion of seedlings in mineral soil, age of clear-cut, and temperature sum; Temperature sum in the model can be adjusted to reflect future climate scenarios.

The pine weevil Hylobius abietis L. is an economically important pest insect that kills high proportions of conifer seedlings in reforestation areas. It is present in conifer forests all over Europe but weevil abundance and risk for damage varies considerably between areas. This study aimed to obtain a useful model for predicting damage risks by analyzing survey data from 292 regular forest plantations in northern Sweden. A model of pine weevil attack was constructed using various site characteristics, including both climatic factors and factors related to forest management activities. The optimal model was rather imprecise but showed that the risk of pine weevil attack can be predicted approximatively with three principal variables: 1) the proportion of seedlings expected to be planted in mineral soil rather than soil covered with duff and debris, 2) age of clear-cut at the time of planting, and 3) calculated temperature sum at the location. The model was constructed using long-run average temperature sums for epoch 2010, and so effects of climate change can be inferred from the model by adjustment to future epochs. Increased damage risks with a warmer climate are strongly indicated by the model. Effects of a warmer climate on the geographical distribution and abundance of the pine weevil are also discussed. The new tool to better estimate the risk of damage should provide a basis for foresters in their choice of countermeasures against pine weevil damage in northern Europe.

  • Nordlander, Swedish University of Agricultural Sciences (SLU), Department of Ecology, P.O. Box 7044, SE-750 07 Uppsala, Sweden ORCID ID:E-mail: Goran.Nordlander@slu.se
  • Mason, University of Canterbury, School of Forestry, Private Bag 4800, Christchurch 8140, New Zealand; Swedish University of Agricultural Sciences, Southern Swedish Forest Research Centre, P.O. Box 49, SE-230 53 Alnarp, Sweden ORCID ID: http://orcid.org/0000-0001-9024-9106 E-mail: euan.mason@canterbury.ac.nz (email)
  • Hjelm, Skogforsk, The Forest Research Institute of Sweden, Ekebo 2250, SE-268 90 Svalöv, Sweden; Swedish University of Agricultural Sciences, Southern Swedish Forest Research Centre, P.O. Box 49, SE-230 53 Alnarp, Sweden ORCID ID:E-mail: karin.hjelm@skogforsk.se
  • Nordenhem, Swedish University of Agricultural Sciences (SLU), Department of Ecology, P.O. Box 7044, SE-750 07 Uppsala, Sweden ORCID ID:E-mail: h.nordenhem@telia.com
  • Hellqvist, Swedish University of Agricultural Sciences (SLU), Department of Ecology, P.O. Box 7044, SE-750 07 Uppsala, Sweden ORCID ID:E-mail: Claes.Hellqvist@slu.se
article id 7746, category Research article
Jānis Donis, Māra Kitenberga, Guntars Šņepsts, Roberts Matisons, Juris Zariņš, Āris Jansons. (2017). The forest fire regime in Latvia during 1922–2014. Silva Fennica vol. 51 no. 5 article id 7746. https://doi.org/10.14214/sf.7746
Highlights: Climate effects and human influence on forest fire activity in Latvia was assessed using time-series analysis; Drought conditions during summer season had the strongest effect on fire activity of tested climatic variables; Negative trends and spatial distribution pattern of fire activity suggests of prevailing human influence on forest fire regime over the 20th century.

Fire as disturbance of forests has an important ecological and economical role in boreal and hemiboreal forests. The occurrence of forest fires is both climatically and anthropogenically determined and shifts in fire regimes are expected due to climate change. Although fire histories have been well documented in boreal regions, there is still insufficient information about fire occurrence in the Baltic States. In this study, spatio-temporal patterns and climatic drivers of forest fires were assessed by means of spatial and time-series analysis. The efficiency of Canadian Fire Weather (FWI) indices as indicators for fire activity was tested. The study was based on data from the literature, archives, and the Latvian State Forest service database. During the period 1922–2014, the occurrence and area affected by forest fires has decreased although the total area of forest land has nearly doubled, suggesting improvement of the fire suppression system as well as changes in socioeconomic situation. The geographical distribution of forest fires revealed two pronounced clusters near the largest cities of Riga and Daugavpils, suggesting dominance of human causes of ignitions. The occurrence of fires was mainly influenced by drought. FWI appeared to be efficient in predicting the fire occurrence: 23–34% of fires occurred on days with a high or extremely high fire danger class, which overall had a relative occurrence of only 4.3–4.6%. During the 20th century, the peak of fire activity shifted from May to April, probably due to global warming and socioeconomic reasons. The results of this study are relevant for forest hazard mitigation and development of fire activity prediction system in Latvia.

  • Donis, LSFRI “Silava”, Rigas str. 111, Salaspils, Latvia, LV2169 ORCID ID:E-mail: janis.donis@silava.lv
  • Kitenberga, LSFRI “Silava”, Rigas str. 111, Salaspils, Latvia, LV2169 ORCID ID:E-mail: mara.kitenberga@gmail.com (email)
  • Šņepsts, LSFRI “Silava”, Rigas str. 111, Salaspils, Latvia, LV2169 ORCID ID:E-mail: guntars.snepsts@silava.lv
  • Matisons, LSFRI “Silava”, Rigas str. 111, Salaspils, Latvia, LV2169 ORCID ID:E-mail: robism@inbox.lv
  • Zariņš, LSFRI “Silava”, Rigas str. 111, Salaspils, Latvia, LV2169 ORCID ID:E-mail: juris.zarins@silava.lv
  • Jansons, LSFRI “Silava”, Rigas str. 111, Salaspils, Latvia, LV2169 ORCID ID:E-mail: aris.jansons@silava.lv
article id 7723, category Research article
Mihails Čugunovs, Eeva-Stiina Tuittila, Ida Sara-Aho, Laura Pekkola, Jari Kouki. (2017). Recovery of boreal forest soil and tree stand characteristics a century after intensive slash-and-burn cultivation. Silva Fennica vol. 51 no. 5 article id 7723. https://doi.org/10.14214/sf.7723
Highlights: Soil organic matter stocks have still not fully recovered after a century of stand succession and passive recovery after slash-and-burn period; Historical slash-and-burn stands feature higher live birch and standing dead wood volume than controls; If passive rewildening is used, Fennoscandian boreal forests need more than a century to regain naturalness.

Passive rewildening of forest ecosystems is commonly used for rehabilitating degraded habitats closer to their natural origin in addition to costly active restoration measures. However, it is not clear if passive processes are effective and how long the recovery of main ecosystem properties takes. We investigate the recovery of forest soil and tree stand characteristics a century after cessation of slash-and-burn cultivation, a major historical intensive disturbance regime that was applied widely in boreal zone of Finland until late 1800s. We systematically sampled soil and tree stand parameters within former slash-and-burn and nearby control areas. Humus layer thickness and soil organic matter (SOM) stocks were still lower in the historical slash-and-burn than in control areas. Slash-and-burn areas also had a larger volume of live birch trees and a higher standing dead wood volume than control areas. Accordingly, organic matter (humus layer thickness and SOM stocks) correlated negatively with birch standing live tree volume. Combined OM stock in humus and uppermost 10 cm mineral soil layer was positively correlated with lying dead wood volume. Overall, we observed clear recovery of several natural properties but we also found that a century after cessation of frequent anthropogenic burnings, clear legacies of disturbance in the above- and below-ground parts of boreal ecosystem were evident. Our results indicate that if only passive rewildening is applied as a restoration measure, the full recovery of boreal forest is slow and the effects of historical land-use may persist for over hundred years in soil and tree properties.

  • Čugunovs, University of Eastern Finland, School of Forest Sciences, Yliopistokatu 7, P.O. Box 111, FI-80101 Joensuu, Finland ORCID ID:E-mail: mihails.cugunovs@uef.fi (email)
  • Tuittila, University of Eastern Finland, School of Forest Sciences, Yliopistokatu 7, P.O. Box 111, FI-80101 Joensuu, Finland ORCID ID: http://orcid.org/0000-0001-8861-3167 E-mail: eeva-stiina.tuittila@uef.fi
  • Sara-Aho, University of Eastern Finland, School of Forest Sciences, Yliopistokatu 7, P.O. Box 111, FI-80101 Joensuu, Finland ORCID ID:E-mail: ida.sara-aho@mhy.fi
  • Pekkola, University of Eastern Finland, School of Forest Sciences, Yliopistokatu 7, P.O. Box 111, FI-80101 Joensuu, Finland ORCID ID:E-mail: laura.pekkola@gmail.com
  • Kouki, University of Eastern Finland, School of Forest Sciences, Yliopistokatu 7, P.O. Box 111, FI-80101 Joensuu, Finland ORCID ID: http://orcid.org/0000-0003-2624-8592 E-mail: jari.kouki@uef.fi
article id 7721, category Research article
Sakari Tuominen, Andras Balazs, Eija Honkavaara, Ilkka Pölönen, Heikki Saari, Teemu Hakala, Niko Viljanen. (2017). Hyperspectral UAV-imagery and photogrammetric canopy height model in estimating forest stand variables. Silva Fennica vol. 51 no. 5 article id 7721. https://doi.org/10.14214/sf.7721
Highlights: Hyperspectral imagery and photogrammetric 3D point cloud based on RGB imagery were acquired under weather conditions changing from cloudy to sunny; Calibration of hyperspectral imagery was required for compensating the effect of varying weather conditions; The combination of hyperspectral imagery and photogrammetric point cloud data resulted in accurate forest estimates, especially for volumes per tree species.

Remote sensing using unmanned aerial vehicle (UAV) -borne sensors is currently a highly interesting approach for the estimation of forest characteristics. 3D remote sensing data from airborne laser scanning or digital stereo photogrammetry enable highly accurate estimation of forest variables related to the volume of growing stock and dimension of the trees, whereas recognition of tree species dominance and proportion of different tree species has been a major complication in remote sensing-based estimation of stand variables. In this study the use of UAV-borne hyperspectral imagery was examined in combination with a high-resolution photogrammetric canopy height model in estimating forest variables of 298 sample plots. Data were captured from eleven separate test sites under weather conditions varying from sunny to cloudy and partially cloudy. Both calibrated hyperspectral reflectance images and uncalibrated imagery were tested in combination with a canopy height model based on RGB camera imagery using the k-nearest neighbour estimation method. The results indicate that this data combination allows accurate estimation of stand volume, mean height and diameter: the best relative RMSE values for those variables were 22.7%, 7.4% and 14.7%, respectively. In estimating volume and dimension-related variables, the use of a calibrated image mosaic did not bring significant improvement in the results. In estimating the volumes of individual tree species, the use of calibrated hyperspectral imagery generally brought marked improvement in the estimation accuracy; the best relative RMSE values for the volumes for pine, spruce, larch and broadleaved trees were 34.5%, 57.2%, 45.7% and 42.0%, respectively.

  • Tuominen, Natural Resources Institute Finland (Luke), Economics and society, P.O. Box 2, FI-00791 Helsinki, Finland ORCID ID: http://orcid.org/0000-0001-5429-3433 E-mail: sakari.tuominen@luke.fi (email)
  • Balazs, Natural Resources Institute Finland (Luke), Economics and society, P.O. Box 2, FI-00791 Helsinki, Finland ORCID ID:E-mail: andras.balazs@luke.fi
  • Honkavaara, Finnish Geospatial Research Institute, National Land Survey of Finland, Geodeetinrinne 2, FI-02430 Masala, Finland ORCID ID:E-mail: eija.honkavaara@nls.fi
  • Pölönen, University of Jyväskylä, Faculty of Information Technology, P.O. Box 35, FI-40014 Jyväskylä, Finland ORCID ID:E-mail: ilkka.polonen@jyu.fi
  • Saari, VTT Microelectronics, P.O. Box 1000, FI-02044 VTT, Finland ORCID ID:E-mail: heikki.saari@vtt.fi
  • Hakala, Finnish Geospatial Research Institute, National Land Survey of Finland, Geodeetinrinne 2, FI-02430 Masala, Finland ORCID ID:E-mail: teemu.hakala@nls.fi
  • Viljanen, Finnish Geospatial Research Institute, National Land Survey of Finland, Geodeetinrinne 2, FI-02430 Masala, Finland ORCID ID:E-mail: niko.viljanen@nls.fi
article id 7693, category Research article
Chunyu Zhu, Jiaojun Zhu, Xiao Zheng, Deliang Lu, Xiufen Li. (2017). Comparison of gap formation and distribution pattern induced by wind/snowstorm and flood in a temperate secondary forest ecosystem, Northeast China. Silva Fennica vol. 51 no. 5 article id 7693. https://doi.org/10.14214/sf.7693
Highlights: The canopy gaps induced by wind/snowstorm were aggregated in steep slope and high altitude areas, while the gaps formed by flood were gathered in steep slope and low altitude areas; The wind/snowstorm mainly driven the formation of medium gaps, while the flood mainly promoted the percentage of small gaps and vacant lands.

Canopy gap is the driving force of forest succession. Due to the uncontrollability, however, the influences of natural disturbances on gap formation and gap distribution pattern have been rarely understood in temperate secondary forest ecosystems. We monitored the gap formation and gap distribution pattern using high-resolution remote sensing images before and after two disturbances (wind/snowstorm in 2003 and flood in 2013). The results showed that after wind/snowstorm, the gap nearest neighbor index (GNNI) decreased, the vacant land area did not obviously change while the gap fraction and gaps density (especially medium size) increased. After the flood, GNNI decreased, the number of small gaps increased but larger gaps were in many cases extended to vacant land areas leading to a smaller total number of medium and large gaps but considerable increase in vacant land area. We also found that the gap densities increased with slope and altitude for wind/snowstorm-formed gaps, but they increased with increasing slope and decreasing altitude for flood-formed gaps. These results indicated that gaps were aggregated in steep slope and high altitude areas after wind/snowstorm, but in steep slope and low altitude areas after the flood. Medium gaps were mainly created by the wind/snowstorm due to the individual-level death of dominant tree with the continuous fall of surrounding trees. While, vacant lands were obviously created during the flood because of integral sweeping. Besides, smaller trees were easily damaged by runoff of flood, which induced small gaps. In summary, forest managers may pay more attention to use gaps to accelerate forest succession after wind/snowstorms and to restore vegetation in vacant lands after floods.

  • Zhu, ORCID ID:E-mail: Chunyuzhu123@126.com
  • Zhu, ORCID ID:E-mail: jiaojunzhu@iae.ac.cn (email)
  • Zheng, ORCID ID:E-mail: xiaozheng@iae.ac.cn
  • Lu, ORCID ID:E-mail: delianglu14@hotmail.com
  • Li, ORCID ID:E-mail: delianglu14@hotmail.com
article id 2018, category Research article
Sima Mohtashami, Lars Eliasson, Gunnar Jansson, Johan Sonesson. (2017). Influence of soil type, cartographic depth-to-water, road reinforcement and traffic intensity on rut formation in logging operations: a survey study in Sweden. Silva Fennica vol. 51 no. 5 article id 2018. https://doi.org/10.14214/sf.2018
Highlights: Soil type and traffic intensity had significant effects on rut formation; Further studies are required to identify all factors affecting rut formation, especially on soils with medium bearing capacity; The cartographic depth-to-water index (DTW) alone did not predict rut formation, but used in combination with other information, e.g. soil type, could be an interesting tool for delineating soil areas that are potentially vulnerable to rut formation in logging operations.

Rut formation caused by logging operations has been recognised as a challenge for Swedish forestry. Frequent traffic with heavy machines on extraction roads, together with a warmer climate, is one of the factors that increases the risk of rut formation in forests. One possible way to control this impact of logging operations is to design and apply decision support tools that enable operators to take sensitive areas into account when planning extraction roads. In this study, 16 different logging sites in south-eastern Sweden were surveyed after clear-cut. Information was collected about extraction roads (i.e. traffic intensity, whether the roads had been reinforced with slash) and ruts. Digital maps such as cartographic depth-to-water (DTW) index and soil type were also examined for any connection to rut positions. Soil type and traffic intensity were found to be significant factors in rut formation, while DTW and slash reinforcement were not. However, the DTW map combined with other information, such as soil type, could contribute to decision support tools that improve planning of extraction roads.

  • Mohtashami, The forestry research institute of Sweden, Skogforsk, Uppsala Science Park, SE-751 83 Uppsala, Sweden ORCID ID:E-mail: sima.mohtashami@skogforsk.se (email)
  • Eliasson, The forestry research institute of Sweden, Skogforsk, Uppsala Science Park, SE-751 83 Uppsala, Sweden ORCID ID: http://orcid.org/0000-0002-2038-9864 E-mail: lars.eliasson@skogforsk.se
  • Jansson, The forestry research institute of Sweden, Skogforsk, Uppsala Science Park, SE-751 83 Uppsala, Sweden ORCID ID: http://orcid.org/0000-0002-3018-9161 E-mail: gunnar.jansson@skogforsk.se
  • Sonesson, The forestry research institute of Sweden, Skogforsk, Uppsala Science Park, SE-751 83 Uppsala, Sweden ORCID ID: http://orcid.org/0000-0002-2018-7496 E-mail: johan.sonesson@skogforsk.se
article id 7743, category Research article
Sakari Tuominen, Timo Pitkänen, Andras Balazs, Annika Kangas. (2017). Improving Finnish Multi-Source National Forest Inventory by 3D aerial imaging. Silva Fennica vol. 51 no. 4 article id 7743. https://doi.org/10.14214/sf.7743
Highlights: 3D aerial imaging provides a feasible method for estimating forest variables in the form of thematic maps in large area inventories; Photogrammetric 3D data based on aerial imagery that was originally acquired for orthomosaic production was tested in estimating stand variables; Photogrammetric 3D data highly improved the accuracy of forest estimates compared to traditional 2D remote sensing imagery.

Optical 2D remote sensing techniques such as aerial photographing and satellite imaging have been used in forest inventory for a long time. During the last 15 years, airborne laser scanning (ALS) has been adopted in many countries for the estimation of forest attributes at stand and sub-stand levels. Compared to optical remote sensing data sources, ALS data are particularly well-suited for the estimation of forest attributes related to the physical dimensions of trees due to its 3D information. Similar to ALS, it is possible to derive a 3D forest canopy model based on aerial imagery using digital aerial photogrammetry. In this study, we compared the accuracy and spatial characteristics of 2D satellite and aerial imagery as well as 3D ALS and photogrammetric remote sensing data in the estimation of forest inventory variables using k-NN imputation and 2469 National Forest Inventory (NFI) sample plots in a study area covering approximately 5800 km2. Both 2D data were very close to each other in terms of accuracy, as were both the 3D materials. On the other hand, the difference between the 2D and 3D materials was very clear. The 3D data produce a map where the hotspots of volume, for instance, are much clearer than with 2D remote sensing imagery. The spatial correlation in the map produced with 2D data shows a lower short-range correlation, but the correlations approach the same level after 200 meters. The difference may be of importance, for instance, when analyzing the efficiency of different sampling designs and when estimating harvesting potential.

  • Tuominen, Natural Resources Institute Finland (Luke), Economics and Society, P.O. Box 2, FI-00791 Helsinki, Finland ORCID ID:E-mail: sakari.tuominen@luke.fi (email)
  • Pitkänen, Natural Resources Institute Finland (Luke), Economics and Society, P.O. Box 2, FI-00791 Helsinki, Finland ORCID ID:E-mail: timo.p.pitkanen@luke.fi
  • Balazs, Natural Resources Institute Finland (Luke), Economics and Society, P.O. Box 2, FI-00791 Helsinki, Finland ORCID ID:E-mail: andras.balazs@luke.fi
  • Kangas, Natural Resources Institute Finland (Luke), Economics and Society, P.O. Box 68, FI-80101 Joensuu, Finland ORCID ID:E-mail: Annika.Kangas@luke.fi
article id 7728, category Research article
Liam Donnelly, Sven-Olof Lundqvist, Conor O’Reilly. (2017). Inter- and intra-annual wood property variation in juvenile wood between six Sitka spruce clones. Silva Fennica vol. 51 no. 4 article id 7728. https://doi.org/10.14214/sf.7728
Highlights: Wood property differences resulted primarily from variation in the proportions of early- and latewood in each annual ring; Width of early- and latewood bands in each ring was found to be a more important determinant of juvenile wood quality than the characteristics of the cells within each band; Wood properties differed greatly between clones, suggesting that there is potential to improve juvenile wood properties through selective breeding.

Increased growth rates have reduced rotation lengths, increasing the proportion of juvenile wood relative to mature wood, which may negatively affect mechanical performance of sawn timber. However, there is limited information available on the potential impact of breeding for vigour on juvenile wood in Sitka spruce (Picea sitchensis (Bong.) Carrière). In this study, the relationship between vigour (based on total height) and wood properties was investigated in six-year-old Sitka spruce clones grown in two replicated field trials in Ireland. Six clones were evaluated, two clones from each of three vigour (high, intermediate and low) classes. Discs were cut from the base of one ramet per replication for each clone to assess wood quality attributes. Radial tracheid width was significantly and positively correlated with ring width and height, and was negatively correlated with density. The wood of the most vigorous clone had significantly larger ring width with thinner cell walls and wider tracheids than all clones in the two other vigour classes, resulting in lower mean wood density. Latewood properties for all wood attributes measured differed significantly between the two sites. Wood property differences resulted primarily from variation in the proportions of early- and latewood in each annual ring. Additionally, the width of early- and latewood bands in each ring was found to be a more important determinant of juvenile wood quality than the characteristics of the cells within each band. Wood properties differed greatly between clones, suggesting that there is potential to improve juvenile wood properties through selective breeding.

  • Donnelly, UCD Forestry, University College Dublin, Belfield, Dublin 4, Ireland ORCID ID:E-mail: liam.donnelly@ucdconnect.ie (email)
  • Lundqvist, Innventia Ab, Drottning Kristinas väg 61, SE-114 86 Stockholm, Sweden ORCID ID:E-mail: svenolof.lundqvist@innventia.com
  • O’Reilly, UCD Forestry, University College Dublin, Belfield, Dublin 4, Ireland ORCID ID:E-mail: conor.oreilly@ucd.ie
article id 6977, category Research article
Anett Schibalski, Aleksi Lehtonen, Thomas Hickler, Boris Schröder. (2017). Identifying important topics for model refinement in a widely used process-based model informed by correlative model analyses in a boreal forest. Silva Fennica vol. 51 no. 4 article id 6977. https://doi.org/10.14214/sf.6977
Highlights: Continental-scale model parameterization of widely used LPJ-GUESS experiences problems when applied on the regional level; Competition, disturbances and soil conditions are crucial for explaining treeline position in Finland, besides climatic limitation; Picea abies is overly dominant in LPJ-GUESS model, as key competitive mechanisms are not implemented in sufficient detail.

Models attempting to predict treeline shifts in changing climates must include the relevant ecological processes in sufficient detail. A previous correlative model study has pointed to nutrients, competition, and temperature as the most important factors shaping the treelines of Pinus sylvestris L., Picea abies (L.) H. Karst. and Betula pubescens Ehrh. in Finnish Lapland. Here, we applied a widely used process-based dynamic vegetation model (LPJ-GUESS) to (i) test its capability to simulate observed spatial and temporal patterns of the main tree species in Finnish Lapland, and (ii) to explore the model representation of important processes in order to guide further model development. A European parameterization of LPJ-GUESS overestimated especially P. abies biomass and the species’ northern range limit. We identified implemented processes to adjust (competition, disturbance) and crucial processes in boreal forests to include (nutrient limitation, forest management) which account for the model’s failure to (edaphically) restrict P. abies in Finnish Lapland and the resulting species imbalance. Key competitive mechanisms are shade and drought tolerance, nutrient limitation, fire resistance, and susceptibility to disturbances (storm, herbivory) which we discussed with respect to boreal ecology and promising model developments to provide a starting point for future model development.

  • Schibalski, Institute of Geoecology, Technische Universität Braunschweig, Langer Kamp 19c, D-38106 Braunschweig, Germany ORCID ID:E-mail: a.schibalski@tu-braunschweig.de (email)
  • Lehtonen, Natural Resources Institute Finland (Luke), Management and Production of Renewable Resources, P.O. Box 2, FI-00791 Helsinki, Finland ORCID ID:E-mail: aleksi.lehtonen@luke.fi
  • Hickler, Biodiversity and Climate Research Centre (BiK-F), Senckenberganlage 25, D-60325 Frankfurt am Main, Germany; Department of Physical Geography, Goethe University, Altenhöferallee 1, D-60438 Frankfurt am Main, Germany ORCID ID:E-mail: thomas.hickler@senckenberg.de
  • Schröder, Institute of Geoecology, Technische Universität Braunschweig, Langer Kamp 19c, D-38106 Braunschweig, Germany; Berlin-Brandenburg Institute of Advanced Biodiversity Research BBIB, Altensteinstr. 6, D-14195 Berlin, Germany ORCID ID:E-mail: boris.schroeder@tu-bs.de
article id 5659, category Research article
Juha Laitila, Anssi Ahtikoski, Jaakko Repola, Johanna Routa. (2017). Pre-feasibility study of supply systems based on artificial drying of delimbed stem forest chips. Silva Fennica vol. 51 no. 4 article id 5659. https://doi.org/10.14214/sf.5659
Highlights: With artificial drying and quick delivery, avoiding dry material losses of harvested timber, it could be possible to reduce the current costs of the prevailing procurement system based on natural drying of stored timber at roadside landings; The maximum cost for the prospective drying process of fresh chips corresponds to, e.g., organization costs or stumpage price of delimbed stems.

This study was aimed at determining the maximum cost level of artificial drying required for cost-efficient operation. This was done using a system analysis approach, in which the harvesting potential and procurement cost of alternative fuel chip production systems were compared at the stand and regional level. The accumulation and procurement cost of chipped delimbed stems from young forests were estimated within a 100 km transport distance from a hypothetical end use facility located in northern Finland. Logging and transportation costs, stumpage prices, tied up capital, dry matter losses and moisture content of harvested timber were considered in the study. Moisture content of artificially dried fuel chips made of fresh timber (55%) was set to 20%, 30% and 40% in the comparisons. Moisture content of fuel chips based on natural drying during storing was 40%. Transporting costs were calculated according to new higher permissible dimensions and weight limits for truck-trailers. The procurement cost calculations indicated that with artificial drying and by avoiding dry material losses of timber, it could be possible to reduce current costs of the prevailing procurement system based on natural drying of timber at roadside landings. The maximum cost level of artificial drying ranged between 1.2–3.2 € MWh–1 depending on the supply chain, moisture content and procurement volume of fuel chips. This cost margin corresponds to, e.g., organization, forwarding and transportation costs or stumpage price of delimbed stems.

  • Laitila, Natural Resources Institute Finland (Luke), Bio-based business and industry, P.O. Box 68, FI-80101 Joensuu, Finland ORCID ID:E-mail: juha.laitila@luke.fi (email)
  • Ahtikoski, Natural Resources Institute Finland (Luke), Management and Production of Renewable Resources, Paavo Havaksen tie 3, FI-90570 Oulu, Finland ORCID ID:E-mail: anssi.ahtikoski@luke.fi
  • Repola, Natural Resources Institute Finland (Luke), Management and Production of Renewable Resources, Eteläranta 55, FI-96300 Rovaniemi, Finland ORCID ID:E-mail: jaakko.repola@luke.fi
  • Routa, Natural Resources Institute Finland (Luke), Bio-based business and industry, P.O. Box 68, FI-80101 Joensuu, Finland ORCID ID:E-mail: johanna.routa@luke.fi
article id 1691, category Research article
Enéas Ricardo Konzen, Raquel Peron, Márcio Akira Ito, Gilvano Ebling Brondani, Siu Mui Tsai. (2017). Molecular identification of bamboo genera and species based on RAPD-RFLP markers. Silva Fennica vol. 51 no. 4 article id 1691. https://doi.org/10.14214/sf.1691
Highlights: We investigated the potential of RAPD-RFLP (Random Amplified Polymorphic DNA, Restriction Fragment Length Polymorphism) in detecting genetic relationships among bamboo genera and species; RFLP profiles resolved in acrylamide gels revealed high number of markers, which accurately differentiated species and genera, based on cophenetic correlation coefficients; We recommend RAPD-RFLP for analyses of genetic diversity and divergence among bamboo genera, species and varieties.

Bamboo species have a very significant ecological and economic impact. Determining morphological and genetic differences among bamboo genera and species are crucial to explore desirable traits for breeding purposes. Several advances have been made in the taxonomy of bamboos by using molecular fingerprinting tools and next generation sequencing technologies. Nevertheless, classical molecular markers such as RAPD (Random Amplified Polymorphic DNA), AFLP (Amplified Fragment Length Polymorphism) and ISSR (Inter Simple Sequence Repeats) also provide an accurate discrimination among genera and species. Moreover, the RAPD-RFLP (Random Amplified Polymorphic DNA, Restriction Fragment Length Polymorphism) method, in which amplification products from RAPD are digested with restriction enzymes, is a reliable, fast and cost-effective method for fingerprinting. RAPD-RFLP has been scarcely used in the literature and no report regarding bamboo taxonomy is available with this method. Here we explored the molecular (RAPD, RAPD-RFLP) variation among genera (Bambusa, Dendrocalamus, Guadua and Phyllostachys) and species of bamboo cultivated in Brazil. Both molecular markers allowed clear distinction among the genera studied. Moreover, high cophenetic correlation values in UPGMA clusters indicated their potential for discriminating bamboo species. The digestion of RAPD products (RFLP) resulted in high number of polymorphic bands and produced very characteristic profiles for each genus with three enzyme combinations (HindIII/HaeIII, HinfI/RsaI, and single digestion with MspI). We recommend RAPD-RFLP as a reproducible and informative method for screening differences among genera, species and varieties of bamboos. Providing a cost-effective and accurate method for species identification and characterization is straightforward for bamboo conservation, management and breeding.

  • Konzen, Cell and Molecular Biology Laboratory, Center for Nuclear Energy in Agriculture (CENA), University of Sao Paulo (USP), Centenário Av., 303, Piracicaba, SP, P.O. Box 96, Brazil; Forest Sciences, Federal University of Lavras (UFLA), Lavras, MG, P.O. Box 3037, Brazil ORCID ID:E-mail: erkonzen@gmail.com (email)
  • Peron, Cell and Molecular Biology Laboratory, Center for Nuclear Energy in Agriculture (CENA), University of Sao Paulo (USP), Centenário Av., 303, Piracicaba, SP, P.O. Box 96, Brazil ORCID ID:E-mail: rperon@purdue.edu
  • Ito, Embrapa Western Agriculture, Brazilian Agricultural Research Corporation (EMBRAPA), BR 163 Rd., km 253, Dourados, MS, P.O. Box 449, Brazil ORCID ID:E-mail: marcio.ito@embrapa.br
  • Brondani, Forest Sciences, Federal University of Lavras (UFLA), Lavras, MG, P.O. Box 3037, Brazil ORCID ID:E-mail: gebrondani@gmail.com
  • Tsai, Cell and Molecular Biology Laboratory, Center for Nuclear Energy in Agriculture (CENA), University of Sao Paulo (USP), Centenário Av., 303, Piracicaba, SP, P.O. Box 96, Brazil ORCID ID:E-mail: tsai@cena.usp.br
article id 1683, category Research article
Karol Przeździecki, Jarosław Zawadzki, Chris Cieszewski, Pete Bettinger. (2017). Estimation of soil moisture across broad landscapes of Georgia and South Carolina using the triangle method applied to MODIS satellite imagery. Silva Fennica vol. 51 no. 4 article id 1683. https://doi.org/10.14214/sf.1683
Highlights: Temperature vegetation dryness indices were calculated from MODIS satellite imagery to estimate subsurface soil moisture at different depths using the triangle method; Observations were carried out over the vast areas of Georgia and South Carolina, USA, covered with diverse land uses that, included dense forests and agricultural areas; The triangle method may be useful in forestry management applications where the productivity potential of a region and the hydrologic role of forests in that region are of concern.

We describe here a study based on analysis of vegetation indices and land surface temperatures, which provides relevant information for estimating soil moisture at regional scales. Through an analysis of MODIS satellite imagery and in situ moisture data, the triangle method was used to develop a conceptual land surface temperature−vegetation index model, and spatial temperature-vegetation dryness index (TVDI) values to describe soil moisture relationships for a broad landscape. This study was situated mainly within two states of the southern United States (Georgia and South Carolina). The total study area was about 30 million hectares. The analyses were conducted using information gathered from the 2009 growing season (from the end of March to September). The results of the study showed that soil moisture content was inversely proportional to TVDI, and that TVDI based on the normalized difference vegetation index (NDVI) had a slightly higher correlation with soil moisture than TVDI based on the enhanced vegetation index (EVI).

  • Przeździecki, Warsaw University of Technology, Faculty of Building Services, Hydro and Environmental Engineering, 00-653, Nowowiejska 20, Warszawa, Poland ORCID ID: http://orcid.org/0000-0002-2275-5223 E-mail: karol_przezdziecki@is.pw.edu.pl (email)
  • Zawadzki, Warsaw University of Technology, Faculty of Building Services, Hydro and Environmental Engineering, 00-653, Nowowiejska 20, Warszawa, Poland ORCID ID: http://orcid.org/0000-0003-2842-0018 E-mail: j.j.zawadzki@gmail.com
  • Cieszewski, University of Georgia, Warnell School of Forestry and Natural Resources, 180 E Green St, Athens, GA 30602, USA ORCID ID: http://orcid.org/0000-0003-2842-4406 E-mail: thebiomat@gmail.com
  • Bettinger, University of Georgia, Warnell School of Forestry and Natural Resources, 180 E Green St, Athens, GA 30602, USA ORCID ID: http://orcid.org/0000-0002-5454-3970 E-mail: pbettinger@warnell.uga.edu
article id 2017, category Research article
Pentti Niemistö, Soili Kojola, Anssi Ahtikoski, Raija Laiho. (2017). From useless thickets to valuable resource? – Financial performance of downy birch management on drained peatlands. Silva Fennica vol. 51 no. 3 article id 2017. https://doi.org/10.14214/sf.2017
Highlights: The most profitable management regimes for pulpwood and energy wood production in dense downy birch stands on drained peatlands include no thinnings, but final cutting at the stand age of 40–45 years as whole-tree harvesting, or as integrated harvesting of pulpwood and delimbed energy wood stems about 10 years later depending on applicable harvesting method; A competitive management regime is early precommercial thinning at 4 m dominant height to a density of 2500 stems per hectare and production of pulpwood with a rotation of 55–65 years. Equal profitability is achieved with or without traditional first thinning, which can thus be included for other reasons, for example to improve regeneration of spruce.

Downy birch (Betula pubescens Ehrh.) stands on drained peatlands are often considered useless because they typically do not yield good-quality sawn timber. However, covering an area of ca. 0.5 million hectares and with total yields of up to 250 m3 ha–1, downy birch stands on peatlands in Finland have a potential for pulpwood and/or energy wood production. We examined the financial performance of alternative management regimes (with or without thinnings, different thinning intensities, several rotation lengths) combined with alternative harvesting methods (pulpwood, energy wood, or integrated, energy wood being delimbed stems or whole trees). We used data from 19 experimental stands, monitored for 20–30 years. For harvesting removals we considered both actual thinning removals and final-cutting removals with alternative timings that were based on the monitoring data. We assessed the profitability as a combination of the net present value of the birch generation and the bare land value of future generations of Norway spruce (Picea abies (L.) Karst.). The most profitable management was growing without thinnings until whole-tree final cutting at the stand age of 40–45 years with an advanced multi-tree harvesting method. In contrast, the standard method in whole-tree final cutting resulted in the lowest profitability, and an integrated method with the energy wood as delimbed stems was the best of the standard methods. Thinnings were unprofitable especially when aiming to produce energy wood, whereas aiming for pulpwood, light precommercial thinning was competitive. Commercial thinning at the traditional “pulpwood stage” had little effect on profitability. The best stand age for final cutting was 40–65 years – earlier for very dense stands and whole-tree energy wood harvesting with advanced method, later for precommercially thinned stands and pulpwood harvesting.

  • Niemistö, Natural Resources Institute Finland (Luke), Management and Production of Renewable Resources, Kampusranta 9 C, 60320 Seinäjoki, Finland ORCID ID:E-mail: pentti.niemisto@luke.fi (email)
  • Kojola, Natural Resources Institute Finland (Luke), Management and Production of Renewable Resources, Latokartanonkaari 9, 00790 Helsinki, Finland ORCID ID:E-mail: soili.kojola@luke.fi
  • Ahtikoski, Natural Resources Institute Finland (Luke), Management and Production of Renewable Resources, Paavo Havaksentie 3, 90014 University of Oulu, Finland ORCID ID:E-mail: anssi.ahtikoski@luke.fi
  • Laiho, Natural Resources Institute Finland (Luke), Management and Production of Renewable Resources, Latokartanonkaari 9, 00790 Helsinki, Finland ORCID ID:E-mail: raija.laiho@luke.fi
article id 1741, category Research article
Seppo Nevalainen. (2017). Comparison of damage risks in even- and uneven-aged forestry in Finland. Silva Fennica vol. 51 no. 3 article id 1741. https://doi.org/10.14214/sf.1741
Highlights: Damage risks in two forest management regimes were estimated by means of a literature review and a questionnaire to Finnish forestry experts; Damage risks were usually estimated to be higher in even-aged than in uneven-aged management regimes; In some cases, however, damage risks may be higher in uneven-aged stands (root-rot infected Norway spruce stands and mechanical damage due to repeated thinnings).

The literature on the most prominent forest damage related to even-aged and uneven-aged forest management regimes was reviewed. A questionnaire to expert researchers was conducted to estimate risks in even-aged and uneven-aged forest management chains in Finland. There are only a few empirical comparisons of damage risks in even- and uneven-aged stands in the literature. The results from the expert survey showed that the damage risks were higher in even-aged management in Norway spruce and Scots pine. However, the variation in the risks between individual chains and between individual causes was high. The highest risks in Scots pine were caused by moose (in even-aged chains) and harvesting damage (in uneven-aged chains). In Norway spruce, root rot caused the highest risks in both even-aged and uneven-aged chains. The higher risks in even-aged forestry are largely due to the many associated practices which favour various types of damage. However, there are some important exceptions: the damage risks may be higher in some uneven-aged stands, especially in Norway spruce stands infected with root rot where the utilization of undergrowth or natural regeneration can be risky. Moreover, the repeated thinnings in uneven-aged stands may lead to increased mechanical damage.

  • Nevalainen, Natural Resources Institute Finland (Luke), Natural Resources and Bioproduction, Yliopistokatu 6, FI-80100 Joensuu, Finland ORCID ID:E-mail: seppo.nevalainen@luke.fi (email)
article id 1741, category Research article
Seppo Nevalainen. (2017). Comparison of damage risks in even- and uneven-aged forestry in Finland. Silva Fennica vol. 51 no. 3 article id 1741. https://doi.org/10.14214/sf.1741
Highlights: Damage risks in two forest management regimes were estimated by means of a literature review and a questionnaire to Finnish forestry experts; Damage risks were usually estimated to be higher in even-aged than in uneven-aged management regimes; In some cases, however, damage risks may be higher in uneven-aged stands (root-rot infected Norway spruce stands and mechanical damage due to repeated thinnings).

The literature on the most prominent forest damage related to even-aged and uneven-aged forest management regimes was reviewed. A questionnaire to expert researchers was conducted to estimate risks in even-aged and uneven-aged forest management chains in Finland. There are only a few empirical comparisons of damage risks in even- and uneven-aged stands in the literature. The results from the expert survey showed that the damage risks were higher in even-aged management in Norway spruce and Scots pine. However, the variation in the risks between individual chains and between individual causes was high. The highest risks in Scots pine were caused by moose (in even-aged chains) and harvesting damage (in uneven-aged chains). In Norway spruce, root rot caused the highest risks in both even-aged and uneven-aged chains. The higher risks in even-aged forestry are largely due to the many associated practices which favour various types of damage. However, there are some important exceptions: the damage risks may be higher in some uneven-aged stands, especially in Norway spruce stands infected with root rot where the utilization of undergrowth or natural regeneration can be risky. Moreover, the repeated thinnings in uneven-aged stands may lead to increased mechanical damage.

  • Nevalainen, Natural Resources Institute Finland (Luke), Natural Resources and Bioproduction, Yliopistokatu 6, FI-80100 Joensuu, Finland ORCID ID:E-mail: seppo.nevalainen@luke.fi (email)
article id 1741, category Research article
Seppo Nevalainen. (2017). Comparison of damage risks in even- and uneven-aged forestry in Finland. Silva Fennica vol. 51 no. 3 article id 1741. https://doi.org/10.14214/sf.1741
Highlights: Damage risks in two forest management regimes were estimated by means of a literature review and a questionnaire to Finnish forestry experts; Damage risks were usually estimated to be higher in even-aged than in uneven-aged management regimes; In some cases, however, damage risks may be higher in uneven-aged stands (root-rot infected Norway spruce stands and mechanical damage due to repeated thinnings).

The literature on the most prominent forest damage related to even-aged and uneven-aged forest management regimes was reviewed. A questionnaire to expert researchers was conducted to estimate risks in even-aged and uneven-aged forest management chains in Finland. There are only a few empirical comparisons of damage risks in even- and uneven-aged stands in the literature. The results from the expert survey showed that the damage risks were higher in even-aged management in Norway spruce and Scots pine. However, the variation in the risks between individual chains and between individual causes was high. The highest risks in Scots pine were caused by moose (in even-aged chains) and harvesting damage (in uneven-aged chains). In Norway spruce, root rot caused the highest risks in both even-aged and uneven-aged chains. The higher risks in even-aged forestry are largely due to the many associated practices which favour various types of damage. However, there are some important exceptions: the damage risks may be higher in some uneven-aged stands, especially in Norway spruce stands infected with root rot where the utilization of undergrowth or natural regeneration can be risky. Moreover, the repeated thinnings in uneven-aged stands may lead to increased mechanical damage.

  • Nevalainen, Natural Resources Institute Finland (Luke), Natural Resources and Bioproduction, Yliopistokatu 6, FI-80100 Joensuu, Finland ORCID ID:E-mail: seppo.nevalainen@luke.fi (email)
article id 2021, category Research article
Jonas Bohlin, Inka Bohlin, Jonas Jonzén, Mats Nilsson. (2017). Mapping forest attributes using data from stereophotogrammetry of aerial images and field data from the national forest inventory. Silva Fennica vol. 51 no. 2 article id 2021. https://doi.org/10.14214/sf.2021
Highlights: Image based forest attribute map generated using NFI plots show similar accuracy as currently used LiDAR based forest attribute map; Also similar accuracies were found for different forest types; Aerial images from leaf-off season is not recommended.

Exploring the possibility to produce nation-wide forest attribute maps using stereophotogrammetry of aerial images, the national terrain model and data from the National Forest Inventory (NFI). The study areas are four image acquisition blocks in mid- and south Sweden. Regression models were developed and applied to 12.5 m × 12.5 m raster cells for each block and validation was done with an independent dataset of forest stands. Model performance was compared for eight different forest types separately and the accuracies between forest types clearly differs for both image- and LiDAR methods, but between methods the difference in accuracy is small at plot level. At stand level, the root mean square error in percent of the mean (RMSE%) were ranging: from 7.7% to 10.5% for mean height; from 12.0% to 17.8% for mean diameter; from 21.8% to 22.8% for stem volume; and from 17.7% to 21.1% for basal area. This study clearly shows that aerial images from the national image program together with field sample plots from the NFI can be used for large area forest attribute mapping.

  • Bohlin, Department of Forest Resource Management, Swedish University of Agricultural Sciences, S-901 35 Umeå, Sweden ORCID ID: http://orcid.org/0000-0002-3318-5967 E-mail: jonas.bohlin@slu.se (email)
  • Bohlin, Department of Forest Resource Management, Swedish University of Agricultural Sciences, S-901 35 Umeå, Sweden ORCID ID: http://orcid.org/0000-0003-1224-6684 E-mail: inka.bohlin@slu.se
  • Jonzén, Department of Forest Resource Management, Swedish University of Agricultural Sciences, S-901 35 Umeå, Sweden ORCID ID:E-mail: jonas.jonzen@slu.se
  • Nilsson, Department of Forest Resource Management, Swedish University of Agricultural Sciences, S-901 35 Umeå, Sweden ORCID ID: http://orcid.org/0000-0001-7394-6305 E-mail: mats.nilsson@slu.se
article id 2021, category Research article
Jonas Bohlin, Inka Bohlin, Jonas Jonzén, Mats Nilsson. (2017). Mapping forest attributes using data from stereophotogrammetry of aerial images and field data from the national forest inventory. Silva Fennica vol. 51 no. 2 article id 2021. https://doi.org/10.14214/sf.2021
Highlights: Image based forest attribute map generated using NFI plots show similar accuracy as currently used LiDAR based forest attribute map; Also similar accuracies were found for different forest types; Aerial images from leaf-off season is not recommended.

Exploring the possibility to produce nation-wide forest attribute maps using stereophotogrammetry of aerial images, the national terrain model and data from the National Forest Inventory (NFI). The study areas are four image acquisition blocks in mid- and south Sweden. Regression models were developed and applied to 12.5 m × 12.5 m raster cells for each block and validation was done with an independent dataset of forest stands. Model performance was compared for eight different forest types separately and the accuracies between forest types clearly differs for both image- and LiDAR methods, but between methods the difference in accuracy is small at plot level. At stand level, the root mean square error in percent of the mean (RMSE%) were ranging: from 7.7% to 10.5% for mean height; from 12.0% to 17.8% for mean diameter; from 21.8% to 22.8% for stem volume; and from 17.7% to 21.1% for basal area. This study clearly shows that aerial images from the national image program together with field sample plots from the NFI can be used for large area forest attribute mapping.

  • Bohlin, Department of Forest Resource Management, Swedish University of Agricultural Sciences, S-901 35 Umeå, Sweden ORCID ID: http://orcid.org/0000-0002-3318-5967 E-mail: jonas.bohlin@slu.se (email)
  • Bohlin, Department of Forest Resource Management, Swedish University of Agricultural Sciences, S-901 35 Umeå, Sweden ORCID ID: http://orcid.org/0000-0003-1224-6684 E-mail: inka.bohlin@slu.se
  • Jonzén, Department of Forest Resource Management, Swedish University of Agricultural Sciences, S-901 35 Umeå, Sweden ORCID ID:E-mail: jonas.jonzen@slu.se
  • Nilsson, Department of Forest Resource Management, Swedish University of Agricultural Sciences, S-901 35 Umeå, Sweden ORCID ID: http://orcid.org/0000-0001-7394-6305 E-mail: mats.nilsson@slu.se
article id 1693, category Research article
Olalla Díaz-Yáñez, Blas Mola-Yudego, José Ramón González-Olabarria. (2017). What variables make a forest stand vulnerable to browsing damage occurrence? Silva Fennica vol. 51 no. 2 article id 1693. https://doi.org/10.14214/sf.1693
Highlights: Stands more vulnerable to browsing damage are young with lower densities and dominated by birch, pine or mixed species; Stand size could play a role on forest susceptibility to browsing occurrence.

Ungulate browsing results in important damages on the forests, affecting their structure, composition and development. In the present paper, we examine the occurrence of browsing damage in Norwegian forests, using data provided by the National Forest Inventory along several consecutive measurements (entailing the period 1995–2014). A portfolio of variables describing the stand, site and silvicultural treatments are analyzed using classification trees to retrieve combinations related to browsing damage. Our results indicate that the most vulnerable forest stands are young with densities below 1400 trees ha–1 and dominated by birch, pine or mixed species. In addition, stand diversity and previous treatments (e.g. thinnings) increase the damage occurrence and other variables, like stand size, could play a role on forest susceptibility to browsing occurrence although the latter is based on weaker evidence. The methods and results of our study can be applied to implement management measures aiming at reducing the browsing damages of forests.

  • Díaz-Yáñez, School of Forest Sciences, University of Eastern Finland, PO Box 111, 80101 Joensuu, Finland ORCID ID: http://orcid.org/0000-0003-3829-5759 E-mail: olalla.diaz@gmail.com (email)
  • Mola-Yudego, Norwegian Institute of Bioenergy Research, P.O. Box, 115, 1431 Ås, Norway; School of Forest Sciences, University of Eastern Finland, PO Box 111, 80101 Joensuu, Finland ORCID ID: http://orcid.org/0000-0003-0286-0170 E-mail: blas.mola@uef.fi
  • González-Olabarria, Forest Sciences Centre of Catalonia (CTFC-CEMFOR), Ctra. de St. Llorenç de Morunys, km 2, 25280 Solsona, Spain ORCID ID: http://orcid.org/0000-0002-5040-712X E-mail: jr.gonzalez@ctfc.es
article id 1657, category Research article
Razvan Vasile Campu, Arcadie Ciubotaru. (2017). Time consumption and productivity in manual tree felling with a chainsaw – a case study of resinous stands from mountainous areas. Silva Fennica vol. 51 no. 2 article id 1657. https://doi.org/10.14214/sf.1657
Highlights: An important preoccupation in sustainable logging management is represented by the analysis of work time structure and productivity level in manual tree felling with a chainsaw; Sound knowledge of the factors which influence work time allows better planning of harvesting operations so that deadlines could be met and damage to forest ecosystems be minimized.

The purpose of this research is to establish time consumption and productivity when using Husqvarna 365 chainsaw for resinous tree felling in mountainous regions. The research was conducted in the Romanian Southern Carpathians, in two mixed spruce (Picea abies (L.) H. Karst.) and fir (Abies alba Mill.) tree stands (S1 and S2). Only one team of workers, made up of a feller and an assistant, was used in the felling operation. This was divided into nine specific stages for which work times were measured. Work time structure used here includes WP – workplace time (PW – productive work time; SW – supportive work time, NT – non-work time) and NW – non-workplace time. The results indicated a productivity of 10.138 m3 h–1 (4.55 tree h–1) in S1 and of 11.374 m3 h–1 (4.33 tree h–1) in S2. Work time structure was WP 88.61% (PW 19.59%; SW 33.88%; NT 35.14%) and NW 11.39% in S1 and WP 83.77% (PW 17.66%; SW 30.73%; NT 35.38%) and NW 16.23% in S2. The results obtained showed that the power function best describes the relationship between productivity expressed by tree h–1 and breast height diameter (dbh) (R2 = 0.89 in S1 and R2 = 0.94 in S2). When productivity is expressed by m3 h–1 the results obtained in the case of power, exponential and linear functions are comparable (R2 = 0.65 to 0.67 in S1 and R2 = 0.81 to 0.92 in S2). Productivity is also influenced by stump diameter and the distance between trees. Their influence on productivity was emphasized by linear regression equations.

  • Campu, Transilvania University of Braşov, Faculty of Silviculture and Forest Engineering, Department of Forest Engineering, Forest Management Planning and Terrestrial Measurements, Şirul Beethoven no. 1, 500123, Braşov, Romania ORCID ID:E-mail: vasile.campu@unitbv.ro (email)
  • Ciubotaru, Transilvania University of Braşov, Faculty of Silviculture and Forest Engineering, Department of Forest Engineering, Forest Management Planning and Terrestrial Measurements, Şirul Beethoven no. 1, 500123, Braşov, Romania ORCID ID:E-mail: ciuboarc@unitbv.ro
article id 1618, category Research article
Miguel Genin, Mohamed Alifriqui, Abdessamad Fakhech, Mohamed Hafidi, Lahcen Ouahmane, Didier Genin. (2017). Back to forests in pre-Saharan Morocco? When prickly pear cultivation and traditional agropastoralism reduction promote argan tree regeneration. Silva Fennica vol. 51 no. 1B article id 1618. https://doi.org/10.14214/sf.1618
Highlights: There was a significant positive relationship between the age of implanted prickly pear orchards and natural argan tree regeneration; This relationship is mainly associated with interconnected changes in traditional land uses and the activation of facilitation factors such as an enhancement of the soil’s organic matter and nurse plant phenomena; This example constitutes a remarkable alternative model for thinking about agricultural development while combating desertification.

In the southwestern pre-Saharan arid zone of Morocco, the endemic argan forest (Argania spinosa) had been almost completely destroyed in the 1960s due to intensive coal mining and mixed cereal-livestock farming. These activities turned out to be unviable and a massive rural exodus occurred in the 1970s. Local populations started to develop maintenance-free prickly pear (Opuntia ficus-indica) cultivation at large scale in order to keep their land ownership rights, while reducing their traditional agropastoral activity. We conducted a survey in order to characterize the relationships between the age of prickly pear orchards and argan tree regeneration. We also explored facilitating factors, such as soil organic matter and mycorrhiza. Results showed a high positive correlation (r2 = 0.75, p < 0.001) between the age of prickly pear orchards and argan tree resprouts, but with differences depending on a continentality gradient. The soil organic matter content also showed highly significant differences (p < 0.001) depending on the age of the prickly pear plantation, while spora density did not show such differences. The recent high economic value attributed to prickly pear fruits, and to both argan and prickly pear seed oil, has given farmers the opportunity to develop a lucrative agricultural activity, while promoting the recovery of native vegetation. This situation constitutes a remarkable example of speculative agricultural development in a very harsh environment, in phase with ecological priorities for combating desertification. It could represent an alternative to the externally-generated projects sustained by high levels of public funding, with ecological, economic and social impacts which are sometimes questionable.

  • Genin, Institut de Recherche pour le Développement (IRD) & Aix-Marseille Université, Laboratoire Population, Environnement, Développement, UMR151 AMU-IRD, Marseille, France ORCID ID:E-mail: miguel.genin@gmail.com
  • Alifriqui, Cadi Ayyad University (UCAM), Laboratoire d’Ecologie et Environnement (CNRST, URAC 32), Faculté des Sciences Semlalia, Marrakech, Morocco ORCID ID:E-mail: alifriqui@gmail.com
  • Fakhech, Cadi Ayyad University (UCAM), Laboratoire d’Ecologie et Environnement (CNRST, URAC 32), Faculté des Sciences Semlalia, Marrakech, Morocco ORCID ID:E-mail: abdessamad.fakhech@edu.uca.ac.ma
  • Hafidi, Cadi Ayyad University (UCAM), Laboratoire d’Ecologie et Environnement (CNRST, URAC 32), Faculté des Sciences Semlalia, Marrakech, Morocco ORCID ID:E-mail: hafidi.ucam@gmail.com
  • Ouahmane, Cadi Ayyad University (UCAM), Laboratoire d’Ecologie et Environnement (CNRST, URAC 32), Faculté des Sciences Semlalia, Marrakech, Morocco ORCID ID:E-mail: l.ouahmane@gmail.com
  • Genin, Institut de Recherche pour le Développement (IRD) & Aix-Marseille Université, Laboratoire Population, Environnement, Développement, UMR151 AMU-IRD, Marseille, France ORCID ID:E-mail: didier.genin@univ-amu.fr (email)
article id 1778, category Research article
Adriano Mazziotta, Dmitry Podkopaev, María Triviño, Kaisa Miettinen, Tähti Pohjanmies, Mikko Mönkkönen. (2017). Quantifying and resolving conservation conflicts in forest landscapes via multiobjective optimization. Silva Fennica vol. 51 no. 1 article id 1778. https://doi.org/10.14214/sf.1778
Highlights: We introduce a compatibility index quantifying how targeting a management objective in the forest landscape affects another objective; To resolve conflicts we find compromise solutions minimizing the maximum deterioration among objectives; We apply our approach for a case study of forest management for biodiversity conservation and development; Multiple use management and careful planning can reduce biodiversity conflicts in forest ecosystems.

Environmental planning for of the maintenance of different conservation objectives should take into account multiple contrasting criteria based on alternative uses of the landscape. We develop new concepts and approaches to describe and measure conflicts among conservation objectives and for resolving them via multiobjective optimization. To measure conflicts we introduce a compatibility index that quantifies how much targeting a certain conservation objective affects the capacity of the landscape for providing another objective. To resolve such conflicts we find compromise solutions defined in terms of minimax regret, i.e. minimizing the maximum percentage of deterioration among conservation objectives. Finally, we apply our approach for a case study of management for biodiversity conservation and development in a forest landscape. We study conflicts between six different forest species, and we identify management solutions for simultaneously maintaining multiple species’ habitat while obtaining timber harvest revenues. We employ the method for resolving conflicts at a large landscape level across a long 50-years forest planning horizon. Our multiobjective approach can be an instrument for guiding hard choices in the conservation-development nexus with a perspective of developing decision support tools for land use planning. In our case study multiple use management and careful landscape level planning using our approach can reduce conflicts among biodiversity objectives and offer room for synergies in forest ecosystems.

  • Mazziotta, University of Jyväskylä, Department of Biological and Environmental Science, P.O. Box 35, FI-40014 University of Jyväskylä, Finland; Center for Macroecology Evolution and Climate, University of Copenhagen, Universitetsparken 15, DK-2100 Copenhagen, Denmark; Stockholm Resilience Centre, Stockholm University, Kräftriket 2b, 11429 Stockholm, Sweden ORCID ID: http://orcid.org/0000-0003-2088-3798 E-mail: a_mazziotta@hotmail.com (email)
  • Podkopaev, University of Jyväskylä, Department of Biological and Environmental Science, P.O. Box 35, FI-40014 University of Jyväskylä, Finland; Systems Research Institute, Polish Academy of Sciences, Newelska 6, 01-447 Warsaw, Poland ORCID ID:E-mail: dmitry.podkopaev@ibspan.waw.pl
  • Triviño, University of Jyväskylä, Department of Biological and Environmental Science, P.O. Box 35, FI-40014 University of Jyväskylä, Finland ORCID ID:E-mail: maria.trivino@jyu.fi
  • Miettinen, University of Jyväskylä, Faculty of Information Technology, P.O. Box 35, FI-40014 University of Jyväskylä, Finland ORCID ID:E-mail: kaisa.miettinen@jyu.fi
  • Pohjanmies, University of Jyväskylä, Department of Biological and Environmental Science, P.O. Box 35, FI-40014 University of Jyväskylä, Finland ORCID ID:E-mail: tahti.t.pohjanmies@jyu.fi
  • Mönkkönen, University of Jyväskylä, Department of Biological and Environmental Science, P.O. Box 35, FI-40014 University of Jyväskylä, Finland ORCID ID:E-mail: mikko.monkkonen@jyu.fi
article id 1718, category Research article
Mihails Čugunovs, Eeva-Stiina Tuittila, Lauri Mehtätalo, Laura Pekkola, Ida Sara-Aho, Jari Kouki. (2017). Variability and patterns in forest soil and vegetation characteristics after prescribed burning in clear-cuts and restoration burnings. Silva Fennica vol. 51 no. 1 article id 1718. https://doi.org/10.14214/sf.1718
Highlights: Soil parameter variability is similar across sites of different disturbance type; Variability of understory vegetation biomass and cover is higher and more different between sites than soil variability; Sites studied here reflect well the assumed disturbance-type gradient based on PCA; Sampling six forest sites per treatment should provide good statistical power to capture the differences in soil organic matter stocks.

Forest ecological restoration by burning is widely applied to promote natural, early-successional sites and increase landscape biodiversity. Burning is also used as a forest management practice to facilitate forest regeneration after clearcutting. Besides the desired goals, restoration burnings also affect soil biogeochemistry, particularly soil organic matter (SOM) and related soil carbon stocks but the long-term effects are poorly understood. However, in order to study these effects, a reliable estimate of spatial variability is first needed for effective sampling. Here we investigate spatial variability of SOM and vegetation features 13 years after burnings and in combination with variable harvest levels. We sampled four experimental sites representing distinct management and restoration treatments with an undisturbed control. While variability of vegetation cover and biomass was generally higher in disturbed sites, soil parameter variability was not different between the four sites. The joint ecological patterns of soil and vegetation parameters across the whole sample continuum support well the prior assumptions on the characteristic disturbance conditions within each of the study sites. We designed and employed statistical simulations as a means to plan prospective sampling. Sampling six forest sites for each treatment type with 30 independent soil cores per site would provide enough statistical power to adequately capture the impacts of burning on SOM based on the data we obtained here and statistical simulations. In conclusion, we argue that an informed design-based approach to documenting the ecosystem effects of forest burnings is worth applying both through obtaining new data and meta-analysing the existing.

  • Čugunovs, University of Eastern Finland, School of Forest Sciences, Yliopistokatu 7, P.O. Box 111, FI-80101 Joensuu, Finland ORCID ID:E-mail: mihails.cugunovs@uef.fi (email)
  • Tuittila, University of Eastern Finland, School of Forest Sciences, Yliopistokatu 7, P.O. Box 111, FI-80101 Joensuu, Finland ORCID ID: http://orcid.org/0000-0001-8861-3167 E-mail: eeva-stiina.tuittila@uef.fi
  • Mehtätalo, University of Eastern Finland, School of Computing, Science Park, Länsikatu 15, P.O. Box 111, 80101 Joensuu, Finland ORCID ID: http://orcid.org/0000-0002-8128-0598 E-mail: lauri.mehtatalo@uef.fi
  • Pekkola, University of Eastern Finland, School of Forest Sciences, Yliopistokatu 7, P.O. Box 111, FI-80101 Joensuu, Finland ORCID ID:E-mail: laura.pekkola@gmail.com
  • Sara-Aho, University of Eastern Finland, School of Forest Sciences, Yliopistokatu 7, P.O. Box 111, FI-80101 Joensuu, Finland ORCID ID:E-mail: ida.sara-aho@mhy.fi
  • Kouki, University of Eastern Finland, School of Forest Sciences, Yliopistokatu 7, P.O. Box 111, FI-80101 Joensuu, Finland ORCID ID: http://orcid.org/0000-0003-2624-8592 E-mail: jari.kouki@uef.fi
article id 1709, category Research article
Guoping Chen, Cong Shi, Shanshan Cheng, Tiejian Zhao, Guoquan Liu, Fuchen Shi. (2017). The structure and soil characteristics of a Pinus tabuliformis planted forest after 60 years of natural development in North China. Silva Fennica vol. 51 no. 1 article id 1709. https://doi.org/10.14214/sf.1709
Highlights: Increasing proportions of broadleaf tree species was shown to affect nutrient content of the forest floor and soil, and the soil microbial community in the process of natural development of Pinus tabuliformis planted forest. In this regard, this study can act as a reference for management of the near-natural transformation of P. tabuliformis planted forests and for the choice of the tree species used.

This study evaluated the transformation of a Pinus tabuliformis Carrière forest into a near-natural forest after 60 years of natural development. The structure and soil characteristics of P. tabuliformis planted forest, the near-natural forest (coniferous-broadleaved P. tabuliformis mixed forest), and secondary forest (Quercus mongolica Fisch. ex Ledeb. forest) were compared. Tree, shrub and herb species diversity of the mixed and Q. mongolica forests was higher than that of the planted P. tabuliformis forest. Examination of soil characteristics revealed that compared to the pure pine forest, nitrogen (N) and phosphorus (P) concentrations of the mixed and Q. mongolica forests increased in the forest floor and soil, but total carbon (C) concentration decreased in the forest floor, countered by increases in the soil. Furthermore, soil cation exchange capacity (CEC) and pH in the P. tabuliformis forest increased when deciduous broadleaved species were present. Total microbial biomass and bacterial biomass in the soils were greatest in the Q. mongolica forest, followed by the mixed, and then the P. tabuliformis forests. However, fungal biomass did not significantly differ among the three forests. Overall, the findings of this study suggest that different forest types can affect soil microbial biomass and community structure. Meanwhile, the natural development is recommended as a potential management alternative to near-natural transformation of a P. tabuliformis planted forest.

  • Chen, Department of Plant Biology & Ecology, College of Life Sciences, Nankai University, Weijin Road 94, Tianjin 300071, P.R. China ORCID ID:E-mail: guopingchern@mail.nankai.edu.cn
  • Shi, Graduate School of Agriculture, Hokkaido University, Sapporo, Hokkaido 060-8689, Japan ORCID ID:E-mail: cshi1@for.agr.hokudai.ac.jp
  • Cheng, School of Environment and Energy, Shenzhen Graduate School of Peking University, Shenzhen 518055, China ORCID ID:E-mail: 1401213932@sz.pku.edu.cn
  • Zhao, Baxian Mountain National Nature Reserve, Tianjin 301900, China Received 29 September 2016 Revised ORCID ID:E-mail: zhaotiejiann456@sina.com
  • Liu, Baxian Mountain National Nature Reserve, Tianjin 301900, China Received 29 September 2016 Revised ORCID ID:E-mail: liuguoquan01@163.com
  • Shi, Department of Plant Biology & Ecology, College of Life Sciences, Nankai University, Weijin Road 94, Tianjin 300071, P.R. China ORCID ID:E-mail: fcshi@nankai.edu.cn (email)
article id 1684, category Research article
Anna Kowalska, Jan Marek Matuszkiewicz, Jerzy Solon, Anna Kozłowska. (2017). Indicators of ancient forests in nutrient-deficient pine habitats. Silva Fennica vol. 51 no. 1 article id 1684. https://doi.org/10.14214/sf.1684
Highlights: Distinct groups of species with a preference for ancient pine and mixed oak-pine forests can be determined; The ancient forest indicator composition in pine habitats differs remarkably from ancient forest indicators in deciduous forests; Dispersal-related traits significantly distinguish ancient forest indicators from other species found in nutrient-poor forest habitats.

Pine forests are common in many European regions. Nonetheless, there are only a few studies on regeneration of plant species populations in nutrient-deficient pine habitats. Ancient temperate forests are perceived to be particularly important objects of environmental conservation, due to their ability to sustain a considerable number of rare and vulnerable species. In this paper, we present indicator species of ancient pine and mixed oak-pine forests, together with their trait profiles. Phytosociological relevés were collected from mature stands in the Masuria and Kurpie regions of central Poland. Forest persistence was determined on the basis of historical maps, with the data set divided into three categories. The indicator value of species was evaluated using Tichý and Chytrý’s phi coefficient. Functional response traits of indicator species were identified. Distinct groups of species with a preference for ancient forests can be determined. The dispersal-related traits significantly distinguish ancient forest indicators from other species found in nutrient-poor forest habitats. Since the low potential for long-distance dispersal hinders the establishment of new plant populations in isolated stands, we stress the need to avoid ancient forest clearance and fragmentation of woodland; afforestation should be located in the vicinity of ancient stands. Moreover, as recent forests have turned out to support several rare plant species, to maintain phytodiversity on a landscape level a mixture of ancient and recent forests, both managed and strictly protected, is needed.

  • Kowalska, Institute of Geography and Spatial Organization, Polish Academy of Science, Twarda 51/55, 00-818 Warsaw, Poland ORCID ID:E-mail: aniak@twarda.pan.pl (email)
  • Matuszkiewicz, Institute of Geography and Spatial Organization, Polish Academy of Science, Twarda 51/55, 00-818 Warsaw, Poland ORCID ID:E-mail: jan.mat@twarda.pan.pl
  • Solon, Institute of Geography and Spatial Organization, Polish Academy of Science, Twarda 51/55, 00-818 Warsaw, Poland ORCID ID:E-mail: j.solon@twarda.pan.pl
  • Kozłowska, Institute of Geography and Spatial Organization, Polish Academy of Science, Twarda 51/55, 00-818 Warsaw, Poland ORCID ID:E-mail: a.kozl@twarda.pan.pl
article id 1684, category Research article
Anna Kowalska, Jan Marek Matuszkiewicz, Jerzy Solon, Anna Kozłowska. (2017). Indicators of ancient forests in nutrient-deficient pine habitats. Silva Fennica vol. 51 no. 1 article id 1684. https://doi.org/10.14214/sf.1684
Highlights: Distinct groups of species with a preference for ancient pine and mixed oak-pine forests can be determined; The ancient forest indicator composition in pine habitats differs remarkably from ancient forest indicators in deciduous forests; Dispersal-related traits significantly distinguish ancient forest indicators from other species found in nutrient-poor forest habitats.

Pine forests are common in many European regions. Nonetheless, there are only a few studies on regeneration of plant species populations in nutrient-deficient pine habitats. Ancient temperate forests are perceived to be particularly important objects of environmental conservation, due to their ability to sustain a considerable number of rare and vulnerable species. In this paper, we present indicator species of ancient pine and mixed oak-pine forests, together with their trait profiles. Phytosociological relevés were collected from mature stands in the Masuria and Kurpie regions of central Poland. Forest persistence was determined on the basis of historical maps, with the data set divided into three categories. The indicator value of species was evaluated using Tichý and Chytrý’s phi coefficient. Functional response traits of indicator species were identified. Distinct groups of species with a preference for ancient forests can be determined. The dispersal-related traits significantly distinguish ancient forest indicators from other species found in nutrient-poor forest habitats. Since the low potential for long-distance dispersal hinders the establishment of new plant populations in isolated stands, we stress the need to avoid ancient forest clearance and fragmentation of woodland; afforestation should be located in the vicinity of ancient stands. Moreover, as recent forests have turned out to support several rare plant species, to maintain phytodiversity on a landscape level a mixture of ancient and recent forests, both managed and strictly protected, is needed.

  • Kowalska, Institute of Geography and Spatial Organization, Polish Academy of Science, Twarda 51/55, 00-818 Warsaw, Poland ORCID ID:E-mail: aniak@twarda.pan.pl (email)
  • Matuszkiewicz, Institute of Geography and Spatial Organization, Polish Academy of Science, Twarda 51/55, 00-818 Warsaw, Poland ORCID ID:E-mail: jan.mat@twarda.pan.pl
  • Solon, Institute of Geography and Spatial Organization, Polish Academy of Science, Twarda 51/55, 00-818 Warsaw, Poland ORCID ID:E-mail: j.solon@twarda.pan.pl
  • Kozłowska, Institute of Geography and Spatial Organization, Polish Academy of Science, Twarda 51/55, 00-818 Warsaw, Poland ORCID ID:E-mail: a.kozl@twarda.pan.pl
article id 1684, category Research article
Anna Kowalska, Jan Marek Matuszkiewicz, Jerzy Solon, Anna Kozłowska. (2017). Indicators of ancient forests in nutrient-deficient pine habitats. Silva Fennica vol. 51 no. 1 article id 1684. https://doi.org/10.14214/sf.1684
Highlights: Distinct groups of species with a preference for ancient pine and mixed oak-pine forests can be determined; The ancient forest indicator composition in pine habitats differs remarkably from ancient forest indicators in deciduous forests; Dispersal-related traits significantly distinguish ancient forest indicators from other species found in nutrient-poor forest habitats.

Pine forests are common in many European regions. Nonetheless, there are only a few studies on regeneration of plant species populations in nutrient-deficient pine habitats. Ancient temperate forests are perceived to be particularly important objects of environmental conservation, due to their ability to sustain a considerable number of rare and vulnerable species. In this paper, we present indicator species of ancient pine and mixed oak-pine forests, together with their trait profiles. Phytosociological relevés were collected from mature stands in the Masuria and Kurpie regions of central Poland. Forest persistence was determined on the basis of historical maps, with the data set divided into three categories. The indicator value of species was evaluated using Tichý and Chytrý’s phi coefficient. Functional response traits of indicator species were identified. Distinct groups of species with a preference for ancient forests can be determined. The dispersal-related traits significantly distinguish ancient forest indicators from other species found in nutrient-poor forest habitats. Since the low potential for long-distance dispersal hinders the establishment of new plant populations in isolated stands, we stress the need to avoid ancient forest clearance and fragmentation of woodland; afforestation should be located in the vicinity of ancient stands. Moreover, as recent forests have turned out to support several rare plant species, to maintain phytodiversity on a landscape level a mixture of ancient and recent forests, both managed and strictly protected, is needed.

  • Kowalska, Institute of Geography and Spatial Organization, Polish Academy of Science, Twarda 51/55, 00-818 Warsaw, Poland ORCID ID:E-mail: aniak@twarda.pan.pl (email)
  • Matuszkiewicz, Institute of Geography and Spatial Organization, Polish Academy of Science, Twarda 51/55, 00-818 Warsaw, Poland ORCID ID:E-mail: jan.mat@twarda.pan.pl
  • Solon, Institute of Geography and Spatial Organization, Polish Academy of Science, Twarda 51/55, 00-818 Warsaw, Poland ORCID ID:E-mail: j.solon@twarda.pan.pl
  • Kozłowska, Institute of Geography and Spatial Organization, Polish Academy of Science, Twarda 51/55, 00-818 Warsaw, Poland ORCID ID:E-mail: a.kozl@twarda.pan.pl
article id 1672, category Research article
Maiju Peura, María Triviño, Adriano Mazziotta, Dmitry Podkopaev, Artti Juutinen, Mikko Mönkkönen. (2016). Managing boreal forests for the simultaneous production of collectable goods and timber revenues. Silva Fennica vol. 50 no. 5 article id 1672. https://doi.org/10.14214/sf.1672
Highlights: We found a strong conflict between bilberry production and timber revenues, resulting in large losses of timber revenues when increasing bilberry production; The conflicts between other collectables (cowberry, cep) and timber production were relatively small; With careful forest planning, there is potential to simultaneously produce high levels of collectable goods and timber revenues in the landscape.

Timber production is an economically important provisioning ecosystem service in forests, but is often in conflict with the provision of other ecosystem services. In multifunctional forestry, the production of timber and non-timber ecosystem services should coexist in the same landscape. To this end, we explored the capacity of a boreal landscape to simultaneously produce collectable goods bilberry (Vaccimium myrtillus L.), cowberry (Vaccinium vitis-idaea L.) and cep (Boletus edulis Bull.) alongside timber revenues. We also identified optimal forest management plans to achieve this. Furthermore, we analyzed trade-offs between collectable good yields and timber production, as well as between their economic values. We ran forest growth simulations under seven alternative management regimes at a landscape level across 50-year planning horizons. Then, we used multi-objective optimization to explore trade-offs and identify optimal forest management plans. The results showed that the strongest trade-off was between bilberry and timber production, resulting in a large loss in timber revenues for a gain in bilberry production. However, the conflicts between other collectables and timber production were relatively small: it was possible to increase the provision of collectable goods 4–15% with small reductions (35%) from timber revenues. With careful forest planning, there is the potential to simultaneously produce high levels of collectable goods and timber revenues in the landscape.

  • Peura, University of Jyvaskyla, Department of Biological and Environmental Sciences, P.O. Box 35, FI-40014, University of Jyväskylä, Finland ORCID ID:E-mail: maiju.h.peura@jyu.fi (email)
  • Triviño, University of Jyvaskyla, Department of Biological and Environmental Sciences, P.O. Box 35, FI-40014, University of Jyväskylä, Finland ORCID ID:E-mail: maria.trivino@jyu.fi
  • Mazziotta, University of Jyvaskyla, Department of Biological and Environmental Sciences, P.O. Box 35, FI-40014, University of Jyväskylä, Finland; Center for Macroecology, Evolution and Climate, Natural History Museum of Denmark, University of Copenhagen, Universitetsparken 15, DK-2100 Copenhagen, Denmark ORCID ID:E-mail: adriano.mazziotta@snm.ku.dk
  • Podkopaev, University of Jyvaskyla, Department of Biological and Environmental Sciences, P.O. Box 35, FI-40014, University of Jyväskylä, Finland; Systems Research Institute, Polish Academy of Sciences, Newelska 6, 01-447 Warsaw, Poland ORCID ID:E-mail: dmitry.podkopaev@gmail.com
  • Juutinen, Natural Resources Institute Finland (Luke), Economics and Society, P.O. Box 413, FI-90014 University of Oulu, Finland; University of Oulu, Department of Economics, P.O. Box 4600, FI-90014 University of Oulu, Finland ORCID ID:E-mail: artti.juutinen@luke.fi
  • Mönkkönen, University of Jyvaskyla, Department of Biological and Environmental Sciences, P.O. Box 35, FI-40014, University of Jyväskylä, Finland ORCID ID:E-mail: mikko.monkkonen@jyu.fi
article id 1672, category Research article
Maiju Peura, María Triviño, Adriano Mazziotta, Dmitry Podkopaev, Artti Juutinen, Mikko Mönkkönen. (2016). Managing boreal forests for the simultaneous production of collectable goods and timber revenues. Silva Fennica vol. 50 no. 5 article id 1672. https://doi.org/10.14214/sf.1672
Highlights: We found a strong conflict between bilberry production and timber revenues, resulting in large losses of timber revenues when increasing bilberry production; The conflicts between other collectables (cowberry, cep) and timber production were relatively small; With careful forest planning, there is potential to simultaneously produce high levels of collectable goods and timber revenues in the landscape.

Timber production is an economically important provisioning ecosystem service in forests, but is often in conflict with the provision of other ecosystem services. In multifunctional forestry, the production of timber and non-timber ecosystem services should coexist in the same landscape. To this end, we explored the capacity of a boreal landscape to simultaneously produce collectable goods bilberry (Vaccimium myrtillus L.), cowberry (Vaccinium vitis-idaea L.) and cep (Boletus edulis Bull.) alongside timber revenues. We also identified optimal forest management plans to achieve this. Furthermore, we analyzed trade-offs between collectable good yields and timber production, as well as between their economic values. We ran forest growth simulations under seven alternative management regimes at a landscape level across 50-year planning horizons. Then, we used multi-objective optimization to explore trade-offs and identify optimal forest management plans. The results showed that the strongest trade-off was between bilberry and timber production, resulting in a large loss in timber revenues for a gain in bilberry production. However, the conflicts between other collectables and timber production were relatively small: it was possible to increase the provision of collectable goods 4–15% with small reductions (35%) from timber revenues. With careful forest planning, there is the potential to simultaneously produce high levels of collectable goods and timber revenues in the landscape.

  • Peura, University of Jyvaskyla, Department of Biological and Environmental Sciences, P.O. Box 35, FI-40014, University of Jyväskylä, Finland ORCID ID:E-mail: maiju.h.peura@jyu.fi (email)
  • Triviño, University of Jyvaskyla, Department of Biological and Environmental Sciences, P.O. Box 35, FI-40014, University of Jyväskylä, Finland ORCID ID:E-mail: maria.trivino@jyu.fi
  • Mazziotta, University of Jyvaskyla, Department of Biological and Environmental Sciences, P.O. Box 35, FI-40014, University of Jyväskylä, Finland; Center for Macroecology, Evolution and Climate, Natural History Museum of Denmark, University of Copenhagen, Universitetsparken 15, DK-2100 Copenhagen, Denmark ORCID ID:E-mail: adriano.mazziotta@snm.ku.dk
  • Podkopaev, University of Jyvaskyla, Department of Biological and Environmental Sciences, P.O. Box 35, FI-40014, University of Jyväskylä, Finland; Systems Research Institute, Polish Academy of Sciences, Newelska 6, 01-447 Warsaw, Poland ORCID ID:E-mail: dmitry.podkopaev@gmail.com
  • Juutinen, Natural Resources Institute Finland (Luke), Economics and Society, P.O. Box 413, FI-90014 University of Oulu, Finland; University of Oulu, Department of Economics, P.O. Box 4600, FI-90014 University of Oulu, Finland ORCID ID:E-mail: artti.juutinen@luke.fi
  • Mönkkönen, University of Jyvaskyla, Department of Biological and Environmental Sciences, P.O. Box 35, FI-40014, University of Jyväskylä, Finland ORCID ID:E-mail: mikko.monkkonen@jyu.fi
article id 1615, category Research article
Minna Blomqvist, Päivi Lyytikäinen-Saarenmaa, Tuula Kantola, Maiju Kosunen, Mervi Talvitie, Markus Holopainen. (2016). Impacts of natural enemies and stand characteristics on cocoon mortality of the pine sawfly Diprion pini in a Fennoscandian boreal forest. Silva Fennica vol. 50 no. 5 article id 1615. https://doi.org/10.14214/sf.1615
Highlights: Annual cocoon mortality caused by natural enemies varied between 66% and 80% during the six-year study period, most of it caused by the family Ichneumonidae; Basal area, and coverage of lichen (Lichenes) and lingonberry (Vaccinium vitis-idaea L.) best explained cocoon parasitism and predation; Combination of suitable stand characteristics, abiotic environmental factors, and incomplete control by natural enemies enabled pest species to extend its gradation phase.

We investigated the impact of natural enemies on the cocoon mortality of the common pine sawfly (Diprion pini L.) during a six-year period in eastern Finland. The enemies were classified into parasitoids (insect families Chalcidoidea, Ichneumonidae, and Tachinidae), and predators (birds, small mammals, and insect families Elateridae and Carabidae). The appearance of D. pini was estimated as the intensity of annual defoliation. The impact of stand characteristics on the performance of parasitoids and predators was also investigated. Influence of the natural enemy complex on cocoon mortality of D. pini was nearly stable, but defoliation intensity slowly declined towards the end of the study period. Annual cocoon mortality by natural enemies varied between 66% and 80%. Our results verified that the most significant mortality factors were ichneumonid parasitoids and small mammals. Random Forest classification indicated that stand characteristics, such as basal area, and coverage of lichen (Lichenes) and lingonberry (Vaccinium vitis-idaea L.) affected the performance of parasites and predators. We suggest that a combination of optimal stand characteristics, abiotic environmental factors and mild to moderate control by natural enemies acted as drivers, which drove the pine sawfly population to extended gradation. For future forest health management, detailed information on abiotic and biotic regulating factors, along with long-term monitoring campaigns for conifer sawflies are needed to adapt Fennoscandian forests to altered climatic and silvicultural conditions.

  • Blomqvist, University of Helsinki, Department of Forest Sciences, P.O. Box 27 (Latokartanonkaari 7), FI-00014 University of Helsinki, Finland ORCID ID: http://orcid.org/0000-0003-2328-8839 E-mail: minna.blomqvist@helsinki.fi (email)
  • Lyytikäinen-Saarenmaa, University of Helsinki, Department of Forest Sciences, P.O. Box 27 (Latokartanonkaari 7), FI-00014 University of Helsinki, Finland ORCID ID:E-mail: paivi.lyytikainen-saarenmaa@helsinki.fi
  • Kantola, Knowledge Engineering Laboratory, Department of Entomology, Texas A&M University, College Station, TX 77843-2475, USA ORCID ID:E-mail: tuula.kantola@helsinki.fi
  • Kosunen, University of Helsinki, Department of Forest Sciences, P.O. Box 27 (Latokartanonkaari 7), FI-00014 University of Helsinki, Finland ORCID ID:E-mail: maiju.kosunen@helsinki.fi
  • Talvitie, University of Helsinki, Department of Forest Sciences, P.O. Box 27 (Latokartanonkaari 7), FI-00014 University of Helsinki, Finland ORCID ID:E-mail: mervi.talvitie@dnainternet.net
  • Holopainen, University of Helsinki, Department of Forest Sciences, P.O. Box 27 (Latokartanonkaari 7), FI-00014 University of Helsinki, Finland ORCID ID:E-mail: markus.holopainen@helsinki.fi
article id 1628, category Research article
Jürgen Aosaar, Ülo Mander, Mats Varik, Hardo Becker, Gunnar Morozov, Martin Maddison, Veiko Uri. (2016). Biomass production and nitrogen balance of naturally afforested silver birch (Betula pendula Roth.) stand in Estonia. Silva Fennica vol. 50 no. 4 article id 1628. https://doi.org/10.14214/sf.1628
Highlights: Leafless aboveground biomass of the 17-year-old natural silver birch stand growing in abandoned agricultural land reached 94 Mg ha–1; The largest fluxes in N budget were net nitrogen mineralization and gaseous N2-N emission; Nitrogen leaching was low; Soil N content increased with the stand age, soil C content remained stable; N2O and N2 fluxes in boreal deciduous forest were analysed.

Silver birch (Betula pendula Roth.) is one of the main pioneer tree species occupying large areas of abandoned agricultural lands under natural succession in Estonia. We estimated aboveground biomass (AGB) dynamics during 17 growing seasons, and analysed soil nitrogen (N) and carbon (C) dynamics for 10 year period in a silver birch stand growing on former arable land. Main N fluxes were estimated and nitrogen budget for 10-year-old stand was compiled. The leafless AGB and stem mass of the stand at the age of 17-years were 94 and 76 Mg ha–1 respectively. The current annual increment (CAI) of stemwood fluctuated, peaking at 10 Mg ha–1 yr–1 at the age of 15 years; the mean annual increment (MAI) fluctuated at around 4–5 Mg ha–1. The annual leaf mass of the stand stabilised at around 3 Mg ha–1 yr–1. The stand density decreased from 11600 to 2700 trees ha–1 in the 8- and 17-year-old stand, respectively. The largest fluxes in N budget were net nitrogen mineralization and gaseous N2-N emission. The estimated fluxes of N2O and N2 were 0.12 and 83 kg ha–1 yr–1, respectively; N leaching was negligible. Nitrogen retranslocation from senescing leaves was approximately 45 kg ha–1, N was mainly retranslocated into stembark. The N content in the upper 0–10 cm soil layer increased significantly (145 kg ha–1) from 2004 to 2014; soil C content remained stable. Both the woody biomass dynamics and the N cycling of the stand witness the potential for bioenergetics of such ecosystems.

  • Aosaar, Estonian University of Life Sciences, Institute of Forestry and Rural Engineering, Kreutzwaldi 1, 51014 Tartu, Estonia ORCID ID:E-mail: jyrgen.aosaar@emu.ee (email)
  • Mander, University of Tartu, Institute of Ecology and Earth Sciences, Ülikooli 18, 50090 Tartu, Estonia ORCID ID:E-mail: ulo.mander@ut.ee
  • Varik, Estonian University of Life Sciences, Institute of Forestry and Rural Engineering, Kreutzwaldi 1, 51014 Tartu, Estonia ORCID ID:E-mail: mats.varik@emu.ee
  • Becker, Estonian University of Life Sciences, Institute of Forestry and Rural Engineering, Kreutzwaldi 1, 51014 Tartu, Estonia ORCID ID:E-mail: hardo.becker@emu.ee
  • Morozov, Estonian University of Life Sciences, Institute of Forestry and Rural Engineering, Kreutzwaldi 1, 51014 Tartu, Estonia ORCID ID:E-mail: gunnar.morozov@emu.ee
  • Maddison, University of Tartu, Institute of Ecology and Earth Sciences, Ülikooli 18, 50090 Tartu, Estonia ORCID ID:E-mail: martin.maddison@ut.ee
  • Uri, Estonian University of Life Sciences, Institute of Forestry and Rural Engineering, Kreutzwaldi 1, 51014 Tartu, Estonia ORCID ID:E-mail: veiko.uri@emu.ee
article id 1567, category Research article
Eetu Kotivuori, Lauri Korhonen, Petteri Packalen. (2016). Nationwide airborne laser scanning based models for volume, biomass and dominant height in Finland. Silva Fennica vol. 50 no. 4 article id 1567. https://doi.org/10.14214/sf.1567
Highlights: Pooled data from nine inventory projects in Finland were used to create nationwide laser-based regression models for dominant height, volume and biomass; Volume and biomass models provided regionally different means than real means, but for dominant height the mean difference was small; The accuracy of general volume predictions was nevertheless comparable to relascope-based field inventory by compartments.

The aim of this study was to examine how well stem volume, above-ground biomass and dominant height can be predicted using nationwide airborne laser scanning (ALS) based regression models. The study material consisted of nine practical ALS inventory projects taken from different parts of Finland. We used field sample plots and airborne laser scanning data to create nationwide and regional models for each response variable. The final models had one or two ALS predictors, which were chosen based on the root mean square error (RMSE), and cross-validated. Finally, we tested how much predictions would improve if the nationwide models were calibrated with a small number of regional sample plots. Although forest structures differ among different parts of Finland, the nationwide volume and biomass models performed quite well (leave-inventory-area-out RMSE 22.3% to 33.8%, mean difference [MD] –13.8% to 18.7%) compared with regional models (leave-plot-out RMSE 20.2% to 26.8%). However, the nationwide dominant height model (RMSE 5.4% to 7.7%, MD –2.0% to 2.8%, with the exception of the Tornio region – RMSE 11.4%, MD –9.1%) performed nearly as well as the regional models (RMSE 5.2% to 6.7%). The results show that the nationwide volume and biomass models provided different means than real means at regional level, because forest structure and ALS device have a considerable effect on the predictions. Large MDs appeared especially in northern Finland. Local calibration decreased the MD and RMSE of volume and biomass models. However, the nationwide dominant height model did not benefit much from calibration.

  • Kotivuori, University of Eastern Finland, School of Forest Sciences, P.O. Box 111, FI-80101 Joensuu, Finland ORCID ID:E-mail: eetu.kotivuori@uef.fi (email)
  • Korhonen, University of Eastern Finland, School of Forest Sciences, P.O. Box 111, FI-80101 Joensuu, Finland ORCID ID:E-mail: lauri.korhonen@uef.fi
  • Packalen, University of Eastern Finland, School of Forest Sciences, P.O. Box 111, FI-80101 Joensuu, Finland ORCID ID:E-mail: petteri.packalen@uef.fi
article id 1568, category Research article
Jouni Siipilehto, Harri Lindeman, Mikko Vastaranta, Xiaowei Yu, Jori Uusitalo. (2016). Reliability of the predicted stand structure for clear-cut stands using optional methods: airborne laser scanning-based methods, smartphone-based forest inventory application Trestima and pre-harvest measurement tool EMO. Silva Fennica vol. 50 no. 3 article id 1568. https://doi.org/10.14214/sf.1568
Highlights: An airborne laser scanning grid-based approach for determining stand structure enabled bi- or multimodal predicted distributions that fitted well to the ground-truth harvester data; EMO and Trestima applications needed stand-specific inventory for sample measurements or sample photos, respectively, and at their best, provided superior accuracy for predicting certain stand characteristics.

Accurate timber assortment information is required before cuttings to optimize wood allocation and logging activities. Timber assortments can be derived from diameter-height distribution that is most often predicted from the stand characteristics provided by forest inventory. The aim of this study was to assess and compare the accuracy of three different pre-harvest inventory methods in predicting the structure of mainly Scots pine-dominated, clear-cut stands. The investigated methods were an area-based approach (ABA) based on airborne laser scanning data, the smartphone-based forest inventory Trestima app and the more conventional pre-harvest inventory method called EMO. The estimates of diameter-height distributions based on each method were compared to accurate tree taper data measured and registered by the harvester’s measurement systems during the final cut. According to our results, grid-level ABA and Trestima were generally the most accurate methods for predicting diameter-height distribution. ABA provides predictions for systematic 16 m × 16 m grids from which stand-wise characteristics are aggregated. In order to enable multimodal stand-wise distributions, distributions must be predicted for each grid cell and then aggregated for the stand level, instead of predicting a distribution from the aggregated stand-level characteristics. Trestima required a sufficient sample for reliable results. EMO provided accurate results for the dominating Scots pine but, it could not capture minor admixtures. ABA seemed rather trustworthy in predicting stand characteristics and diameter distribution of standing trees prior to harvesting. Therefore, if up-to-date ABA information is available, only limited benefits can be obtained from stand-specific inventory using Trestima or EMO in mature pine or spruce-dominated forests.

  • Siipilehto, Natural Research Institute Finland (Luke), Management and Production of Renewable Resources, P.O. Box 18, FI-01301 Vantaa, Finland ORCID ID:E-mail: jouni.siipilehto@luke.fi (email)
  • Lindeman,  Natural Research Institute Finland, Green Technology, Kaironiementie 15, 39700 Parkano ORCID ID:E-mail: harri.lindeman@luke.fi
  • Vastaranta, University of Helsinki, Department of Forest Sciences, P.O. Box 62 (Viikinkaari 11), FI-00014 University of Helsinki ORCID ID:E-mail: mikko.vastaranta@helsinki.fi
  • Yu, Finnish Geospatial Research Institute (FGI), Department of Remote Sensing and Photogrammetry, National Land Survey of Finland, P.O. Box 15 (Geodeetinrinne 2), FI-02431, Masala, Finland ORCID ID:E-mail: xiaowei.yu@maanmittauslaitos.fi
  • Uusitalo,  Natural Research Institute Finland, Green Technology, Kaironiementie 15, 39700 Parkano ORCID ID:E-mail: jori.uusitalo@luke.fi
article id 1562, category Research article
Mats Erik Berlin, Torgny Persson, Gunnar Jansson, Matti Haapanen, Seppo Ruotsalainen, Lars Bärring, Bengt Andersson Gull. (2016). Scots pine transfer effect models for growth and survival in Sweden and Finland. Silva Fennica vol. 50 no. 3 article id 1562. https://doi.org/10.14214/sf.1562
Highlights: Scots pine transfer effect models for growth and survival, valid in both Sweden and Finland have been developed; The models use high-resolution gridded climate data and can predict performance in future climatic conditions; The models perform well both for unimproved and genetically improved material and can be used to develop deployment recommendations of contemporary forest regeneration material in Sweden and Finland.

In this study, we developed models of transfer effects for growth and survival of Scots pine (Pinus sylvestris L.) in Sweden and Finland using a general linear mixed-model approach. For model development, we used 378 provenance and progeny trials with a total of 276 unimproved genetic entries (provenances and stand seed check-lots) distributed over a wide variety of climatic conditions in both countries. In addition, we used 119 progeny trials with 3921 selected genetic entries (open- and control pollinated plus-tree families) for testing model performance. As explanatory variables, both climatic indices derived from high-resolution gridded climate datasets and geographical variables were used. For transfer, latitude (photoperiod) and, for describing the site, temperature sum were found to be main drivers for both survival and growth. In addition, interaction terms (between transfer in latitude and site altitude for survival, and transfer in latitude and temperature sum for growth) entail changed reaction patterns of the models depending on climatic conditions of the growing site. The new models behave in a way that corresponds well to previous studies and recommendations for both countries. The model performance was tested using selected plus-trees from open and control pollinated progeny tests. Results imply that the models are valid for both countries and perform well also for genetically improved material. These models are the first step in developing common deployment recommendations for genetically improved forest regeneration material in both Sweden and Finland.

  • Berlin, Uppsala Science Park, SE-75183 Uppsala, Sweden ORCID ID:E-mail: mats.berlin@skogforsk.se (email)
  • Persson, Skogforsk, Box 3, SE-91821 Sävar, Sweden ORCID ID:E-mail: torgny.persson@skogforsk.se
  • Jansson, Uppsala Science Park, SE-75183 Uppsala, Sweden ORCID ID:E-mail: gunnar.jansson@skogforsk.se
  • Haapanen, Natural Resources Institute Finland (Luke), Green Technology, Box 18, FI-01301 Vantaa, Finland ORCID ID:E-mail: matti.haapanen@luke.fi
  • Ruotsalainen, Natural Resources Institute Finland (Luke), Green Technology, Finlandiantie 18, FI-58450 Punkaharju, Finland ORCID ID:E-mail: seppo.ruotsalainen@luke.fi
  • Bärring, Rossby Centre, Swedish Meteorological and Hydrological Institute, Folkborgsvägen 17, SE-60176 Norrköping, Sweden ORCID ID:E-mail: lars.barring@smhi.se
  • Andersson Gull, Skogforsk, Box 3, SE-91821 Sävar, Sweden ORCID ID:E-mail: bengt.andersson@skogforsk.se
article id 1492, category Research article
Li-Bin Liu, Yang-Yang Wu, Gang Hu, Zhong-Hua Zhang, An-Yun Cheng, Shi-Jie Wang, Jian Ni. (2016). Biomass of karst evergreen and deciduous broad-leaved mixed forest in central Guizhou province, southwestern China: a comprehensive inventory of a 2 ha plot. Silva Fennica vol. 50 no. 3 article id 1492. https://doi.org/10.14214/sf.1492
Highlights: Comprehensive inventory of the karst secondary forest based on a 2 ha large plot enhanced the reliability of biomass estimates; The biomass was 158.1 Mg ha−1, and the five dominant tree species accounted for 92.4% of aboveground tree biomass; The estimated necromass of woody debris and litter in the karst secondary forest was 17.6 Mg ha−1.

The biomass of a secondary evergreen and deciduous broad-leaved mixed forest was comprehensively inventoried in a permanent 2 ha plot in southwestern China. Biomass models, sub-sampling, soil pit method, and published data were utilized to determine the biomass of all components. Results showed that the total biomass of the forest was 158.1 Mg ha−1; the total biomass included the major aboveground (137.7 Mg ha−1) and belowground (20.3 Mg ha−1) biomass components of vascular plants as well as the minor biomass components of bryophytes (0.078 Mg ha−1) and lichens (0.043 Mg ha−1). The necromass was 17.6 Mg ha−1 and included woody debris (9.0 Mg ha−1) and litter (8.6 Mg ha−1). The spatial pattern of the aboveground biomass was determined by the spatial distribution of dominant trees with large diameter, tall height, and dense wood. The belowground biomass differed in terms of root diameter and decreased with increasing soil depth. The belowground biomass in each soil pit in local habitats was not related to the spatial distribution of woody plants and soil pit depth. The karst forest presented lower biomass compared than the nonkarst forests in the subtropical zone. Biomass carbon in the karst terrains would increase substantially if degraded karst vegetation could be successfully restored to the forest. Comprehensive site-based biomass inventory of karst vegetation will contribute not only to provide data for benchmarking global and regional vegetation and carbon models but also for regional carbon inventory and vegetation restoration.

  • Liu, State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Lincheng West Road 99, 550081 Guiyang, China; Puding Karst Ecosystem Research Station, Chinese Academy of Sciences, 562100 Puding, China; University of Chinese Academy of Sciences, 100049 Beijing, China ORCID ID:E-mail: liulibin@mail.gyig.ac.cn
  • Wu, State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Lincheng West Road 99, 550081 Guiyang, China; Puding Karst Ecosystem Research Station, Chinese Academy of Sciences, 562100 Puding, China; University of Chinese Academy of Sciences, 100049 Beijing, China ORCID ID:E-mail: wuyang2468@hotmail.com
  • Hu, School of Chemistry and Life Science, Guangxi Teachers Education University, 530001 Nanning, China; Key Laboratory of Beibu Gulf Environment Change and Resources Utilization of Ministry of Education, Guangxi Teachers Education University, 530001 Nanning, China ORCID ID:E-mail: ahhugang@gmail.com
  • Zhang, School of Chemistry and Life Science, Guangxi Teachers Education University, 530001 Nanning, China; Key Laboratory of Beibu Gulf Environment Change and Resources Utilization of Ministry of Education, Guangxi Teachers Education University, 530001 Nanning, China ORCID ID:E-mail: gxtczzh@gmail.com
  • Cheng, State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Lincheng West Road 99, 550081 Guiyang, China; Puding Karst Ecosystem Research Station, Chinese Academy of Sciences, 562100 Puding, China ORCID ID:E-mail: chenganyun@vip.skleg.cn
  • Wang, State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Lincheng West Road 99, 550081 Guiyang, China; Puding Karst Ecosystem Research Station, Chinese Academy of Sciences, 562100 Puding, China ORCID ID:E-mail: wangshijie@vip.skleg.cn
  • Ni, State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Lincheng West Road 99, 550081 Guiyang, China; Puding Karst Ecosystem Research Station, Chinese Academy of Sciences, 562100 Puding, China ORCID ID:E-mail: nijian@vip.skleg.cn (email)
article id 1441, category Research article
Dorota Zawadzka, Stanisław Drozdowski, Grzegorz Zawadzki, Jerzy Zawadzki. (2016). The availability of cavity trees along an age gradient in fresh pine forests. Silva Fennica vol. 50 no. 3 article id 1441. https://doi.org/10.14214/sf.1441
Highlights: The density of cavity trees in pine-dominated, managed forests varied in relation to stand age and was highest in stands older than 130 years of age; Cavities excavated by woodpeckers dominated among all cavities; The number of trees with cavities appears insufficient to ensure the effective protection of bird diversity in managed stands of Augustów Forest.

Given their importance as a resource for many forest organisms, tree cavities were inventoried in the managed pine forests of north-east Poland, in relation to the: 70–100, 101–130 and >130 year age-classes within the clear-cutting system. The densities at which cavities were present was found to depend on forest age, given that stands 70–100 years old were characterised by an average density of 0.62 trees ha–1, while forests older than 130 years reported 3.28 trees ha–1. Stands aged 70–100 years differed from those aged 130+ in having just 0.27 trees ha–1 of cavity trees, as compared with 2.91 trees ha–1. The total volume of cavity trees in stands up to 100 years old was 0.37 m3 ha–1 on average, as compared with 5.42 m3 ha–1 in stands over 130 years old. The cavities created by woodpeckers constituted 76% of all of those found, and included 53% excavated by great spotted woodpeckers (Dendrocopos major L.) and 23% by black woodpeckers (Dryocopus martius L.) The proportion of cavities excavated by D. major was highest in the youngest age class of stands. There, cavities made by D. martius constituted only 8% of the total, as compared with 31% in the oldest stands. The abundance of cavity trees thus differed along an age gradient, though in any event the availability of cavity trees appears to be too limited to provide for the needs of hole-nesting birds. Forest managers must thus take more account than hitherto of the need to protect cavity trees.

  • Zawadzka, Institute of Forest Science, University of Łódź, Branch in Tomaszów Mazowiecki, Konstytucji 3 Maja 65/67, 97-200 Tomaszów Mazowiecki, Poland ORCID ID:E-mail: dorota_zaw@wp.pl
  • Drozdowski, Department of Silviculture, Warsaw University of Life Sciences - SGGW, Nowoursynowska 159, 02-776 Warsaw, Poland ORCID ID:E-mail: stanislaw_drozdowski@sggw.pl (email)
  • Zawadzki, Eagle Conservation Committee, Okółek 14, 16-506 Giby, Poland ORCID ID:E-mail: grzesiekgfz@op.pl
  • Zawadzki, Eagle Conservation Committee, Okółek 14, 16-506 Giby, Poland ORCID ID:E-mail: jerzy_zaw@wp.pl
article id 1441, category Research article
Dorota Zawadzka, Stanisław Drozdowski, Grzegorz Zawadzki, Jerzy Zawadzki. (2016). The availability of cavity trees along an age gradient in fresh pine forests. Silva Fennica vol. 50 no. 3 article id 1441. https://doi.org/10.14214/sf.1441
Highlights: The density of cavity trees in pine-dominated, managed forests varied in relation to stand age and was highest in stands older than 130 years of age; Cavities excavated by woodpeckers dominated among all cavities; The number of trees with cavities appears insufficient to ensure the effective protection of bird diversity in managed stands of Augustów Forest.

Given their importance as a resource for many forest organisms, tree cavities were inventoried in the managed pine forests of north-east Poland, in relation to the: 70–100, 101–130 and >130 year age-classes within the clear-cutting system. The densities at which cavities were present was found to depend on forest age, given that stands 70–100 years old were characterised by an average density of 0.62 trees ha–1, while forests older than 130 years reported 3.28 trees ha–1. Stands aged 70–100 years differed from those aged 130+ in having just 0.27 trees ha–1 of cavity trees, as compared with 2.91 trees ha–1. The total volume of cavity trees in stands up to 100 years old was 0.37 m3 ha–1 on average, as compared with 5.42 m3 ha–1 in stands over 130 years old. The cavities created by woodpeckers constituted 76% of all of those found, and included 53% excavated by great spotted woodpeckers (Dendrocopos major L.) and 23% by black woodpeckers (Dryocopus martius L.) The proportion of cavities excavated by D. major was highest in the youngest age class of stands. There, cavities made by D. martius constituted only 8% of the total, as compared with 31% in the oldest stands. The abundance of cavity trees thus differed along an age gradient, though in any event the availability of cavity trees appears to be too limited to provide for the needs of hole-nesting birds. Forest managers must thus take more account than hitherto of the need to protect cavity trees.

  • Zawadzka, Institute of Forest Science, University of Łódź, Branch in Tomaszów Mazowiecki, Konstytucji 3 Maja 65/67, 97-200 Tomaszów Mazowiecki, Poland ORCID ID:E-mail: dorota_zaw@wp.pl
  • Drozdowski, Department of Silviculture, Warsaw University of Life Sciences - SGGW, Nowoursynowska 159, 02-776 Warsaw, Poland ORCID ID:E-mail: stanislaw_drozdowski@sggw.pl (email)
  • Zawadzki, Eagle Conservation Committee, Okółek 14, 16-506 Giby, Poland ORCID ID:E-mail: grzesiekgfz@op.pl
  • Zawadzki, Eagle Conservation Committee, Okółek 14, 16-506 Giby, Poland ORCID ID:E-mail: jerzy_zaw@wp.pl
article id 1462, category Research article
Pekka Punttila, Olli Autio, Janne S. Kotiaho, D. Johan Kotze, Olli J. Loukola, Norbertas Noreika, Anna Vuori, Kari Vepsäläinen. (2016). The effects of drainage and restoration of pine mires on habitat structure, vegetation and ants. Silva Fennica vol. 50 no. 2 article id 1462. https://doi.org/10.14214/sf.1462
Highlights: Mire drainage shifted floristic composition and ant assemblages towards forest communities; Raising the water-table level by ditch filling and the thinning of trees affected mire communities positively already 1–3 years after the start of restoration; The extent of tree cover, the coverage of Sphagnum mosses and the water-table level were major determinants of ant assemblage structure.

Habitat loss and degradation are the main threats to biodiversity worldwide. For example, nearly 80% of peatlands in southern Finland have been drained. There is thus a need to safeguard the remaining pristine mires and to restore degraded ones. Ants play a pivotal role in many ecosystems and like many keystone plant species, shape ecosystem conditions for other biota. The effects of mire restoration and subsequent vegetation succession on ants, however, are poorly understood. We inventoried tree stands, vegetation, water-table level, and ants (with pitfall traps) in nine mires in southern Finland to explore differences in habitats, vegetation and ant assemblages among pristine, drained (30–40 years ago) and recently restored (1–3 years ago) pine mires. We expected that restoring the water-table level by ditch filling and reconstructing sparse tree stands by cuttings will recover mire vegetation and ants. We found predictable responses in habitat structure, floristic composition and ant assemblage structure both to drainage and restoration. However, for mire-specialist ants the results were variable and longer-term monitoring is needed to confirm the success of restoration since these social insects establish perennial colonies with long colony cycles. We conclude that restoring the water-table level and tree stand structure seem to recover the characteristic vegetation and ant assemblages in the short term. This recovery was likely enhanced because drained mires still had both acrotelm and catotelm, and connectedness was still reasonable for mire organisms to recolonize the restored mires either from local refugia or from populations of nearby mires.

  • Punttila, Finnish Environment Institute, P.O. Box 140, FI-00251 Helsinki, Finland ORCID ID:E-mail: pekka.punttila@ymparisto.fi (email)
  • Autio, Centre for Economic Development, Transport and the Environment in South Ostrobothnia, P.O. Box 252, FI-65101 Vaasa, Finland ORCID ID:E-mail: olli.autio@ely-keskus.fi
  • Kotiaho, University of Jyväskylä, Department of Biology & Environmental Sciences, P.O. Box 35, FI-40014 Jyväskylä, Finland ORCID ID:E-mail: janne.kotiaho@jyu.fi
  • Kotze, University of Helsinki, Department of Environmental Sciences, P.O. Box 65, FI-00014, University of Helsinki, Finland ORCID ID:E-mail: johan.kotze@helsinki.fi
  • Loukola, University of Oulu, Department of Biology, P.O. Box 3000, FI-90014 Oulu, Finland ORCID ID:E-mail: olli.loukola@gmail.com
  • Noreika, University of Helsinki, Department of Environmental Sciences, P.O. Box 65, FI-00014, University of Helsinki, Finland; University of Helsinki, Department of Biosciences, P.O. Box 65, FI-00014 University of Helsinki, Finland ORCID ID:E-mail: norbertas.noreika@gmail.com
  • Vuori, University of Jyväskylä, Department of Biology & Environmental Sciences, P.O. Box 35, FI-40014 Jyväskylä, Finland ORCID ID:E-mail: anna@kureniemi.fi
  • Vepsäläinen, University of Helsinki, Department of Biosciences, P.O. Box 65, FI-00014 University of Helsinki, Finland ORCID ID:E-mail: kari.vepsalainen@helsinki.fi
article id 1448, category Research article
Andrew McEwan, Natascia Magagnotti, Raffaele Spinelli. (2016). The effects of number of stems per stool on cutting productivity in coppiced Eucalyptus plantations. Silva Fennica vol. 50 no. 2 article id 1448. https://doi.org/10.14214/sf.1448
Highlights: Double- and single stem coppice stools were harvested mechanically; Stem size had the strongest impact on productivity; An experienced operator performed equally well with both stool treatments; Cost was ~10% higher with double stems for the less experienced operator; Operator experience may play a major role when cutting coppice stands.

A time study was conducted to determine whether stem crowding had any impact on harvester productivity in Eucalyptus grandis stands. This represents an important element when trying to balance the advantages and disadvantages of coppice management in fast growing plantations designated for mechanized harvesting (i.e. machine felling, delimbing, debarking and cross-cutting). The study material consisted of 446 coppice stems, half of which grew as single stems per stool and half as double stems per stool as a result of different coppice reduction strategies. The dataset was balanced and randomized, with both subsets replicating exactly the same stem size distribution and the single and double stems alternating randomly. Harvester productivity ranged between 6 and 50 m3 under bark per productive machine hour, following the variation of tree diameter from 10 to 40 cm at breast height (1.37 m according to South African standards). Regression analysis indicated that both tree size and stem crowding (e.g. one or two stems per stool) had a significant effect on harvester productivity, which increased with stem size and decreased with stem crowding. However, operator experience may overcome the effect of stem crowding, which was not significant when the harvester was manned by a highly experienced operator. In any case, the effect of stem size was much greater than that of stem crowding, which resulted in a cost difference of less than 10%. However, this figure excludes the possible effects of stem crowding on volume recovery and stem development, which should be addressed in the future.

  • McEwan, Nelson Mandela Metropolitan University – George Campus, Saasveld, 6529, George, South Africa ORCID ID:E-mail: Andrew.McEwan@nmmu.ac.za
  • Magagnotti, CNR IVALSA, Via Madonna del Piano 10, I-50019 Sesto Fiorentino (FI), Italy ORCID ID:E-mail: magagnotti@ivalsa.cnr.it
  • Spinelli, CNR IVALSA, Via Madonna del Piano 10, I-50019 Sesto Fiorentino (FI), Italy ORCID ID:E-mail: spinelli@ivalsa.cnr.it (email)
article id 1414, category Research article
Rami Saad, Jörgen Wallerman, Johan Holmgren, Tomas Lämås. (2016). Local pivotal method sampling design combined with micro stands utilizing airborne laser scanning data in a long term forest management planning setting. Silva Fennica vol. 50 no. 2 article id 1414. https://doi.org/10.14214/sf.1414
Highlights: Most similar neighbor imputation was used to estimate forest variables using airborne laser scanning data as auxiliary data; For selecting field reference plots the local pivotal method (LPM) was compared to systematic sampling design; The LPM sampling design combined with a micro stand approach showed potential for improvement and has the potential to be a competitive method when considering cost efficiency.

A new sampling design, the local pivotal method (LPM), was combined with the micro stand approach and compared with the traditional systematic sampling design for estimation of forest stand variables. The LPM uses the distance between units in an auxiliary space – in this case airborne laser scanning (ALS) data – to obtain a well-spread sample. Two sets of reference plots were acquired by the two sampling designs and used for imputing data to evaluation plots. The first set of reference plots, acquired by LPM, made up four imputation alternatives (varying number of reference plots) and the second set of reference plots, acquired by systematic sampling design, made up two alternatives (varying plot radius). The forest variables in these alternatives were estimated using the nonparametric method of most similar neighbor imputation, with the ALS data used as auxiliary data. The relative root mean square error (RelRMSE), stem diameter distribution error index and suboptimal loss were calculated for each alternative, but the results showed that neither sampling design, i.e. LPM vs. systematic, offered clear advantages over the other. It is likely that the obtained results were a consequence of the small evaluation dataset used in the study (n = 30). Nevertheless, the LPM sampling design combined with the micro stand approach showed potential for improvement and might be a competitive method when considering the cost efficiency.

  • Saad, Swedish University of Agricultural Sciences (SLU), Department of Forest Resource Management, Skogsmarksgränd, SE-901 83 Umeå, Sweden ORCID ID:E-mail: rami.saad@slu.se (email)
  • Wallerman, Swedish University of Agricultural Sciences (SLU), Department of Forest Resource Management, Skogsmarksgränd, SE-901 83 Umeå, Sweden ORCID ID:E-mail: jorgen.wallerman@slu.se
  • Holmgren, Swedish University of Agricultural Sciences (SLU), Department of Forest Resource Management, Skogsmarksgränd, SE-901 83 Umeå, Sweden ORCID ID:E-mail: johan.holmgren@slu.se
  • Lämås, Swedish University of Agricultural Sciences (SLU), Department of Forest Resource Management, Skogsmarksgränd, SE-901 83 Umeå, Sweden ORCID ID:E-mail: tomas.lamas@slu.se
article id 1323, category Research article
Tiina Laine, Kalle Kärhä, Antti Hynönen. (2016). A survey of the Finnish mechanized tree-planting industry in 2013 and its success factors. Silva Fennica vol. 50 no. 2 article id 1323. https://doi.org/10.14214/sf.1323
Highlights: In 2013, 31 planting machines were operated by 22 businesses and planted 4.7 million seedlings on 2663 hectares in Finland; Critical success factors included expertise of planting machine operators, high quality planting, adequate amount of work, stoniness, and removal of slash; Growth of the industry will depend on improved cost-efficiency, appropriate worksites, marketing, development of planting machines.

The aim of the study was to update the information pertaining to mechanized tree-planting activity in Finland in 2013 and its success factors. All businesses providing a mechanized tree-planting service were interviewed and asked to describe their equipment and activities, identify critical success factors (CSFs), and suggest areas for improvement. In 2013, 31 planting machines (18 Bracke P11.a, 11 M-Planter and 2 Risutec) operated by 22 businesses planted approximately 4.7 million seedlings on 2663 hectares. CSFs included expertise of planting machine operators, high quality planting, adequate amount of work, stoniness, and removal of slash. Based on the survey, some recommendations for improving mechanized planting work can be made. Firstly, improving the cost-efficiency of mechanized planting is necessary to enhance businesses’ profitability. Secondly, worksite selection is crucial as stoniness, stumps and slash debris diminish productivity. Lastly, the popularity of mechanized planting in the future will benefit from more marketing. Many businesses were unwilling to increase the area of service, invest in new equipment, or increase the volume of planting work but they believed that mechanized planting will become more popular in the near future.

  • Laine, Natural Resources Institute Finland (Luke), Management and Production of Renewable Resources, Juntintie 154, FI-77600 Suonenjoki, Finland ORCID ID:E-mail: tiina.laine@luke.fi (email)
  • Kärhä, Stora Enso Wood Supply Finland, P.O. Box 309, FI-00101 Helsinki, Finland ORCID ID:E-mail: kalle.karha@storaenso.com
  • Hynönen, University of Eastern Finland, Faculty of Science and Forestry, P.O. Box 111, FI-80101 Joensuu, Finland ORCID ID:E-mail: hynonena@gmail.com
article id 1413, category Research article
Ilya Potapov, Marko Järvenpää, Markku Åkerblom, Pasi Raumonen, Mikko Kaasalainen. (2016). Data-based stochastic modeling of tree growth and structure formation. Silva Fennica vol. 50 no. 1 article id 1413. https://doi.org/10.14214/sf.1413
Highlights: We propose a stochastic version of the tree growth model LIGNUM for producing tree structures consistent with detailed terrestrial laser scanning data, and we provide the proof-of-concept by using model-based simulations and real laser scanning data; Trees produced with the data-based model resemble the trees of the dataset, and are statistically similar but not copies of each other; the number of such synthetic trees is not limited.

We introduce a general procedure to match a stochastic functional-structural tree model (here LIGNUM augmented with stochastic rules) with real tree structures depicted by quantitative structure models (QSMs) based on terrestrial laser scanning. The matching is done by iteratively finding the maximum correspondence between the measured tree structure and the stochastic choices of the algorithm. First, we analyze the match to synthetic data (generated by the model itself), where the target values of the parameters to be estimated are known in advance, and show that the algorithm converges properly. We then carry out the procedure on real data obtaining a realistic model. We thus conclude that the proposed stochastic structure model (SSM) approach is a viable solution for formulating realistic plant models based on data and accounting for the stochastic influences.

  • Potapov, Tampere University of Technology, Department of Mathematics, P.O. Box 553, FI-33101 Tampere, Finland ORCID ID:E-mail: ilya.potapov@tut.fi (email)
  • Järvenpää, Tampere University of Technology, Department of Mathematics, P.O. Box 553, FI-33101 Tampere, Finland ORCID ID:E-mail: marko.jarvenpaa@tut.fi
  • Åkerblom, Tampere University of Technology, Department of Mathematics, P.O. Box 553, FI-33101 Tampere, Finland ORCID ID:E-mail: markku.akerblom@tut.fi
  • Raumonen, Tampere University of Technology, Department of Mathematics, P.O. Box 553, FI-33101 Tampere, Finland ORCID ID:E-mail: pasi.raumonen@tut.fi
  • Kaasalainen, Tampere University of Technology, Department of Mathematics, P.O. Box 553, FI-33101 Tampere, Finland ORCID ID:E-mail: mikko.kaasalainen@tut.fi
article id 1384, category Research article
Staffan Berg, Erik Valinger, Torgny Lind, Tommi Suominen, Diana Tuomasjukka. (2016). Comparison of co-existing forestry and reindeer husbandry value chains in northern Sweden. Silva Fennica vol. 50 no. 1 article id 1384. https://doi.org/10.14214/sf.1384
Highlights: Forestry adapted to reindeer husbandry results in: potential economic improvement of reindeer husbandry, potential reduced cuttings in forestry and reduced wood flow to industry, reduced gross value added for forest industry and increased carbon storage in standing forest.

Forestry in Malå, northern Sweden, coexists with other land uses. Reindeer husbandry is in the area for centuries and requires large areas of grazing land. Competing land uses may threaten the Malå Sami village. The aim of the study was to evaluate increased consideration in forest management towards 1) reindeer husbandry, 2) nature and 3) a combination of the two. These scenarios were compared with forest management as it was in 2009. Results indicate that all three scenarios lead to a decrease in annual harvesting volumes of 0.2 to 0.4 million m3. Forest industry dominated the economic viability in the area. Forest management adapted to the needs of reindeer husbandry resulted in less potential for yearly harvest, employment and profits from forest industry. On the other hand, it led to an increase in growing stock and consequently the potential for carbon sequestration over time. Indeed the increased sequestration would compensate for all fossil emissions of carbon from the Forest Wood Chain (FWC). The nature scenario had minor effects on economic result and on the emissions of fossil carbon. The combined scenario gave a reduced economic performance for the FWC. A scenario based on forest management accommodating the needs of reindeer husbandry gave the best economic result for the reindeer chain, due to high survival rate of the reindeer. However the economic importance of reindeer husbandry in the region was small compared to the FWC. Results from scenario analysis could serve as a platform for mutual understanding between stakeholders.

  • Berg, Swedish University of Agricultural Sciences (SLU), Department of Forest Ecology and Management, Skogsmarksgränd, SE-90 183 Umeå, Sweden ORCID ID:E-mail: staffan.berg@efi.int (email)
  • Valinger, Swedish University of Agricultural Sciences (SLU), Department of Forest Ecology and Management, Skogsmarksgränd, SE-90 183 Umeå, Sweden ORCID ID:E-mail: erik.valinger@slu.se
  • Lind, Swedish University of Agricultural Sciences (SLU), Department of Forest Resource Management, Skogsmarksgränd, SE-90 183 Umeå, Sweden ORCID ID:E-mail: torgny.lind@slu.se
  • Suominen, European Forest Institute, Sustainability and Climate Change Research Programme, Yliopistokatu 6, FI-80100 Joensuu, Finland ORCID ID:E-mail: tommi.suominen@efi.int
  • Tuomasjukka, European Forest Institute, Sustainability and Climate Change Research Programme, Yliopistokatu 6, FI-80100 Joensuu, Finland ORCID ID:E-mail: diana.tuomasjukka@efi.int
article id 1405, category Research article
Lauri Korhonen, Daniela Ali-Sisto, Timo Tokola. (2015). Tropical forest canopy cover estimation using satellite imagery and airborne lidar reference data. Silva Fennica vol. 49 no. 5 article id 1405. https://doi.org/10.14214/sf.1405
Highlights: The fusion of airborne lidar data and satellite images enables accurate canopy cover mapping; The zero-and-one inflated beta regression is demonstrated in large area estimation; Forest/non-forest classification should be done directly, for example by using logistic regression.

The fusion of optical satellite imagery, strips of lidar data and field plots is a promising approach for the inventory of tropical forests. Airborne lidars also enable an accurate direct estimation of the forest canopy cover (CC), and thus a sample of lidar strips can be used as reference data for creating CC maps which are based on satellite images. In this study, our objective was to validate CC maps obtained from an ALOS AVNIR-2 satellite image wall-to-wall, against a lidar-based CC map of a tropical forest area located in Laos. The reference CC values which were needed for model training were obtained from a sample of four lidar strips. Zero-and-one inflated beta regression (ZOINBR) models were applied to link the spectral vegetation indices derived from the ALOS image with the lidar-based CC estimates. In addition, we compared ZOINBR and logistic regression models in the forest area estimation by using >20% CC as a forest definition. Using a total of 409 217 30 × 30 m population units as validation, our model showed a strong correlation between lidar-based CC and spectral satellite features (root mean square error = 12.8%, R2 = 0.82). In the forest area estimation, a direct classification using logistic regression provided better accuracy than the estimation of CC values as an intermediate step (kappa = 0.61 vs. 0.53). It is important to obtain sufficient training data from both ends of the CC range. The forest area estimation should be done before the CC estimation, rather than vice versa.

  • Korhonen, University of Eastern Finland, School of Forest Sciences, P.O. Box 111, FI-80101 Joensuu, Finland; (current) University of Helsinki, Department of Forest Sciences, P.O. Box 27, FI-00014 University of Helsinki, Finland ORCID ID: http://orcid.org/0000-0002-9352-0114 E-mail: lauri.z.korhonen@helsinki.fi (email)
  • Ali-Sisto, University of Eastern Finland, School of Forest Sciences, P.O. Box 111, FI-80101 Joensuu, Finland ORCID ID:E-mail: dheikkil@student.uef.fi
  • Tokola, University of Eastern Finland, School of Forest Sciences, P.O. Box 111, FI-80101 Joensuu, Finland. ORCID ID:E-mail: timo.tokola@uef.fi
article id 1405, category Research article
Lauri Korhonen, Daniela Ali-Sisto, Timo Tokola. (2015). Tropical forest canopy cover estimation using satellite imagery and airborne lidar reference data. Silva Fennica vol. 49 no. 5 article id 1405. https://doi.org/10.14214/sf.1405
Highlights: The fusion of airborne lidar data and satellite images enables accurate canopy cover mapping; The zero-and-one inflated beta regression is demonstrated in large area estimation; Forest/non-forest classification should be done directly, for example by using logistic regression.

The fusion of optical satellite imagery, strips of lidar data and field plots is a promising approach for the inventory of tropical forests. Airborne lidars also enable an accurate direct estimation of the forest canopy cover (CC), and thus a sample of lidar strips can be used as reference data for creating CC maps which are based on satellite images. In this study, our objective was to validate CC maps obtained from an ALOS AVNIR-2 satellite image wall-to-wall, against a lidar-based CC map of a tropical forest area located in Laos. The reference CC values which were needed for model training were obtained from a sample of four lidar strips. Zero-and-one inflated beta regression (ZOINBR) models were applied to link the spectral vegetation indices derived from the ALOS image with the lidar-based CC estimates. In addition, we compared ZOINBR and logistic regression models in the forest area estimation by using >20% CC as a forest definition. Using a total of 409 217 30 × 30 m population units as validation, our model showed a strong correlation between lidar-based CC and spectral satellite features (root mean square error = 12.8%, R2 = 0.82). In the forest area estimation, a direct classification using logistic regression provided better accuracy than the estimation of CC values as an intermediate step (kappa = 0.61 vs. 0.53). It is important to obtain sufficient training data from both ends of the CC range. The forest area estimation should be done before the CC estimation, rather than vice versa.

  • Korhonen, University of Eastern Finland, School of Forest Sciences, P.O. Box 111, FI-80101 Joensuu, Finland; (current) University of Helsinki, Department of Forest Sciences, P.O. Box 27, FI-00014 University of Helsinki, Finland ORCID ID: http://orcid.org/0000-0002-9352-0114 E-mail: lauri.z.korhonen@helsinki.fi (email)
  • Ali-Sisto, University of Eastern Finland, School of Forest Sciences, P.O. Box 111, FI-80101 Joensuu, Finland ORCID ID:E-mail: dheikkil@student.uef.fi
  • Tokola, University of Eastern Finland, School of Forest Sciences, P.O. Box 111, FI-80101 Joensuu, Finland. ORCID ID:E-mail: timo.tokola@uef.fi
article id 1403, category Research article
Kristina Mjöfors, Monika Strömgren, Hans-Örjan Nohrstedt, Annemieke Ingrid Gärdenäs. (2015). Impact of site-preparation on soil-surface CO2 fluxes and litter decomposition in a clear-cut in Sweden. Silva Fennica vol. 49 no. 5 article id 1403. https://doi.org/10.14214/sf.1403
Highlights: Disturbances of the soil did not lead to higher CO2 emissions from the soil; Heavy mixing of the soil lead to lower CO2 emissions from the soil; Buried needles and coarse roots decomposed faster than those on the surface; Abundance of δ15N decreased in needles and roots after site preparation.

Boreal forest soil contains significant amounts of organic carbon. Soil disturbance, caused for example by site preparation or stump extraction, may increase decomposition and thus lead to higher CO2 emissions, contributing to global warming. The aim of this study was to quantify responses of soil-surface CO2 fluxes (Rs) and litter (needle and root) decomposition rates following various kinds of soil disturbance commonly caused by mechanical site preparation and stump harvest. For this purpose four treatments were applied in a clear-cut site in central Sweden: i) removal of the humus layer and top 2 cm of mineral soil, ii) placement of a humus layer and 2 cm of mineral soil upside down on top of undisturbed soil, forming a double humus layer buried under mineral soil, iii) heavy mixing of the humus layer and mineral soil, and iv) no disturbance (control). Rs measurements were acquired with a portable respiration system during two growing seasons. To assess the treatments’ effects on litter decomposition rates, needles or coarse roots (Ø = 6 mm) were incubated in litterbags at positions they would be located after the treatments (buried, or on top of the soil). The results indicate that site preparation-simulating treatments have no effect or may significantly reduce, rather than increase, CO2 emissions during the following two years. They also show that buried litter decomposes more rapidly than litter on the surface, but in other respects the treatments have little effect on litter decomposition rates.

  • Mjöfors, Swedish University of Agricultural Sciences (SLU), Department of Soil and Environment, P.O. Box 7014, 150 07 Uppsala, Sweden ORCID ID:E-mail: kristina.mjofors@slu.se (email)
  • Strömgren, Swedish University of Agricultural Sciences (SLU), Department of Soil and Environment, P.O. Box 7014, 150 07 Uppsala, Sweden ORCID ID:E-mail: Monika.stromgren@slu.se
  • Nohrstedt, Swedish University of Agricultural Sciences (SLU), Department of Soil and Environment, P.O. Box 7014, 150 07 Uppsala, Sweden ORCID ID:E-mail: Hans-orjan.nohrstedt@slu.se
  • Gärdenäs, Swedish University of Agricultural Sciences (SLU), Department of Soil and Environment, P.O. Box 7014, 150 07 Uppsala, Sweden ORCID ID:E-mail: Annemieke.gardenas@slu.se
article id 1348, category Research article
Sakari Tuominen, Andras Balazs, Heikki Saari, Ilkka Pölönen, Janne Sarkeala, Risto Viitala. (2015). Unmanned aerial system imagery and photogrammetric canopy height data in area-based estimation of forest variables. Silva Fennica vol. 49 no. 5 article id 1348. https://doi.org/10.14214/sf.1348
Highlights: Orthoimage mosaic and 3D canopy height model were derived from UAV-borne colour-infrared digital camera imagery and ALS-based terrain model; Features extracted from orthomosaic and canopy height data were used for estimating forest variables; The accuracy of forest estimates was similar to that of the combination of ALS and digital aerial imagery.

In this paper we examine the feasibility of data from unmanned aerial vehicle (UAV)-borne aerial imagery in stand-level forest inventory. As airborne sensor platforms, UAVs offer advantages cost and flexibility over traditional manned aircraft in forest remote sensing applications in small areas, but they lack range and endurance in larger areas. On the other hand, advances in the processing of digital stereo photography make it possible to produce three-dimensional (3D) forest canopy data on the basis of images acquired using simple lightweight digital camera sensors. In this study, an aerial image orthomosaic and 3D photogrammetric canopy height data were derived from the images acquired by a UAV-borne camera sensor. Laser-based digital terrain model was applied for estimating ground elevation. Features extracted from orthoimages and 3D canopy height data were used to estimate forest variables of sample plots. K-nearest neighbor method was used in the estimation, and a genetic algorithm was applied for selecting an appropriate set of features for the estimation task. Among the selected features, 3D canopy features were given the greatest weight in the estimation supplemented by textural image features. Spectral aerial photograph features were given very low weight in the selected feature set. The accuracy of the forest estimates based on a combination of photogrammetric 3D data and orthoimagery from UAV-borne aerial imaging was at a similar level to those based on airborne laser scanning data and aerial imagery acquired using purpose-built aerial camera from the same study area.

  • Tuominen, Natural Resources Institute Finland (Luke), Economics and society, P.O. Box 18, FI-01301 Vantaa, Finland ORCID ID:E-mail: sakari.tuominen@luke.fi (email)
  • Balazs, Natural Resources Institute Finland (Luke), Economics and society, P.O. Box 18, FI-01301 Vantaa, Finland ORCID ID:E-mail: andras.balazs@luke.fi
  • Saari, VTT Technical Research Centre of Finland Ltd, P.O. Box 1000, FI-02044 VTT, Finland ORCID ID:E-mail: Heikki.Saari@vtt.fi
  • Pölönen, University of Jyväskylä, Department of Mathematical Information Technology, P.O. Box 35, FI-40014 University of Jyväskylä, Finland ORCID ID:E-mail: ilkka.polonen@jyu.fi
  • Sarkeala, Mosaicmill Oy, Kultarikontie 1, FI-01300 Vantaa, Finland ORCID ID:E-mail: janne.sarkeala@mosaicmill.com
  • Viitala, Häme University of Applied Sciences (HAMK), P.O. Box 230, FI-13101 Hämeenlinna, Finland ORCID ID:E-mail: Risto.Viitala@hamk.fi
article id 1347, category Research article
Paulo Borges, Even Bergseng, Tron Eid, Terje Gobakken. (2015). Impact of maximum opening area constraints on profitability and biomass availability in forestry – a large, real world case. Silva Fennica vol. 49 no. 5 article id 1347. https://doi.org/10.14214/sf.1347
Highlights: We solved a large and real world near city forestry problem; The inclusion of maximum open area constraints caused 7.0% loss in NPV; Solution value at maximum deviated 0.01% from the true optimum value; The annual energy supply of 20–30 GWh estimated from harvest residues could provide a small, but stable supply of energy to the municipality.

The nature areas surrounding the capital of Norway (Oslomarka), comprising 1 700 km2 of forest land, are the recreational home turf for a population of 1.2 mill. people. These areas are highly valuable, not only for recreational purposes and biodiversity, but also for commercial activities. To assess the impacts of the challenges that Oslo municipality forest face in their management, we developed four optimization problems with different levels of management constraints. The constraints consider control of harvest level, guarantee of minimum old-growth forest area and maximum open area after final harvest. For the latter, to date, no appropriate analyses quantifying the impact of such a constraint on economy and biomass production have been carried out in Norway. The problem solved is large due to both the number of stands and number of treatment schedules. However, the model applied demonstrated its relevance for solving large problems involving maximum opening areas. The inclusion of maximum open area constraints caused 7.0% loss in NPV compared to the business as usual case with controlled harvest volume and minimum old-growth area. The estimated supply of 20-30 GWh annual energy from harvest residues could provide a small, but stable supply of energy to the municipality.

  • Borges, Department of Ecology and Natural Resource Management, Norwegian University of Life Sciences, P.O. Box 5003, 1432 Aas, Norway ORCID ID:E-mail: paulo.borges@nmbu.no (email)
  • Bergseng, Department of Ecology and Natural Resource Management, Norwegian University of Life Sciences, P.O. Box 5003, 1432 Aas, Norway ORCID ID:E-mail: even.bergseng@nmbu.no
  • Eid, Department of Ecology and Natural Resource Management, Norwegian University of Life Sciences, P.O. Box 5003, 1432 Aas, Norway ORCID ID:E-mail: tron.eid@nmbu.no
  • Gobakken, Department of Ecology and Natural Resource Management, Norwegian University of Life Sciences, P.O. Box 5003, 1432 Aas, Norway ORCID ID:E-mail: terje.gobakken@nmbu.no
article id 1347, category Research article
Paulo Borges, Even Bergseng, Tron Eid, Terje Gobakken. (2015). Impact of maximum opening area constraints on profitability and biomass availability in forestry – a large, real world case. Silva Fennica vol. 49 no. 5 article id 1347. https://doi.org/10.14214/sf.1347
Highlights: We solved a large and real world near city forestry problem; The inclusion of maximum open area constraints caused 7.0% loss in NPV; Solution value at maximum deviated 0.01% from the true optimum value; The annual energy supply of 20–30 GWh estimated from harvest residues could provide a small, but stable supply of energy to the municipality.

The nature areas surrounding the capital of Norway (Oslomarka), comprising 1 700 km2 of forest land, are the recreational home turf for a population of 1.2 mill. people. These areas are highly valuable, not only for recreational purposes and biodiversity, but also for commercial activities. To assess the impacts of the challenges that Oslo municipality forest face in their management, we developed four optimization problems with different levels of management constraints. The constraints consider control of harvest level, guarantee of minimum old-growth forest area and maximum open area after final harvest. For the latter, to date, no appropriate analyses quantifying the impact of such a constraint on economy and biomass production have been carried out in Norway. The problem solved is large due to both the number of stands and number of treatment schedules. However, the model applied demonstrated its relevance for solving large problems involving maximum opening areas. The inclusion of maximum open area constraints caused 7.0% loss in NPV compared to the business as usual case with controlled harvest volume and minimum old-growth area. The estimated supply of 20-30 GWh annual energy from harvest residues could provide a small, but stable supply of energy to the municipality.

  • Borges, Department of Ecology and Natural Resource Management, Norwegian University of Life Sciences, P.O. Box 5003, 1432 Aas, Norway ORCID ID:E-mail: paulo.borges@nmbu.no (email)
  • Bergseng, Department of Ecology and Natural Resource Management, Norwegian University of Life Sciences, P.O. Box 5003, 1432 Aas, Norway ORCID ID:E-mail: even.bergseng@nmbu.no
  • Eid, Department of Ecology and Natural Resource Management, Norwegian University of Life Sciences, P.O. Box 5003, 1432 Aas, Norway ORCID ID:E-mail: tron.eid@nmbu.no
  • Gobakken, Department of Ecology and Natural Resource Management, Norwegian University of Life Sciences, P.O. Box 5003, 1432 Aas, Norway ORCID ID:E-mail: terje.gobakken@nmbu.no
article id 1408, category Research article
Anna Katharina Franke, Pasi Aatsinki, Ville Hallikainen, Esa Huhta, Mikko Hyppönen, Vesa Juntunen, Kari Mikkola, Seppo Neuvonen, Pasi Rautio. (2015). Quantifying changes of the coniferous forest line in Finnish Lapland during 1983–2009. Silva Fennica vol. 49 no. 4 article id 1408. https://doi.org/10.14214/sf.1408
Highlights: Volume of the growing stock of spruce and pine has increased in forests and in timber lines during the past 26 years; Spruce stem numbers increased on average, while pine stem numbers remained stable and location-specific variation was observed; Presuming that the ongoing trend of increasing temperature will remain, the enhanced forest regeneration and growth may result in extension of forests in the future.

The boreal timber- and tree-line forests grow in harsh environmental conditions in their outermost distribution limit. Here even small environmental changes may cause dramatic changes in the distribution of tree species. We examined changes of the forest lines of Norway spruce (Picea abies (L.) H. Karst.) and Scots pine (Pinus sylvestris L.) in Finnish Lapland five times during 1983–2009. We monitored the number of stems and the volume of the growing stock in thirteen different locations in forest-line areas. The linear temporal trends and the variations of these response variables were used as indicators of a possible change during the study period. Spruce showed a significant increase both in the volume of the growing stock (up to 40% increase) and in the total stem number (up to 100% increase). A significant increase in the volume of the growing stock was observed in the pine data as well (up to 70% increase), whereas the stem number stagnated or even decreased. The results suggest that spruce needs favourable conditions to have an abundant regeneration, but after the establishment the seedlings seem to be more resistant against biotic and abiotic disturbances than pine seedlings. The increasing stand volume might result in a climate-related northward and upward extension of forests in the future. However, our results show that responses in the boreal forest line are species and location specific and a more favourable climate does not necessarily lead to an advance of the coniferous forest line.

  • Franke, Natural Resources Institute Finland (Luke), Management and Production of Renewable Resources, Eteläranta 55, FI-96301 Rovaniemi, Finland ORCID ID:E-mail: anna.franke@fau.de (email)
  • Aatsinki, Natural Resources Institute Finland (Luke), Management and Production of Renewable Resources, Eteläranta 55, FI-96301 Rovaniemi, Finland ORCID ID:E-mail: pasi.aatsinki@luke.fi
  • Hallikainen, Natural Resources Institute Finland (Luke), Management and Production of Renewable Resources, Eteläranta 55, FI-96301 Rovaniemi, Finland ORCID ID:E-mail: ville.hallikainen@luke.fi
  • Huhta, Natural Resources Institute Finland (Luke), Management and Production of Renewable Resources, Eteläranta 55, FI-96301 Rovaniemi, Finland ORCID ID:E-mail: esa.huhta@luke.fi
  • Hyppönen, Natural Resources Institute Finland (Luke), Management and Production of Renewable Resources, Eteläranta 55, FI-96301 Rovaniemi, Finland ORCID ID:E-mail: mikko.hypponen@luke.fi
  • Juntunen, The Sámi Education Institute, Menesjärventie 4, P.O. Box 50, FI-99871 Inari, Finland ORCID ID:E-mail: vesa.juntunen@sogsakk.fi
  • Mikkola, Natural Resources Institute Finland (Luke), Economics and society, Eteläranta 55, FI-96301 Rovaniemi, Finland ORCID ID:E-mail: kari.mikkola@luke.fi
  • Neuvonen, Natural Resources Institute Finland (Luke), Management and Production of Renewable Resources, P.O. Box 68, FI-80101, Joensuu, Finland ORCID ID:E-mail: seppo.neuvonen@luke.fi
  • Rautio, Natural Resources Institute Finland (Luke), Bio-based business and industry, Eteläranta 55, FI-96301 Rovaniemi, Finland ORCID ID:E-mail: pasi.rautio@luke.fi
article id 1302, category Research article
Nils Fahlvik, Per Magnus Ekö, Nils Petersson. (2015). Effects of precommercial thinning strategies on stand structure and growth in a mixed even-aged stand of Scots pine, Norway spruce and birch in southern Sweden. Silva Fennica vol. 49 no. 3 article id 1302. https://doi.org/10.14214/sf.1302
Highlights: Precommercial thinning (PCT) was a useful tool to influence the stand structure in accordance to silvicultural goals; PCT had a great impact on tree species composition; The seemingly great potential to influence the structure of a heterogeneous, mixed stand was restrained by natural settings and unconditional considerations at PCT (e.g. tree vitality, stem quality, regular spacing).
Four different management strategies were applied to a young mixed stand of Scots pine (Pinus sylvestris L.), Norway spruce (Pices abies (L.) Karst.) and birch (Betula pendula Roth and Betula pubescens Ehrh.) in southern Sweden. All strategies included an initial precommercial thinning to ca. 2400 stems ha–1. The different aims were: (i) a conifer-dominated stand with focus on high productivity; (ii) a conifer-dominated stand with high quality timber; (iii) keeping a stem-wise species mixture; (iv) a mosaic-wise species mixture. Stem selection according to the different strategies were simulated with a starting point from plots with a 5 m radius. All strategies were applied to all of the plots. A growth simulator was used to simulate the stand development up to final felling. This study illustrates the possibilities for influencing the structure of a mixed stand through precommercial thinning. The study also illustrates the long-term effects on stand structure and volume yield by consequently applying a management strategy from precommercial thinning until final felling. Precommercial thinning was found to be a useful tool to influence the stand structure in accordance to the aims set. However, the opportunities for influencing the stand by precommercial thinning were restricted by natural settings and unconditional considerations (e.g. tree vitality, stem quality, regular spacing), beyond what could be judged from stand average data. The stem volume production during a rotation was 6% lower for (iii) and (iv) compared to (i) and (ii), mainly due to a greater proportion of birch in the former strategies.
  • Fahlvik, Southern Swedish Forest Research Centre, Swedish University of Agricultural Sciences, P.O. Box 49, SE-230 53 Alnarp, Sweden ORCID ID:E-mail: nils.fahlvik@slu.se (email)
  • Ekö, Southern Swedish Forest Research Centre, Swedish University of Agricultural Sciences, P.O. Box 49, SE-230 53 Alnarp, Sweden ORCID ID:E-mail: per.magnus.eko@slu.se
  • Petersson, StoraEnso Skog AB, Åsgatan 22, SE-791 80 Falun, Sweden ORCID ID:E-mail: nils.petersson@storaenso.com
article id 1267, category Research article
Caroline Mary Adrianne Franklin, Karen A Harper, Liam Kyte Murphy. (2015). Structural dynamics at boreal forest edges created by a spruce budworm outbreak. Silva Fennica vol. 49 no. 3 article id 1267. https://doi.org/10.14214/sf.1267
Highlights: Insect outbreak edges were 10 m wide with different canopy cover, stem density and tree structural diversity than adjacent ecosystems; Although edge influence on forest structure was weak, forest influence was stronger and extended further, creating an edge zone skewed towards the disturbed area; After thirty years, high-contrast and structurally-diverse transition zones persist on the landscape.
Natural disturbances such as insect outbreaks create boundaries that influence vegetation patterns and ecological processes.  To better understand the effects of natural edge creation on relatively intact forests and adjacent disturbed areas, we investigated forest structure on both sides of 30 year-old forest edges created by a spruce budworm (Choristoneura fumiferana Clemens) outbreak in the boreal forest of Cape Breton Highlands National Park, Canada.  Our objectives were: 1) to determine edge influence (compared to interior forest) and forest influence (compared to disturbed areas) on vegetation structure, and 2) to gain insight into the structural development of the edges.  Canopy cover, tree density, radial growth and deadwood were sampled in 5 m x 20 m plots along 120 m transects across six edges.  Randomization tests were used to estimate the magnitude and distance of edge and forest influence.  Narrow transition zones approximately 10 m wide characterized the spruce budworm-induced edges.  Edge influence did not extend into the forest; however, forest influence on structure was detected up to 40 m from the edge into the disturbed area.  We found evidence of the insect outbreak in the form of reduced radial growth during the disturbance across the entire disturbed area-forest gradient, which indicates that spruce budworm activity may not have ceased directly at the edge.  Tree mortality caused by the insect outbreak resulted in snags, many of which have transformed into logs since the outbreak collapsed.  Spruce budworm outbreak-induced forest edges are narrow but dynamic boundaries separating two distinct vegetation communities in the boreal landscape.
  • Franklin, Department of Renewable Resources, University of Alberta, 751 General Services Building, Edmonton, Alberta, T6G 2H1, Canada ORCID ID:E-mail: cfrankli@ualberta.ca (email)
  • Harper, School for Resource and Environmental Studies, Dalhousie University, Suite 5010, 6100 University Ave., Halifax, Nova Scotia, B3H 3J5, Canada ORCID ID:E-mail: Karen.Harper@dal.ca
  • Murphy, Department of Environmental Science, Saint Mary’s University, 923 Robie St., Halifax, Nova Scotia, B3H 3C3, Canada ORCID ID:E-mail: liamkmurphy@gmail.com
article id 1226, category Research article
Santiago Pereira, Antonio Prieto, Rafael Calama, Luis Diaz-Balteiro. (2015). Optimal management in Pinus pinea L. stands combining silvicultural schedules for timber and cone production. Silva Fennica vol. 49 no. 3 article id 1226. https://doi.org/10.14214/sf.1226
Highlights: Three management scenarios are proposed to integrate timber and pine nuts; Different silvicultural regimes for each output are addressed jointly; Goal programming is used in order to solve forest management models; In the mixed scenario, the area allocated to pine nuts should be notably greater.

This work aimed to tackle a timber harvest scheduling problem by simultaneously integrating into the analysis two forestry products derived from the same species: the timber and the pine nut. For this purpose, three management scenarios were proposed: two in which each of the productions is maximised separately, and a third mixed where, in each management unit, the product to which the silvicultural effort should be devoted is decided. After defining a set of objectives, and optimising the rotation length, a multi-criteria model based on goal programming was considered since no feasible solutions have been obtained when employing linear programming. The results in our case study show how the feasible solutions reached can be more attractive for the manager. Specifically, the area to be devoted to timber and cone/pine-nut production was computed in a scenario where the optimal silviculture (oriented towards timber or pine nuts) in each stand was selected, and it was concluded that the area allocated to pine nuts should be notably greater. This situation is the opposite of the current management.

  • Pereira, Technical University of Madrid, ETS Ingenieros de Montes, Ciudad Universitaria s/n, 28040 Madrid, Spain ORCID ID:E-mail: spereirasaez@gmail.com
  • Prieto, Technical University of Madrid, ETS Ingenieros de Montes, Ciudad Universitaria s/n, 28040 Madrid, Spain ORCID ID:E-mail: antonio.prieto@upm.es
  • Calama, Dpto. Selvicultura y Gestión Forestal, INIA-CIFOR, Ctra. A Coruña km 7.5, 28040 Madrid, Spain ORCID ID:E-mail: rcalama@inia.es
  • Diaz-Balteiro, Technical University of Madrid, ETS Ingenieros de Montes, Ciudad Universitaria s/n, 28040 Madrid, Spain ORCID ID:E-mail: luis.diaz.balteiro@upm.es (email)
article id 1226, category Research article
Santiago Pereira, Antonio Prieto, Rafael Calama, Luis Diaz-Balteiro. (2015). Optimal management in Pinus pinea L. stands combining silvicultural schedules for timber and cone production. Silva Fennica vol. 49 no. 3 article id 1226. https://doi.org/10.14214/sf.1226
Highlights: Three management scenarios are proposed to integrate timber and pine nuts; Different silvicultural regimes for each output are addressed jointly; Goal programming is used in order to solve forest management models; In the mixed scenario, the area allocated to pine nuts should be notably greater.

This work aimed to tackle a timber harvest scheduling problem by simultaneously integrating into the analysis two forestry products derived from the same species: the timber and the pine nut. For this purpose, three management scenarios were proposed: two in which each of the productions is maximised separately, and a third mixed where, in each management unit, the product to which the silvicultural effort should be devoted is decided. After defining a set of objectives, and optimising the rotation length, a multi-criteria model based on goal programming was considered since no feasible solutions have been obtained when employing linear programming. The results in our case study show how the feasible solutions reached can be more attractive for the manager. Specifically, the area to be devoted to timber and cone/pine-nut production was computed in a scenario where the optimal silviculture (oriented towards timber or pine nuts) in each stand was selected, and it was concluded that the area allocated to pine nuts should be notably greater. This situation is the opposite of the current management.

  • Pereira, Technical University of Madrid, ETS Ingenieros de Montes, Ciudad Universitaria s/n, 28040 Madrid, Spain ORCID ID:E-mail: spereirasaez@gmail.com
  • Prieto, Technical University of Madrid, ETS Ingenieros de Montes, Ciudad Universitaria s/n, 28040 Madrid, Spain ORCID ID:E-mail: antonio.prieto@upm.es
  • Calama, Dpto. Selvicultura y Gestión Forestal, INIA-CIFOR, Ctra. A Coruña km 7.5, 28040 Madrid, Spain ORCID ID:E-mail: rcalama@inia.es
  • Diaz-Balteiro, Technical University of Madrid, ETS Ingenieros de Montes, Ciudad Universitaria s/n, 28040 Madrid, Spain ORCID ID:E-mail: luis.diaz.balteiro@upm.es (email)
article id 1279, category Research article
Andreas Kreutz, Tuomas Aakala, Russell Grenfell, Timo Kuuluvainen. (2015). Spatial tree community structure in three stands across a forest succession gradient in northern boreal Fennoscandia. Silva Fennica vol. 49 no. 2 article id 1279. https://doi.org/10.14214/sf.1279
Highlights: We studied the tree community spatial structure in three 1.2-ha plots representing naturally developed northern boreal forests of varying ages; Spatial structure showed little differences between the mid-successional, late-successional and old-growth stands; The occurrence of Picea abies relative to Betula spp. indicated a mosaic-like spatial assembly; Mosaics are likely maintained by species-specific replacement, not reciprocal replacement as thought earlier.
Development of species composition during succession is well studied in natural boreal forests, but empirical assessments of how within-stand spatial structure develops in late-successional stages are few. Here, we quantified spatial patterns in three unmanaged stands consisting of Picea abies (L.) Karst. and Betula pubescens Ehrh. and Betula pendula Roth (hereafter Betula spp.) in northern boreal Fennoscandia. We conducted a comprehensive analysis of small-scale spatial point patterns in three fully mapped 1.2-ha sample plots, representing different forest developmental stages: mid-successional, late-successional and old-growth forest. We used several variants of Ripley’s K-function to analyze the spatial point patterns along the successional gradient. Univariate analyses showed that mature trees of both species were either randomly distributed or clumped. P. abies saplings were clumped, and Betula spp. saplings occurred in a random or clumped manner. In the bivariate analyses, saplings were more likely to be found in the surroundings of mature trees of the same species, but occurred independent of the individuals of other tree species. Mature trees showed interspecific repulsion. Only modest differences occurred in the univariate patterns between the three successional stages, but in the bivariate analyses the most evident patterns, i.e. intraspecific attraction and interspecific repulsion, were stronger in the older successional stages. Overall, the studied stands appear structured as species-specific mosaics. These mosaics, along with mixed species composition, seem to be maintained by species self-replacement, which contrasts with findings from earlier studies.
  • Kreutz, Department of Forest Sciences, University of Helsinki, P.O. Box 27, FI-00014 University of Helsinki, Finland ORCID ID:E-mail: andreas.kreutz@wald-rpl.de
  • Aakala, Department of Forest Sciences, University of Helsinki, P.O. Box 27, FI-00014 University of Helsinki, Finland ORCID ID: http://orcid.org/0000-0003-0160-6410 E-mail: tuomas.aakala@helsinki.fi (email)
  • Grenfell, Department of Forest Sciences, University of Helsinki, P.O. Box 27, FI-00014 University of Helsinki, Finland ORCID ID:E-mail: russell.grenfell@gmail.com
  • Kuuluvainen, Department of Forest Sciences, University of Helsinki, P.O. Box 27, FI-00014 University of Helsinki, Finland ORCID ID:E-mail: timo.kuuluvainen@helsinki.fi
article id 1232, category Research article
Pete Bettinger, Mehmet Demirci, Kevin Boston. (2015). Search reversion within s-metaheuristics: impacts illustrated with a forest planning problem. Silva Fennica vol. 49 no. 2 article id 1232. https://doi.org/10.14214/sf.1232
Highlights: The interruption of the sequence of events used to explore a solution space and develop a forest plan, and the re-initiation of the search process from a high-quality, known starting point (reversion) seems necessary for some s-metaheuristics; When using a s-metaheuristic, higher quality forest plans may be developed when the reversion interval is around six iterations of the model.
The use of a reversion technique during the search process of s-metaheuristics has received little attention with respect to forest management and planning problems. Reversion involves the interruption of the sequence of events that are used to explore the solution space and the re-initiation of the search process from a high-quality, known starting point. We explored four reversion rates when applied to three different types of s-metaheuristics that have previously shown promise for the forest planning problem explored, threshold accepting, tabu search, and the raindrop method. For two of the s-metaheuristics, we also explored three types of decision choices, a change to the harvest timing of a single management unit (1-opt move), the swapping of two management unit’s harvest timing (2-opt moves), and the swapping of three management unit’s harvest timing (3-opt moves). One hundred independent forest plans were developed for each of the metaheuristic / reversion rate combinations, all beginning with randomly-generated feasible starting solutions. We found that (a) reversion does improve the quality of the solutions generated, and (b) the rate of reversion is an important factor that can affect solution quality.
  • Bettinger, School of Forestry and Natural Resources, 180 E. Green Street, University of Georgia, Athens, Georgia, USA 30602 ORCID ID:E-mail: pbettinger@warnell.uga.edu (email)
  • Demirci, General Directorate of Forestry, Ministry of Forest and Water Affairs, Republic of Turkey ORCID ID:E-mail: mehmetdemirci@yahoo.com
  • Boston, Department of Forest Engineering, Resources and Management, College of Forestry, Oregon State University, USA ORCID ID:E-mail: Kevin.Boston@oregonstate.edu
article id 1218, category Research article
Mikko Niemi, Mikko Vastaranta, Jussi Peuhkurinen, Markus Holopainen. (2015). Forest inventory attribute prediction using airborne laser scanning in low-productive forestry-drained boreal peatlands. Silva Fennica vol. 49 no. 2 article id 1218. https://doi.org/10.14214/sf.1218
Highlights: Following current forest inventory practises, stem volume was predicted in low-productive drained peatlands (LPDPs) with a root mean square error (RMSE) of 13.7 m3 ha–1; When 30 reference plots measured from LPDPs were added to the prediction, RMSE was decreased to 10.0 m3 ha–1; Additional reference plots from LPDPs did not affect the forest inventory attribute predictions in productive forests.
Nearly 30% of Finland’s land area is covered by peatlands. In Northern parts of the country there is a significant amount of low-productive drained peatlands (LPDPs) where the average annual stem volume growth is less than 1 m3 ha–1. The re-use of LPDPs has been considered thoroughly since Finnish forest legislation was updated and the forest regeneration prerequisite was removed from LPDPs in January 2014. Currently, forestry is one of the re-use alternatives, thus detailed forest resource information is required for allocating activities. However, current forest inventory practices have not been evaluated for sparse growing stocks (e.g., LPDPs). The purpose of our study was to evaluate the suitability of airborne laser scanning (ALS) for mapping forest inventory attributes in LPDPs. We used ALS data with a density of 0.8 pulses per m2, 558 field-measured reference plots (500 from productive forests and 58 from LPDPs) and k nearest neighbour (k-NN) estimation. Our main aim was to study the sensitivity of predictions to the number of LPDP reference plots used in the k-NN estimation. When the reference data consisted of 500 plots from productive forest stands, the root mean square errors (RMSEs) for the prediction accuracy of Lorey’s height, basal area and stem volume were 1.4 m, 2.7 m2 ha–1 and 13.7 m3 ha–1 in LPDPs, respectively. When 30 additional reference plots were allocated to LPDPs, the respective RMSEs were 1.1 m, 1.7 m2 ha–1 and 10.0 m3 ha–1. Additional reference plot allocation did not affect the predictions in productive forest stands.
  • Niemi, Department of Forest Sciences, University of Helsinki, P.O. Box 27, FI-00014, Finland & Centre of Excellence in Laser Scanning Research, Finnish Geospatial Research Institute FGI, Geodeetinrinne 2, FI-02430, Finland ORCID ID:E-mail: mikko.t.niemi@helsinki.fi (email)
  • Vastaranta, Department of Forest Sciences, University of Helsinki, P.O. Box 27, FI-00014, Finland & Centre of Excellence in Laser Scanning Research, Finnish Geospatial Research Institute FGI, Geodeetinrinne 2, FI-02430, Finland ORCID ID:E-mail: mikko.vastaranta@helsinki.fi
  • Peuhkurinen, Arbonaut Oy Ltd., Latokartanontie 7 A, FI-00700, Finland ORCID ID:E-mail: jussi.peuhkurinen@arbonaut.com
  • Holopainen, Department of Forest Sciences, University of Helsinki, P.O. Box 27, FI-00014, Finland & Centre of Excellence in Laser Scanning Research, Finnish Geospatial Research Institute FGI, Geodeetinrinne 2, FI-02430, Finland ORCID ID:E-mail: markus.holopainen@helsinki.fi
article id 1218, category Research article
Mikko Niemi, Mikko Vastaranta, Jussi Peuhkurinen, Markus Holopainen. (2015). Forest inventory attribute prediction using airborne laser scanning in low-productive forestry-drained boreal peatlands. Silva Fennica vol. 49 no. 2 article id 1218. https://doi.org/10.14214/sf.1218
Highlights: Following current forest inventory practises, stem volume was predicted in low-productive drained peatlands (LPDPs) with a root mean square error (RMSE) of 13.7 m3 ha–1; When 30 reference plots measured from LPDPs were added to the prediction, RMSE was decreased to 10.0 m3 ha–1; Additional reference plots from LPDPs did not affect the forest inventory attribute predictions in productive forests.
Nearly 30% of Finland’s land area is covered by peatlands. In Northern parts of the country there is a significant amount of low-productive drained peatlands (LPDPs) where the average annual stem volume growth is less than 1 m3 ha–1. The re-use of LPDPs has been considered thoroughly since Finnish forest legislation was updated and the forest regeneration prerequisite was removed from LPDPs in January 2014. Currently, forestry is one of the re-use alternatives, thus detailed forest resource information is required for allocating activities. However, current forest inventory practices have not been evaluated for sparse growing stocks (e.g., LPDPs). The purpose of our study was to evaluate the suitability of airborne laser scanning (ALS) for mapping forest inventory attributes in LPDPs. We used ALS data with a density of 0.8 pulses per m2, 558 field-measured reference plots (500 from productive forests and 58 from LPDPs) and k nearest neighbour (k-NN) estimation. Our main aim was to study the sensitivity of predictions to the number of LPDP reference plots used in the k-NN estimation. When the reference data consisted of 500 plots from productive forest stands, the root mean square errors (RMSEs) for the prediction accuracy of Lorey’s height, basal area and stem volume were 1.4 m, 2.7 m2 ha–1 and 13.7 m3 ha–1 in LPDPs, respectively. When 30 additional reference plots were allocated to LPDPs, the respective RMSEs were 1.1 m, 1.7 m2 ha–1 and 10.0 m3 ha–1. Additional reference plot allocation did not affect the predictions in productive forest stands.
  • Niemi, Department of Forest Sciences, University of Helsinki, P.O. Box 27, FI-00014, Finland & Centre of Excellence in Laser Scanning Research, Finnish Geospatial Research Institute FGI, Geodeetinrinne 2, FI-02430, Finland ORCID ID:E-mail: mikko.t.niemi@helsinki.fi (email)
  • Vastaranta, Department of Forest Sciences, University of Helsinki, P.O. Box 27, FI-00014, Finland & Centre of Excellence in Laser Scanning Research, Finnish Geospatial Research Institute FGI, Geodeetinrinne 2, FI-02430, Finland ORCID ID:E-mail: mikko.vastaranta@helsinki.fi
  • Peuhkurinen, Arbonaut Oy Ltd., Latokartanontie 7 A, FI-00700, Finland ORCID ID:E-mail: jussi.peuhkurinen@arbonaut.com
  • Holopainen, Department of Forest Sciences, University of Helsinki, P.O. Box 27, FI-00014, Finland & Centre of Excellence in Laser Scanning Research, Finnish Geospatial Research Institute FGI, Geodeetinrinne 2, FI-02430, Finland ORCID ID:E-mail: markus.holopainen@helsinki.fi
article id 1218, category Research article
Mikko Niemi, Mikko Vastaranta, Jussi Peuhkurinen, Markus Holopainen. (2015). Forest inventory attribute prediction using airborne laser scanning in low-productive forestry-drained boreal peatlands. Silva Fennica vol. 49 no. 2 article id 1218. https://doi.org/10.14214/sf.1218
Highlights: Following current forest inventory practises, stem volume was predicted in low-productive drained peatlands (LPDPs) with a root mean square error (RMSE) of 13.7 m3 ha–1; When 30 reference plots measured from LPDPs were added to the prediction, RMSE was decreased to 10.0 m3 ha–1; Additional reference plots from LPDPs did not affect the forest inventory attribute predictions in productive forests.
Nearly 30% of Finland’s land area is covered by peatlands. In Northern parts of the country there is a significant amount of low-productive drained peatlands (LPDPs) where the average annual stem volume growth is less than 1 m3 ha–1. The re-use of LPDPs has been considered thoroughly since Finnish forest legislation was updated and the forest regeneration prerequisite was removed from LPDPs in January 2014. Currently, forestry is one of the re-use alternatives, thus detailed forest resource information is required for allocating activities. However, current forest inventory practices have not been evaluated for sparse growing stocks (e.g., LPDPs). The purpose of our study was to evaluate the suitability of airborne laser scanning (ALS) for mapping forest inventory attributes in LPDPs. We used ALS data with a density of 0.8 pulses per m2, 558 field-measured reference plots (500 from productive forests and 58 from LPDPs) and k nearest neighbour (k-NN) estimation. Our main aim was to study the sensitivity of predictions to the number of LPDP reference plots used in the k-NN estimation. When the reference data consisted of 500 plots from productive forest stands, the root mean square errors (RMSEs) for the prediction accuracy of Lorey’s height, basal area and stem volume were 1.4 m, 2.7 m2 ha–1 and 13.7 m3 ha–1 in LPDPs, respectively. When 30 additional reference plots were allocated to LPDPs, the respective RMSEs were 1.1 m, 1.7 m2 ha–1 and 10.0 m3 ha–1. Additional reference plot allocation did not affect the predictions in productive forest stands.
  • Niemi, Department of Forest Sciences, University of Helsinki, P.O. Box 27, FI-00014, Finland & Centre of Excellence in Laser Scanning Research, Finnish Geospatial Research Institute FGI, Geodeetinrinne 2, FI-02430, Finland ORCID ID:E-mail: mikko.t.niemi@helsinki.fi (email)
  • Vastaranta, Department of Forest Sciences, University of Helsinki, P.O. Box 27, FI-00014, Finland & Centre of Excellence in Laser Scanning Research, Finnish Geospatial Research Institute FGI, Geodeetinrinne 2, FI-02430, Finland ORCID ID:E-mail: mikko.vastaranta@helsinki.fi
  • Peuhkurinen, Arbonaut Oy Ltd., Latokartanontie 7 A, FI-00700, Finland ORCID ID:E-mail: jussi.peuhkurinen@arbonaut.com
  • Holopainen, Department of Forest Sciences, University of Helsinki, P.O. Box 27, FI-00014, Finland & Centre of Excellence in Laser Scanning Research, Finnish Geospatial Research Institute FGI, Geodeetinrinne 2, FI-02430, Finland ORCID ID:E-mail: markus.holopainen@helsinki.fi
article id 1214, category Research article
Katri Hamunen, Outi Virkkula, Teppo Hujala, Juha Hiedanpää, Mikko Kurttila. (2015). Enhancing informal interaction and knowledge co-construction among forest owners. Silva Fennica vol. 49 no. 1 article id 1214. https://doi.org/10.14214/sf.1214
Highlights: Forest owners’ own communities could complement the present expert-driven forestry extension; Enhancing informal interaction between forest owners calls for sufficiently homogeneous reference groups and also new communication contexts; New purposes of forest ownership and innovative forest management practices are suggested topics for novel owner communities; Forest professionals may initiate these communities, but the continuity depends on the owners themselves.
It is a common concern that non-resident private forest owners are less able to make informed decisions regarding their forests. Moreover, the present guidance given by forest professionals is not reaching all owners. In this study, we suggest enhancing knowledge exchange among forest owners by increasing their mutual and informal interaction that could inspire them to co-construct new knowledge. The first objective is to identify present emerging activities that constitute knowledge exchange contexts (communities) for Finnish forest owners. The second objective is to discuss the challenges of current Finnish forest extension and their implications when introducing Communities of Practice as a complementary response to existing, yet insufficient, professional-led extension. Data consist of Finnish forest owners’ and forest professionals’ (n = 43) focus group interviews. The qualitative analysis was theoretically oriented followed by data-driven coding and grouping. According to the results, the role of expert-led encounters is strong in Finland and owners’ opportunities for good mutual communication are rare. Informal communities exist mainly in the countryside among neighbouring owners and within families. To enhance knowledge sharing among owners, one needs to identify innovative topics and activities that would inspire owners to commit to their forest property and perform active silviculture. These communities would operate as creative learning environments allowing participation of different levels. When cultivating forest owners’ communities it is important to consider actors’ roles. Forest owners themselves are responsible for the functions and continuity of these communities, although forest professionals could also initiate new and sufficiently homogenous reference groups for the owners.
  • Hamunen, Natural Resources Institute Finland (Luke), New Business Opportunities, P.O. Box 68, FI-80101 Joensuu, Finland ORCID ID:E-mail: katri.hamunen@luke.fi
  • Virkkula, Oulu University of Applied Sciences, Kotkantie 1, FI-90250 Oulu, Finland ORCID ID:E-mail: outi.virkkula@oamk.fi
  • Hujala, Natural Resources Institute Finland (Luke), New Business Opportunities, P.O. Box 18, FI-01301 Vantaa, Finland ORCID ID: http://orcid.org/0000-0002-7905-7602 E-mail: teppo.hujala@luke.fi (email)
  • Hiedanpää, Natural Resources Institute Finland (Luke), Economy and Society, Itäinen Pitkäkatu 3, FI-20520 Turku, Finland ORCID ID:E-mail: juha.hiedanpaa@luke.fi
  • Kurttila, Natural Resources Institute Finland (Luke), New Business Opportunities, P.O. Box 68, FI-80101 Joensuu, Finland ORCID ID:E-mail: mikko.kurttila@luke.fi
article id 1219, category Research article
Thomas P. Sullivan, Druscilla S. Sullivan. (2014). Diversifying clearcuts with green-tree retention and woody debris structures: conservation of mammals across forest ecological zones. Silva Fennica vol. 48 no. 5 article id 1219. https://doi.org/10.14214/sf.1219
Highlights: Species diversity of small mammals increased with structural complexity left on clearcut sites; Productivity of red-backed vole populations was higher in sites with green-tree retention (GTR) and windrows of woody debris; GTR and windrows may provide additive effect for providing habitat to conserve mammals on clearcuts.
We tested the hypotheses (H) that on newly clearcut-harvested sites, (H1) abundance and species diversity of the forest-floor small mammal community, and (H2) abundance, reproduction, and recruitment of red-backed voles (Myodes gapperi Vigors), would increase with higher levels of structural retention via green-tree retention (GTR) and woody debris (dispersed and constructed into windrows). Study areas were located in three forest ecological zones in southern British Columbia, Canada. For H1, mean total abundance did generally increase with the gradient of retained habitat structure. Mean species richness and diversity were similar among treatment sites but did show an increasing gradient with structural compexity. For H2, mean abundance, reproduction, and recruitment of M. gapperi were higher in GTR and windrow sites than those without retained structures. There was a positive relationship between mean abundance of M. gapperi and total volume of woody debris across treatments. This study is the first investigation of the responses of forest-floor small mammals to an increasing gradient of retained habitat structure via GTR and woody debris on clearcuts. Our assessment of a combination of these two interventions suggested a potentially strong additive effect that could be cautiously extrapolated across three forest ecological zones. With the advent of low levels of GTR on clearcuts, woody debris structures should help provide some habitat to conserve forest mammals on harvest openings.
  • Sullivan, Department of Forest and Conservation Sciences, Faculty of Forestry, University of BC, 2424 Main Mall, Vancouver, BC, Canada V6T 1Z4 ORCID ID:E-mail: tom.sullivan@ubc.ca (email)
  • Sullivan, Applied Mammal Research Institute, 11010 Mitchell Avenue, Summerland, BC, Canada V0H 1Z8 ORCID ID:E-mail: dru.sullivan@appliedmammal.com
article id 1190, category Research article
Jaakko Repola, Kristina Ahnlund Ulvcrona. (2014). Modelling biomass of young and dense Scots pine (Pinus sylvestris L.) dominated mixed forests in northern Sweden. Silva Fennica vol. 48 no. 5 article id 1190. https://doi.org/10.14214/sf.1190
Highlights: The biomass allocation to tree components is different in unmanaged and managed young stands; Higher foliage biomass and lower stem and branch biomass were detected in the unmanaged stands; Models for trees from young and dense stands provide better estimates of biomass in such stands than those based on data from managed stands.
Biomass models for the biomass of above-ground tree components of Scots pine (Pinus sylvestris L.), Norway spruce (Picea abies [L.] Karst.) and birch (Betula pendula Roth and Betula pubescens Ehrh.) in young dense Scots pine dominated forest stands in northern Sweden were constructed. Destructive above-ground biomass sampling was conducted in naturally generated young, dense, Scots pine dominated mixed stands. Three sampling campaigns were undertaken, the first in 1997 and 1998. The second was six years later (2003), and the last 13 years after the first (2010). In total, 280 trees (126 Scots pine, 68 Norway spruce and 86 birches) were sampled from six different stands in northern Sweden. The sampled trees’ diameter at breast height (dbh) was in the range 1–22 cm (Scots pine), 1–21 cm (Norway spruce) and 1–11 cm (birch). Biomass predictions were tested using our models and the widely used biomass models originally constructed for managed stands. The results showed that the biomass allocation to tree components is different in unmanaged and managed young stands; higher foliage biomass and lower stem and branch biomass were detected in the unmanaged stands. The overall conclusion is that the biomass models for managed stands did not produce satisfactory biomass estimates in unthinned, dense, young stands.
  • Repola, Finnish Forest Research Institute, Rovaniemi Research Unit, P.O. Box 16, FI-96301 Rovaniemi, Finland ORCID ID:E-mail: jaakko.repola@metla.fi (email)
  • Ahnlund Ulvcrona, SLU, Forest Biomaterials and Technology, Skogsmarksgränd, SE-901 83 Umeå, Sweden ORCID ID:E-mail: kristina.ulvcrona@slu.se
article id 1135, category Research article
Matts Lindbladh, Per-Ola Hedwall, Ida Wallin, Annika M. Felton, Henrik Böhlenius, Adam Felton. (2014). Short-rotation bioenergy stands as an alternative to spruce plantations: implications for bird biodiversity. Silva Fennica vol. 48 no. 5 article id 1135. https://doi.org/10.14214/sf.1135
Highlights: There is a gap in knowledge regarding the biodiversity implications of replacing production forests with bioenergy stands; We compared the avian biodiversity of early rotation hybrid aspen stands and spruce plantations, the latter being the dominant production forest type in southern Sweden; Our results indicate that young hybrid aspen stands can support relatively diverse and distinctive bird communities.
Global efforts to decrease dependence on fossil fuels have increased interest in bioenergy production. One source of bioenergy is fast growing deciduous tree species, such as hybrid aspen (Populus × wettsteinii Hämet-Ahti). The majority of research on hybrid aspen which assesses biodiversity implications, has however primarily focused on agricultural lands as the reference condition. This has resulted in a substantial gap in our knowledge regarding the biodiversity implications of replacing production forest types with hybrid aspen, a form of reforestation taking place in northern Europe. In this study we address this knowledge gap by comparing the avian biodiversity of young hybrid aspen and spruce (Picea abies L.) plantations of similar age, the latter being the most prevalent forestry alternative in in southern Sweden. We found that hybrid aspen stands had higher bird species richness and abundance as well as a distinct community composition compared to the spruce stands. We suggest that the most likely driver was the greater structural and tree species complexity in the aspen stands, provided for by the fenced exclusion of ungulates from the regenerating hybrid aspen stands. Our results indicate that at least during early stages of regeneration, and in comparison to the dominating production forest type in the region, hybrid aspen stands can support relatively high levels of bird diversity, and a bird species composition more closely associated with broadleaf habitat types requiring restoration in this region.
  • Lindbladh, Southern Swedish Forest Research Centre, SLU – Swedish University of Agricultural Sciences, P.O. Box 49, SE-230 53 Alnarp, Sweden ORCID ID:E-mail: matts.lindbladh@slu.se (email)
  • Hedwall, Southern Swedish Forest Research Centre, SLU – Swedish University of Agricultural Sciences, P.O. Box 49, SE-230 53 Alnarp, Sweden ORCID ID:E-mail: per-ola.hedwall@slu.se
  • Wallin, Southern Swedish Forest Research Centre, SLU – Swedish University of Agricultural Sciences, P.O. Box 49, SE-230 53 Alnarp, Sweden ORCID ID:E-mail: ida.wallin@slu.se
  • Felton, Southern Swedish Forest Research Centre, SLU – Swedish University of Agricultural Sciences, P.O. Box 49, SE-230 53 Alnarp, Sweden ORCID ID:E-mail: annika.felton@slu.se
  • Böhlenius, Southern Swedish Forest Research Centre, SLU – Swedish University of Agricultural Sciences, P.O. Box 49, SE-230 53 Alnarp, Sweden ORCID ID:E-mail: henrik.bohlenius@slu.se
  • Felton, Southern Swedish Forest Research Centre, SLU – Swedish University of Agricultural Sciences, P.O. Box 49, SE-230 53 Alnarp, Sweden ORCID ID:E-mail: adam.felton@slu.se
article id 1207, category Research article
Olli-Pekka Tikkanen, Irina A. Chernyakova. (2014). Past human population history affects current forest landscape structure of Vodlozero National Park, Northwest Russia. Silva Fennica vol. 48 no. 4 article id 1207. https://doi.org/10.14214/sf.1207
Highlights: In large scale (0–20 km), the proportion of spruce in forest stands was positively affected by distance from old villages. This relationship was non-linear with a threshold distance of 15 km; In small scale (0–5 km), old villages affected tree species composition and age structure of forests. Effect on age structure was the strongest on stands growing on mineral soils.
The information about location and size of past human settlements can give new insights into the analysis of landscape structures. Vodlozero National Park (NP) is one the largest strictly protected areas in Northwestern Europe. We mapped the location of historic villages, which were abandoned in 1958, and studied the effect of past human activity in the forest landscape in two different scales using forest survey data. We assessed the possible change in age, volume and tree species composition from the edge of open fields up to the distance of 5 km from villages. We made a larger landscape analysis using a grid of forest stands covering the whole northern part of the NP. The past human activity was clearly visible in the present forest landscape. Distance from villages affected age, volume and tree species composition of the forest stands. This effect was the strongest within the first two kilometers from the villages. At the level of whole northern NP, the proportion of spruce markedly increased after approximately 15 km from the nearest old village. The changes in the forests surrounding the villages were most likely the result of the intensive use of wood for different commodities needed in households and farming, in addition to short rotation slash and burn agriculture. If the occurrence of forest fires was more frequent closer to villages than in more remote areas, it can well explain the observed pattern in the abundance of spruce in the larger landscape that is less tolerant to fire than pine.
  • Tikkanen, Department of Biology, University of Eastern Finland, P.O. Box 111, FI-80101 Joensuu, Finland (Current: School of Forest Sciences, University of Eastern Finland, P.O. Box 111, FI-80101 Joensuu, Finland) & Interdisciplinary Research and Educational Center of Cross-border Communication CARELICA, Institute of History, Political and Social Sciences, Petrozavodsk State University, 33 Lenin Prospectus, 185910 Petrozavodsk, Republic of Karelia, Russia ORCID ID:E-mail: Olli-Pekka.Tikkanen@uef.fi (email)
  • Chernyakova, Interdisciplinary Research and Educational Center of Cross-border Communication CARELICA, Institute of History, Political and Social Sciences, Petrozavodsk State University, 33 Lenin Prospectus, 185910 Petrozavodsk, Republic of Karelia, Russia ORCID ID:E-mail: irina.chernyakova@onego.ru
article id 1207, category Research article
Olli-Pekka Tikkanen, Irina A. Chernyakova. (2014). Past human population history affects current forest landscape structure of Vodlozero National Park, Northwest Russia. Silva Fennica vol. 48 no. 4 article id 1207. https://doi.org/10.14214/sf.1207
Highlights: In large scale (0–20 km), the proportion of spruce in forest stands was positively affected by distance from old villages. This relationship was non-linear with a threshold distance of 15 km; In small scale (0–5 km), old villages affected tree species composition and age structure of forests. Effect on age structure was the strongest on stands growing on mineral soils.
The information about location and size of past human settlements can give new insights into the analysis of landscape structures. Vodlozero National Park (NP) is one the largest strictly protected areas in Northwestern Europe. We mapped the location of historic villages, which were abandoned in 1958, and studied the effect of past human activity in the forest landscape in two different scales using forest survey data. We assessed the possible change in age, volume and tree species composition from the edge of open fields up to the distance of 5 km from villages. We made a larger landscape analysis using a grid of forest stands covering the whole northern part of the NP. The past human activity was clearly visible in the present forest landscape. Distance from villages affected age, volume and tree species composition of the forest stands. This effect was the strongest within the first two kilometers from the villages. At the level of whole northern NP, the proportion of spruce markedly increased after approximately 15 km from the nearest old village. The changes in the forests surrounding the villages were most likely the result of the intensive use of wood for different commodities needed in households and farming, in addition to short rotation slash and burn agriculture. If the occurrence of forest fires was more frequent closer to villages than in more remote areas, it can well explain the observed pattern in the abundance of spruce in the larger landscape that is less tolerant to fire than pine.
  • Tikkanen, Department of Biology, University of Eastern Finland, P.O. Box 111, FI-80101 Joensuu, Finland (Current: School of Forest Sciences, University of Eastern Finland, P.O. Box 111, FI-80101 Joensuu, Finland) & Interdisciplinary Research and Educational Center of Cross-border Communication CARELICA, Institute of History, Political and Social Sciences, Petrozavodsk State University, 33 Lenin Prospectus, 185910 Petrozavodsk, Republic of Karelia, Russia ORCID ID:E-mail: Olli-Pekka.Tikkanen@uef.fi (email)
  • Chernyakova, Interdisciplinary Research and Educational Center of Cross-border Communication CARELICA, Institute of History, Political and Social Sciences, Petrozavodsk State University, 33 Lenin Prospectus, 185910 Petrozavodsk, Republic of Karelia, Russia ORCID ID:E-mail: irina.chernyakova@onego.ru
article id 1207, category Research article
Olli-Pekka Tikkanen, Irina A. Chernyakova. (2014). Past human population history affects current forest landscape structure of Vodlozero National Park, Northwest Russia. Silva Fennica vol. 48 no. 4 article id 1207. https://doi.org/10.14214/sf.1207
Highlights: In large scale (0–20 km), the proportion of spruce in forest stands was positively affected by distance from old villages. This relationship was non-linear with a threshold distance of 15 km; In small scale (0–5 km), old villages affected tree species composition and age structure of forests. Effect on age structure was the strongest on stands growing on mineral soils.
The information about location and size of past human settlements can give new insights into the analysis of landscape structures. Vodlozero National Park (NP) is one the largest strictly protected areas in Northwestern Europe. We mapped the location of historic villages, which were abandoned in 1958, and studied the effect of past human activity in the forest landscape in two different scales using forest survey data. We assessed the possible change in age, volume and tree species composition from the edge of open fields up to the distance of 5 km from villages. We made a larger landscape analysis using a grid of forest stands covering the whole northern part of the NP. The past human activity was clearly visible in the present forest landscape. Distance from villages affected age, volume and tree species composition of the forest stands. This effect was the strongest within the first two kilometers from the villages. At the level of whole northern NP, the proportion of spruce markedly increased after approximately 15 km from the nearest old village. The changes in the forests surrounding the villages were most likely the result of the intensive use of wood for different commodities needed in households and farming, in addition to short rotation slash and burn agriculture. If the occurrence of forest fires was more frequent closer to villages than in more remote areas, it can well explain the observed pattern in the abundance of spruce in the larger landscape that is less tolerant to fire than pine.
  • Tikkanen, Department of Biology, University of Eastern Finland, P.O. Box 111, FI-80101 Joensuu, Finland (Current: School of Forest Sciences, University of Eastern Finland, P.O. Box 111, FI-80101 Joensuu, Finland) & Interdisciplinary Research and Educational Center of Cross-border Communication CARELICA, Institute of History, Political and Social Sciences, Petrozavodsk State University, 33 Lenin Prospectus, 185910 Petrozavodsk, Republic of Karelia, Russia ORCID ID:E-mail: Olli-Pekka.Tikkanen@uef.fi (email)
  • Chernyakova, Interdisciplinary Research and Educational Center of Cross-border Communication CARELICA, Institute of History, Political and Social Sciences, Petrozavodsk State University, 33 Lenin Prospectus, 185910 Petrozavodsk, Republic of Karelia, Russia ORCID ID:E-mail: irina.chernyakova@onego.ru
article id 1188, category Research article
Kristina Wallertz, Henrik Nordenhem, Göran Nordlander. (2014). Damage by the pine weevil Hylobius abietis to seedlings of two native and five introduced tree species in Sweden. Silva Fennica vol. 48 no. 4 article id 1188. https://doi.org/10.14214/sf.1188
Highlights: Both native and introduced confer species in Sweden can be highly susceptible to damage by the pine weevil; Douglas fir and Sitka spruce were generally the most damaged among six studied conifer species; The results highlight some of the risks in establishing exotic tree species for forest production.
There is increasing interest in using introduced species in Swedish forestry in response to climate change, but it is important to assess their resistance to native pests. Thus, we compared the extent of pine weevil feeding on two dominant native conifers, Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies (L.) Karst.), the non-host deciduous broadleaf hybrid aspen (Populus × wettsteinii Hämet-Ahti) and four introduced conifers: Douglas fir (Pseudotsuga menziesii (Mirb.) Franco), hybrid larch (Larix × marschlinsii Coaz), Sitka spruce (Picea sitchensis (Bong.) Carriére) and lodgepole pine (Pinus contorta Douglas ex Loudon). The extent of feeding damage on seedlings and its effect on their vitality were examined in a field study in south-central Sweden and a laboratory experiment, which gave largely consistent results. Generally, the species most heavily attacked by the pine weevil, in both experiments, were Douglas fir and Sitka spruce. In the field experiment pine weevils killed or severely damaged significantly higher proportions of Douglas fir and Sitka spruce seedlings (60%) than any other species except Norway spruce (49%). Among conifer seedlings the proportions of killed or severely damaged seedlings were lowest for Scots pine and hybrid larch (27%) and Lodgepole pine (36%). The results indicate that most conifer species planted on young clear-cuttings in Sweden need some kind of pine weevil protection, and the possibility that introducing new tree species might increase damage caused by pests must be considered. For instance, widespread use of hybrid aspen could reduce damage by pine weevils, but increase damage by other, untested pests or pathogens.
  • Wallertz, Unit for Field-based Forest Research, Swedish University of Agricultural Sciences (SLU), Asa Research Station, SE-36030 Lammhult, Sweden ORCID ID:E-mail: kristina.wallertz@slu.se (email)
  • Nordenhem, Department of Ecology, Swedish University of Agricultural Sciences (SLU), P.O. Box 7044, SE-75007 Uppsala, Sweden ORCID ID:E-mail: henrik.nordenhem@slu.se
  • Nordlander, Department of Ecology, Swedish University of Agricultural Sciences (SLU), P.O. Box 7044, SE-75007 Uppsala, Sweden ORCID ID:E-mail: goran.nordlander@slu.se
article id 1188, category Research article
Kristina Wallertz, Henrik Nordenhem, Göran Nordlander. (2014). Damage by the pine weevil Hylobius abietis to seedlings of two native and five introduced tree species in Sweden. Silva Fennica vol. 48 no. 4 article id 1188. https://doi.org/10.14214/sf.1188
Highlights: Both native and introduced confer species in Sweden can be highly susceptible to damage by the pine weevil; Douglas fir and Sitka spruce were generally the most damaged among six studied conifer species; The results highlight some of the risks in establishing exotic tree species for forest production.
There is increasing interest in using introduced species in Swedish forestry in response to climate change, but it is important to assess their resistance to native pests. Thus, we compared the extent of pine weevil feeding on two dominant native conifers, Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies (L.) Karst.), the non-host deciduous broadleaf hybrid aspen (Populus × wettsteinii Hämet-Ahti) and four introduced conifers: Douglas fir (Pseudotsuga menziesii (Mirb.) Franco), hybrid larch (Larix × marschlinsii Coaz), Sitka spruce (Picea sitchensis (Bong.) Carriére) and lodgepole pine (Pinus contorta Douglas ex Loudon). The extent of feeding damage on seedlings and its effect on their vitality were examined in a field study in south-central Sweden and a laboratory experiment, which gave largely consistent results. Generally, the species most heavily attacked by the pine weevil, in both experiments, were Douglas fir and Sitka spruce. In the field experiment pine weevils killed or severely damaged significantly higher proportions of Douglas fir and Sitka spruce seedlings (60%) than any other species except Norway spruce (49%). Among conifer seedlings the proportions of killed or severely damaged seedlings were lowest for Scots pine and hybrid larch (27%) and Lodgepole pine (36%). The results indicate that most conifer species planted on young clear-cuttings in Sweden need some kind of pine weevil protection, and the possibility that introducing new tree species might increase damage caused by pests must be considered. For instance, widespread use of hybrid aspen could reduce damage by pine weevils, but increase damage by other, untested pests or pathogens.
  • Wallertz, Unit for Field-based Forest Research, Swedish University of Agricultural Sciences (SLU), Asa Research Station, SE-36030 Lammhult, Sweden ORCID ID:E-mail: kristina.wallertz@slu.se (email)
  • Nordenhem, Department of Ecology, Swedish University of Agricultural Sciences (SLU), P.O. Box 7044, SE-75007 Uppsala, Sweden ORCID ID:E-mail: henrik.nordenhem@slu.se
  • Nordlander, Department of Ecology, Swedish University of Agricultural Sciences (SLU), P.O. Box 7044, SE-75007 Uppsala, Sweden ORCID ID:E-mail: goran.nordlander@slu.se
article id 1153, category Research article
Anu Akujärvi, Ville Hallikainen, Mikko Hyppönen, Eero Mattila, Kari Mikkola, Pasi Rautio. (2014). Effects of reindeer grazing and forestry on ground lichens in Finnish Lapland. Silva Fennica vol. 48 no. 3 article id 1153. https://doi.org/10.14214/sf.1153
Highlights: Both reindeer grazing and forestry affect the cover and biomass of reindeer lichens; Reindeer grazing has bigger impact than forestry; The lichen cover was about five-fold and the biomass about fifteen-fold in the ungrazed (fenced) sites than in the grazed ones; The decrease of not only the biomass, but also the cover of lichens, is alarming.
Reindeer husbandry and forestry are practiced in the same areas in northern Fennoscandia. Reindeer pastures have largely deteriorated. We aimed to quantify the separate and combined effects of reindeer grazing and forestry on the amount of ground lichens. To do this, we mapped and inventoried all larger enclosures (49) in Finnish Lapland where forest management practices were similar in both sides of the fence. The average time since fencing was 43 years. We recorded the cover and estimated dry biomass of ground lichens, as well as parameters describing forest stand characteristics. The effect of reindeer grazing on both the cover and estimated dry biomass of lichens was clear: in the ungrazed (fenced) sites, the lichen cover (35.8%) was on average 5.3-fold and the dry biomass (1929 kg ha–1) 14.8-fold compared with the corresponding estimates in the grazed sites (6.8% and 130 kg ha–1). The effect of forestry on lichens was smaller. In the grazed stands the cover and biomass of lichens were higher in the mature stands compared to the younger stand development classes, whereas in the ungrazed stands there were no significant differences between the development classes. Both reindeer grazing and forestry affect the cover and biomass of ground lichens. The influence of reindeer grazing is, however, much heavier than that of forestry. The decrease of not only the biomass, but also the lichen cover, is alarming. The decrease of lichen cover may hinder the recovery of reindeer pastures, which in the long run endangers the sustainability of reindeer husbandry.
  • Akujärvi, Finnish Environment Institute, Helsinki, Finland ORCID ID:E-mail: anu.akujarvi@ymparisto.fi
  • Hallikainen, Finnish Forest Research Institute, Northern Unit, P.O. Box 16, FI-96301 Rovaniemi, Finland ORCID ID:E-mail: ville.hallikainen@metla.fi
  • Hyppönen, Finnish Forest Research Institute, Northern Unit, P.O. Box 16, FI-96301 Rovaniemi, Finland ORCID ID:E-mail: mikko.hypponen@metla.fi (email)
  • Mattila, Finnish Forest Research Institute, Northern Unit, P.O. Box 16, FI-96301 Rovaniemi, Finland ORCID ID:E-mail: eero.mattila@metla.fi
  • Mikkola, Finnish Forest Research Institute, Northern Unit, P.O. Box 16, FI-96301 Rovaniemi, Finland ORCID ID:E-mail: kari.mikkola@metla.fi
  • Rautio, Finnish Forest Research Institute, Northern Unit, P.O. Box 16, FI-96301 Rovaniemi, Finland ORCID ID:E-mail: pasi.rautio@metla.fi
article id 1120, category Research article
Ilari Lehtonen, Petri Hoppula, Pentti Pirinen, Hilppa Gregow. (2014). Modelling crown snow loads in Finland: a comparison of two methods. Silva Fennica vol. 48 no. 3 article id 1120. https://doi.org/10.14214/sf.1120
Highlights: A new method to model crown snow loads is presented and compared with a previously published simpler method; The heaviest crown snow loads in Finland are found to typically occur in the eastern parts of the country; The relative importance of different snow load types varies between different regions of Finland.
The spatial occurrence of heavy crown snow loads in Finland between 1961 and 2010 is studied by using for the first time a model that classifies the snow load into four different types: rime, dry snow, wet snow and frozen snow. In producing this climatology, we used meteorological observations made at 29 locations across Finland. The model performance is evaluated against classified daily images of canopy snow cover and with the help of two short case studies. The results are further compared to those achieved with a simpler method used in previous studies. The heaviest crown snow loads are found to occur typically in eastern Finland. The new method reveals that this holds not only for the total snow loads but also for the different snow load types, although there are certain differences in their geographical occurrence. The greatest benefit achieved with the new method is the inclusion of rime accretion. The forests most prone to heavy riming are those located on tree-covered hills in northern Finland, but as the terrain elevation affects riming efficiency greatly, these small-scale variations in the snow load amounts could not be described in this study in great detail. Moreover, the results are more inaccurate in northern Finland where variations in the terrain elevation are greater than elsewhere. Otherwise, the largest uncertainties in this study are related to wind speed measurements and possibly partly because of that, we were not able to detect any significant trends in the crown snow-load amounts over the study period.
  • Lehtonen, Finnish Meteorological Institute, P.O. Box 503, FI-00101 Helsinki, Finland ORCID ID:E-mail: ilari.lehtonen@fmi.fi (email)
  • Hoppula, Finnish Meteorological Institute, P.O. Box 503, FI-00101 Helsinki, Finland ORCID ID:E-mail: petri.hoppula@fmi.fi
  • Pirinen, Finnish Meteorological Institute, P.O. Box 503, FI-00101 Helsinki, Finland ORCID ID:E-mail: pentti.pirinen@fmi.fi
  • Gregow, Finnish Meteorological Institute, P.O. Box 503, FI-00101 Helsinki, Finland ORCID ID:E-mail: hilppa.gregow@fmi.fi
article id 1087, category Research article
Ilkka Korpela, Lauri Mehtätalo, Lauri Markelin, Anne Seppänen, Annika Kangas. (2014). Tree species identification in aerial image data using directional reflectance signatures. Silva Fennica vol. 48 no. 3 article id 1087. https://doi.org/10.14214/sf.1087
Highlights: Multispectral reflectance data showed a strong and spectrally correlated tree effect; There was no gain in species classification from using species-specific differences of directional reflectance in real data and only a marginal improvement in simulated data; The directional signatures extracted in multiple images are obscured by the intrinsic within-species variation, correlated observations and inherent reflectance calibration errors.
Tree species identification using optical remote sensing is challenging. Modern digital photogrammetric cameras enable radiometrically quantitative remote sensing and the estimation of reflectance images, in which the observations depend largely on the reflectance properties of targets. Previous research has shown that there are species-specific differences in how the brightness observed changes when the viewing direction in an aerial image is altered. We investigated if accounting for such directional signatures enhances species classification, using atmospherically corrected, real and simulated multispectral Leica ADS40 line-camera data. Canopy in direct and diffuse illumination were differentiated and species-specific variance-covariance structures were analyzed in real reflectance data, using mixed-effects modeling. Species classification simulations aimed at elucidating the level of accuracy that can be achieved by using images of different quality, number and view-illumination geometry. In real data, a substantial variance component was explained by tree effect, which demonstrates that observations from a tree correlate between observation geometries as well as spectrally. Near-infrared band showed the strongest tree effect, while the directionality was weak in that band. The gain from directional signatures was insignificant in real data, while simulations showed a potential gain of 1–3 percentage points in species classification accuracy. The quality of reflectance calibration was found to be important as well as the image acquisition geometry. We conclude that increasing the number of image observations cancels out random observation noise and reflectance calibration errors, but fails to eliminate the tree effect and systematic calibration inaccuracy. Directional reflectance constitutes a marginal improvement in tree species classification.
  • Korpela, Department of Forest Sciences, University of Helsinki, P.O. Box 27, FI-00014, Finland ORCID ID:E-mail: ilkka.korpela@helsinki.fi (email)
  • Mehtätalo, Faculty of Science and Forestry, University of Eastern Finland, P.O. Box 111, FI-80101 Joensuu, Finland ORCID ID:E-mail: lauri.mehtatalo@uef.fi
  • Markelin, Department of Remote Sensing and Photogrammetry, Finnish Geodetic Institute, P.O. Box 15, FI-02431 Masala, Finland ORCID ID:E-mail: lauri.markelin@fgi.fi
  • Seppänen, Faculty of Science and Forestry, University of Eastern Finland, P.O. Box 111, FI-80101 Joensuu, Finland ORCID ID:E-mail: anne.seppanen@arbonaut.com
  • Kangas, Department of Forest Sciences, University of Helsinki, P.O. Box 27, FI-00014, Finland ORCID ID:E-mail: annika.kangas@helsinki.fi
article id 1054, category Research article
Karin Kolis, Juhana Hiironen, Esa Ärölä, Arvo Vitikainen. (2014). Effects of sale-specific factors on stumpage prices in Finland. Silva Fennica vol. 48 no. 3 article id 1054. https://doi.org/10.14214/sf.1054
Highlights: Data on 4824 individual sales were used to estimate which factors affect stumpage prices; The time of sale, seasonal harvest restrictions, the location and the assortment affected prices; Larger total volumes and shorter forest haulage distances raised unit prices; A higher percentage of the assortment and percentage of sawlogs within the sale corresponded to higher prices.
Buyers of standing timber take not only the market situation but also the harvest costs into consideration when making purchase offers. In Finland, 85% of all timber is sold as standing timber, but there is little information for forest owners and third parties regarding how differences in harvest costs are reflected in the stumpage prices. This article analyses the relationship between sale-specific factors and stumpage prices in Finland. Data on 4824 standing timber sales between 2008 and 2012 were gathered from five local Forest Management Associations. Regression analyses were run on the stumpage prices (euros m–3) paid for sawlogs and pulpwood. Seasonal harvest restrictions, the volume of the sale and the timber assortment influenced stumpage prices, as did the presence of forest damages. Prices also differed over time and between locations. Furthermore, the forest haulage distance was statistically significant for pulpwood. The results suggest that the size of the individual sales and the composition of assortments affect the income owners earn from their forest. The results can be used to estimate stumpage prices and the monetary impacts on forest owners of procedures such as forest road network planning and land consolidation, as well as for valuation of forests.
  • Kolis, Aalto University, Department of Real Estate, Planning and Geoinformatics, P.O. Box 12200, FI-00076 Aalto, Finland ORCID ID:E-mail: karin.kolis@aalto.fi (email)
  • Hiironen, Aalto University, Department of Real Estate, Planning and Geoinformatics, P.O. Box 12200, FI-00076 Aalto, Finland ORCID ID:E-mail: juhana.hiironen@aalto.fi
  • Ärölä, National Land Survey of Finland, Production Support Services, P.O. Box 84, FI-00521 Helsinki, Finland ORCID ID:E-mail: esa.arola@nls.fi
  • Vitikainen, Aalto University, Department of Real Estate, Planning and Geoinformatics, P.O. Box 12200, FI-00076 Aalto, Finland ORCID ID:E-mail: arvo.vitikainen@aalto.fi
article id 983, category Research article
Sakari Tuominen, Juho Pitkänen, Andras Balazs, Kari T. Korhonen, Pekka Hyvönen, Eero Muinonen. (2014). NFI plots as complementary reference data in forest inventory based on airborne laser scanning and aerial photography in Finland. Silva Fennica vol. 48 no. 2 article id 983. https://doi.org/10.14214/sf.983
Highlights: Using NFI plots in forest management inventories could provide a way for rationalising forest inventory data acquisition; NFI plots were used as additional reference data in laser scanning and aerial image based forest inventory; NFI plots improved the estimates of some forest variables; There are differences between the two inventory types that cause difficulties in combining the data.
In Finland, there are currently two, parallel sample-plot-based forest inventory systems, which differ in their methodologies, sampling designs, and objectives. One is the National Forest Inventory (NFI), aimed at unbiased inventory results at national and regional level. The other is the Forest Centre’s management-oriented forest inventory based on interpretation of airborne laser scanning and aerial images, with the aim of locally accurate stand-level forest estimates. The National Forest Inventory utilises relascope sample plots with systematic cluster sampling. This inventory method is optimised for accuracy of regional volume estimates. In contrast, the management-oriented forest inventory utilises circular sample plots with an allocation system covering certain pre-defined forest classes in the inventory area. This method is optimised to produce reference data for interpretation of the remote-sensing materials in use. In this study, we tested the feasibility of the National Forest Inventory sample plots in provision of additional reference data for the management-oriented inventory. Various combinations of NFI plots and management inventory plots were tested in the interpretation of the laser and aerial-image data. Adding NFI plots in the reference data generally improved the accuracy of the volume estimates by tree species but not the estimates of total volume or stand mean height and diameter. The difference between the plot types in the NFI and management inventories causes difficulties in combination of the two datasets.
  • Tuominen, Finnish Forest Research Institute, P.O. Box 18, FI-01301 Vantaa, Finland ORCID ID:E-mail: sakari.tuominen@metla.fi (email)
  • Pitkänen, Finnish Forest Research Institute, P.O. Box 68, FI-80101 Joensuu, Finland ORCID ID:E-mail: juho.pitkanen@metla.fi
  • Balazs, Finnish Forest Research Institute, P.O. Box 18, FI-01301 Vantaa, Finland ORCID ID:E-mail: andras.balazs@metla.fi
  • Korhonen, Finnish Forest Research Institute, P.O. Box 68, FI-80101 Joensuu, Finland ORCID ID:E-mail: kari.t.korhonen@metla.fi
  • Hyvönen, Finnish Forest Research Institute, P.O. Box 68, FI-80101 Joensuu, Finland ORCID ID:E-mail: pekka.hyvonen@metla.fi
  • Muinonen, Finnish Forest Research Institute, P.O. Box 68, FI-80101 Joensuu, Finland ORCID ID:E-mail: eero.muinonen@metla.fi
article id 982, category Research article
Karri Uotila, Timo Saksa, Juho Rantala, Nuutti Kiljunen. (2014). Labour consumption models applied to motor-manual pre-commercial thinning in Finland. Silva Fennica vol. 48 no. 2 article id 982. https://doi.org/10.14214/sf.982
Highlights: When a young stand grows and gets older, the work time needed to make pre-commercial thinning increases. The stands of Norway spruce (Picea abies (L.) Karst.), Scots pine (Pinus sylvestris L.) and hardwoods (Betula spp.) required an additional 8.2%, 5.2%, and 3.3% work-time per year, respectively.
Labour models were developed to estimate the time required to Pre-Commercially Thin (PCT) with a clearing saw 4- to 20-year-old stands of the main commercial tree species in Finland. Labour (i.e., work-time consumption) was estimated from the density and stem diameter of the removal of 448 stands via an existing work productivity function. The removal based estimator attained was used as the basis for a priori mixed linear regression models. The main finding was that when a young stand grows and gets older, the work time needed to make a PCT increases. The stands of Norway spruce (Picea abies (L.) Karst.), Scots pine (Pinus sylvestris L.) and hardwoods (Betula spp.) required an additional 8.2%, 5.2%, and 3.3% work-time per year, respectively. Site fertility also played a role in that the most fertile site (mesic OMT) had an estimated labour requirement 114% higher than that for dryish VT. We also note that, per unit area, small stands require less labour than large ones and soil preparation method had a minor effect on the labour estimate. The stands which had previously gone through PCT were separately analysed. In those stands, the only significant variable concerning the labour estimate was age. The a priori models described here can help foresters to develop economic management programmes and issue quotes for forestry services.
  • Uotila, Finnish Forest Research Institute, Juntintie 154, FI-77600 Suonenjoki, Finland ORCID ID:E-mail: karri.uotila@metla.fi (email)
  • Saksa, Finnish Forest Research Institute, Juntintie 154, FI-77600 Suonenjoki, Finland ORCID ID:E-mail: timo.saksa@metla.fi
  • Rantala, Metsä Group, Lielahdenkatu 10, FI-33400 Tampere, Finland ORCID ID:E-mail: juho.rantala@metsagroup.com
  • Kiljunen, Metsähallitus, Asemakatu 7, FI-70107 Kuopio, Finland ORCID ID:E-mail: nuutti.kiljunen@metsa.fi
article id 975, category Research article
Renats Trubins, Ola Sallnäs. (2014). Categorical mapping from estimates of continuous forest attributes – classification and accuracy. Silva Fennica vol. 48 no. 2 article id 975. https://doi.org/10.14214/sf.975
Highlights: The paper presents an approach to classification and accuracy assessment of ad-hoc categorical maps based on existing spatial datasets with estimates of continuous forest variables; Pixel level class membership probabilities are estimated using a Bayesian network model.
Spatially explicit data on forest attributes is demanded for various research with landscape perspective. Existing datasets with estimates of continuous forest variables are often used as the basis for producing categorical forest type maps. Normally, this type of maps are used without knowing their accuracy. This paper presents a Bayesian network model for estimating pixel level class membership probabilities of thus derived categorical maps. Class membership probabilities can be used as a post-classification measure of map accuracy and in the process of map classification affecting the assignments of class labels. The method is applied in mapping deciduous dominated forests on the basis of the k-NN Sweden 2005 dataset in a study area in southern Sweden. The results indicate rather low accuracy for deciduous class regardless of the map classification method: 0.48 versus 0.50 in the maps classified without and with the use of the class membership probabilities given equal deciduous area. When probability-based classification is applied, the level of accuracy varies with the assumed map class proportions. Thus, when deciduous class area corresponding to the National Forest Inventory estimate was used, the accuracy of only 0.35 was obtained for the deciduous map class.
  • Trubins, Southern Swedish Forest Research Centre, Swedish University of Agricultural Sciences, Box 49, 230 53 Alnarp, Sweden ORCID ID:E-mail: renats.trubins@slu.se (email)
  • Sallnäs, Southern Swedish Forest Research Centre, Swedish University of Agricultural Sciences, Box 49, 230 53 Alnarp, Sweden ORCID ID:E-mail: ola.sallnas@slu.se
article id 989, category Research article
Anna Saarsalmi, Pekka Tamminen, Mikko Kukkola. (2014). Effects of long-term fertilisation on soil properties in Scots pine and Norway spruce stands. Silva Fennica vol. 48 no. 1 article id 989. https://doi.org/10.14214/sf.989
Highlights: N fertilisation increased the amount of carbon in the organic layer; N fertilisation decreased the C/N ratio in the surface soil; N addition increased the amount of most nutrients in the organic layer; N fertilisation tended to lower pH, although only slightly.
The response of surface soil after 45- to 52-years to repeated nitrogen and phosphorus fertilisation was studied. This study included 30 factorial experiments established in young (5- to 30-year-old) stands using plots of 900 m2, on average, and by randomising treatments within each experiment. Total amount of N added varied from 534 to 1908 kg ha–1 and that of P from 69 to 193 kg ha–1, repeated at every second N fertilisation. Liming was performed twice; in total, 6000 kg ha–1 of dolomite was applied. Nitrogen fertilisation increased the mass of the organic layer and the amount of carbon and consequently the amounts of most of the elements in the organic layer. In both the organic layer and the 0–10 cm layer of mineral soil, nitrogen fertilisation decreased the C/N ratio and tended to lower pH, although only slightly. Phosphorus fertilisation increased the amounts of P and Ca. Liming increased the total amounts of most elements in the organic layer, except for C and N. We were able to derive models to describe how changes in the chemical properties of the surface soil depended on doses of elements and on site and stand properties.
  • Saarsalmi, Finnish Forest Research Institute, P.O. Box 18, FI-01301 Vantaa, Finland ORCID ID:E-mail: anna.saarsalmi@metla.fi (email)
  • Tamminen, Finnish Forest Research Institute, P.O. Box 18, FI-01301 Vantaa, Finland ORCID ID:E-mail: pekka.tamminen@metla.fi
  • Kukkola, Finnish Forest Research Institute, P.O. Box 18, FI-01301 Vantaa, Finland ORCID ID:E-mail: mikko.kukkola@metla.fi
article id 989, category Research article
Anna Saarsalmi, Pekka Tamminen, Mikko Kukkola. (2014). Effects of long-term fertilisation on soil properties in Scots pine and Norway spruce stands. Silva Fennica vol. 48 no. 1 article id 989. https://doi.org/10.14214/sf.989
Highlights: N fertilisation increased the amount of carbon in the organic layer; N fertilisation decreased the C/N ratio in the surface soil; N addition increased the amount of most nutrients in the organic layer; N fertilisation tended to lower pH, although only slightly.
The response of surface soil after 45- to 52-years to repeated nitrogen and phosphorus fertilisation was studied. This study included 30 factorial experiments established in young (5- to 30-year-old) stands using plots of 900 m2, on average, and by randomising treatments within each experiment. Total amount of N added varied from 534 to 1908 kg ha–1 and that of P from 69 to 193 kg ha–1, repeated at every second N fertilisation. Liming was performed twice; in total, 6000 kg ha–1 of dolomite was applied. Nitrogen fertilisation increased the mass of the organic layer and the amount of carbon and consequently the amounts of most of the elements in the organic layer. In both the organic layer and the 0–10 cm layer of mineral soil, nitrogen fertilisation decreased the C/N ratio and tended to lower pH, although only slightly. Phosphorus fertilisation increased the amounts of P and Ca. Liming increased the total amounts of most elements in the organic layer, except for C and N. We were able to derive models to describe how changes in the chemical properties of the surface soil depended on doses of elements and on site and stand properties.
  • Saarsalmi, Finnish Forest Research Institute, P.O. Box 18, FI-01301 Vantaa, Finland ORCID ID:E-mail: anna.saarsalmi@metla.fi (email)
  • Tamminen, Finnish Forest Research Institute, P.O. Box 18, FI-01301 Vantaa, Finland ORCID ID:E-mail: pekka.tamminen@metla.fi
  • Kukkola, Finnish Forest Research Institute, P.O. Box 18, FI-01301 Vantaa, Finland ORCID ID:E-mail: mikko.kukkola@metla.fi
article id 980, category Research article
Atte Komonen, Panu Halme, Mari Jäntti, Tuuli Koskela, Janne S. Kotiaho, Tero Toivanen. (2014). Created substrates do not fully mimic natural substrates in restoration: the occurrence of polypores on spruce logs. Silva Fennica vol. 48 no. 1 article id 980. https://doi.org/10.14214/sf.980
Highlights: Polypore communities were more homogeneous among created than among natural logs; The old-growth forest indicator Phellinus ferrugineofuscus occurred frequently on natural logs, but occupied only a few created logs; Results show that created logs do not fully mimic natural logs.
Many protected areas have been under intensive forest management prior to protection and thus lack natural ecosystem structures and dynamics. Dead wood is a key structure in forests harboring hundreds of threatened species. We investigated the ecological success of dead wood creation as a boreal forest restoration measure. We analysed whether the polypore communities of chain-saw felled and girdled (subsequently fallen) Norway spruce (Picea abies (L.) H. Karst.) logs differ from naturally formed spruce logs of similar decay stage and size. The study was conducted in Leivonmäki National Park in central Finland 8 years after the restoration measures. The average number of polypore species was highest on the chain-saw felled logs and most of the common polypore species were most frequent on this substrate. However, among the natural logs, number of species increased more steeply with increasing number of logs, suggesting greater variation in community composition on this substrate. The old-growth forest indicator Phellinus ferrugineofuscus occurred frequently on natural logs, occupied a few girdled logs but was absent from chain-saw felled logs. Our results show that from the polypore perspective created logs do not fully mimic natural logs, suggesting that creating substrates for species may pose a challenge for restoration.
  • Komonen, Department of Biological and Environmental Science, P.O. Box 35, FI-40014, University of Jyväskylä, Finland ORCID ID:E-mail: atte.komonen@jyu.fi (email)
  • Halme, Department of Biological and Environmental Science, P.O. Box 35, FI-40014, University of Jyväskylä, Finland ORCID ID:E-mail: panu.halme@jyu.fi
  • Jäntti, Department of Biological and Environmental Science, P.O. Box 35, FI-40014, University of Jyväskylä, Finland ORCID ID:E-mail: mari.j.jantti@student.jyu.fi
  • Koskela, Department of Biological and Environmental Science, P.O. Box 35, FI-40014, University of Jyväskylä, Finland ORCID ID:E-mail: tuuli.e.koskela@student.jyu.fi
  • Kotiaho, Department of Biological and Environmental Science, P.O. Box 35, FI-40014, University of Jyväskylä, Finland ORCID ID:E-mail: janne.kotiaho@jyu.fi
  • Toivanen, Department of Biological and Environmental Science, P.O. Box 35, FI-40014, University of Jyväskylä, Finland; Current: Birdlife Finland, Annankatu 29 A 16, FI-00100 Helsinki, Finland ORCID ID:E-mail: tero.toivanen@birdlife.fi
article id 980, category Research article
Atte Komonen, Panu Halme, Mari Jäntti, Tuuli Koskela, Janne S. Kotiaho, Tero Toivanen. (2014). Created substrates do not fully mimic natural substrates in restoration: the occurrence of polypores on spruce logs. Silva Fennica vol. 48 no. 1 article id 980. https://doi.org/10.14214/sf.980
Highlights: Polypore communities were more homogeneous among created than among natural logs; The old-growth forest indicator Phellinus ferrugineofuscus occurred frequently on natural logs, but occupied only a few created logs; Results show that created logs do not fully mimic natural logs.
Many protected areas have been under intensive forest management prior to protection and thus lack natural ecosystem structures and dynamics. Dead wood is a key structure in forests harboring hundreds of threatened species. We investigated the ecological success of dead wood creation as a boreal forest restoration measure. We analysed whether the polypore communities of chain-saw felled and girdled (subsequently fallen) Norway spruce (Picea abies (L.) H. Karst.) logs differ from naturally formed spruce logs of similar decay stage and size. The study was conducted in Leivonmäki National Park in central Finland 8 years after the restoration measures. The average number of polypore species was highest on the chain-saw felled logs and most of the common polypore species were most frequent on this substrate. However, among the natural logs, number of species increased more steeply with increasing number of logs, suggesting greater variation in community composition on this substrate. The old-growth forest indicator Phellinus ferrugineofuscus occurred frequently on natural logs, occupied a few girdled logs but was absent from chain-saw felled logs. Our results show that from the polypore perspective created logs do not fully mimic natural logs, suggesting that creating substrates for species may pose a challenge for restoration.
  • Komonen, Department of Biological and Environmental Science, P.O. Box 35, FI-40014, University of Jyväskylä, Finland ORCID ID:E-mail: atte.komonen@jyu.fi (email)
  • Halme, Department of Biological and Environmental Science, P.O. Box 35, FI-40014, University of Jyväskylä, Finland ORCID ID:E-mail: panu.halme@jyu.fi
  • Jäntti, Department of Biological and Environmental Science, P.O. Box 35, FI-40014, University of Jyväskylä, Finland ORCID ID:E-mail: mari.j.jantti@student.jyu.fi
  • Koskela, Department of Biological and Environmental Science, P.O. Box 35, FI-40014, University of Jyväskylä, Finland ORCID ID:E-mail: tuuli.e.koskela@student.jyu.fi
  • Kotiaho, Department of Biological and Environmental Science, P.O. Box 35, FI-40014, University of Jyväskylä, Finland ORCID ID:E-mail: janne.kotiaho@jyu.fi
  • Toivanen, Department of Biological and Environmental Science, P.O. Box 35, FI-40014, University of Jyväskylä, Finland; Current: Birdlife Finland, Annankatu 29 A 16, FI-00100 Helsinki, Finland ORCID ID:E-mail: tero.toivanen@birdlife.fi
article id 949, category Research article
Ken Olaf Storaunet, Jørund Rolstad, Erlend Rolstad. (2014). Effects of logging on the threatened epiphytic lichen Usnea longissima: an experimental approach. Silva Fennica vol. 48 no. 1 article id 949. https://doi.org/10.14214/sf.949
Highlights: A re-inventory of the threatened lichen Usnea longissima in ten Norway spruce forest stands where experimental selective loggings had been conducted 5 to 8 years before revealed that the number of lichen thalli had increased with 34%; The number of thalli increased more where the forest was open whether or not the low tree density was caused by the loggings.
Usnea longissima Ach. is a circumboreal epiphytic lichen draping tree canopies in moist coastal and mountainous forests. It is extinct from many European and North-American localities, presumably due to industrial forestry and air pollution, but still has a stronghold in parts of Scandinavia and U.S. and Canadian Pacific Northwest. In 2005/06 we used a comparative and retrospective approach to evaluate how present and historic tree and stand characteristics influenced the occurrence and abundance of the lichen (Storaunet et al. 2008). In 2012, we re-inventoried ten Norway spruce forest stands with 401 U. longissima-bearing trees and recorded changes in the number of U. longissima thalli. Seven of the stands had been experimentally, selectively logged 5–8 years before, where the lichen-bearing trees had been marked in the field and were avoided during the logging operation. Total number of lichen-bearing trees decreased slightly (2.9%), whereas the number of thalli had increased with 34%. Number of thalli increased more where the forest was open (low basal area, m2ha-1) whether or not the low tree density was caused by the logging events. At high tree densities the change in number of thalli was negligible. We suggest that selective logging, securing lichen-bearing trees, may be a viable management option to keep tree density from becoming too dense, thereby enhancing growth and establishment of U. longissima.
  • Storaunet, Norwegian Forest and Landscape Institute, P.O. Box 115, NO-1431 Ås, Norway ORCID ID:E-mail: stk@skogoglandskap.no (email)
  • Rolstad, Norwegian Forest and Landscape Institute, P.O. Box 115, NO-1431 Ås, Norway ORCID ID:E-mail: roj@skogoglandskap.no
  • Rolstad, Skogfaglig Rådgivning, Holmsida 126, NO-1488 Hakadal, Norway ORCID ID:E-mail: roe@skogoglandskap.no
article id 1071, category Research article
Ursula Kretschmer, Nadeschda Kirchner, Christopher Morhart, Heinrich Spiecker. (2013). A new approach to assessing tree stem quality characteristics using terrestrial laser scans. Silva Fennica vol. 47 no. 5 article id 1071. https://doi.org/10.14214/sf.1071
Highlights: Minimal deviations of the bark surface can be detected and visualized based on terrestrial laser scan data; Additionally the geometrical properties of bark scars and branched knots can be assessed; Two methods using two different approaches are presented: (1) a method using intensity data and (2) a method using bark surface models.
This paper presents an approach to assess and measure bark characteristics as indicators of wood quality using terrestrial laser scan data. In addition to the detection and measurement by use of the intensity information of the scan data a new approach was established. Bark surface models are calculated for each tree. They offer the representation of the bark as a height model. The reference is the tree stem approximated by a chain of cylinders. Minimal deviations of the bark surface can be detected and visualized and the geometrical properties of bark scars and branched knots can be assessed. Results of the measurement of 18 scars are presented using the two approaches: (1) a method using intensity data or (2) using bark surface models. The selection of the adequate approach depends on the stem characteristics. In a next step, methods for automatic measurement of bark scars will be developed.
  • Kretschmer, Chair of Forest Growth, Albert-Ludwigs-University Freiburg, Tennenbacher Str. 4, 79106 Freiburg, Germany ORCID ID:E-mail: ursula.kretschmer@iww.uni-freiburg.de (email)
  • Kirchner, VOLKE Consulting Engineers GmbH, Schätzweg 7-9, 80935 München, Germany ORCID ID:E-mail: nadeschda.kirchner@volke.muc.de
  • Morhart, Chair of Forest Growth, Albert-Ludwigs-University Freiburg, Tennenbacher Str. 4, 79106 Freiburg, Germany ORCID ID:E-mail: christopher.morhart@iww.uni-freiburg.de
  • Spiecker, Chair of Forest Growth, Albert-Ludwigs-University Freiburg, Tennenbacher Str. 4, 79106 Freiburg, Germany ORCID ID:E-mail: instww@uni-freiburg.de
article id 943, category Research article
Terje Gobakken, Lauri Korhonen, Erik Næsset. (2013). Laser-assisted selection of field plots for an area-based forest inventory. Silva Fennica vol. 47 no. 5 article id 943. https://doi.org/10.14214/sf.943
Highlights: Using laser data as auxiliary information in the selection of field plot locations helps to decrease costs in forest inventories based on airborne laser scanning; Two independent, differently selected sets of field plots were used for model fitting, and third for validation; Using partial instead of ordinary least squares had no major influence on the results; Forty well placed plots produced fairly reliable volume estimates.
Field measurements conducted on sample plots are a major cost component in airborne laser scanning (ALS) based forest inventories, as field data is needed to obtain reference variables for the statistical models. The ALS data also provides an excellent source of prior information that may be used in the design phase of the field survey to reduce the size of the field data set. In the current study, we acquired two independent modeling data sets: one with ALS-assisted and another with random plot selection. A third data set was used for validation. One canopy height and one canopy density variable were used as a basis for the ALS-assisted selection. Ordinary and partial least squares regressions for stem volume were fitted for four different strata using the two data sets separately. The results show that the ALS-assisted plot selection helped to decrease the root mean square error (RMSE) of the predicted volume. Although the differences in RMSE were relatively small, models based on random plot selection showed larger mean differences from the reference in the independent validation data. Furthermore, a sub-sampling experiment showed that 40 well placed plots should be enough for fairly reliable predictions.
  • Gobakken, Norwegian University of Life Sciences, Department of Ecology and Natural Resource Management, Ås, Norway ORCID ID:E-mail: terje.gobakken@umb.no
  • Korhonen, University of Eastern Finland, School of Forest Sciences, P.O. Box 111, FI-80101 Joensuu, Finland ORCID ID:E-mail: lauri.korhonen@uef.fi (email)
  • Næsset, Norwegian University of Life Sciences, Department of Ecology and Natural Resource Management, Ås, Norway ORCID ID:E-mail: erik.naesset@umb.no
article id 937, category Research article
Rene Zamora-Cristales, Kevin Boston, John Sessions, Glen Murphy. (2013). Stochastic simulation and optimization of mobile chipping economics in processing and transport of forest biomass from residues. Silva Fennica vol. 47 no. 5 article id 937. https://doi.org/10.14214/sf.937
Highlights: A stochastic simulation model is proposed to analyze forest biomass operations; The cost of chipper and truck waiting times was estimated in forest biomass recovery operations; The economic effect of truck-machine interactions under uncertainty was analyzed; Road characteristics and processing location have an economic impact in truck and chipper waiting times
We analyzed the economics of mobile chipping and transport of biomass from forest residues for energy purposes under uncertainty. A discrete-event simulation model was developed and utilized to quantify the impacts of controllable and environmental variables on productivity in order to determine the most cost effective transportation options under steep terrain conditions. Truck-chipper interactions were analyzed to show their effect on truck and chipper standing time. A costing model was developed to account for operating and standing time cost (for the chipper and trucks). The model used information from time studies of each activity in the productive cycle and spatial-temporal information obtained from geographic information system (GIS) devices, and tracking analysis of machine and truck movements. The model was validated in field operations, and proved to be accurate in providing the expected productivity. A cost distribution was elaborated to support operational decisions of forest managers, landowners and risk-averse contractors. Different scenarios were developed to illustrate the economic effects due to changes in road characteristics such as in-highway transport distance, in-forest internal road distance and pile to trailer chipper traveling distances.
  • Zamora-Cristales, Department of Forest Engineering, Resources, and Management, College of Forestry, Oregon State University, 280 Peavy Hall, Corvallis, OR 97331, USA ORCID ID:E-mail: rene.zamora@oregonstate.edu (email)
  • Boston, Department of Forest Engineering, Resources, and Management, College of Forestry, Oregon State University, 280 Peavy Hall, Corvallis, OR 97331, USA ORCID ID:E-mail: kevin.boston@oregonstate.edu
  • Sessions, Department of Forest Engineering, Resources, and Management, College of Forestry, Oregon State University, 280 Peavy Hall, Corvallis, OR 97331, USA ORCID ID:E-mail: john.sessions@oregonstate.edu
  • Murphy, Waiariki Institute of Technology, Rotorua, New Zealand ORCID ID:E-mail: glen.murphy@waiariki.ac.nz
article id 937, category Research article
Rene Zamora-Cristales, Kevin Boston, John Sessions, Glen Murphy. (2013). Stochastic simulation and optimization of mobile chipping economics in processing and transport of forest biomass from residues. Silva Fennica vol. 47 no. 5 article id 937. https://doi.org/10.14214/sf.937
Highlights: A stochastic simulation model is proposed to analyze forest biomass operations; The cost of chipper and truck waiting times was estimated in forest biomass recovery operations; The economic effect of truck-machine interactions under uncertainty was analyzed; Road characteristics and processing location have an economic impact in truck and chipper waiting times
We analyzed the economics of mobile chipping and transport of biomass from forest residues for energy purposes under uncertainty. A discrete-event simulation model was developed and utilized to quantify the impacts of controllable and environmental variables on productivity in order to determine the most cost effective transportation options under steep terrain conditions. Truck-chipper interactions were analyzed to show their effect on truck and chipper standing time. A costing model was developed to account for operating and standing time cost (for the chipper and trucks). The model used information from time studies of each activity in the productive cycle and spatial-temporal information obtained from geographic information system (GIS) devices, and tracking analysis of machine and truck movements. The model was validated in field operations, and proved to be accurate in providing the expected productivity. A cost distribution was elaborated to support operational decisions of forest managers, landowners and risk-averse contractors. Different scenarios were developed to illustrate the economic effects due to changes in road characteristics such as in-highway transport distance, in-forest internal road distance and pile to trailer chipper traveling distances.
  • Zamora-Cristales, Department of Forest Engineering, Resources, and Management, College of Forestry, Oregon State University, 280 Peavy Hall, Corvallis, OR 97331, USA ORCID ID:E-mail: rene.zamora@oregonstate.edu (email)
  • Boston, Department of Forest Engineering, Resources, and Management, College of Forestry, Oregon State University, 280 Peavy Hall, Corvallis, OR 97331, USA ORCID ID:E-mail: kevin.boston@oregonstate.edu
  • Sessions, Department of Forest Engineering, Resources, and Management, College of Forestry, Oregon State University, 280 Peavy Hall, Corvallis, OR 97331, USA ORCID ID:E-mail: john.sessions@oregonstate.edu
  • Murphy, Waiariki Institute of Technology, Rotorua, New Zealand ORCID ID:E-mail: glen.murphy@waiariki.ac.nz
article id 1046, category Research article
Eva-Maria Nordström, Hampus Holmström, Karin Öhman. (2013). Evaluating continuous cover forestry based on the forest owner’s objectives by combining scenario analysis and multiple criteria decision analysis. Silva Fennica vol. 47 no. 4 article id 1046. https://doi.org/10.14214/sf.1046
Highlights: Scenario analysis and multiple criteria decision analysis were combined to evaluate alternative forest management strategies for Linköping municipality, Sweden; Continuous cover forestry (CCF) promoted ecological and social objectives better than even-aged forestry but was worse for economic objectives; Ecological and social objectives were important to the municipality and thus, in summary, CCF seemed to be a suitable strategy.
Forests are increasingly managed both to provide a sustainable yield of timber and for supplying a range of ecosystem services in line with the concept of sustainable forest management. Several incommensurable interests must then be considered, and it is necessary to strike a balance between different objectives. In evaluation of trade-offs to be made, both objective factors and subjective values need to be taken into account. In recent years, continuous cover forestry (CCF) has been put forward as an alternative to even-aged forestry. The aim of this study was to use scenario analysis in combination with multi criteria decision analysis (MCDA) to evaluate whether CCF is a suitable strategy based on the decision makers’ objectives and preferences for sustainable forest management in a specific landscape. This approach was applied to a planning case on the forest estate of the Linköping municipality in southwestern Sweden. The scenario analyses provided insights into relevant quantitative factors, while the MCDA evaluation helped in clarifying the objectives of the forest management and in assessing the relative importance of various objectives. The scenario analyses showed that in this case CCF is a good management strategy in ecological and social terms but yields worse economic outcomes than conventional even-aged forestry. In the Linköping case, there was a relatively strong emphasis on ecological and social aspects and thus, in summary, CCF seemed to be the most suitable option.
  • Nordström, Swedish University of Agricultural Sciences, Department of Forest Resource Management, Skogsmarksgränd, SE-901 83 Umeå, Sweden ORCID ID:E-mail: eva-maria.nordstrom@slu.se (email)
  • Holmström, Swedish University of Agricultural Sciences, Department of Forest Resource Management, Skogsmarksgränd, SE-901 83 Umeå, Sweden ORCID ID:E-mail: hampus.holmstrom@slu.se
  • Öhman, Swedish University of Agricultural Sciences, Department of Forest Resource Management, Skogsmarksgränd, SE-901 83 Umeå, Sweden ORCID ID:E-mail: karin.ohman@slu.se
article id 1046, category Research article
Eva-Maria Nordström, Hampus Holmström, Karin Öhman. (2013). Evaluating continuous cover forestry based on the forest owner’s objectives by combining scenario analysis and multiple criteria decision analysis. Silva Fennica vol. 47 no. 4 article id 1046. https://doi.org/10.14214/sf.1046
Highlights: Scenario analysis and multiple criteria decision analysis were combined to evaluate alternative forest management strategies for Linköping municipality, Sweden; Continuous cover forestry (CCF) promoted ecological and social objectives better than even-aged forestry but was worse for economic objectives; Ecological and social objectives were important to the municipality and thus, in summary, CCF seemed to be a suitable strategy.
Forests are increasingly managed both to provide a sustainable yield of timber and for supplying a range of ecosystem services in line with the concept of sustainable forest management. Several incommensurable interests must then be considered, and it is necessary to strike a balance between different objectives. In evaluation of trade-offs to be made, both objective factors and subjective values need to be taken into account. In recent years, continuous cover forestry (CCF) has been put forward as an alternative to even-aged forestry. The aim of this study was to use scenario analysis in combination with multi criteria decision analysis (MCDA) to evaluate whether CCF is a suitable strategy based on the decision makers’ objectives and preferences for sustainable forest management in a specific landscape. This approach was applied to a planning case on the forest estate of the Linköping municipality in southwestern Sweden. The scenario analyses provided insights into relevant quantitative factors, while the MCDA evaluation helped in clarifying the objectives of the forest management and in assessing the relative importance of various objectives. The scenario analyses showed that in this case CCF is a good management strategy in ecological and social terms but yields worse economic outcomes than conventional even-aged forestry. In the Linköping case, there was a relatively strong emphasis on ecological and social aspects and thus, in summary, CCF seemed to be the most suitable option.
  • Nordström, Swedish University of Agricultural Sciences, Department of Forest Resource Management, Skogsmarksgränd, SE-901 83 Umeå, Sweden ORCID ID:E-mail: eva-maria.nordstrom@slu.se (email)
  • Holmström, Swedish University of Agricultural Sciences, Department of Forest Resource Management, Skogsmarksgränd, SE-901 83 Umeå, Sweden ORCID ID:E-mail: hampus.holmstrom@slu.se
  • Öhman, Swedish University of Agricultural Sciences, Department of Forest Resource Management, Skogsmarksgränd, SE-901 83 Umeå, Sweden ORCID ID:E-mail: karin.ohman@slu.se
article id 1046, category Research article
Eva-Maria Nordström, Hampus Holmström, Karin Öhman. (2013). Evaluating continuous cover forestry based on the forest owner’s objectives by combining scenario analysis and multiple criteria decision analysis. Silva Fennica vol. 47 no. 4 article id 1046. https://doi.org/10.14214/sf.1046
Highlights: Scenario analysis and multiple criteria decision analysis were combined to evaluate alternative forest management strategies for Linköping municipality, Sweden; Continuous cover forestry (CCF) promoted ecological and social objectives better than even-aged forestry but was worse for economic objectives; Ecological and social objectives were important to the municipality and thus, in summary, CCF seemed to be a suitable strategy.
Forests are increasingly managed both to provide a sustainable yield of timber and for supplying a range of ecosystem services in line with the concept of sustainable forest management. Several incommensurable interests must then be considered, and it is necessary to strike a balance between different objectives. In evaluation of trade-offs to be made, both objective factors and subjective values need to be taken into account. In recent years, continuous cover forestry (CCF) has been put forward as an alternative to even-aged forestry. The aim of this study was to use scenario analysis in combination with multi criteria decision analysis (MCDA) to evaluate whether CCF is a suitable strategy based on the decision makers’ objectives and preferences for sustainable forest management in a specific landscape. This approach was applied to a planning case on the forest estate of the Linköping municipality in southwestern Sweden. The scenario analyses provided insights into relevant quantitative factors, while the MCDA evaluation helped in clarifying the objectives of the forest management and in assessing the relative importance of various objectives. The scenario analyses showed that in this case CCF is a good management strategy in ecological and social terms but yields worse economic outcomes than conventional even-aged forestry. In the Linköping case, there was a relatively strong emphasis on ecological and social aspects and thus, in summary, CCF seemed to be the most suitable option.
  • Nordström, Swedish University of Agricultural Sciences, Department of Forest Resource Management, Skogsmarksgränd, SE-901 83 Umeå, Sweden ORCID ID:E-mail: eva-maria.nordstrom@slu.se (email)
  • Holmström, Swedish University of Agricultural Sciences, Department of Forest Resource Management, Skogsmarksgränd, SE-901 83 Umeå, Sweden ORCID ID:E-mail: hampus.holmstrom@slu.se
  • Öhman, Swedish University of Agricultural Sciences, Department of Forest Resource Management, Skogsmarksgränd, SE-901 83 Umeå, Sweden ORCID ID:E-mail: karin.ohman@slu.se
article id 1030, category Research article
Jussi Manner, Tomas Nordfjell, Ola Lindroos. (2013). Effects of the number of assortments and log concentration on time consumption for forwarding. Silva Fennica vol. 47 no. 4 article id 1030. https://doi.org/10.14214/sf.1030
Highlights: We analysed the effects of total and forwarded log concentrations (m3 (100 m)–1) and the number of loaded assortments on forwarding; The combination of the number of loaded assortments and their abundance (i.e. forwarded log concentration) affected time consumption most; This knowledge enables improved efficiency by optimizing number and assortment proportions in the various loads required to forward a stand.
Forwarding has been carried out for 50 years, but much is still unknown about this work. Its complexity comes from both stand features and essential decision-making. Forwarding time consumption is influenced by e.g. log concentrations and number of assortments. Traditionally, focus has been on the total log concentration (TLC), referring to all logs at the harvesting site. However, we focused on forwarded log concentration (FLC), the load-specific log concentration which depends on the assortment distribution at harvesting site and the load-specific number of assortments. To evaluate the effects of TLC, number of assortments in a load and FLC on the loading and unloading times, a standardized field experiment was carried out. Pile and load sizes were constant, while TLC and FLC were manipulated by varying the pile distribution on the test path. For all work elements, the time consumption per m3 was significantly affected by the number of assortments that were loaded, but only the “driving while loading” work element was also significantly influenced by TLC. However, when untangling the intercorrelation between tested factors, it was found that the time consumption for driving while loading significantly decreased as a function of FLC and was unaffected by the number of assortments in a load. That FLC influences the forwarding time consumption highlights the need to study the effects of combining various assortment proportions in a load. Such knowledge will enable analysis of the most efficient number and assortment proportions to combine in the various loads required to forward a given stand.
  • Manner, Swedish University of Agricultural Sciences, Department of Forest Biomaterial and Technology, SE-901 83 Umeå, Sweden ORCID ID:E-mail: jussi.manner@slu.se (email)
  • Nordfjell, Swedish University of Agricultural Sciences, Department of Forest Biomaterial and Technology, SE-901 83 Umeå, Sweden ORCID ID:E-mail: tomas.nordfjell@slu.se
  • Lindroos, Swedish University of Agricultural Sciences, Department of Forest Biomaterial and Technology, SE-901 83 Umeå, Sweden ORCID ID:E-mail: ola.lindroos@slu.se
article id 1022, category Research article
Eero Muinonen, Perttu Anttila, Jaakko Heinonen, Jukka Mustonen. (2013). Estimating the bioenergy potential of forest chips from final fellings in Central Finland based on biomass maps and spatially explicit constraints. Silva Fennica vol. 47 no. 4 article id 1022. https://doi.org/10.14214/sf.1022
The technical potential of forest chips from final fellings in Central Finland was estimated using a method based on biomass maps derived from a multi-source forest inventory technique. Image segmentation techniques were applied to a satellite image mosaic to detect stand boundaries. The technical potential of forest chips was computed based on primary forestry residues, i.e. logging residues and stumps from final fellings. Harvesting level definitions for final fellings were established using realized statistics for roundwood at the municipality level as well as larger area statistics. The sensitivity of the potential to ecological and technical constraints in the model was also examined. The technical recovery rate of stump harvesting according to biomass harvesting guidelines was evaluated separately. The critical prerequisites for using the advanced, spatially explicit approach to analysing forest energy potentials may lie in the existence of spatially explicit forest inventory data and the biometric models for tree biomass assortments. The method applied was capable of taking into account the constraints that rely upon map data, such the actual forwarding distance or steepness of the slope in the terrain. The calculation results can be used for strategic decision making in the field of forest bioenergy production.
  • Muinonen, Finnish Forest Research Institute, Joensuu Unit, P.O. Box 68, FI-80101 Joensuu, Finland ORCID ID:E-mail: eero.muinonen@metla.fi (email)
  • Anttila, Finnish Forest Research Institute, Joensuu Unit, P.O. Box 68, FI-80101 Joensuu, Finland ORCID ID:E-mail: perttu.anttila@metla.fi
  • Heinonen, Finnish Forest Research Institute, Joensuu Unit, P.O. Box 68, FI-80101 Joensuu, Finland ORCID ID:E-mail: jaakko.heinonen@metla.fi
  • Mustonen, Stora Enso, Talvikkitie 40 C, FI-01300 Vantaa, Finland ORCID ID:E-mail: jukka.mustonen@storaenso.com
article id 1000, category Research article
Sören Wulff, Cornelia Roberge, Anna Hedström Ringvall, Sören Holm, Göran Ståhl. (2013). On the possibility to monitor and assess forest damage within large scale monitoring programmes – a simulation study. Silva Fennica vol. 47 no. 3 article id 1000. https://doi.org/10.14214/sf.1000
There is a growing demand for information on forest health due to fears that climate change may cause new kinds of damage that have not previously been encountered. In many cases, forest damage monitoring is conducted exclusively within sparse large-scale grids of sample plots and it is doubtful whether these are capable of providing relevant information to support mitigation programmes or other actions required to reduce economic losses due to damage outbreaks. In this study, we used simulated sampling to assess the precision of estimators related to forest state and changes in the damage sustained by trees within an area corresponding to the Swedish region Götaland, assuming a sampling design corresponding to that used in the Swedish National Forest Inventory (NFI) under different damage scenarios. Large and uniformly distributed damage outbreaks were well captured by an NFI-type inventory, but scattered damage outbreaks produced estimates with poor precision. As a consequence, we propose that there might be a need to revise current forest damage monitoring programmes to make them more useful for monitoring the kinds of damage that are likely to arise as a consequence of climate change.
  • Wulff, Swedish University of Agricultural Sciences, Department of Forest Resource Management, Skogsmarksgränd, SE-901 83 Umeå, Sweden ORCID ID:E-mail: soren.wulff@slu.se (email)
  • Roberge, Swedish University of Agricultural Sciences, Department of Forest Resource Management, Skogsmarksgränd, SE-901 83 Umeå, Sweden ORCID ID:E-mail: cornelia.roberge@slu.se
  • Ringvall, Swedish University of Agricultural Sciences, Department of Forest Resource Management, Skogsmarksgränd, SE-901 83 Umeå, Sweden ORCID ID:E-mail: anna.ringvall@slu.se
  • Holm, Swedish University of Agricultural Sciences, Department of Forest Resource Management, Skogsmarksgränd, SE-901 83 Umeå, Sweden ORCID ID:E-mail: soren.holm@slu.se
  • Ståhl, Swedish University of Agricultural Sciences, Department of Forest Resource Management, Skogsmarksgränd, SE-901 83 Umeå, Sweden ORCID ID:E-mail: goran.stahl@slu.se
article id 1000, category Research article
Sören Wulff, Cornelia Roberge, Anna Hedström Ringvall, Sören Holm, Göran Ståhl. (2013). On the possibility to monitor and assess forest damage within large scale monitoring programmes – a simulation study. Silva Fennica vol. 47 no. 3 article id 1000. https://doi.org/10.14214/sf.1000
There is a growing demand for information on forest health due to fears that climate change may cause new kinds of damage that have not previously been encountered. In many cases, forest damage monitoring is conducted exclusively within sparse large-scale grids of sample plots and it is doubtful whether these are capable of providing relevant information to support mitigation programmes or other actions required to reduce economic losses due to damage outbreaks. In this study, we used simulated sampling to assess the precision of estimators related to forest state and changes in the damage sustained by trees within an area corresponding to the Swedish region Götaland, assuming a sampling design corresponding to that used in the Swedish National Forest Inventory (NFI) under different damage scenarios. Large and uniformly distributed damage outbreaks were well captured by an NFI-type inventory, but scattered damage outbreaks produced estimates with poor precision. As a consequence, we propose that there might be a need to revise current forest damage monitoring programmes to make them more useful for monitoring the kinds of damage that are likely to arise as a consequence of climate change.
  • Wulff, Swedish University of Agricultural Sciences, Department of Forest Resource Management, Skogsmarksgränd, SE-901 83 Umeå, Sweden ORCID ID:E-mail: soren.wulff@slu.se (email)
  • Roberge, Swedish University of Agricultural Sciences, Department of Forest Resource Management, Skogsmarksgränd, SE-901 83 Umeå, Sweden ORCID ID:E-mail: cornelia.roberge@slu.se
  • Ringvall, Swedish University of Agricultural Sciences, Department of Forest Resource Management, Skogsmarksgränd, SE-901 83 Umeå, Sweden ORCID ID:E-mail: anna.ringvall@slu.se
  • Holm, Swedish University of Agricultural Sciences, Department of Forest Resource Management, Skogsmarksgränd, SE-901 83 Umeå, Sweden ORCID ID:E-mail: soren.holm@slu.se
  • Ståhl, Swedish University of Agricultural Sciences, Department of Forest Resource Management, Skogsmarksgränd, SE-901 83 Umeå, Sweden ORCID ID:E-mail: goran.stahl@slu.se
article id 1000, category Research article
Sören Wulff, Cornelia Roberge, Anna Hedström Ringvall, Sören Holm, Göran Ståhl. (2013). On the possibility to monitor and assess forest damage within large scale monitoring programmes – a simulation study. Silva Fennica vol. 47 no. 3 article id 1000. https://doi.org/10.14214/sf.1000
There is a growing demand for information on forest health due to fears that climate change may cause new kinds of damage that have not previously been encountered. In many cases, forest damage monitoring is conducted exclusively within sparse large-scale grids of sample plots and it is doubtful whether these are capable of providing relevant information to support mitigation programmes or other actions required to reduce economic losses due to damage outbreaks. In this study, we used simulated sampling to assess the precision of estimators related to forest state and changes in the damage sustained by trees within an area corresponding to the Swedish region Götaland, assuming a sampling design corresponding to that used in the Swedish National Forest Inventory (NFI) under different damage scenarios. Large and uniformly distributed damage outbreaks were well captured by an NFI-type inventory, but scattered damage outbreaks produced estimates with poor precision. As a consequence, we propose that there might be a need to revise current forest damage monitoring programmes to make them more useful for monitoring the kinds of damage that are likely to arise as a consequence of climate change.
  • Wulff, Swedish University of Agricultural Sciences, Department of Forest Resource Management, Skogsmarksgränd, SE-901 83 Umeå, Sweden ORCID ID:E-mail: soren.wulff@slu.se (email)
  • Roberge, Swedish University of Agricultural Sciences, Department of Forest Resource Management, Skogsmarksgränd, SE-901 83 Umeå, Sweden ORCID ID:E-mail: cornelia.roberge@slu.se
  • Ringvall, Swedish University of Agricultural Sciences, Department of Forest Resource Management, Skogsmarksgränd, SE-901 83 Umeå, Sweden ORCID ID:E-mail: anna.ringvall@slu.se
  • Holm, Swedish University of Agricultural Sciences, Department of Forest Resource Management, Skogsmarksgränd, SE-901 83 Umeå, Sweden ORCID ID:E-mail: soren.holm@slu.se
  • Ståhl, Swedish University of Agricultural Sciences, Department of Forest Resource Management, Skogsmarksgränd, SE-901 83 Umeå, Sweden ORCID ID:E-mail: goran.stahl@slu.se
article id 973, category Research article
Sergio Rossi, Hubert Morin, François Gionest, Danielle Laprise. (2013). Spatially explicit structure of natural stands dominated by black spruce. Silva Fennica vol. 47 no. 3 article id 973. https://doi.org/10.14214/sf.973
Black spruce [Picea mariana (Mill.) BSP] regeneration emerges in clusters near the pre-existing boles within a few years after the passage of fire. This paper tested the hypothesis that black spruce forests still maintain the spatial structure deriving from postfire stand initiation. Trees and saplings were monitored during 2000-2007 and the horizontal and vertical structure of the stands were investigated on four permanent plots in the boreal forest of Quebec, Canada. Plots showed 1300-2150 trees ha-1, and were composed of trees with homogeneous sizes and a very small proportion of saplings. These characteristics identify single cohorts generated by complete, or almost-complete, stand replacement by fire. Ripley’s L(r) functions showed that the spatial pattern of trees and saplings ranged from random to aggregated, thus demonstrating that the clustering distribution of the individuals in black spruce forests can be maintained even after 80-120 years from stand initiation. These findings could results from incomplete self-thinning or from an environment with heterogeneous distribution of resources. The practices of ecosystem management recently developed in Eastern Canada should take into account both the horizontal and vertical structure to better modulate the competition among individuals during partial harvesting.
  • Rossi, Département des Sciences Fondamentales, Université du Québec à Chicoutimi, 555 boulevard de l’Université, Chicoutimi (QC), G7H2B1, Canada ORCID ID:E-mail: sergio.rossi@uqac.ca (email)
  • Morin, Département des Sciences Fondamentales, Université du Québec à Chicoutimi, 555 boulevard de l’Université, Chicoutimi (QC), G7H2B1, Canada ORCID ID:E-mail: hubert_morin@uqac.ca
  • Gionest, Département des Sciences Fondamentales, Université du Québec à Chicoutimi, 555 boulevard de l’Université, Chicoutimi (QC), G7H2B1, Canada ORCID ID:E-mail: francois_gionest@uqac.ca
  • Laprise, Département des Sciences Fondamentales, Université du Québec à Chicoutimi, 555 boulevard de l’Université, Chicoutimi (QC), G7H2B1, Canada ORCID ID:E-mail: danielle_laprise@uqac.ca
article id 972, category Research article
Outi H. Manninen, Rainer Peltola. (2013). Effects of picking methods on the berry production of bilberry (Vaccinium myrtillus), lingonberry (V. vitis-idaea) and crowberry (Empetrum nigrum ssp. hermaphroditum) in Northern Finland. Silva Fennica vol. 47 no. 3 article id 972. https://doi.org/10.14214/sf.972
Highlights: Berry production of bilberry, lingonberry and crowberry was studied after picking the berries by plastic hand rake, long-handed metal rake, and powerful picking by long-handed metal rake; Berry production was not affected by the damage caused by any of the picking method; Current commercial picking methods do not endanger the berry production of the berry species at least in short-term.
The effect of commercial wild berry picking on berry yields is under a strong public debate in Finland. Especially high concern has been arisen over damages caused by metal rakes used in commercial picking to subsequent berry production. We studied the berry production of bilberry (Vaccinium myrtillus L.), lingonberry (V. vitis-idaea L.) and crowberry (E. nigrum ssp. hermaphroditum (Hagerup) Böcher) after picking the berries by 1) plastic hand rake, 2) long-handed metal rake and 3) powerful picking by long-handed metal rake, in northern Finland during 2010–2012. In the powerful long-handed metal rake treatment the aboveground vegetation was raked twice to the moss layer after berry picking. Biomass, which was removed from the vegetation by rakes was collected and used as a measure of the damage. We assumed that picking by plastic hand rake would result in lowest, long-handed metal rake intermediate and powerful picking by long-handed metal rake highest biomass loss from vegetation. The amount of biomass loss should in turn be reversely reflected into berry production. However, only the powerful picking by long-handed metal rake removed higher amount of biomass than other picking methods in bilberry and lingonberry. In crowberry, the amount of biomass removed by rakes increased from treatment to treatment. Contrary to our assumption, berry production of bilberry, lingonberry and crowberry was not affected by the damage caused by any of the picking method. We conclude that long-handed metal rake used in commercial picking is comparable to hand rake in terms of berry production.
  • Manninen, Agrifood Research Finland MTT, Eteläranta 55, FI-96300 Rovaniemi, Finland ORCID ID:E-mail: outi.h.manninen@mtt.fi (email)
  • Peltola, Agrifood Research Finland MTT, Eteläranta 55, FI-96300 Rovaniemi, Finland ORCID ID:E-mail: rainer.peltola@mtt.fi
article id 970, category Research article
Zhen-Yu Du, Qing-Hua Wang, Shang-Jun Xing, Fang-Chun Liu, Bing-Yao Ma, Hai-Lin Ma, De-Xi Liu. (2013). Fine root distribution, characteristics and rhizosphere soil properties in a mixed stand of Robinia pseudoacacia and Fraxinus velutina in a saline soil. Silva Fennica vol. 47 no. 3 article id 970. https://doi.org/10.14214/sf.970
The spatial distribution and characteristics of fine roots (< 2 mm in diameter), and rhizosphere soil properties were studied in a mixed planted forest of black locust (Robinia pseudoacacia L.) and velvet ash (Fraxinus velutina Torr.) 27 years after planting in a coastal saline soil of the Yellow River delta, China. The results of fine root analysis showed that the fine roots of both black locust and velvet ash were mainly distributed in the soil layer at 0–20 cm depth and 50–150 cm from trees. The fine root distribution of both species suggests a strategy of avoiding salinity rather than salt –tolerance. The horizontal spread distance of fine roots of velvet ash was evidently longer than that of black locust. The fine root biomass, specific root length, specific root area, specific root volume and root activity were significantly higher for velvet ash in comparison with black locust. The results of soil analysis showed that rhizosphere soil pH of black locust and velvet ash were significantly lower compared with non-rhizosphere soil. The available N content in rhizosphere soil of black locust was higher than that of velvet ash. However, the contents of soluble salt, organic matter, available P and available K in rhizosphere soil of velvet ash were higher than those of black locust. The above results indicated that the differences between black locust and velvet ash in fine root distribution, characteristics and rhizosphere soil properties were the major reasons for that velvet ash showed stronger acclimation responses than black locust to the coastal saline soil.
  • Du, Shandong Academy of Forestry, 42 Wenhua East Road, Jinan 250014, P. R. China ORCID ID:E-mail: zydu@qq.com (email)
  • Wang, Shandong Academy of Forestry, Jinan, P. R. China ORCID ID:E-mail: wqh0228@163.com
  • Xing, Shandong Academy of Forestry, Jinan, P. R. China ORCID ID:E-mail: xingsj-126@126.com
  • Liu, Shandong Academy of Forestry, Jinan, P. R. China ORCID ID:E-mail: fchliu@126.com
  • Ma, Shandong Academy of Forestry, Jinan, P. R. China ORCID ID:E-mail: mby777@163.com
  • Ma, Shandong Academy of Forestry, Jinan, P. R. China ORCID ID:E-mail: mahlin@163.com
  • Liu, Shandong Academy of Forestry, Jinan, P. R. China ORCID ID:E-mail: llyldx@163.com
article id 958, category Research article
Back Tomas Ersson, Linus Jundén, Urban Bergsten, Martin Servin. (2013). Simulated productivity of one- and two-armed tree planting machines. Silva Fennica vol. 47 no. 2 article id 958. https://doi.org/10.14214/sf.958
Highlights: Using discrete-event simulation and detailed terrain and machine models, the productivities of excavator-based one- and two-armed tree planting machines were simulated; The machines’ arms were equipped with one-and two-headed planting devices; Two planting heads per arm rather than two arms per base machine is better for increasing the productivity of intermittently advancing planting machines on Nordic clearcuts.
To increase mechanized planting, planting machine productivity must increase in order to improve cost-efficiency. To determine if excavators with two crane arms could potentially help to increase planting machine productivity under Nordic clearcut conditions, we modelled one-armed and semi-automated two-armed excavators with one- and two-headed planting devices. Using a recently developed tool for discrete-event simulation, these machine models then mounded and planted seedlings on terrain models with moraine soil having various frequencies of obstacles (stumps, roots and stones). Compared to if the two heads were mounted pairwise on only one arm, the results showed that productivity did not increase if two planting heads were attached individually to two separate crane arms. But productivity did increase if the planting machine had four planting heads mounted pairwise on two separate arms. However, despite assuming automated mounding and crane motion between planting spots, the two-armed, four-headed model never achieved high enough productivity levels to make it more cost-efficient than one-armed machines. The simulations illustrate that our terrain models generate realistic root architecture and boulder content distributions in moraine soil, while our machine models functionally describe mechanized planting work. Based on our assumptions, we conclude that further development work on two-armed excavator-based planting machines for Nordic clearcut conditions is not warranted. Our simulations reveal that increasing the number of planting heads per crane arm rather than number of crane arms per base machine offers the greatest potential to raise the productivity of intermittently advancing planting machines.
  • Ersson,  Swedish University of Agricultural Sciences, Department of Forest Biomaterials and Technology, SE-901 83 Umeå, Sweden ORCID ID:E-mail: back.tomas.ersson@slu.se (email)
  • Jundén,  UMIT Research Lab, Umeå University, SE-901 87 Umeå, Sweden ORCID ID:E-mail: linus.junden@gmail.com
  • Bergsten,  Swedish University of Agricultural Sciences, Department of Forest Biomaterials and Technology, SE-901 83 Umeå, Sweden ORCID ID:E-mail: urban.bergsten@slu.se
  • Servin,  UMIT Research Lab, Umeå University, SE-901 87 Umeå, Sweden ORCID ID:E-mail: martin.servin@physics.umu.se
article id 952, category Research article
Lauri Korhonen, Inka Pippuri, Petteri Packalén, Ville Heikkinen, Matti Maltamo, Juho Heikkilä. (2013). Detection of the need for seedling stand tending using high-resolution remote sensing data. Silva Fennica vol. 47 no. 2 article id 952. https://doi.org/10.14214/sf.952
Seedling stands are problematic in airborne laser scanning (ALS) based stand level forest management inventories, as the stem density and species proportions are difficult to estimate accurately using only remotely sensed data. Thus the seedling stands must still be checked in the field, which results in an increase in costs. In this study we tested an approach where ALS data and aerial images are used to directly classify the seedling stands into two categories: those that involve tending within the next five years and those which involve no tending. Standard ALS-based height and density features, together with texture and spectral features calculated from aerial images, were used as inputs to two classifiers: logistic regression and the support vector machine (SVM). The classifiers were trained using 208 seedling plots whose tending need was estimated by a local forestry expert. The classification was validated on 68 separate seedling stands. In the training data, the logistic model’s kappa coefficient was 0.55 and overall accuracy (OA) 77%. The SVM did slightly better with a kappa = 0.71 and an OA = 86%. In the stand level validation data, the performance decreased for both the logistic model (kappa = 0.38, OA = 71%) and the SVM (kappa = 0.37, OA = 72%). Thus our approach cannot totally replace the field checks. However, in considering the stands where the logistic model predictions had high reliability, the number of misclassifications reduced drastically. The SVM however, was not as good at recognizing reliable cases.
  • Korhonen, School of Forest Sciences, University of Eastern Finland, P.O. Box 111, FI-80101 Joensuu, Finland ORCID ID:E-mail: lauri.korhonen@uef.fi (email)
  • Pippuri, School of Forest Sciences, University of Eastern Finland, P.O. Box 111, FI-80101 Joensuu, Finland ORCID ID:E-mail: inka.pippuri@uef.fi
  • Packalén, School of Forest Sciences, University of Eastern Finland, P.O. Box 111, FI-80101 Joensuu, Finland ORCID ID:E-mail: petteri.packalen@uef.fi
  • Heikkinen, School of Computing, University of Eastern Finland, P.O. Box 111, FI-80101 Joensuu, Finland ORCID ID:E-mail: ville.heikkinen@uef.fi
  • Maltamo, School of Forest Sciences, University of Eastern Finland, P.O. Box 111, FI-80101 Joensuu, Finland ORCID ID:E-mail: matti.maltamo@uef.fi
  • Heikkilä, Finnish Forest Centre, Public Services, Maistraatinportti 4 A, FI-00240 Helsinki, Finland ORCID ID:E-mail: juho.heikkila@metsakeskus.fi
article id 935, category Research article
Loice M. A. Omoro, Mike Starr, Petri K. E. Pellikka. (2013). Tree biomass and soil carbon stocks in indigenous forests in comparison to plantations of exotic species in the Taita Hills of Kenya. Silva Fennica vol. 47 no. 2 article id 935. https://doi.org/10.14214/sf.935
Carbon (C) densities of the tree biomass and soil (0–50 cm) in indigenous forest and plantations of eucalyptus, cypress and pine in the Taita Hills, Kenya were determined and compared. The cypress and pine plantations were about 30-years-old and eucalyptus plantations about 50-years-old. Biomass C densities were estimated from breast height diameter and wood density using allometric functions developed for tropical species and an assumed C content of 50%. Belowground biomass C densities were estimated using root:shoot biomass ratios. Soil organic C (SOC) densities were calculated from measured organic carbon contents (0–20 and 20–50 cm layers) and modelled bulk density values. Mean total biomass C and SOC densities for indigenous forest were greater than those of the plantations, and the difference was significant (p < 0.05) in the cases of cypress and pine biomass and pine SOC. The correlation between biomass C and SOC densities was nearly significant in the case of indigenous forest, but negative. Biomass C densities were not significantly correlated with mean annual precipitation, mean annual temperature or potential evapotranspiration, but pine biomass C densities were significantly correlated to actual evapotranspiration. SOC densities were more strongly correlated to mean annual precipitation than biomass C densities, but only significantly so in the case of pine. Neither biomass C nor SOC densities were correlated to plant available water capacity of the soil. Indigenous forest SOC densities were significantly correlated to soil clay contents, but negatively. Indigenous forests sequester more C in biomass and soil than do 30 to 50-year-old plantations of exotics, but it remains unclear if this is an intrinsic difference between indigenous forest and plantations of exotics or because of insufficient time for SOC levels in plantations to recover after clearance of original indigenous forest.
  • Omoro, Viikki Tropical Resources Institute, Department of Forest Sciences, P.O. Box 27 (Latokartanonkaari 7), FI-00014 University of Helsinki, Finland ORCID ID:E-mail: loice.omoro@helsinki.fi
  • Starr, Department of Forest Sciences, P. O. Box 27 (Latokartanonkaari 7), FI-00014 University of Helsinki, Finland ORCID ID:E-mail: mike.starr@helsinki.fi (email)
  • Pellikka, Department of Geosciences and Geography, P. O. Box 64 (Gustaf Hällströminkatu 2), FI-00014 University of Helsinki, Finland ORCID ID:E-mail: petri.pellikka@helsinki.fi
article id 935, category Research article
Loice M. A. Omoro, Mike Starr, Petri K. E. Pellikka. (2013). Tree biomass and soil carbon stocks in indigenous forests in comparison to plantations of exotic species in the Taita Hills of Kenya. Silva Fennica vol. 47 no. 2 article id 935. https://doi.org/10.14214/sf.935
Carbon (C) densities of the tree biomass and soil (0–50 cm) in indigenous forest and plantations of eucalyptus, cypress and pine in the Taita Hills, Kenya were determined and compared. The cypress and pine plantations were about 30-years-old and eucalyptus plantations about 50-years-old. Biomass C densities were estimated from breast height diameter and wood density using allometric functions developed for tropical species and an assumed C content of 50%. Belowground biomass C densities were estimated using root:shoot biomass ratios. Soil organic C (SOC) densities were calculated from measured organic carbon contents (0–20 and 20–50 cm layers) and modelled bulk density values. Mean total biomass C and SOC densities for indigenous forest were greater than those of the plantations, and the difference was significant (p < 0.05) in the cases of cypress and pine biomass and pine SOC. The correlation between biomass C and SOC densities was nearly significant in the case of indigenous forest, but negative. Biomass C densities were not significantly correlated with mean annual precipitation, mean annual temperature or potential evapotranspiration, but pine biomass C densities were significantly correlated to actual evapotranspiration. SOC densities were more strongly correlated to mean annual precipitation than biomass C densities, but only significantly so in the case of pine. Neither biomass C nor SOC densities were correlated to plant available water capacity of the soil. Indigenous forest SOC densities were significantly correlated to soil clay contents, but negatively. Indigenous forests sequester more C in biomass and soil than do 30 to 50-year-old plantations of exotics, but it remains unclear if this is an intrinsic difference between indigenous forest and plantations of exotics or because of insufficient time for SOC levels in plantations to recover after clearance of original indigenous forest.
  • Omoro, Viikki Tropical Resources Institute, Department of Forest Sciences, P.O. Box 27 (Latokartanonkaari 7), FI-00014 University of Helsinki, Finland ORCID ID:E-mail: loice.omoro@helsinki.fi
  • Starr, Department of Forest Sciences, P. O. Box 27 (Latokartanonkaari 7), FI-00014 University of Helsinki, Finland ORCID ID:E-mail: mike.starr@helsinki.fi (email)
  • Pellikka, Department of Geosciences and Geography, P. O. Box 64 (Gustaf Hällströminkatu 2), FI-00014 University of Helsinki, Finland ORCID ID:E-mail: petri.pellikka@helsinki.fi
article id 933, category Research article
Per-Ola Hedwall, Harald Grip, Sune Linder, Lars Lövdahl, Urban Nilsson, Johan Bergh. (2013). Effects of clear-cutting and slash removal on soil water chemistry and forest-floor vegetation in a nutrient optimised Norway spruce stand. Silva Fennica vol. 47 no. 2 article id 933. https://doi.org/10.14214/sf.933
Fertilisation with nutrient optimisation has in Sweden resulted in large increases in volume growth in young stands of Norway spruce. There are, however, environmental concerns about repeated fertilisation and one is the risk of nutrient leakage to ground water resources and aquatic ecosystems after clear-cutting of such forests. The present study followed soil-water chemistry in optimised fertilised stands after clear-cutting, as well as effects of harvest of slash on nutrient leakage. Parts of a 30-year-old stand of Norway spruce, which had been subject to a nutrient optimisation experiment for 17 years, were clear-cut. A split-plot design with whole-tree harvesting as the sub-plot treatment was applied. Lysimeters were installed and soil-water sampled at nine occasions during the following four years. No significant effects of fertilisation on nitrate leaching were found, while harvest of slash reduced the concentration of Ca, DOC, DON, K, Mg, ammonium and nitrate, as well as pH in the soil solution. While no effects of fertilisation could be seen on the soil water concentration of N, the results indicate an interaction between fertilisation and harvest of slash on the concentration of nitrate in the soil solution. The results indicate that forest-floor vegetation plays an important role in the retention of N after clear-cutting of fertilised forests.
  • Hedwall, Southern Swedish Forest Research Centre, Swedish University of Agricultural Sciences (SLU), P.O. Box 49, SE-230 53 Alnarp, Sweden ORCID ID:E-mail: per-ola.hedwall@slu.se (email)
  • Grip, Department of Forest Ecology and Management, SLU, SE-901 83 Umeå, Sweden ORCID ID:E-mail: harald@grip2.se
  • Linder, Southern Swedish Forest Research Centre, Swedish University of Agricultural Sciences (SLU), P.O. Box 49, SE-230 53 Alnarp, Sweden ORCID ID:E-mail: sune.linder@slu.se
  • Lövdahl, Department of Forest Ecology and Management, SLU, SE-901 83 Umeå, Sweden ORCID ID:E-mail:
  • Nilsson, Southern Swedish Forest Research Centre, Swedish University of Agricultural Sciences (SLU), P.O. Box 49, SE-230 53 Alnarp, Sweden ORCID ID:E-mail: urban.nilsson@slu.se
  • Bergh, Southern Swedish Forest Research Centre, Swedish University of Agricultural Sciences (SLU), P.O. Box 49, SE-230 53 Alnarp, Sweden ORCID ID:E-mail: johan.bergh@slu.se
article id 933, category Research article
Per-Ola Hedwall, Harald Grip, Sune Linder, Lars Lövdahl, Urban Nilsson, Johan Bergh. (2013). Effects of clear-cutting and slash removal on soil water chemistry and forest-floor vegetation in a nutrient optimised Norway spruce stand. Silva Fennica vol. 47 no. 2 article id 933. https://doi.org/10.14214/sf.933
Fertilisation with nutrient optimisation has in Sweden resulted in large increases in volume growth in young stands of Norway spruce. There are, however, environmental concerns about repeated fertilisation and one is the risk of nutrient leakage to ground water resources and aquatic ecosystems after clear-cutting of such forests. The present study followed soil-water chemistry in optimised fertilised stands after clear-cutting, as well as effects of harvest of slash on nutrient leakage. Parts of a 30-year-old stand of Norway spruce, which had been subject to a nutrient optimisation experiment for 17 years, were clear-cut. A split-plot design with whole-tree harvesting as the sub-plot treatment was applied. Lysimeters were installed and soil-water sampled at nine occasions during the following four years. No significant effects of fertilisation on nitrate leaching were found, while harvest of slash reduced the concentration of Ca, DOC, DON, K, Mg, ammonium and nitrate, as well as pH in the soil solution. While no effects of fertilisation could be seen on the soil water concentration of N, the results indicate an interaction between fertilisation and harvest of slash on the concentration of nitrate in the soil solution. The results indicate that forest-floor vegetation plays an important role in the retention of N after clear-cutting of fertilised forests.
  • Hedwall, Southern Swedish Forest Research Centre, Swedish University of Agricultural Sciences (SLU), P.O. Box 49, SE-230 53 Alnarp, Sweden ORCID ID:E-mail: per-ola.hedwall@slu.se (email)
  • Grip, Department of Forest Ecology and Management, SLU, SE-901 83 Umeå, Sweden ORCID ID:E-mail: harald@grip2.se
  • Linder, Southern Swedish Forest Research Centre, Swedish University of Agricultural Sciences (SLU), P.O. Box 49, SE-230 53 Alnarp, Sweden ORCID ID:E-mail: sune.linder@slu.se
  • Lövdahl, Department of Forest Ecology and Management, SLU, SE-901 83 Umeå, Sweden ORCID ID:E-mail:
  • Nilsson, Southern Swedish Forest Research Centre, Swedish University of Agricultural Sciences (SLU), P.O. Box 49, SE-230 53 Alnarp, Sweden ORCID ID:E-mail: urban.nilsson@slu.se
  • Bergh, Southern Swedish Forest Research Centre, Swedish University of Agricultural Sciences (SLU), P.O. Box 49, SE-230 53 Alnarp, Sweden ORCID ID:E-mail: johan.bergh@slu.se
article id 925, category Research article
Steen Magnussen. (2013). An assessment of three variance estimators for the k-nearest neighbour technique. Silva Fennica vol. 47 no. 1 article id 925. https://doi.org/10.14214/sf.925
A jackknife (JK), a bootstrap (BOOT), and an empirical difference estimator (EDE) of totals and variance were assessed in simulated sampling from three artificial but realistic complex multivariate populations (N = 8000 elements) organized in clusters of four elements. Intra-cluster correlations of the target variables (Y) varied from 0.03 to 0.26. Time-saving implementations of JK and BOOT are detailed. In simple random sampling (SRS), bias in totals was ≤ 0.4% for the two largest sample sizes (n = 200, 300), but slightly larger for n = 50, and 100. In cluster sampling (CLU) bias was typically 0.1% higher and more variable. The lowest overall bias was in EDE. In both SRS and CLU, JK estimates of standard error were slightly (3%) too high, while the bootstrap estimates in both SRS and CLU were too low (8%). Estimates of error suggested a trend in EDE toward an overestimation with increasing sample size. Calculated 95% confidence intervals achieved a coverage that in most cases was fairly close (± 2%) to the nominal level. For estimation of a population total the EDE estimator appears to be slightly better than the JK estimator.
  • Magnussen, Canadian Forest Service, Natural Resources Canada, 505 West Burnside Road, Victoria BC V8Z 1M5 Canada ORCID ID:E-mail: steen.magnussen@nrcan.gc.ca (email)
article id 902, category Research article
Sakari Tuominen, Reija Haapanen. (2013). Estimation of forest biomass by means of genetic algorithm-based optimization of airborne laser scanning and digital aerial photograph features. Silva Fennica vol. 47 no. 1 article id 902. https://doi.org/10.14214/sf.902
Information on forest biomass is required for several purposes, including estimation of forest bioenergy resources and forest carbon stocks. Airborne laser scanning is today considered the most accurate remote sensing method for forest inventory. The three-dimensional nature of laser scanning data enables estimation of the volumes of the tree canopies. The dimensions of the tree canopies show high correlation with the amount of forest biomass. Optical aerial photographs are often used to complement laser data, for improved distinction between tree species. The paper reports on a study testing the estimation of forest biomass variables in two study areas in Southern Finland. The biomass variables were derived on the basis of tree-level field measurements, with biomass models used for pine, spruce, and birch. The sample-plot-level biomass components were derived on the basis of tree-level data and used as reference data for airborne-laser- and aerial‑photograph-based estimation. Results were slightly better for total biomass (RMSE 22.5% and 23.6% for the two study areas) than total volume (RMSE: 23.4% and 26.1%). Species-specific estimation errors were large in general but varied between the study areas, because of differences in their forest structures.
  • Tuominen, Finnish Forest Research Institute, P.O.Box 18, FI-01301 Vantaa, Finland ORCID ID:E-mail: sakari.tuominen@metla.fi (email)
  • Haapanen, Finnish Forest Research Institute, P.O.Box 18, FI-01301 Vantaa, Finland ORCID ID:E-mail: reija.haapanen@gmail.com
article id 899, category Research article
Franz Holzleitner, Christian Kanzian, Norbert Höller. (2013). Monitoring the chipping and transportation of wood fuels with a fleet management system. Silva Fennica vol. 47 no. 1 article id 899. https://doi.org/10.14214/sf.899
Controlling and organizing the complex forest-to-consumer supply chain of wood fuels is a challenging task, especially for the chipping and transport processes. Truck mounted chippers and transport trailer-trucks must be scheduled to minimize delay to be profitable. Job management within the supply chain, including machine activity based controlling, offers a new way to increase efficiency and productivity. However, detailed data are required to detect and analyze potential gaps and improve forest fuel supply. Generally, data regarding the wood fuel supply chain process are obtained from extensive time studies that are based on a specific process step. Although time studies can detect details during the production of forest fuels, they only describe certain time frames. Long-term data that are recorded during the entire year could encompass seasonal and short term effects. This study aims to monitor the forest fuel supply processes (semi-automated), specifically regarding time and fuel consumption. Large data sets were automatically and efficiently gathered with little effort by drivers and operators. Data were recorded with fleet management equipment for more than 14 months. Vehicle data, including GPS data, were logged at an interval of one minute. Data management was conducted in a pre-configured database that contained pre-defined reports and were run by the Institute of Forest Engineering, Vienna. Work step assignments were implemented with Structured Query Language (SQL)-routines by using the raw machine activities data and GPS. The chipping and transport activities of more than 240 loads were analyzed by focusing on fuel consumption, time needed and traffic. The average distance between chipping sites and plants was approximately 54 kilometers. Fuel consumption from transport reached 50 l/100 km. The chipping unit reached a productivity of 12.8 odt/PSH15 and had a fuel consumption of 58 liters per operating hour.
  • Holzleitner, Institute of Forest Engineering, Department of Forest and Soil Sciences, University of Natural Resources and Life Sciences, Peter Jordanstrasse 82/3, 1190 Vienna, Austria ORCID ID:E-mail: franz.holzleitner@boku.ac.at (email)
  • Kanzian, Institute of Forest Engineering, Department of Forest and Soil Sciences, University of Natural Resources and Life Sciences, Peter Jordanstrasse 82/3, 1190 Vienna, Austria ORCID ID:E-mail: christian.kanzian@boku.ac.at
  • Höller, Institute of Forest Engineering, Department of Forest and Soil Sciences, University of Natural Resources and Life Sciences, Peter Jordanstrasse 82/3, 1190 Vienna, Austria ORCID ID:E-mail: norbert.hoeller@boku.ac.at
article id 894, category Research article
Heimo Karppinen, Mika Korhonen. (2013). Do forest owners share the public’s values? An application of Schwartz’s value theory. Silva Fennica vol. 47 no. 1 article id 894. https://doi.org/10.14214/sf.894
The purpose of this study is to investigate the differences in value priorities between Finnish forest owners and the general public. A conclusion is drawn whether and to what extent value changes in society are reflected in forest owners’ values and objectives, and, finally, in their actual forestry behavior. In addition, the study highlights the differences in value priorities among forest owners in various demographic groups. The data set used in this study was based on a nationwide mail survey on Finnish non-industrial private forest owners conducted in 2009 and consisting of 2116 observations of forest owners. Schwartz’s value theory was a good fit for testing the value priorities of forest owners. The three most important values were benevolence, security and conformity, both among the forest owners and the public. Tradition was ranked the fourth most important value by the forest owners, but very low by the public. The forest owners ranked universalism slightly lower than the public in general. This difference was clearly greater when the female forest owners were compared to women in the whole population. The probability of a forest owner belonging to the Softies (high emphasis on universalism and benevolence) increased with age and was higher for the female owners and the owners with recreational or multiple objectives compared to the indifferent owners. The multiobjective owners and recreationists had relatively similar value profiles. The previous literature suggests that multiobjective owners are the most active forest owner group and that recreationists and indifferent owners are the most passive groups in their timber supply behavior. The relationship between values and forestry behavior thus remains ambiguous.
  • Karppinen, Department of Forest Sciences, P.O. Box 27, FI-00014 University of Helsinki, Finland ORCID ID:E-mail: heimo.karppinen@helsinki.fi (email)
  • Korhonen, Kämnerintie 7e 41, FI-00750 Helsinki, Finland ORCID ID:E-mail: mika.korhonen@gmx.com
article id 894, category Research article
Heimo Karppinen, Mika Korhonen. (2013). Do forest owners share the public’s values? An application of Schwartz’s value theory. Silva Fennica vol. 47 no. 1 article id 894. https://doi.org/10.14214/sf.894
The purpose of this study is to investigate the differences in value priorities between Finnish forest owners and the general public. A conclusion is drawn whether and to what extent value changes in society are reflected in forest owners’ values and objectives, and, finally, in their actual forestry behavior. In addition, the study highlights the differences in value priorities among forest owners in various demographic groups. The data set used in this study was based on a nationwide mail survey on Finnish non-industrial private forest owners conducted in 2009 and consisting of 2116 observations of forest owners. Schwartz’s value theory was a good fit for testing the value priorities of forest owners. The three most important values were benevolence, security and conformity, both among the forest owners and the public. Tradition was ranked the fourth most important value by the forest owners, but very low by the public. The forest owners ranked universalism slightly lower than the public in general. This difference was clearly greater when the female forest owners were compared to women in the whole population. The probability of a forest owner belonging to the Softies (high emphasis on universalism and benevolence) increased with age and was higher for the female owners and the owners with recreational or multiple objectives compared to the indifferent owners. The multiobjective owners and recreationists had relatively similar value profiles. The previous literature suggests that multiobjective owners are the most active forest owner group and that recreationists and indifferent owners are the most passive groups in their timber supply behavior. The relationship between values and forestry behavior thus remains ambiguous.
  • Karppinen, Department of Forest Sciences, P.O. Box 27, FI-00014 University of Helsinki, Finland ORCID ID:E-mail: heimo.karppinen@helsinki.fi (email)
  • Korhonen, Kämnerintie 7e 41, FI-00750 Helsinki, Finland ORCID ID:E-mail: mika.korhonen@gmx.com
article id 893, category Research article
Juha Heiskanen, Timo Saksa, Jaana Luoranen. (2013). Soil preparation method affects outplanting success of Norway spruce container seedlings on till soils susceptible to frost heave. Silva Fennica vol. 47 no. 1 article id 893. https://doi.org/10.14214/sf.893
Soil preparation is a common practice that precedes outplanting of Norway spruce (Picea abies (L.) Karst.) in Finland as it enhances the survival and early growth of seedlings. Mounding in particular has become more common with Norway spruce planting in recent years. However, on fine-grained soils, the postplanting performance of seedlings has been poorer than on coarser soils even with mounding. This study examined the effects of different soil preparation treatments (spot and ditch mounding with varying mound height, inverting, unprepared control with or without a herbicide) on the postplanting performance of Norway spruce container seedlings on till soil susceptible to frost heave in two outplanting forest sites in central Finland. The results indicate higher soil temperature and lower soil water content especially in the highest mounds. Mounds, however, subsided gradually during the study years. Seedling mortality was higher and the proportion of vigorous seedlings was lower in the unprepared treatments, mainly due to increased pine weevil (Hylobius abietis L.) damage. Frost heave was present mainly on ditch mounded and inverted spots. Glyphosate herbicide treatment showed no benefit compared to the untreated control in two years. Consequently, seedling damage and conditions in the planting spots were reflected in seedling growth which was enhanced in the mounded spots. However, varying mound height or thickness of mineral capping showed no clear difference in seedling growth. The results therefore suggest that ditch or spot mounding should be used on frost heave susceptible forest soils to promote plantation establishment. Inverting or having no soil preparation with or without herbicide is not recommended.
  • Heiskanen, Finnish Forest Research Institute, Suonenjoki Unit, Juntintie 154, FI-77600, Suonenjoki, Finland ORCID ID:E-mail: juha.heiskanen@metla.fi (email)
  • Saksa, Finnish Forest Research Institute, Suonenjoki Unit, Juntintie 154, FI-77600, Suonenjoki, Finland ORCID ID:E-mail: timo.saksa@metla.fi
  • Luoranen, Finnish Forest Research Institute, Suonenjoki Unit, Juntintie 154, FI-77600, Suonenjoki, Finland ORCID ID:E-mail: jaana.luoranen@metla.fi
article id 924, category Research article
Minna Pulkkinen. (2012). On non-circularity of tree stem cross-sections: effect of diameter selection on cross-section area estimation, Bitterlich sampling and stem volume estimation in Scots pine. Silva Fennica vol. 46 no. 5B article id 924. https://doi.org/10.14214/sf.924
In the common methods of forest mensuration, including stem volume models and Bitterlich sampling, stem cross-sections are assumed to be circular. In nature this assumption is never exactly fulfilled. Errors due to non-circularity have been presumed to be small and unimportant but studied little: theoretical and empirical studies exist on cross-section area estimation, but errors in stem volume estimation have not been investigated at all, and errors in Bitterlich sampling are theoretically known only for stand basal area estimation. In the theoretical part of this study, we developed methods for quantifying the systematic and sampling errors that 22 common ways of selecting diameter within non-circular cross-sections induce (i) in area estimates by the circle area formula, (ii) in stand total estimates by Bitterlich sampling, and (iii) in stem volume estimates by a volume equation, by a cubic-spline-interpolated stem curve, and by a generalised volume estimator. In the empirical part, based on the digital images of 709 discs taken at 6–10 heights in 81 Scots pine stems from different parts of Finland, we investigated the variation in cross-section shape, and demonstrated the magnitude of the errors presented in the theoretical part. We found that non-circularity causes systematic overestimation of area and volume, and inflicts potentially systematic error on stand total estimates by Bitterlich sampling. In our data these effects were small, but the finding is not generalisable due the skewed size distribution and poor geographical representativeness of the data. We recommend using diameter derived from girth for both tree and stand level estimation, as it involves no sampling error and produces clearly the most stable systematic errors.
  • Pulkkinen, ORCID ID:E-mail: minna.pulkkinen@iki.fi (email)
article id 922, category Research article
Malin Nilsson, Dianne Staal Westerlund, Olof Wahlberg, Ljusk Ola Eriksson. (2012). Forest planning in a Swedish company – a knowledge management analysis of forest information. Silva Fennica vol. 46 no. 5 article id 922. https://doi.org/10.14214/sf.922
Forest data and forest information are central to forest management planning. The knowledge a large forest-owning company possesses about its forests could potentially be a strategic capability. In this study, the forest-planning process of a large forest company is analyzed in terms of knowledge management (KM). The study was conducted as a case study of Sveaskog – the largest forest-owning company in Sweden. The study focuses on the long-term harvest strategy through medium-term planning until the stands are transferred to the tract bank and ready for operational planning. Interviews with key persons within the organization were conducted to assess how forest knowledge is used in this process. The results are presented for the four knowledge management processes: creation, storage-retrieving, transferring and applying. They show that the planning system relies to a great extent on codified knowledge realized by a push strategy.
  • Nilsson, Swedish University of Agricultural Sciences, Department of Forest Resource Management, SE-901 83 Umeå, Sweden ORCID ID:E-mail: malin.nilsson@slu.se (email)
  • Staal Westerlund, Swedish University of Agricultural Sciences, Department of Forest Resource Management, SE-901 83 Umeå, Sweden ORCID ID:E-mail: dianne.wasterlund@slu.se
  • Wahlberg, Swedish University of Agricultural Sciences, Department of Forest Resource Management, SE-901 83 Umeå, Sweden ORCID ID:E-mail:
  • Eriksson, Swedish University of Agricultural Sciences, Department of Forest Resource Management, SE-901 83 Umeå, Sweden ORCID ID:E-mail: ljusk.ola.eriksson@slu.se
article id 919, category Research article
Karri Uotila, Juho Rantala, Timo Saksa. (2012). Estimating the need for early cleaning in Norway spruce plantations in Finland. Silva Fennica vol. 46 no. 5 article id 919. https://doi.org/10.14214/sf.919
Effective management of Norway spruce (Picea abies (L.) Karst.) plantations requires detailed information on stand development, which is costly to measure. However, estimating the need for early stand management from site attributes that persists stabile after ones measured, may provide an inexpensive alternative. This study compared hardwood competition in spruce plantations of varying ages and tested the usability of this information in estimating the need for early cleaning. The data included 197 spruce plantations (4–7 years old) inventoried in southern Finland in 2007. The level (Low, Substantial, High) of need for early cleaning was subjectively determined by contrasting location and size of competing hardwoods to a conifer crop tree. Then the stage of the need for early cleaning was modelled according to site and stand attributes. Nearly 60% of the conifer crop trees in the plantations were subjectively judged to require early cleaning (Substantial 37.2%, High 21.2%), but only 10 per cent of the evaluated area was cleaned. Need for cleaning was intense on peatlands or damp soils, whereas it was mild on unprepared soils or cleaned sites. Traditional site characteristics used in forest management planning can be useful for recognising the peripheral cases, where need for cleaning is probably high or low. However, on a typical mineral soil plantation (uncleaned, soil prepared) the model indicates the differences in the need for early cleaning weakly. The need for early cleaning was already high in 4-year-old plantations, why stand age did not have significant effect on development of the need. Thus, the timing of an operation can not be predicted with the model. Nonetheless, early cleaning very likely opens growth space of crop trees in a 4–7-year-old spruce plantation. Therefore, from an aspect of crop growth, an uncleaned Norway spruce plantation in this age group is quite consistently worth cleaning.
  • Uotila, Finnish Forest Research Institute, Suonenjoki Unit, Juntintie 154, FI-77600 Suonenjoki, Finland ORCID ID:E-mail: karri.uotila@metla.fi (email)
  • Rantala, Metsä Group, Tampere, Finland ORCID ID:E-mail: juho.rantala@metsagroup.com
  • Saksa, Finnish Forest Research Institute, Suonenjoki Unit, Juntintie 154, FI-77600 Suonenjoki, Finland ORCID ID:E-mail: timo.saksa@metla.fi
article id 909, category Research article
Veikko Hiltunen, Mikko Kurttila, Jouni Pykäläinen. (2012). Strengthening top-level guidance in geographically hierarchical large scale forest planning: experiences from the Finnish state forests. Silva Fennica vol. 46 no. 4 article id 909. https://doi.org/10.14214/sf.909
Different planning approaches conclude to different results. The top-down approach allocates resources efficiently from the top-level perspective, while the bottom-up approach provides optimal results for the lower levels. Integrated approach that combines the elements of these two basic approaches provides compromise solutions for decision makers. The aim of this study was to examine potential efficiency improvements in hierarchically structured large scale forest management through increased top-level guidance. The resulting effects on the acceptability of the plans on the lower level were also studied. Large scale planning typically considers forests owned by states, companies and municipalities. In the case study of the Finnish state forests, alternative country level solutions were generated by combining regional forest plans in different ways. The results showed that the currently applied bottom-up approach, which produces regionally optimal management strategies, did not result in the most efficient use of resources on the country level. However, the new country level solutions did not produce huge improvements in the country level objective values compared to the results of the current approach. Furthermore, if country level efficiency improvements were emphasized more, together with wide approval by regional stakeholders and local residents, new kind of interaction and participation between the planning levels and also between the regions would be needed.
  • Hiltunen, Metsähallitus, Viestitie 2, FI-87700 Kajaani, Finland ORCID ID:E-mail: veikko.hiltunen@metsa.fi (email)
  • Kurttila, Finnish Forest Research Institute, Joensuu Unit, P.O. Box 68, FI-80101 Joensuu, Finland ORCID ID:E-mail: mikko.kurttila@metla.fi
  • Pykäläinen, Finnish Forest Research Institute, Joensuu Unit, P.O. Box 68, FI-80101 Joensuu, Finland ORCID ID:E-mail: jouni.pykalainen@metla.fi
article id 908, category Research article
Sattar Ezzati, Akbar Najafi, M. A. Rab, Eric K. Zenner. (2012). Recovery of soil bulk density, porosity and rutting from ground skidding over a 20-year period after timber harvesting in Iran. Silva Fennica vol. 46 no. 4 article id 908. https://doi.org/10.14214/sf.908
Ground-based skidding can have detrimental effects on soil properties trough soil profile disturbance and compaction that can persist for decades. We investigated the recovery of physical properties of disturbed brown soils on four abandoned downhill skid trails in a deciduous mountain forest in northern Iran. The most recent skidding operations had taken place 1–5 yrs, 6–10 yrs, 11–15 yrs, and 16–20 yrs ago, providing a 20-year chronosequence with four 5-year recovery periods. For each recovery period, mean values for soil bulk density (BD), total porosity (TP), macroporosity (MP), soil moisture content (SM), and rut depth (RD) were assessed for three levels of traffic intensity (Primary (PS), Secondary (SS) and Tertiary (TS) skid trails) and two levels of slope gradients (Gentle (G) and Steep (S)) and compared to those in undisturbed (control) areas. Over the 20-year recovery period, PS trails on gentle slopes exhibited mean values that were 35–42% (BD), 3–7% (SM), and 13–19 cm (RD) greater and 18–24% (TP) and 19–28% (MP) lower compared to undisturbed areas; on steep PS trails, values were 40–46% (BD), 2–13% (SM), and 13–21 cm (RD) greater and 23–27% (TP) and 28–35% (MP) lower, respectively. While RD and SM recovered, 20 years was not long enough for the other physical soil properties, particularly on steep slopes. To minimize soil disturbance, skidding should be confined to areas with gentle slopes and alternative harvesting methods such as cable yarding should be used where slope gradients exceed 20%.
  • Ezzati, Department of Forestry and Forest Engineering, Tarbiat Modares University, P.O. Box 64414-356, Iran ORCID ID:E-mail:
  • Najafi, Department of Forestry and Forest Engineering, Tarbiat Modares University, P. Box 64414-356, Iran ORCID ID:E-mail: a.najafi@modares.ac.ir (email)
  • Rab, Soil Physics Future Farming Systems Research Division, Department of Primary Industries, Victoria, Australia ORCID ID:E-mail:
  • Zenner, Department of Ecosystem Science and Management, Pennsylvania State University, University Park, PA, USA ORCID ID:E-mail: eric.zenner@psu.edu
article id 906, category Research article
Eivind Meen, Anders Nielsen, Mikael Ohlson. (2012). Forest stand modelling as a tool to predict performance of the understory herb Cornus suecica. Silva Fennica vol. 46 no. 4 article id 906. https://doi.org/10.14214/sf.906
Forest simulation models have been widely used to predict future stand structure. Generally these models do not include the understory vegetation and its response on stand structure change or other environmental factors. Previous simulation studies have shown that stand structure related variables, e.g. basal area, can explain diversity of the forest floor vegetation in boreal forests. We hypothesise that such variables also can be used to explain the performance of understory species and we conceptualise how plant ecology and forest modelling can be combined to predict the performance of understory plants in Norwegian boreal forests. We predict the performance of an understory plant species (Cornus suecica) over time using simulated values of forest variables as input to models expressing the relationship between forest environment variables and plant performance variables (viz. plant height, plant dry weight, number of flowers, number of branches and number of leaves). We also present relationships between plant performance and explanatory variables commonly used in basic ecological research, variables that currently not are readily compatible with forest simulators (e.g. soil chemical variables).We found basal area of canopy trees being the most important explanatory variable explaining C. suecica performance. The performance variable dry weight was predicted by one single model whereas the other performance variables were best predicted by model averaging. Forest simulations for 150 years showed values of plant performance of C. suecica to be reduced during forest succession.
  • Meen, Norwegian University of Life Sciences, Department of Ecology and Natural Resource Management, P.O. Box 5003, NO-1432 Ås, Norway ORCID ID:E-mail: eivind.meen@umb.no (email)
  • Nielsen, Norwegian University of Life Sciences, Department of Ecology and Natural Resource Management, P.O. Box 5003, NO-1432 Ås, Norway ORCID ID:E-mail:
  • Ohlson, Norwegian University of Life Sciences, Department of Ecology and Natural Resource Management, P.O. Box 5003, NO-1432 Ås, Norway ORCID ID:E-mail:
article id 49, category Research article
Kalle Karttunen, Kari Väätäinen, Antti Asikainen, Tapio Ranta. (2012). The operational efficiency of waterway transport of forest chips on Finland’s Lake Saimaa. Silva Fennica vol. 46 no. 3 article id 49. https://doi.org/10.14214/sf.49
New and cost-efficient methods for use in supply chains for energy wood should be found, to reach the targets of the renewable energy utilisation set by the European Union. The long-distance waterway transportation of forest fuels should be thoroughly investigated, especially in areas where the transport distance is long and waterways could provide a feasible method of conveying forest fuel. In comparison to transport of forest chips by truck, barge-based waterway transport shows a competitive advantage due to the larger loads and higher bulk density of chips it allows. The cost-efficiency of waterway transportation operations related to forest chips in Finland’s Lake Saimaa region was studied using practical demonstrations and discrete-event simulation. The varying demand for fuel wood in three separate bio-power plants on the Saimaa lakeside (near the cities of Varkaus, Mikkeli, and Savonlinna) was addressed in several barge transportation scenarios. Finally, the economy of barge transportation was compared to the economy of truck transportation as a function of transportation distance and in terms of the annual performance of the transportation methods examined. The waterway supply chain of forest chips was cost-competitive to road transport by truck after 100–150 km. According to the simulation study, the most economical waterway transport options were based on fixed barge system and shift-independent harbor logistics where loading and unloading of barges were carried-out with a wheeled loader and a belt conveyor. Total supply chain costs including the best waterway logistics from road side storage to power plant ranged from 10.75 euros to 11.64 euros/MWh in distances of 100–150 km by waterways. The energy-density of forest chips in the barge load was found to be, on average, 25% higher than that in truck hauling, because of the better compaction of chips. Waterway transport is a viable option for long-distance transportation of forest chips in Eastern Finland.
  • Karttunen, Lappeenranta University of Technology, LUT Savo Sustainable Technologies, Mikkeli, Finland ORCID ID:E-mail: kalle.karttunen@lut.fi (email)
  • Väätäinen, The Finnish Forest Research Institute, Joensuu, Finland ORCID ID:E-mail: kari.vaatainen@metla.fi
  • Asikainen, The Finnish Forest Research Institute, Joensuu, Finland ORCID ID:E-mail: antti.asikainen@metla.fi
  • Ranta, Lappeenranta University of Technology, LUT Savo Sustainable Technologies, Mikkeli, Finland ORCID ID:E-mail: tapio.ranta@lut.fi
article id 47, category Research article
Iulian Dragotescu, Daniel D. Kneeshaw. (2012). A comparison of residual forest following fires and harvesting in boreal forests in Quebec, Canada. Silva Fennica vol. 46 no. 3 article id 47. https://doi.org/10.14214/sf.47
Residual forests are a key component of post-burned areas creating structure within burns and providing habitat and seed sources. Yet, despite their importance to biodiversity and ecosystem processes there is little information on how similar or different residuals in burned landscape are to harvested landscapes. Our goal was to examine and compare the density, size, shape, and spatial arrangement of residual forest vegetation after fire and clearcutting. We evaluated residual forest in two locations within the boreal mixedwood region of Quebec, Canada using aerial photo interpretation and ArcGIS 9.1 software. We found residual stands to be larger and more abundant in harvested zones relative to sites affected by fire. Differences with respect to shape and spatial arrangement of residual forest were also observed among disturbance types. Factors such as proximity to watercourses, watercourse shape, and physiography affected residual abundance and spatial distribution. Residual forest in harvested zones tended to be more elongated with greater edge due to rules governing forest operations. Despite greater quantity of residual forest in harvested areas than fires, managers should still be prudent as the surrounding forest matrix is reduced in many managed landscapes.
  • Dragotescu, Université du Québec à Montréal, Centre d’Étude de la Forêt (CEF), Montreal, Quebec, Canada ORCID ID:E-mail: idragot@hotmail.com (email)
  • Kneeshaw, Université du Québec à Montréal, Centre d’Étude de la Forêt (CEF), Montreal, Quebec, Canada ORCID ID:E-mail:
article id 47, category Research article
Iulian Dragotescu, Daniel D. Kneeshaw. (2012). A comparison of residual forest following fires and harvesting in boreal forests in Quebec, Canada. Silva Fennica vol. 46 no. 3 article id 47. https://doi.org/10.14214/sf.47
Residual forests are a key component of post-burned areas creating structure within burns and providing habitat and seed sources. Yet, despite their importance to biodiversity and ecosystem processes there is little information on how similar or different residuals in burned landscape are to harvested landscapes. Our goal was to examine and compare the density, size, shape, and spatial arrangement of residual forest vegetation after fire and clearcutting. We evaluated residual forest in two locations within the boreal mixedwood region of Quebec, Canada using aerial photo interpretation and ArcGIS 9.1 software. We found residual stands to be larger and more abundant in harvested zones relative to sites affected by fire. Differences with respect to shape and spatial arrangement of residual forest were also observed among disturbance types. Factors such as proximity to watercourses, watercourse shape, and physiography affected residual abundance and spatial distribution. Residual forest in harvested zones tended to be more elongated with greater edge due to rules governing forest operations. Despite greater quantity of residual forest in harvested areas than fires, managers should still be prudent as the surrounding forest matrix is reduced in many managed landscapes.
  • Dragotescu, Université du Québec à Montréal, Centre d’Étude de la Forêt (CEF), Montreal, Quebec, Canada ORCID ID:E-mail: idragot@hotmail.com (email)
  • Kneeshaw, Université du Québec à Montréal, Centre d’Étude de la Forêt (CEF), Montreal, Quebec, Canada ORCID ID:E-mail:
article id 44, category Research article
Anabel Aparecida de Mello, Leif Nutto, Karla Simone Weber, Carlos Eduardo Sanquetta, Jorge Luis Monteiro de Matos, Gero Becker. (2012). Individual biomass and carbon equations for Mimosa scabrella Benth. (bracatinga) in southern Brazil. Silva Fennica vol. 46 no. 3 article id 44. https://doi.org/10.14214/sf.44
Mimosa scabrella Benth. is an important native species of southern Brazil widely used for energy and promising for reforestation carbon offsets. Quantification of biomass and carbon stock is valuable for both purposes. From a forest inventory conducted in southern Brazil, data of M. scabrella were analyzed. Thirty sample trees were felled, excavated and weighed in the field and brought to laboratory for biomass and carbon determination. The total aboveground biomass represented 85% of the tree biomass, while roots corresponded to 15%. Correlation matrix of diameter at 1.3 m height (D), tree height (H) versus total and compartment biomass (P) indicated strong association between tree dimensions and biomasses. Five regression models were tested and equations were fitted to data of five biomass compartments and total tree biomass. The best fitting model for total biomass was P = –0.49361 + 0.034865 x D2H whereas for the partial biomass of the compartments was lnP = β0 + β1 x ln(D) + β2 lnH. Carbon concentration was statistically significantly different in foliage than in other compartments. Three approaches of calculating carbon stocks were evaluated and compared to actual data: 1) Estimated total biomass x weighted mean carbon concentration; 2) Estimated partial (compartment) biomass x compartment average carbon concentration; and 3) Carbon regression equations. No statistical difference was detected among them. It was concluded that biomass equations fitted in this study were accurate and useful for fuelwood and carbon estimations.
  • de Mello, Federal University of Sergipe, Brazil ORCID ID:E-mail:
  • Nutto, Federal University of Paraná, Brazil ORCID ID:E-mail: lnutto.ufpr@gmail.com (email)
  • Weber, Federal University of Paraná ORCID ID:E-mail:
  • Sanquetta, Carlos Eduardo Sanquetta ORCID ID:E-mail:
  • Monteiro de Matos, Jorge Luis Monteiro de Matos ORCID ID:E-mail:
  • Becker, University of Freiburg, Institute of Forest Utilization and Work Science, Germany ORCID ID:E-mail:
article id 58, category Research article
Ilona Suuriniemi, Jukka Matero, Harri Hänninen, Jussi Uusivuori. (2012). Factors affecting enlargement of family forest holdings. Silva Fennica vol. 46 no. 2 article id 58. https://doi.org/10.14214/sf.58
This study contributes to the research of enlargement – a counterforce of parcelization – of forest holdings. To help planning policy measures aiming at increased average size of forest holdings, we study the characteristics of family forest owners who acquired additional forestland area during the years 2004–2008. Increases of forestland area due to purchases on the open market, purchases from parents or other relatives, inheritance or gift are studied. Survey data, containing information of 6318 forest owners, are analyzed with logistic regression analysis in order to establish a relationship between the probability of increasing the forestland area and the characteristics of landowners. The results indicate that young male owners, who appreciate economic values of the ownership and are active users of their forest estates, most often expand their forest property. This can be considered as an encouraging result from the point of view of the political objective to boost forest management activity through enlarging family forest holdings.
  • Suuriniemi, University of Eastern Finland, School of Forest Sciences, P.O. Box 111, FI-80101 Joensuu, Finland ORCID ID:E-mail:
  • Matero, University of Eastern Finland, School of Forest Sciences, P.O. Box 111, FI-80101 Joensuu, Finland ORCID ID:E-mail: jukka.matero@uef.fi (email)
  • Hänninen, Finnish Forest Research Institute, Vantaa Unit, P.O. Box 18, FI-01301 Vantaa, Finland ORCID ID:E-mail:
  • Uusivuori, Finnish Forest Research Institute, Vantaa Unit, P.O. Box 18, FI-01301 Vantaa, Finland ORCID ID:E-mail:
article id 58, category Research article
Ilona Suuriniemi, Jukka Matero, Harri Hänninen, Jussi Uusivuori. (2012). Factors affecting enlargement of family forest holdings. Silva Fennica vol. 46 no. 2 article id 58. https://doi.org/10.14214/sf.58
This study contributes to the research of enlargement – a counterforce of parcelization – of forest holdings. To help planning policy measures aiming at increased average size of forest holdings, we study the characteristics of family forest owners who acquired additional forestland area during the years 2004–2008. Increases of forestland area due to purchases on the open market, purchases from parents or other relatives, inheritance or gift are studied. Survey data, containing information of 6318 forest owners, are analyzed with logistic regression analysis in order to establish a relationship between the probability of increasing the forestland area and the characteristics of landowners. The results indicate that young male owners, who appreciate economic values of the ownership and are active users of their forest estates, most often expand their forest property. This can be considered as an encouraging result from the point of view of the political objective to boost forest management activity through enlarging family forest holdings.
  • Suuriniemi, University of Eastern Finland, School of Forest Sciences, P.O. Box 111, FI-80101 Joensuu, Finland ORCID ID:E-mail:
  • Matero, University of Eastern Finland, School of Forest Sciences, P.O. Box 111, FI-80101 Joensuu, Finland ORCID ID:E-mail: jukka.matero@uef.fi (email)
  • Hänninen, Finnish Forest Research Institute, Vantaa Unit, P.O. Box 18, FI-01301 Vantaa, Finland ORCID ID:E-mail:
  • Uusivuori, Finnish Forest Research Institute, Vantaa Unit, P.O. Box 18, FI-01301 Vantaa, Finland ORCID ID:E-mail:
article id 53, category Research article
Saana Kataja-aho, Aino Smolander, Hannu Fritze, Sini Norrgård, Jari Haimi. (2012). Responses of soil carbon and nitrogen transformations to stump removal. Silva Fennica vol. 46 no. 2 article id 53. https://doi.org/10.14214/sf.53
We studied in central Finland whether stump harvesting after clear felling of coniferous forest poses further short-term changes in soil carbon and nitrogen dynamics when compared to the traditional site preparation method, mounding. Exposed mineral soil patches in Norway spruce (Picea abies) dominated clear-cut stands were sampled 1–5 years after the treatments. The extent of the exposed mineral soil surface was significantly larger at the stump removal sites when compared to the mounding sites. No differences were found in soil pH, organic matter content or total concentration of soil C between the treatments or treatment years. Total concentration of soil N was consistently higher and C:N ratio lower in the stump removal plots than in the mounded plots. Further, both net N mineralisation and nitrification were clearly increased in the stump removal plots one year after the treatments. Soil microbial activity (CO2 production) was higher in the stump removal plots but similar difference was not found in sieved soil samples incubated in the laboratory. Fluxes of other important greenhouse gases (CH4 and N2O) did not seem to be affected by stump removal. The differences between the stump removal and mounding procedures were most obviously attributed to more substantial soil disturbance by stump pulling and/or differences in the microbial communities and quality of soil organic matter in the differently treated soil.
  • Kataja-aho, University of Jyväskylä, Dept. of Biological and Environmental Science, Jyväskylä, Finland ORCID ID:E-mail: saana.m.kataja-aho@jyu.fi (email)
  • Smolander, Finnish Forest Research Institute, Vantaa, Finland ORCID ID:E-mail:
  • Fritze, Finnish Forest Research Institute, Vantaa, Finland ORCID ID:E-mail:
  • Norrgård, University of Jyväskylä, Dept. of Biological and Environmental Science, Jyväskylä, Finland ORCID ID:E-mail:
  • Haimi, University of Jyväskylä, Dept. of Biological and Environmental Science, Jyväskylä, Finland ORCID ID:E-mail:
article id 444, category Research article
Sovu, Mulualem Tigabu, Patrice Savadogo, Per Christer Odén. (2012). Facilitation of forest landscape restoration on abandoned swidden fallows in Laos using mixed-species planting and biochar application. Silva Fennica vol. 46 no. 1 article id 444. https://doi.org/10.14214/sf.444
The cessation of swidden cultivation and the increasing trend of abandonment of swidden fallows have created an opportunity for forest landscape restoration. However, ways need to be found to improve the poor soil fertility at these sites with affordable materials and to generate short-term socio-economic benefits for small-scale swidden fallow holders. This study assessed the feasibility of using mixed-planting of eight native species and application of rice husk biochar as soil amendment measure at a site in Laos. The effect of biochar application was compared against addition of inorganic (NPK) fertilizer and the control. The establishment and growth of the planted seedlings was then monitored for four years. The addition of rice husk biochar and NPK fertilizer did not significantly (p = 0.578) improve the survival rate of planted seedlings, which ranged from 72% to 91% (depending on the species) compared to the control. No significant growth responses to the soil amendments were observed for most of the species during the first year after planting compared to the control. The biochar effect was, however, more evident at the fourth year for diameter (p < 0.01) and height (p < 0.01) of sapling for all species; particularly its effect was more vivid on the diameter of slow-growing species. The results indicate that the species tested in the mixed-planting showed marked growth variation while application of rice husk biochar boosted their growth. Thus, planting mixed-species in swidden fallows has potential to provide continuous supplies of wood from different species to diversify the livelihood of swidden field owners, while maintaining ecosystem services.
  • -, Swedish University of Agricultural Sciences, Southern Swedish Forest Research Centre, Alnarp, Sweden ORCID ID:E-mail:
  • Tigabu, Swedish University of Agricultural Sciences, Southern Swedish Forest Research Centre, Alnarp, Sweden ORCID ID:E-mail: mulualem.tigabu@slu.se (email)
  • Savadogo, Swedish University of Agricultural Sciences, Southern Swedish Forest Research Centre, Alnarp, Sweden ORCID ID:E-mail:
  • Odén, Swedish University of Agricultural Sciences, Southern Swedish Forest Research Centre, Alnarp, Sweden ORCID ID:E-mail:
article id 70, category Research article
Joonas Järvinen, Jaakko Linnakangas. (2012). Firm capabilities in the Finnish forest cluster: comparisons based on self-organizing map. Silva Fennica vol. 46 no. 1 article id 70. https://doi.org/10.14214/sf.70
This paper examines the capability portfolios of Finnish forest cluster firms in 1998–2008. In particular, the focus is on what kind of capabilities the firms in the cluster have developed, whether the firms have developed such capabilities consistently, and whether they have developed similar capability portfolios. Further, a particular focus is on the links between innovativeness and other identified capabilities. We approach the topic with an exploratory quantitative analysis of the annual reports of 11 large firms in the cluster by using computerized content analysis and a self-organizing map as the main research methods. Based on the content analysis and earlier literature, we first identify fifteen capabilities, and then build capability portfolios for the firms on the basis of the results of the self-organizing map. At the firm level, the results reveal both similarities and differences in the capability portfolios of the forest cluster firms. Similarly, we identify both continuity and change in the development of the portfolios. At the cluster level, the focus is on innovativeness capability and its relationship with other capabilities. The results suggest that especially being strategic, market-oriented, and monitoring the external environment are positively related with innovativeness; in contrast, a focus on finance and change seems to suppress innovativeness.
  • Järvinen, Department of Industrial Engineering and Management, Aalto University, P.O.Box 15500, FI-00076 Aalto, Finland ORCID ID:E-mail: joonas.jarvinen@aalto.fi (email)
  • Linnakangas, Department of Industrial Engineering and Management, Aalto University, P.O.Box 15500, FI-00076 Aalto, Finland ORCID ID:E-mail:
article id 69, category Research article
Tarja Wallenius, Risto Laamanen, Jussi Peuhkurinen, Lauri Mehtätalo, Annika Kangas. (2012). Analysing the agreement between an Airborne Laser Scanning based forest inventory and a control inventory – a case study in the state owned forests in Finland. Silva Fennica vol. 46 no. 1 article id 69. https://doi.org/10.14214/sf.69
Airborne laser scanning based forest inventories have recently shown to produce accurate results. However, the accuracy varies according to the test area and used methodology and therefore, an unambiguous and practical quality assessment will be needed as a part of each inventory project. In this study, the accuracy of an ALS inventory was evaluated with a field sampling based control inventory. The agreement between the ALS inventory and the control inventory was analysed with four methods: 1) root mean square error (RMSE) and bias, 2) scatter plots with 95% confidence intervals, 3) Bland-Altman plots and 4) tolerance limits within Bland-Altman plots. Each method has its own special features which have to be taken into account when the agreement is analysed. The pre-defined requirements of the ALS inventory were achieved. A simplified control inventory approach with a slightly narrower focus is proposed to be used in the future. The Bland-Altman plots with the tolerance limits are proposed to be used in quality assessments of operational ALS inventories. Further studies to improve the efficiency of quality assessment are needed.
  • Wallenius, Metsähallitus, P.O. Box 94, FI-01301 Vantaa, Finland ORCID ID:E-mail: tarja.wallenius@metsa.fi (email)
  • Laamanen, Metsähallitus, P.O. Box 94, FI-01301 Vantaa, Finland ORCID ID:E-mail:
  • Peuhkurinen, Oy Arbonaut Ltd, Helsinki, Finland ORCID ID:E-mail:
  • Mehtätalo, University of Eastern Finland, School of Forest Sciences, Joensuu, Finland ORCID ID:E-mail:
  • Kangas, University of Helsinki, Department of Forest Sciences, Helsinki, Finland ORCID ID:E-mail:
article id 68, category Research article
Maria Villikka, Petteri Packalén, Matti Maltamo. (2012). The suitability of leaf-off airborne laser scanning data in an area-based forest inventory of coniferous and deciduous trees. Silva Fennica vol. 46 no. 1 article id 68. https://doi.org/10.14214/sf.68
This study examined the suitability of airborne laser scanner (ALS) data collected under leaf-off conditions in a forest inventory, in which deciduous and coniferous trees need to be separated. All analyses were carried out with leaf-on and leaf-off ALS data collected from the same study area. Additionally, aerial photographs were utilized in the Nearest Neighbor (NN) imputations. An area-based approach was used in this study. Regression estimates of plot volume were more accurate in the case of leaf-off than leaf-on data. In addition, regression models were more accurate in coniferous plots than in deciduous plots. The results of applying leaf-on models with leaf-off data, and vice versa, indicate that leaf-on and leaf-off data should not be combined since this causes serious bias. The total volume and volume by coniferous and deciduous trees was estimated by the NN imputation. In terms of total volume, leaf-off data provided more accurate estimates than leaf-on data. In addition, leaf-off data discriminated between coniferous and deciduous trees, even without the use of aerial photographs. Accurate results were also obtained when leaf-off ALS data were used to classify sample plots into deciduous and coniferous dominated plots. The results indicate that the area-based method and ALS data collected under leaf-off conditions are suitable for forest inventory in which deciduous and coniferous trees need to be distinguished.
  • Villikka, University of Easten Finland, Department of Forest Sciences, Joensuu, Finland ORCID ID:E-mail:
  • Packalén, University of Easten Finland, Department of Forest Sciences, Joensuu, Finland ORCID ID:E-mail: petteri.packalen@uef.fi (email)
  • Maltamo, University of Easten Finland, Department of Forest Sciences, Joensuu, Finland ORCID ID:E-mail:
article id 65, category Research article
Kristóf Kelemen, Barbara Mihók, László Gálhidy, Tibor Standovár. (2012). Dynamic response of herbaceous vegetation to gap opening in a Central European beech stand. Silva Fennica vol. 46 no. 1 article id 65. https://doi.org/10.14214/sf.65
Herbaceous ground vegetation in artificially-created gaps was studied in a managed beech (Fagus sylvatica L.) forest over a period of eight years in Northern Hungary, Central Europe. These gaps were being used as an alternative to the regular shelterwood system to create uneven-aged stands. The effects of gap size (15 and 40 m diameter) and canopy openness on herbaceous species colonization and persistence were assessed in a systematic grid of 5 5 m. Overall, herbaceous cover was low before gap creation, increased soon afterwards, and continued to rise over time. The number of herb species increased in the gaps and, to a lesser extent, in adjacent areas under the remaining tree canopy. Colonization of gaps was rapid and there was substantial turnover of species i.e. various species disappeared from the gaps over time whilst others colonized. Species with both long-term persistent seed banks and long distance dispersal abilities were the most successful types colonizing gaps. Six species occurred preferentially in large gaps, while only one species was found to prefer small gaps. Species present before gap creation survived in both gap sizes. Smaller gaps with a diameter of half the height of canopy trees also tended to remain free of common weed species, whereas large cover of Rubus fruticosus L. and Calamagrostis epigejos (L.) Roth could hamper natural regeneration in larger gaps. For the successful regeneration of beech we recommend the use of small gaps complemented by few large gaps.
  • Kelemen, Loránd Eötvös University, Institute of Biology, Department of Plant Systematics, Ecology and Theoretical Biology, Budapest, Hungary ORCID ID:E-mail:
  • Mihók, Loránd Eötvös University, Institute of Biology, Department of Plant Systematics, Ecology and Theoretical Biology, Budapest, Hungary ORCID ID:E-mail:
  • Gálhidy, Loránd Eötvös University, Institute of Biology, Department of Plant Systematics, Ecology and Theoretical Biology, Budapest, Hungary ORCID ID:E-mail:
  • Standovár, Institute of Biology, Department of Plant Systematics, Ecology and Theoretical Biology, Budapest, Hungary ORCID ID:E-mail: standy@ludens.elte.hu (email)
article id 90, category Research article
Per Angelstam, Kjell Andersson, Robert Axelsson, Marine Elbakidze, Bengt Gunnar Jonsson, Jean-Michel Roberge. (2011). Protecting forest areas for biodiversity in Sweden 1991–2010: the policy implementation process and outcomes on the ground. Silva Fennica vol. 45 no. 5 article id 90. https://doi.org/10.14214/sf.90
Swedish forest and environmental policies imply that forests should be managed so that all naturally occurring species are maintained in viable populations. This requires maintenance of functional networks of representative natural forest and cultural woodland habitats. We first review the policy implementation process regarding protected areas in Sweden 1991–2010, how ecological knowledge was used to formulate interim short-term and strategic long-term biodiversity conservation goals, and the development of a hierarchical spatial planning approach. Second, we present data about the amount of formally protected and voluntarily set aside forest stands, and evaluate how much remains in terms of additional forest protection, conservation management and habitat restoration to achieve forest and environmental policy objectives in the long-term. Third, a case study in central Sweden was made to estimate the functionality of old Scots pine, Norway spruce and deciduous forest habitats, as well as cultural woodland, in different forest regions. Finally, we assess operational biodiversity conservation planning processes. We conclude that Swedish policy pronouncements capture the contemporary knowledge about biodiversity and conservation planning well. However, the existing area of protected and set-aside forests is presently too small and with too poor connectivity. To bridge this gap, spatial planning, management and restoration of habitat, as well as collaboration among forest and conservation planners need to be improved.
  • Angelstam, School for Forest Management, Faculty of Forest Sciences, Swedish University of Agricultural Sciences, Skinnskatteberg, Sweden ORCID ID:E-mail: per.angelstam@slu.se (email)
  • Andersson, School for Forest Management, Faculty of Forest Sciences, Swedish University of Agricultural Sciences, Skinnskatteberg, Sweden ORCID ID:E-mail:
  • Axelsson, School for Forest Management, Faculty of Forest Sciences, Swedish University of Agricultural Sciences, Skinnskatteberg, Sweden ORCID ID:E-mail:
  • Elbakidze, School for Forest Management, Faculty of Forest Sciences, Swedish University of Agricultural Sciences, Skinnskatteberg, Sweden ORCID ID:E-mail:
  • Jonsson, Dept of Natural Science, Engineering and Mathematics, Mid Sweden University, Sundsvall, Sweden ORCID ID:E-mail:
  • Roberge, Dept of Wildlife, Fish and Environmental Studies, Faculty of Forest Sciences, Swedish University of Agricultural Sciences, Umeå, Sweden ORCID ID:E-mail:
article id 90, category Research article
Per Angelstam, Kjell Andersson, Robert Axelsson, Marine Elbakidze, Bengt Gunnar Jonsson, Jean-Michel Roberge. (2011). Protecting forest areas for biodiversity in Sweden 1991–2010: the policy implementation process and outcomes on the ground. Silva Fennica vol. 45 no. 5 article id 90. https://doi.org/10.14214/sf.90
Swedish forest and environmental policies imply that forests should be managed so that all naturally occurring species are maintained in viable populations. This requires maintenance of functional networks of representative natural forest and cultural woodland habitats. We first review the policy implementation process regarding protected areas in Sweden 1991–2010, how ecological knowledge was used to formulate interim short-term and strategic long-term biodiversity conservation goals, and the development of a hierarchical spatial planning approach. Second, we present data about the amount of formally protected and voluntarily set aside forest stands, and evaluate how much remains in terms of additional forest protection, conservation management and habitat restoration to achieve forest and environmental policy objectives in the long-term. Third, a case study in central Sweden was made to estimate the functionality of old Scots pine, Norway spruce and deciduous forest habitats, as well as cultural woodland, in different forest regions. Finally, we assess operational biodiversity conservation planning processes. We conclude that Swedish policy pronouncements capture the contemporary knowledge about biodiversity and conservation planning well. However, the existing area of protected and set-aside forests is presently too small and with too poor connectivity. To bridge this gap, spatial planning, management and restoration of habitat, as well as collaboration among forest and conservation planners need to be improved.
  • Angelstam, School for Forest Management, Faculty of Forest Sciences, Swedish University of Agricultural Sciences, Skinnskatteberg, Sweden ORCID ID:E-mail: per.angelstam@slu.se (email)
  • Andersson, School for Forest Management, Faculty of Forest Sciences, Swedish University of Agricultural Sciences, Skinnskatteberg, Sweden ORCID ID:E-mail:
  • Axelsson, School for Forest Management, Faculty of Forest Sciences, Swedish University of Agricultural Sciences, Skinnskatteberg, Sweden ORCID ID:E-mail:
  • Elbakidze, School for Forest Management, Faculty of Forest Sciences, Swedish University of Agricultural Sciences, Skinnskatteberg, Sweden ORCID ID:E-mail:
  • Jonsson, Dept of Natural Science, Engineering and Mathematics, Mid Sweden University, Sundsvall, Sweden ORCID ID:E-mail:
  • Roberge, Dept of Wildlife, Fish and Environmental Studies, Faculty of Forest Sciences, Swedish University of Agricultural Sciences, Umeå, Sweden ORCID ID:E-mail:
article id 90, category Research article
Per Angelstam, Kjell Andersson, Robert Axelsson, Marine Elbakidze, Bengt Gunnar Jonsson, Jean-Michel Roberge. (2011). Protecting forest areas for biodiversity in Sweden 1991–2010: the policy implementation process and outcomes on the ground. Silva Fennica vol. 45 no. 5 article id 90. https://doi.org/10.14214/sf.90
Swedish forest and environmental policies imply that forests should be managed so that all naturally occurring species are maintained in viable populations. This requires maintenance of functional networks of representative natural forest and cultural woodland habitats. We first review the policy implementation process regarding protected areas in Sweden 1991–2010, how ecological knowledge was used to formulate interim short-term and strategic long-term biodiversity conservation goals, and the development of a hierarchical spatial planning approach. Second, we present data about the amount of formally protected and voluntarily set aside forest stands, and evaluate how much remains in terms of additional forest protection, conservation management and habitat restoration to achieve forest and environmental policy objectives in the long-term. Third, a case study in central Sweden was made to estimate the functionality of old Scots pine, Norway spruce and deciduous forest habitats, as well as cultural woodland, in different forest regions. Finally, we assess operational biodiversity conservation planning processes. We conclude that Swedish policy pronouncements capture the contemporary knowledge about biodiversity and conservation planning well. However, the existing area of protected and set-aside forests is presently too small and with too poor connectivity. To bridge this gap, spatial planning, management and restoration of habitat, as well as collaboration among forest and conservation planners need to be improved.
  • Angelstam, School for Forest Management, Faculty of Forest Sciences, Swedish University of Agricultural Sciences, Skinnskatteberg, Sweden ORCID ID:E-mail: per.angelstam@slu.se (email)
  • Andersson, School for Forest Management, Faculty of Forest Sciences, Swedish University of Agricultural Sciences, Skinnskatteberg, Sweden ORCID ID:E-mail:
  • Axelsson, School for Forest Management, Faculty of Forest Sciences, Swedish University of Agricultural Sciences, Skinnskatteberg, Sweden ORCID ID:E-mail:
  • Elbakidze, School for Forest Management, Faculty of Forest Sciences, Swedish University of Agricultural Sciences, Skinnskatteberg, Sweden ORCID ID:E-mail:
  • Jonsson, Dept of Natural Science, Engineering and Mathematics, Mid Sweden University, Sundsvall, Sweden ORCID ID:E-mail:
  • Roberge, Dept of Wildlife, Fish and Environmental Studies, Faculty of Forest Sciences, Swedish University of Agricultural Sciences, Umeå, Sweden ORCID ID:E-mail:
article id 90, category Research article
Per Angelstam, Kjell Andersson, Robert Axelsson, Marine Elbakidze, Bengt Gunnar Jonsson, Jean-Michel Roberge. (2011). Protecting forest areas for biodiversity in Sweden 1991–2010: the policy implementation process and outcomes on the ground. Silva Fennica vol. 45 no. 5 article id 90. https://doi.org/10.14214/sf.90
Swedish forest and environmental policies imply that forests should be managed so that all naturally occurring species are maintained in viable populations. This requires maintenance of functional networks of representative natural forest and cultural woodland habitats. We first review the policy implementation process regarding protected areas in Sweden 1991–2010, how ecological knowledge was used to formulate interim short-term and strategic long-term biodiversity conservation goals, and the development of a hierarchical spatial planning approach. Second, we present data about the amount of formally protected and voluntarily set aside forest stands, and evaluate how much remains in terms of additional forest protection, conservation management and habitat restoration to achieve forest and environmental policy objectives in the long-term. Third, a case study in central Sweden was made to estimate the functionality of old Scots pine, Norway spruce and deciduous forest habitats, as well as cultural woodland, in different forest regions. Finally, we assess operational biodiversity conservation planning processes. We conclude that Swedish policy pronouncements capture the contemporary knowledge about biodiversity and conservation planning well. However, the existing area of protected and set-aside forests is presently too small and with too poor connectivity. To bridge this gap, spatial planning, management and restoration of habitat, as well as collaboration among forest and conservation planners need to be improved.
  • Angelstam, School for Forest Management, Faculty of Forest Sciences, Swedish University of Agricultural Sciences, Skinnskatteberg, Sweden ORCID ID:E-mail: per.angelstam@slu.se (email)
  • Andersson, School for Forest Management, Faculty of Forest Sciences, Swedish University of Agricultural Sciences, Skinnskatteberg, Sweden ORCID ID:E-mail:
  • Axelsson, School for Forest Management, Faculty of Forest Sciences, Swedish University of Agricultural Sciences, Skinnskatteberg, Sweden ORCID ID:E-mail:
  • Elbakidze, School for Forest Management, Faculty of Forest Sciences, Swedish University of Agricultural Sciences, Skinnskatteberg, Sweden ORCID ID:E-mail:
  • Jonsson, Dept of Natural Science, Engineering and Mathematics, Mid Sweden University, Sundsvall, Sweden ORCID ID:E-mail:
  • Roberge, Dept of Wildlife, Fish and Environmental Studies, Faculty of Forest Sciences, Swedish University of Agricultural Sciences, Umeå, Sweden ORCID ID:E-mail:
article id 89, category Research article
Russell Grenfell, Tuomas Aakala, Timo Kuuluvainen. (2011). Microsite occupancy and the spatial structure of understorey regeneration in three late-successional Norway spruce forests in northern Europe. Silva Fennica vol. 45 no. 5 article id 89. https://doi.org/10.14214/sf.89
We compared microsite occupancy and three spatial structure of regeneration in three primeval late-successional Norway spruce dominated forests. One area lay in the middle boreal zone in Russia (Dvina-Pinega) where larger-scale disturbance from bark beetles and drought had occurred; the other areas lay in the northern boreal zone, one in Finland (Pallas-Ylläs) had encountered only small-scale disturbance, and one in Russia (Kazkim) had been influenced by fire. We mapped all spruce (Picea abies) and birch (Betula pendula and Betula pubescens) trees with diameter at breast height (DBH) ≥ 10 cm on 40 m 400 m plots, and those with DBH < 10 cm on 2 m or 4 m 400 m subplots. On the subplots we also recorded microsite occupancy and estimated microsite availability. At all study areas small seedlings (h < 0.3 m) of both spruce and birch were found largely on disturbance-related microsites. Birch saplings (h ≥ 1.3 m, DBH < 10 cm) disproportionately occupied deadwood-related microsites at Dvina-Pinega. In contrast, spruce saplings at all study areas, and birch saplings at Kazkim and Pallas-Ylläs, showed less, or no, preference. Our results thus confirm the importance of disturbance-related microsites for regeneration establishment, but not necessarily for long-term survival. No spatial segregation between the overstorey (DBH ≥ 10 cm) and saplings (h ≥ 1.3 m, DBH < 10 cm) or seedlings (h < 1.3 m) was found at Pallas-Ylläs or Kazkim, and only three instances of very weak segregation were found at Dvina-Pinega. This suggests that the regeneration gap concept may not be useful for describing the regeneration dynamics of primeval boreal forests.
  • Grenfell, University of Helsinki, Dept of Forest Sciences, Helsinki, Finland ORCID ID:E-mail: russell.grenfell@helsinki.fi (email)
  • Aakala, University of Helsinki, Dept of Forest Sciences, Helsinki, Finland ORCID ID:E-mail:
  • Kuuluvainen, University of Helsinki, Dept of Forest Sciences, Helsinki, Finland ORCID ID:E-mail:
article id 89, category Research article
Russell Grenfell, Tuomas Aakala, Timo Kuuluvainen. (2011). Microsite occupancy and the spatial structure of understorey regeneration in three late-successional Norway spruce forests in northern Europe. Silva Fennica vol. 45 no. 5 article id 89. https://doi.org/10.14214/sf.89
We compared microsite occupancy and three spatial structure of regeneration in three primeval late-successional Norway spruce dominated forests. One area lay in the middle boreal zone in Russia (Dvina-Pinega) where larger-scale disturbance from bark beetles and drought had occurred; the other areas lay in the northern boreal zone, one in Finland (Pallas-Ylläs) had encountered only small-scale disturbance, and one in Russia (Kazkim) had been influenced by fire. We mapped all spruce (Picea abies) and birch (Betula pendula and Betula pubescens) trees with diameter at breast height (DBH) ≥ 10 cm on 40 m 400 m plots, and those with DBH < 10 cm on 2 m or 4 m 400 m subplots. On the subplots we also recorded microsite occupancy and estimated microsite availability. At all study areas small seedlings (h < 0.3 m) of both spruce and birch were found largely on disturbance-related microsites. Birch saplings (h ≥ 1.3 m, DBH < 10 cm) disproportionately occupied deadwood-related microsites at Dvina-Pinega. In contrast, spruce saplings at all study areas, and birch saplings at Kazkim and Pallas-Ylläs, showed less, or no, preference. Our results thus confirm the importance of disturbance-related microsites for regeneration establishment, but not necessarily for long-term survival. No spatial segregation between the overstorey (DBH ≥ 10 cm) and saplings (h ≥ 1.3 m, DBH < 10 cm) or seedlings (h < 1.3 m) was found at Pallas-Ylläs or Kazkim, and only three instances of very weak segregation were found at Dvina-Pinega. This suggests that the regeneration gap concept may not be useful for describing the regeneration dynamics of primeval boreal forests.
  • Grenfell, University of Helsinki, Dept of Forest Sciences, Helsinki, Finland ORCID ID:E-mail: russell.grenfell@helsinki.fi (email)
  • Aakala, University of Helsinki, Dept of Forest Sciences, Helsinki, Finland ORCID ID:E-mail:
  • Kuuluvainen, University of Helsinki, Dept of Forest Sciences, Helsinki, Finland ORCID ID:E-mail:
article id 88, category Research article
Seppo Rouvinen, Jari Kouki. (2011). Tree regeneration in artificial canopy gaps established for restoring natural structural variability in a Scots pine stand. Silva Fennica vol. 45 no. 5 article id 88. https://doi.org/10.14214/sf.88
In Finland and elsewhere in Europe, many protected forest areas include also stands that were previously managed and that lack several naturally occurring stand characteristics. In these areas, ecosystem restoration can be used to facilitate and accelerate the formation of structural and habitat features resembling those of natural forests. For example, by creating small gaps it could be possible to diversify forest structure and tree species composition and to produce dead wood while still maintaining mostly continous canopy coverage. We examined experimentally the effects of artificial gap formation on post-disturbance tree regeneration in the gaps in a young protected, but formerly commercially managed pine (Pinus sylvestris L.) dominated forest. In the experimental sites, gap size and the portion of girdled trees out of all treated trees (girdled and felled trees combined) in the gaps varied. Natural and artificial (direct seeding of silver birch Betula pendula Roth) tree regeneration and development was monitored both on disturbed (scarified soil patches) and undisturbed forest floor during three growing seasons. Results show that gaps can be valuable in diversifying stand structure but to be successful and rapid, tree regeneration needs disturbed forest floor. Pine regenerated numerously, but birch had clearly lower regeneration, especially on small-sized gaps. In conclusion, increasing tree diversity in young pine-dominated forests seems to be difficult when only small artificial gaps are used. But even small gaps can be used to create and maintain diverse cohort structure of the dominant species and thus they can contribute to restoration goals.
  • Rouvinen, University of Eastern Finland, School of Forest Sciences, Joensuu, Finland ORCID ID:E-mail: seppo.rouvinen@uef.fi (email)
  • Kouki, University of Eastern Finland, School of Forest Sciences, Joensuu, Finland ORCID ID:E-mail:
article id 85, category Research article
Ville A.O. Selonen, Maija Mussaari, Tero Toivanen, Janne S. Kotiaho. (2011). The conservation potential of brook-side key habitats in managed boreal forests. Silva Fennica vol. 45 no. 5 article id 85. https://doi.org/10.14214/sf.85
Today, maintaining biodiversity is included in the targets of boreal forest management. A widespread approach in northern Europe is to identify and preserve woodland key habitats within managed forests. Woodland key habitats are expected to be patches that host populations of threatened and declining species, and the preservation of these patches is assumed to enable the persistence of the focal species in the landscape. In Finland, the criteria for selecting woodland key habitats are defined in the Finnish Forest Act, and the selection has been done by forest practitioners. Our objective was to determine whether the surroundings of boreal brooks and rivulets qualified as key habitats are truly different from brook-side habitats not granted the key habitat status, and whether the brook-side habitats of the two types differ from the forest matrix managed for timber production. We found that the two brook-side habitats were in most aspects rather alike but there was a difference in the composition of ground vegetation assemblages. In contrast, the control forests were distinct from the brook-sides in terms of dead wood, species richness and assemblages of polypores, species richness of epiphytic mosses, and the composition of beetle assemblages. We conclude that brook-sides in general provide an important habitat clearly diverging from the surrounding matrix but that the conservation value of the brook-sides granted the key habitat status may not be substantially larger than that of the brook-sides without the status.
  • Selonen, University of Jyväskylä, Department of Biological and Environmental Sciences, Lahti, Finland ORCID ID:E-mail: ville.selonen@juy.fi (email)
  • Mussaari, University of Jyväskylä, Department of Biological and Environmental Sciences, Lahti, Finland ORCID ID:E-mail:
  • Toivanen, University of Jyväskylä, Department of Biological and Environmental Sciences, Lahti, Finland ORCID ID:E-mail:
  • Kotiaho, University of Jyväskylä, Department of Biological and Environmental Sciences, Lahti, Finland ORCID ID:E-mail:
article id 84, category Research article
Asko Lõhmus, Piret Lõhmus. (2011). Old-forest species: the importance of specific substrata vs. stand continuity in the case of calicioid fungi. Silva Fennica vol. 45 no. 5 article id 84. https://doi.org/10.14214/sf.84
Appropriate conservation management of old-forest species depends on the causes of their old-forest affinity, which, however, are insufficiently known. Calicioid fungi are often considered old-forest dependent because of their special requirements for microhabitat, microclimate, and stand continuity for at least two tree generations. We demonstrate that, for several methodological or interpretational problems, published studies do not provide unequivocal evidence for such mechanisms and even for old-forest dependency of calicioids in general. We then analyse a large Estonian dataset (ca. 2300 records of 32 species) representing various management types and site types to answer whether old forests have more calicioid species, and any specific species, than could be expected for the substratum availability observed. Although old growth had more species and records than mature managed stands or cutover sites, those substratum types that occurred at roughly similar abundances also hosted comparable numbers of species in different management types. The characteristic substrata adding extra species to old growth were snags and root-plates of treefall mounds; wood surfaces in general comprised more than half of all calicioid records. Although substratum abundance did not fully explain the species-richness contrast between old growth and mature stands, additional evidence suggested that the unexplained variance is rather due to small-scale habitat characteristics than stand-scale continuity or microclimate. Finally, we review the evidence for old-forest affinity of calicioid species and distinguish a set of threatened species. We conclude that the availability of specific substrata is the main limiting factor for calicioid fungi in forests, and its quantitative and stochastic nature explains the large random and region-specific variation in the published lists of ‘old-forest species’.
  • Lõhmus, Department of Zoology, Institute of Ecology and Earth Sciences, University of Tartu, Vanemuise st. 46, EE-51014, Tartu, Estonia ORCID ID:E-mail: asko.lohmus@ut.ee (email)
  • Lõhmus, Department of Botany, Institute of Ecology and Earth Sciences, University of Tartu, Tartu, Estonia ORCID ID:E-mail:
article id 83, category Research article
Inari Ylläsjärvi, Håkan Berglund, Timo Kuuluvainen. (2011). Relationships between wood-inhabiting fungal species richness and habitat variables in old-growth forest stands in the Pallas-Yllästunturi National Park, northern boreal Finland. Silva Fennica vol. 45 no. 5 article id 83. https://doi.org/10.14214/sf.83
Indicators for biodiversity are needed for efficient prioritization of forests selected for conservation. We analyzed the relationships between 86 wood-inhabiting fungal (polypore) species richness and 35 habitat variables in 81 northern boreal old-growth forest stands in Finland. Species richness and the number of red-listed species were analyzed separately using generalized linear models. Most species were infrequent in the studied landscape and no species was encountered in all stands. The species richness increased with 1) the volume of coarse woody debris (CWD), 2) the mean DBH of CWD and 3) the basal area of living trees. The number of red-listed species increased along the same gradients, but the effect of basal area was not significant. Polypore species richness was significantly lower on western slopes than on flat topography. On average, species richness was higher on northern and eastern slopes than on western and southern slopes. The results suggest that a combination of habitat variables used as indicators may be useful in selecting forest stands to be set aside for polypore species conservation.
  • Ylläsjärvi, Rovaniemi University of Applied Sciences, School of Forestry and Rural Industries, Jokiväylä 11 c, FI-96300 Rovaniemi, Finland ORCID ID:E-mail: inari.yllasjarvi@ramk.fi (email)
  • Berglund, University of Helsinki, Department of Forest Sciences, Helsinki, Finland ORCID ID:E-mail:
  • Kuuluvainen, University of Helsinki, Department of Forest Sciences, Helsinki, Finland ORCID ID:E-mail:
article id 82, category Research article
Nicole J. Fenton, Yves Bergeron. (2011). Dynamic old-growth forests? A case study of boreal black spruce forest bryophytes. Silva Fennica vol. 45 no. 5 article id 82. https://doi.org/10.14214/sf.82
Old-growth forests have sparked significant interest over the last twenty years and definitions have evolved from structure based to process based, acknowledging the diversity of forests that could be considered old growth. However studies frequently group all forests over a certain age into a single type, negating the dynamic processes that create old growth. In this study we examine a 2350-year chronosequence in boreal black spruce forests in northwestern Quebec to determine whether continued community change can be observed in the bryophyte layer. Bryophytes dominate the understory of boreal forests and influence ecosystem functioning, particularly in paludified forests where production exceeds decomposition in the organic layer. Community composition and richness changed throughout the chronosequence with no evidence of a steady state associated with an old-growth phase. In contrast the bryophyte community continued to evolve with multiple phases being evident. These results suggest that old-growth forests on the Clay Belt of northwestern Quebec and northeastern Ontario, Canada, should be regarded as part of the continuous gradient in forest development rather than a single state. This complicates conservation of these forests as multiple phases should be considered when planning forest reserves.
  • Fenton, Université du Québec en Abitibi-Témiscamingue, 445 Boulevard de l’Université, Rouyn-Noranda, Québec, Canada J9X 4E5 ORCID ID:E-mail: nicole.fenton@uqat.ca (email)
  • Bergeron, Université du Québec en Abitibi-Témiscamingue, 445 Boulevard de l’Université, Rouyn-Noranda, Québec, Canada J9X 4E5 ORCID ID:E-mail:
article id 81, category Research article
Tuomas Aakala. (2011). Temporal variability of deadwood volume and quality in boreal old-growth forests. Silva Fennica vol. 45 no. 5 article id 81. https://doi.org/10.14214/sf.81
Reference deadwood volumes from natural forests for forest management and restoration are often derived from one-time measurements or from repeated measurements over short time-scales. Such an approach often assumes an equilibrium state between tree mortality and decomposition, which is questionable in many boreal forest ecosystems due to the occurrence of allogenic disturbances. Using a simulation model based on empirical estimates of tree mortality, disturbance chronologies and models of wood decay class dynamics, this study aimed at characterizing variability in the volume and quality of deadwood for the past 200 years. The variability of deadwood volumes in old-growth forests, arising from differences in disturbance regimes and differing decay rates, was exemplified in two areas of Picea abies-dominated forests in northern Europe. The results imply that with stable deadwood input and slow decay rates the deadwood volume may be in an equilibrium state. On the contrary, if moderate-severity disturbances occur such a state seems improbable. Both study areas displayed continuity in deadwood availability, although temporary paucity in the early decay classes with shortest residence times was also observed. The results stress the importance of understanding the dynamic nature of deadwood in old-growth forests, instead of the traditional view of deadwood as a static ecosystem component.
  • Aakala, Department of Forest Sciences, P.O. Box 27, FI-00014 University of Helsinki, Finland ORCID ID:E-mail: tuomas.aakala@helsinki.fi (email)
article id 80, category Research article
Mari T. Jönsson, Shawn Fraver, Bengt Gunnar Jonsson. (2011). Spatio-temporal variation of coarse woody debris input in woodland key habitats in central Sweden. Silva Fennica vol. 45 no. 5 article id 80. https://doi.org/10.14214/sf.80
The persistence of many saproxylic (wood-living) species depends on a readily available supply of coarse woody debris (CWD). Most studies of CWD inputs address stand-level patterns, despite the fact that many saproxylic species depend on landscape-level supplies of CWD. In the present study we used dated CWD inputs (tree mortality events) at each of 14 Norway spruce (Picea abies) dominated woodland key habitat sites to analyze the spatial and temporal patterns of CWD additions between 1950 and 2002 within a small landscape in central Sweden. We found that inputs were episodic within sites, where local windstorms created pulses in CWD input. Pulses occurred simultaneously in many sites, yielding landscape-level synchrony of CWD input. These synchronous pulses, and importantly, the breaks between pulses, may have negative implications for saproxylic species that are dependent on large volume inputs of freshly killed Norway spruce. In addition, the inherent small size and relative isolation of these sites may further increase extinction risks due to stochastic events. However, background CWD input rates occurring between pulses varied substantially among sites, presumably the result of the sites’ varied histories and structural characteristics. This finding suggests that the different sites have varied abilities to provide habitat for saproxylic species during periods with low landscape-level input of CWD.
  • Jönsson, Department of Ecology, SLU, P.O. Box 7044, SE-750 07 Uppsala, Sweden (current); Department of Natural Sciences, Engineering and Mathematics, Mid Sweden University, Sundsvall, Sweden ORCID ID:E-mail: mari.jonsson@slu.se (email)
  • Fraver, U.S. Forest Service, Northern Research Station, Grand Rapids, Minnesota, USA (current); Department of Natural Sciences, Engineering and Mathematics, Mid Sweden University, Sundsvall, Sweden ORCID ID:E-mail:
  • Jonsson, Department of Natural Sciences, Engineering and Mathematics, Mid Sweden University, Sundsvall, Sweden ORCID ID:E-mail:
article id 79, category Research article
Jean-Philippe Légaré, Christian Hébert, Jean-Claude Ruel. (2011). Alternative silvicultural practices in irregular boreal forests: response of beetle assemblages. Silva Fennica vol. 45 no. 5 article id 79. https://doi.org/10.14214/sf.79
In the process of implementing sustainable management in the eastern Canadian boreal forest, we tested two selection cutting methods and compared them with two widely used practices in the boreal forest: clearcutting with protection of the advanced growth and soils and irregular shelterwood cutting leaving small merchantable stems. We used old-growth irregular stands as references in comparing the impact of these silvicultural treatments on the diversity and abundance of beetles. Three groups were targeted: saproxylic flying beetles, epigaeic saproxylic beetles and epigaeic non-saproxylic beetles. A sampling design including 320 pitfall traps and 80 multidirectional flight-interception traps was deployed in 2007. A total of 26 906 beetles was captured including 407 taxa distributed among 52 families. We found that clearcutting with protection of the advanced growth and soils and irregular shelterwood cutting leaving small merchantable stems had a greater impact on beetle communities than both selection cuttings. Canopy opening as well as the presence of snags and downed woody debris appear as important attributes for several saproxylic and non-saproxylic species. Beetle communities in selection cuttings remained more similar to those found in controls; these silvicultural treatments are new tools to implement ecosystemic and sustainable management in irregular boreal forests.
  • Légaré, Université Laval, Faculté de foresterie, de géographie et de géomatique, Pavillon Abitibi-Price, Québec, Canada ORCID ID:E-mail:
  • Hébert, Natural Resources Canada, Canadian Forest Service, Laurentian Forestry Centre, 1055 du P.E.P.S., P.O. Box 10380, Stn. Sainte-Foy, Québec (Québec), G1V 4C7, Canada ORCID ID:E-mail: christian.hebert@rncan.gc.ca (email)
  • Ruel, Université Laval, Faculté de foresterie, de géographie et de géomatique, Pavillon Abitibi-Price, Québec, Canada ORCID ID:E-mail:
article id 76, category Research article
Alessandra Bottero, Matteo Garbarino, Vojislav Dukic, Zoran Govedar, Emanuele Lingua, Thomas A. Nagel, Renzo Motta. (2011). Gap-phase dynamics in the old-growth forest of Lom, Bosnia and Herzegovina. Silva Fennica vol. 45 no. 5 article id 76. https://doi.org/10.14214/sf.76
We investigated forest canopy gaps in the mixed beech (Fagus sylvatica L.), silver fir (Abies alba Miller), and Norway spruce (Picea abies (L.) Karst.) old-growth forest of Lom in the Dinaric Mountains of Bosnia and Herzegovina. Gap size, age, gap fraction, gapmaker characteristics and the structure and composition of gapfillers were documented to investigate gap dynamics. The percentages of forest area in canopy and expanded gaps were 19% and 41%, respectively. The median canopy gap size was 77 m2, and ranged from 11 to 708 m2. Although there were many single tree-fall gaps, the majority had multiple gapmakers that were often in different stages of decay, suggesting gap expansion is important at the study site. Of the gapmakers recorded, 14% were uprooted stems, 60% snapped stems, and 26% were standing dead trees. Dendroecological analysis suggests that gap formation varied in time. The density of gapfillers was not correlated to gap size, and the species composition of gapfillers varied between seedling, sapling, and tree life stages. The results suggest that gaps are mainly formed by endogenous senescence of single canopy trees. Exogenous disturbance agents, most likely related to wind and snow, act mainly as secondary agents in breaking weakened trees and in expanding previously established gaps. Although the findings are partially consistent with other studies of gap disturbance processes in similar old-growth forests in central Europe, the observed gap dynamic places the Lom core area at the end of a gradient that ranges from forests controlled by very small-scale processes to those where large, stand replacing disturbances predominate.
  • Bottero, University of Turin, Department Agroselviter, Via Leonardo da Vinci 44, 10095 Grugliasco (TO), Italy ORCID ID:E-mail: alessandra.bottero@unito.it (email)
  • Garbarino, University of Turin, Department Agroselviter, Via Leonardo da Vinci 44, 10095 Grugliasco (TO), Italy ORCID ID:E-mail:
  • Dukic, University of Banja Luka, Faculty of Forestry, Banja Luka, Bosnia and Herzegovina ORCID ID:E-mail:
  • Govedar, University of Banja Luka, Faculty of Forestry, Banja Luka, Bosnia and Herzegovina ORCID ID:E-mail:
  • Lingua, University of Padua, Department of TeSAF, Legnaro (PD), Italy ORCID ID:E-mail:
  • Nagel, University of Ljubljana, Department of Forestry and Renewable Forest Resources, Ljubljana, Slovenia ORCID ID:E-mail:
  • Motta, University of Turin, Department Agroselviter, Via Leonardo da Vinci 44, 10095 Grugliasco (TO), Italy ORCID ID:E-mail:
article id 75, category Research article
Silvia Lamedica, Emanuele Lingua, Ionel Popa, Renzo Motta, Marco Carrer. (2011). Spatial structure in four Norway spruce stands with different management history in the Alps and Carpathians. Silva Fennica vol. 45 no. 5 article id 75. https://doi.org/10.14214/sf.75
In Europe most Norway spruce (Picea abies (L.) Karst.) mountain forests have been altered by human activities, leading to a lack of reference condition concerning their original structure. Nonetheless, remnants of Norway spruce primeval forests still exist in the Carpathians. Our objective was to assess the differences in structure between managed and unmanaged stands, concerning diameter distributions, amount of standing deadwood, spatial distributions and spatial structure of trees. We established four permanent plots: one in a virgin forest in the Eastern Carpathians and three in a previously managed forest in the Alps. In each plot, species, DBH, and position of the live and dead standing trees were collected. Spatial distribution and structure of all the trees was analysed through several indices. In the Carpathians forest there are clear signs of natural density-dependent mortality processes whereas in the Alpine plots such dynamics are less evident. In these latter plots, the lower snags volume and the random trees spatial distribution can be considered the legacies of past management. Nonetheless, despite the different history of the four stands, they all seem to converge towards a similar spatial structure with the presence of groups (30–40 m) of trees of similar size.
  • Lamedica, Forest Ecology Research Unit, Dept TeSAF, University of Padova, Legnaro (PD), Italy ORCID ID:E-mail:
  • Lingua, Forest Ecology Research Unit, Dept TeSAF, University of Padova, Legnaro (PD), Italy ORCID ID:E-mail:
  • Popa, Forest Research and Management Institute, Research Station for Norway Spruce Silviculture, Câmpulung Moldovenesc, Romania ORCID ID:E-mail:
  • Motta, Department AGROSELVITER, University of Torino, Grugliasco (TO), Italy ORCID ID:E-mail:
  • Carrer, Forest Ecology Research Unit, Dept TeSAF, University of Padova, Legnaro (PD), Italy ORCID ID:E-mail: marco.carrer@unipd.it (email)
article id 101, category Research article
Risto Laamanen, Annika Kangas. (2011). Large-scale forest owner’s information needs in operational planning of timber harvesting - some practical views in Metsähallitus, Finnish state-owned enterprise. Silva Fennica vol. 45 no. 4 article id 101. https://doi.org/10.14214/sf.101
Metsähallitus in Finland is a state enterprise that manages about 3.5 million hectares of productive commercial state-owned forest land. Metsähallitus has a forest management planning system which uses information stored in a GIS-based forest resource information system. The information on forest resources is currently collected using a standwise inventory system with ocular estimation of stand characteristics. New promising inventory methods based on laser scanning have been introduced. Before taking a new system into use, the information needs of Metsähallitus must be analysed. In this study, information needs in operational harvest planning have been analysed with a qualitative approach. A total of eight team leaders in the forestry business unit were interviewed, six of them representing the process responsible for the operational harvest planning and two representing the process responsible for the harvest and deliveries. Based on the study, two main decision making points with different information needs were confirmed. The first decision making point is related to finding the areas potential for immediate or near future harvesting. Here, geographical information on the need for the treatment as well as rough information on the harvestable volume is needed. In the second decision making point, a final decision of sites to be harvested is made with rather intensive field work. Precise delineations of the treatment are needed as well as good estimates of volumes of different timber assortments. When considering a new inventory system it is justified to consider how much of the information needs in these decision making points can be covered. Two different approaches are proposed for further analysis. The interviews revealed a need for a more structured tactical planning system. Some of the findings of this study – especially the decision making points and information needs in them – may be transferable to other large-scale forest owners.
  • Laamanen, Metsähallitus, Vantaa, Finland ORCID ID:E-mail: risto.laamanen@metsa.fi (email)
  • Kangas, Metsähallitus, Vantaa, Finland ORCID ID:E-mail:
article id 100, category Research article
Annika Kangas, Lauri Mehtätalo, Antti Mäkinen, Kalle Vanhatalo. (2011). Sensitivity of harvest decisions to errors in stand characteristics. Silva Fennica vol. 45 no. 4 article id 100. https://doi.org/10.14214/sf.100
In forest planning, the decision maker chooses for each stand a treatment schedule for a predefined planning period. The choice is based either on optimization calculations or on silvicultural guidelines. Schedules for individual stands are obtained using a growth simulator, where measured stand characteristics such as the basal area, mean diameter, site class and mean height are used as input variables. These characteristics include errors, however, which may lead to incorrect decisions. In this study, the aim is to study the sensitivity of harvest decisions to errors in a dataset of 157 stands. Correct schedules according to silvicultural guidelines were first determined using error-free data. Different amounts of errors were then generated to the stand-specific characteristics, and the treatment schedule was selected again using the erroneous data. The decision was defined as correct, if the type of harvest in these two schedules were similar, and if the timings deviated at maximum ±2 for thinning and ±3 years for clear-cut. The dependency of probability of correct decisions on stand characteristics and the degree of errors was then modelled. The proposed model can be used to determine the required level of measurement accuracy for each characteristics in different kinds of stands, with a given accuracy requirement for the timing of treatments. This information can further be utilized in selecting the most appropriate inventory method.
  • Kangas, Department of Forest Sciences, P.O. Box 27, FI-00014 University of Helsinki, Finland ORCID ID:E-mail: annika.kangas@helsinki.fi (email)
  • Mehtätalo, University of Eastern Finland, School of Forest Sciences, Joensuu, Finland ORCID ID:E-mail:
  • Mäkinen, Simosol Oy, Riihimäki, Finland ORCID ID:E-mail:
  • Vanhatalo, Department of Forest Sciences, P.O. Box 27, FI-00014 University of Helsinki, Finland ORCID ID:E-mail:
article id 98, category Research article
Meeri Pearson, Markku Saarinen, Kari Minkkinen, Niko Silvan, Jukka Laine. (2011). Mounding and scalping prior to reforestation of hydrologically sensitive deep-peated sites: factors behind Scots pine regeneration success. Silva Fennica vol. 45 no. 4 article id 98. https://doi.org/10.14214/sf.98
Watering up typically ensues after clearcutting forestry-drained peatland forests. Thus, the effectiveness of maintenance drainage and soil preparation procedures becomes paramount for establishing a new generation of commercial forest. Mounding is the primary method of soil preparation applied in regeneration sites lying on deep peat. As raised planting spots, mounds are resistant to waterlogging and assumed to be beneficial for organic matter (OM) decomposition via, e.g., increased soil aeration and temperature, which would also enhance seedling growth. In recent years, however, less intensive and cheaper alternatives like scalping have been sought with some reported cases of success. Our case study investigated the survival and growth of Scots pine outplants in mounds, scalps, and unprepared microsites along a moisture gradient. After three growing seasons, mounding accelerated neither seedling growth nor OM decomposition relative to the unprepared treatment. Survival in mounds was nonetheless superior overall. Scalps behaved as water collecting depressions leading to a catastrophic regeneration result. Based on our findings, water table level (WTL) overrides other growth-controlling factors in excess moisture conditions. To combat watering up coupled with greater than normal rainfall, we recommend reforestation strategies which provide elevated, prepared planting spots (i.e., mounds) or utilize unprepared, higher microforms.
  • Pearson, Finnish Forest Research Institute, Western Finland Regional Unit, Kaironiementie 15, FI-39700 Parkano, Finland ORCID ID:E-mail: meeri.pearson@metla.fi (email)
  • Saarinen, Finnish Forest Research Institute, Western Finland Regional Unit, Kaironiementie 15, FI-39700 Parkano, Finland ORCID ID:E-mail:
  • Minkkinen, University of Helsinki, Department of Forest Sciences, Helsinki, Finland ORCID ID:E-mail:
  • Silvan, Finnish Forest Research Institute, Western Finland Regional Unit, Kaironiementie 15, FI-39700 Parkano, Finland ORCID ID:E-mail:
  • Laine, Finnish Forest Research Institute, Western Finland Regional Unit, Kaironiementie 15, FI-39700 Parkano, Finland ORCID ID:E-mail:
article id 449, category Research article
Thomas Wutzler, Ingolf Profft, Martina Mund. (2011). Quantifying tree biomass carbon stocks, their changes and uncertainties using routine stand taxation inventory data. Silva Fennica vol. 45 no. 3 article id 449. https://doi.org/10.14214/sf.449
For carbon (C) trading or any other verifiable C reports, it would be reasonable to identify and quantify continuous changes in carbon stocks at regional scales without high investments into additional C-specific, time- and labor-intensive inventories. Our study demonstrates the potential of using routine stand taxation data from large scale forestry inventories for verifiable quantification of tree biomass C stocks, C stock change rates, and associated uncertainties. Empirical models, parameters, and equations of uncertainty propagation have been assembled and applied to data from a forest management unit in Central Germany (550 000 ha), using stand taxation inventories collected between 1993 and 2006. The study showed: 1) The use of stand taxation data resulted in a verifiable and sufficiently precise (cv = 7%) quantification of tree biomass carbon stocks and their changes at the level of growth-regions (1700 to 140 000 ha). 2) The forest of the test region accumulated carbon in tree biomass at a mean annual rate of 1.8 (–0.9 to 4.5) tC/ha/yr over the studied period. 3) The taxation inventory data can reveal spatial patterns of rates of C stock changes, specifically low rates of 0.4 tC/ha/yr in the northwest and high rates of 3.0 tC/ha/yr in the south of the study region.
  • Wutzler, Max Planck Institute for Biogeochemistry, Hans-Knöll-Strasse 10, 07745 Jena, Germany ORCID ID:E-mail: twutz@bgc-jena.mpg.de (email)
  • Profft, Max Planck Institute for Biogeochemistry, Hans-Knöll-Stra§e 10, 07745 Jena, Germany ORCID ID:E-mail:
  • Mund, Max Planck Institute for Biogeochemistry, Hans-Knöll-Stra§e 10, 07745 Jena, Germany ORCID ID:E-mail:
article id 449, category Research article
Thomas Wutzler, Ingolf Profft, Martina Mund. (2011). Quantifying tree biomass carbon stocks, their changes and uncertainties using routine stand taxation inventory data. Silva Fennica vol. 45 no. 3 article id 449. https://doi.org/10.14214/sf.449
For carbon (C) trading or any other verifiable C reports, it would be reasonable to identify and quantify continuous changes in carbon stocks at regional scales without high investments into additional C-specific, time- and labor-intensive inventories. Our study demonstrates the potential of using routine stand taxation data from large scale forestry inventories for verifiable quantification of tree biomass C stocks, C stock change rates, and associated uncertainties. Empirical models, parameters, and equations of uncertainty propagation have been assembled and applied to data from a forest management unit in Central Germany (550 000 ha), using stand taxation inventories collected between 1993 and 2006. The study showed: 1) The use of stand taxation data resulted in a verifiable and sufficiently precise (cv = 7%) quantification of tree biomass carbon stocks and their changes at the level of growth-regions (1700 to 140 000 ha). 2) The forest of the test region accumulated carbon in tree biomass at a mean annual rate of 1.8 (–0.9 to 4.5) tC/ha/yr over the studied period. 3) The taxation inventory data can reveal spatial patterns of rates of C stock changes, specifically low rates of 0.4 tC/ha/yr in the northwest and high rates of 3.0 tC/ha/yr in the south of the study region.
  • Wutzler, Max Planck Institute for Biogeochemistry, Hans-Knöll-Strasse 10, 07745 Jena, Germany ORCID ID:E-mail: twutz@bgc-jena.mpg.de (email)
  • Profft, Max Planck Institute for Biogeochemistry, Hans-Knöll-Stra§e 10, 07745 Jena, Germany ORCID ID:E-mail:
  • Mund, Max Planck Institute for Biogeochemistry, Hans-Knöll-Stra§e 10, 07745 Jena, Germany ORCID ID:E-mail:
article id 109, category Research article
Ann Kristin Raymer, Terje Gobakken, Birger Solberg. (2011). Optimal forest management with carbon benefits included. Silva Fennica vol. 45 no. 3 article id 109. https://doi.org/10.14214/sf.109
In this paper, we analyse how optimal forest management of even aged Norway spruce changes when economic values are placed on carbon fixation, release, and saved greenhouse gas emissions from using wood instead of more energy intensive materials or fossil fuels. The analyses are done for three different site qualities in Norway, assuming present climate and with a range of CO2 prices and real rates of return. Compared to current recommended management, the optimal number of plants per ha and harvest age are considerably higher when carbon benefits are included, and increase with increasing price on CO2. Furthermore, planting becomes more favourable compared to natural regeneration. At the medium site quality, assuming 2% p.a. real rate of return and 20 euros per ton CO2, optimal planting density increases from 1500 per ha to 3000 per ha. Optimal harvest age increases from 90 to 140 years. Including saved greenhouse gas emissions when wood is used instead of more energy intensive materials or fossil fuels, i.e. substitution effects, does not affect optimal planting density much, but implies harvesting up to 20 years earlier. The value of the forest area increases with increasing price on CO2, and most of the income is from carbon. By using the current recommended management in calculations of carbon benefit, our results indicate that the forest’s potential to provide this environmental good is underestimated. The study includes many uncertain factors. Highest uncertainty is related to the accuracy of the forest growth and mortality functions at high stand ages and densities, and that albedo effects and future climate changes are not considered. As such, the results should be viewed as exploratory and not normative.
  • Raymer, Norwegian University of Life Sciences, Department of Ecology and Natural Resource Management, P.O. Box 5003, N-1432 Ås, Norway ORCID ID:E-mail:
  • Gobakken, Norwegian University of Life Sciences, Department of Ecology and Natural Resource Management, P.O. Box 5003, N-1432 Ås, Norway ORCID ID:E-mail: terje.gobakken@umb.no (email)
  • Solberg, Norwegian University of Life Sciences, Department of Ecology and Natural Resource Management, P.O. Box 5003, N-1432 Ås, Norway ORCID ID:E-mail:
article id 107, category Research article
Jaana Luoranen, Risto Rikala, Heikki Smolander. (2011). Machine planting of Norway spruce by Bracke and Ecoplanter: an evaluation of soil preparation, planting method and seedling performance. Silva Fennica vol. 45 no. 3 article id 107. https://doi.org/10.14214/sf.107
We evaluated the effects of planting date and planting machine (Bracke: three machines, 69 regeneration areas in three years; Ecoplanter: six areas, two years) on the quality and field performance one and three years after planting of Norway spruce (Picea abies (L.) Karst.) seedlings in central Finland. Both machine types planted on average 1800 seedlings per hectare, and after three years approximately 1600 (Bracke) and 1200 (Ecoplanter) were still alive. This study suggests that planting with a Bracke machine can achieve better regeneration rates than those observed in privately-owned Finnish forests. We characterized the quality of mounding and planting with the Bracke machine as excellent and that of the Ecoplanter as good. The soil preparation method of the Ecoplanter produced humus-rich mounds where seedlings were susceptible to pine weevils and consequently suffered higher mortality. Different machines were used in different regional areas and each machine was operated by different driver/s which may have influenced the results. No negative effects of planting date were observed. Seedling growth decreased if they were tall in relation to their root plug volume, grown too densely in the nursery, and if stored in the field for several months prior to planting. We conclude that mechanized planting is successful when the soil preparation method produces mounds covered by purely mineral soil. Planting from May to the end of September is suitable for seedlings intended for use during this period.
  • Luoranen, Finnish Forest Research Institute, Suonenjoki Research Unit, Juntintie 154, FI-77600 Suonenjoki, Finland ORCID ID:E-mail: jaana.luoranen@metla.fi (email)
  • Rikala, Finnish Forest Research Institute, Suonenjoki Research Unit, Juntintie 154, FI-77600 Suonenjoki, Finland ORCID ID:E-mail:
  • Smolander, Finnish Forest Research Institute, Suonenjoki Research Unit, Juntintie 154, FI-77600 Suonenjoki, Finland ORCID ID:E-mail:
article id 106, category Research article
Hannu Hökkä, Heli Hyttinen, Hannu Marttila, Juha Jämsen, Bjørn Kløve. (2011). Effect of peak runoff control method on growth of Scots pine stands on drained peatlands in central Finland. Silva Fennica vol. 45 no. 3 article id 106. https://doi.org/10.14214/sf.106
In drained peatland forests ditch networks need regular maintenance operations in order to sustain their drainage capacity. These operations however have a significant impact on the quality of the runoff water from the ditched areas. Peak runoff control (PRC) method has been proposed as a possible method to diminish the load to water courses through retention of the runoff temporarily in the ditch network during maximum runoff events using dams with a plastic control pipe. However, blocking water into the ditched area for periods of varying length during the growing season may have a negative impact on the growth of the tree stands. In this study past stand growth was investigated in Central Finland in altogether 10 sample Scots pine thinning stands in which the PRC method has been applied 5 growing seasons earlier. In each stand, a pair of sample plots was established: one plot next to the dam within the influence of periodic flooding and the other one outside the effect of periodic flooding. For determining stand growth, field measurements were made in August 2009. Stand growth near the dam was on average 0.54 m3 ha-1 a-1 lower than farther away from the dam but the analysis of covariance showed that the dam effect was not significant. The results of this study suggest that the PCR method does not decrease Scots pine stand growth during the first five year growth period after ditch cleaning.
  • Hökkä, Finnish Forest Research Institute, Rovaniemi Research Unit, P.O. Box 16, FI-96301 Rovaniemi, Finland ORCID ID:E-mail: hannu.hokka@metla.fi (email)
  • Hyttinen, Metsänhoitoyhdistys Keski-Suomi, Viitasaari, Finland ORCID ID:E-mail:
  • Marttila, University of Oulu, Water Resources and Environmental Engineering Lab, Oulu, Finland ORCID ID:E-mail:
  • Jämsen, Forestry Centre Keski-Suomi, Pihtipudas, Finland ORCID ID:E-mail:
  • Kløve, University of Oulu, Water Resources and Environmental Engineering Lab, Oulu, Finland ORCID ID:E-mail:
article id 116, category Research article
Eva-Maria Nordström, Ljusk Ola Eriksson, Karin Öhman. (2011). Multiple criteria decision analysis with consideration to place-specific values in participatory forest planning. Silva Fennica vol. 45 no. 2 article id 116. https://doi.org/10.14214/sf.116
The combination of multiple criteria decision analysis (MCDA) and participatory planning is an approach that has been applied in complex planning situations where multiple criteria of very different natures are considered, and several stakeholders or social groups are involved. The spatial character of forest planning problems adds further to the complexity, because a large number of forest stands are to be assigned different treatments at different points in time. In addition, experience from participatory forest planning indicates that stakeholders may think about the forest in terms of place-specific values rather than in forest-wide terms. The objective of this study was to present an approach for including place-specific values in MCDA-based participatory forest planning and illustrate the approach by a case study where the objective was to choose a multipurpose forest plan for an area of urban forest in northern Sweden. Stakeholder values were identified in interviews, and maps were used to capture place-specific spatial values. The nonspatial and nonplace-specific spatial values were formulated as criteria and used to build an objective hierarchy describing the decision situation. The place-specific spatial values were included in the creation of a map showing zones of different silvicultural management classes, which was used as the basis for creation of forest plan alternatives in the subsequent process. The approach seemed to work well for capturing place-specific values, and the study indicates that formalized methods for including and evaluating place-specific values in participatory forest planning processes should be developed and tested further.
  • Nordström, Swedish University of Agricultural Sciences, Department of Forest Resource Management, Skogsmarksgränd 1, SE-901 83 Umeå, Sweden ORCID ID:E-mail: eva-maria.nordstrom@slu.se (email)
  • Eriksson, Swedish University of Agricultural Sciences, Department of Forest Resource Management, Skogsmarksgränd 1, SE-901 83 Umeå, Sweden ORCID ID:E-mail:
  • Öhman, Swedish University of Agricultural Sciences, Department of Forest Resource Management, Skogsmarksgränd 1, SE-901 83 Umeå, Sweden ORCID ID:E-mail:
article id 114, category Research article
Roy V. Rea. (2011). Impacts of moose (Alces alces) browsing on paper birch (Betula papyrifera) morphology and potential timber quality. Silva Fennica vol. 45 no. 2 article id 114. https://doi.org/10.14214/sf.114
Although moose browsing effects on the growth and morphology of birch are well studied, effects of moose browsing on potential timber quality of birch have received little attention. Here, an assessment was made of the impacts of moose (Alces alces L.) damage to Paper Birch (Betula papyrifera Marsh.) trees from a 20-year old clear cut area in a sub-boreal spruce forest within the Aleza Lake Research Forest, near Prince George, British Columbia, Canada. Specifically, differences in overall tree architecture and in the internal characteristics of trees that had been severely damaged and suppressed by moose winter browsing were compared to birch trees that had not been damaged by moose in this way and were considered free-to-grow. The average stem diameter, number of annular growth rings, and height of stem breaks made by moose on suppressed birches at the point of breakage was 17.9 ± 6.6 mm, 4.6 ± 1.2, and 141.8 ± 32.0 cm, respectively. Stem diameters and the heights above-the-ground of stem breaks made by moose during sequential breakage events were not significantly different (all p ≥ 0.05) from one another. Decay was significantly (all p ≤ 0.001) more extensive in trees where branches had been broken off by moose than in trees with no breaks or where breaks were from unknown agents. Suppressed birches were significantly (p = 0.048) more exposed (farther from their nearest tree neighbor) when compared to birches that were free-to-grow. The distance from birch trees to species-specific neighbors (of any species) did not differ (all p ≥ 0.05) between suppressed and free-to-grow birches. Suppressed birches damaged from intense browsing and stem breakage were significantly (≤ 0.001) farther away from other birches showing signs of slight to moderate browsing than free-to-grow birches were from similar conspecifics. Because moose appear to impact the potential wood quality of birch, forest managers should consider the impacts that browsing and stem breakage can have on birch timber where these trees co-occur with and are eaten by moose.
  • Rea, University of Northern British Columbia, 3333 University Way, Prince George, BC, Canada V2N 4Z9 ORCID ID:E-mail: reav@unbc.ca (email)
article id 112, category Research article
Mike R. Saunders, Shawn Fraver, Robert G. Wagner. (2011). Nutrient concentration of down woody debris in mixedwood forests in central Maine, USA. Silva Fennica vol. 45 no. 2 article id 112. https://doi.org/10.14214/sf.112
Both nutrient concentrations and pre- and post-harvest pool sizes were determined across down woody debris decay classes of several hardwood and softwood species in a long-term, natural disturbance based, silvicultural experiment in central Maine. Concentrations of N, P, Ca, Mg, Cu, Fe, and Zn generally increased 2- to 5-fold with increasing decay class. Concentrations of Mn, Al and B did not differ among decay classes, while K decreased by 20–44% from decay class 1 to class 4. C:N-ratios declined with increasing decay class, while N:P-ratios increased from decay class 1 to 2 and then plateaued with further decay. Within decay classes, softwoods generally had lower nutrient concentrations and higher C:N-ratios than hardwoods; N:P-ratios did not differ between hardwoods and softwoods. Although gap harvesting increased the size of the overall down woody debris nutrient pools, mostly through a large pulse of decay class 1 material, harvesting generally reduced the nutrients held in advanced decay classes. Pre-harvest down woody debris pools for N, P, K and Ca were 11.0, 0.6, 2.1 and 21.1 kg ha–1, respectively, while postharvest were 20.0, 1.3, 6.2 and 46.2 kg ha–1, respectively. While the gap-based silvicultural systems sampled in this study doubled the size of the pre-harvest, downed woody debris nutrient pools, the post-harvest pools were estimated to be only 3.2–9.1% of aboveground nutrients.
  • Saunders, Department of Forestry and Natural Resources, Purdue University, 715 State Street, West Lafayette, IN, USA ORCID ID:E-mail: msaunder@purdue.edu (email)
  • Fraver, USFS Northern Research Station, Grand Rapids, MN, USA ORCID ID:E-mail:
  • Wagner, School of Forest Resources, University of Maine, Orono, ME, USA ORCID ID:E-mail:
article id 40, category Research article
Jorge Martín-García, Elba Espiga, Valentín Pando, Julio Javier Diez. (2011). Factors influencing endophytic communities in poplar plantations. Silva Fennica vol. 45 no. 2 article id 40. https://doi.org/10.14214/sf.40
The fungal species associated with leaves and twigs from stands of Populus x euramericana in northern Spain were studied with the aim of evaluating the effects of several factors on endophytic communities in these plantations. Endophyte assemblages were analysed in 12 poplar plantations (clone I-214), chosen according to a factorial scheme with two factors: age and site quality. Crown condition, dendrometric variables and foliar nutrients were recorded in each sampled tree to evaluate their effects on endophytic communities. Fungal species richness and relative isolation frequency (RIF) were higher in young stands than in adult stands. Moreover, the age-related differences depended on site quality, with the lowest richness levels observed in adult stands located in poor sites. At stand level, endophyte assemblages varied among stands according to site quality and, to a lesser extent, stand age. On the other hand, crown discoloration, total height and foliar concentrations of iron and zinc may be key indicators of endophytic communities in poplar plantations, at tree level.
  • Martín-García, Sustainable Forest Management Research Institute, University of Valladolid – INIA, Avenida de Madrid 57, 34004 Palencia, Spain, and Forestry Engineering, University of Extremadura, Plasencia, Spain ORCID ID:E-mail: jorgemg@pvs.uva.es (email)
  • Espiga, Sustainable Forest Management Research Institute, University of Valladolid – INIA, Palencia, Spain ORCID ID:E-mail:
  • Pando, Statistics and Operations Research Department, University of Valladolid, Spain ORCID ID:E-mail:
  • Diez, Sustainable Forest Management Research Institute, University of Valladolid – INIA, Palencia, Spain ORCID ID:E-mail:
article id 35, category Research article
Tapio Rantala. (2011). Democratic legitimacy of the forest sector and nature conservation decision-making in Finnish print media discussion. Silva Fennica vol. 45 no. 1 article id 35. https://doi.org/10.14214/sf.35
The study explores perceived democratic legitimacy of forest-related decision-making processes in the Finnish print media discourse. The data consists of the readers’ letters in four journals (n = 530), and the comments given during the preparation of the Finnish National Forest Program (n = 140). The objective is to identify the patterns of democratic legitimacy and respective performance evaluations of actual decision-making processes. The patterns can be classified as support for: (A) democracy and other forms of government, (B) different forms of participation, and (C) principles of democracy. The principles can be further classified into 1) core regime, 2) input, 3) throughput, and 4) output principles. Democratic legitimacy was found to be an important source of legitimacy in the public discussion since democratic patterns were found in more than half of the texts. The most common core legitimacy principles included freedom of speech, good national and international standing, forerunnership, and legality at national and international level. The central principles related to input legitimacy included popular sovereignty, a voice for the people, popular participation, openness, presenting alternatives, and urgency. The consensus and majority rules were found to be the most prominent throughput principles. Democratic output legitimacy included accountability, responsibility, cooperation, commitment, responsiveness, the possibility to appeal, credibility, comprehensiveness, and understandability. The findings suggest that among the writers of readers’ letters there is less contestation regarding the principles of democratic legitimacy but there are significant disagreements concerning the performance of decision-making processes. The negative performance evaluations were two times more frequent than the positive evaluations.
  • Rantala, Department of Forest Sciences, P.O. Box 27, FI-00014 University of Helsinki, Finland ORCID ID:E-mail: tapio.rantala@helsinki.fi (email)
article id 35, category Research article
Tapio Rantala. (2011). Democratic legitimacy of the forest sector and nature conservation decision-making in Finnish print media discussion. Silva Fennica vol. 45 no. 1 article id 35. https://doi.org/10.14214/sf.35
The study explores perceived democratic legitimacy of forest-related decision-making processes in the Finnish print media discourse. The data consists of the readers’ letters in four journals (n = 530), and the comments given during the preparation of the Finnish National Forest Program (n = 140). The objective is to identify the patterns of democratic legitimacy and respective performance evaluations of actual decision-making processes. The patterns can be classified as support for: (A) democracy and other forms of government, (B) different forms of participation, and (C) principles of democracy. The principles can be further classified into 1) core regime, 2) input, 3) throughput, and 4) output principles. Democratic legitimacy was found to be an important source of legitimacy in the public discussion since democratic patterns were found in more than half of the texts. The most common core legitimacy principles included freedom of speech, good national and international standing, forerunnership, and legality at national and international level. The central principles related to input legitimacy included popular sovereignty, a voice for the people, popular participation, openness, presenting alternatives, and urgency. The consensus and majority rules were found to be the most prominent throughput principles. Democratic output legitimacy included accountability, responsibility, cooperation, commitment, responsiveness, the possibility to appeal, credibility, comprehensiveness, and understandability. The findings suggest that among the writers of readers’ letters there is less contestation regarding the principles of democratic legitimacy but there are significant disagreements concerning the performance of decision-making processes. The negative performance evaluations were two times more frequent than the positive evaluations.
  • Rantala, Department of Forest Sciences, P.O. Box 27, FI-00014 University of Helsinki, Finland ORCID ID:E-mail: tapio.rantala@helsinki.fi (email)
article id 32, category Research article
Susete Marques, Jordi Garcia-Gonzalo, José G. Borges, Brigite Botequim, M. Manuela Oliveira, José Tomé, Margarida Tomé. (2011). Developing post-fire Eucalyptus globulus stand damage and tree mortality models for enhanced forest planning in Portugal. Silva Fennica vol. 45 no. 1 article id 32. https://doi.org/10.14214/sf.32
Forest and fire management planning activities are carried out mostly independently of each other. This paper discusses research aiming at the development of methods and tools that can be used for enhanced integration of forest and fire management planning activities. Specifically, fire damage models were developed for Eucalyptus globulus Labill stands in Portugal. Models are based on easily measurable forest characteristics so that forest managers may predict post-fire mortality based on forest structure. For this purpose, biometric data and fire-damage descriptors from 2005/2006 National Forest Inventory plots and other sample plots within 2006, 2007 and 2008 fire areas were used. A three-step modelling strategy based on logistic regression methods was used. In the first step, a model was developed to predict whether mortality occurs after a wildfire in a eucalypt stand. In the second step the degree of damage caused by wildfires in stands where mortality occurs is quantified (i.e. percentage of mortality). In the third step this mortality is distributed among trees. Data from over 85 plots and 1648 trees were used for modeling purposes. The damage models show that relative damage increases with stand basal area. Tree level mortality models indicate that trees with high diameters, in dominant positions and located in regular stands are less prone to die when a wildfire occurs.
  • Marques, Technical University of Lisbon, School of Agriculture, Forest Research Center, Tapada da Ajuda, 1349-017 Lisboa, Portugal ORCID ID:E-mail: smarques@isa.utl.pt (email)
  • Garcia-Gonzalo, Technical University of Lisbon, School of Agriculture, Forest Research Center, Tapada da Ajuda, 1349-017 Lisboa, Portugal ORCID ID:E-mail:
  • Borges, Technical University of Lisbon, School of Agriculture, Forest Research Center, Tapada da Ajuda, 1349-017 Lisboa, Portugal ORCID ID:E-mail:
  • Botequim, Technical University of Lisbon, School of Agriculture, Forest Research Center, Tapada da Ajuda, 1349-017 Lisboa, Portugal ORCID ID:E-mail:
  • Oliveira, Technical University of Lisbon, School of Agriculture, Forest Research Center, Tapada da Ajuda, 1349-017 Lisboa, Portugal ORCID ID:E-mail:
  • Tomé, Technical University of Lisbon, School of Agriculture, Forest Research Center, Tapada da Ajuda, 1349-017 Lisboa, Portugal ORCID ID:E-mail:
  • Tomé, Technical University of Lisbon, School of Agriculture, Forest Research Center, Tapada da Ajuda, 1349-017 Lisboa, Portugal ORCID ID:E-mail:
article id 32, category Research article
Susete Marques, Jordi Garcia-Gonzalo, José G. Borges, Brigite Botequim, M. Manuela Oliveira, José Tomé, Margarida Tomé. (2011). Developing post-fire Eucalyptus globulus stand damage and tree mortality models for enhanced forest planning in Portugal. Silva Fennica vol. 45 no. 1 article id 32. https://doi.org/10.14214/sf.32
Forest and fire management planning activities are carried out mostly independently of each other. This paper discusses research aiming at the development of methods and tools that can be used for enhanced integration of forest and fire management planning activities. Specifically, fire damage models were developed for Eucalyptus globulus Labill stands in Portugal. Models are based on easily measurable forest characteristics so that forest managers may predict post-fire mortality based on forest structure. For this purpose, biometric data and fire-damage descriptors from 2005/2006 National Forest Inventory plots and other sample plots within 2006, 2007 and 2008 fire areas were used. A three-step modelling strategy based on logistic regression methods was used. In the first step, a model was developed to predict whether mortality occurs after a wildfire in a eucalypt stand. In the second step the degree of damage caused by wildfires in stands where mortality occurs is quantified (i.e. percentage of mortality). In the third step this mortality is distributed among trees. Data from over 85 plots and 1648 trees were used for modeling purposes. The damage models show that relative damage increases with stand basal area. Tree level mortality models indicate that trees with high diameters, in dominant positions and located in regular stands are less prone to die when a wildfire occurs.
  • Marques, Technical University of Lisbon, School of Agriculture, Forest Research Center, Tapada da Ajuda, 1349-017 Lisboa, Portugal ORCID ID:E-mail: smarques@isa.utl.pt (email)
  • Garcia-Gonzalo, Technical University of Lisbon, School of Agriculture, Forest Research Center, Tapada da Ajuda, 1349-017 Lisboa, Portugal ORCID ID:E-mail:
  • Borges, Technical University of Lisbon, School of Agriculture, Forest Research Center, Tapada da Ajuda, 1349-017 Lisboa, Portugal ORCID ID:E-mail:
  • Botequim, Technical University of Lisbon, School of Agriculture, Forest Research Center, Tapada da Ajuda, 1349-017 Lisboa, Portugal ORCID ID:E-mail:
  • Oliveira, Technical University of Lisbon, School of Agriculture, Forest Research Center, Tapada da Ajuda, 1349-017 Lisboa, Portugal ORCID ID:E-mail:
  • Tomé, Technical University of Lisbon, School of Agriculture, Forest Research Center, Tapada da Ajuda, 1349-017 Lisboa, Portugal ORCID ID:E-mail:
  • Tomé, Technical University of Lisbon, School of Agriculture, Forest Research Center, Tapada da Ajuda, 1349-017 Lisboa, Portugal ORCID ID:E-mail:
article id 31, category Research article
Jeovanna Lowe, David Pothier, Jean-Pierre L. Savard, Ghislain Rompré, Mathieu Bouchard. (2011). Snag characteristics and cavity-nesting birds in the unmanaged post-fire northeastern Canadian boreal forest. Silva Fennica vol. 45 no. 1 article id 31. https://doi.org/10.14214/sf.31
We studied the availability and characteristics of snags and their use by cavity-nesting birds in the northeastern part of the Canadian boreal forest. We built up two long-term (> 200 years) chronosequences following time since the last fire in the unmanaged boreal forest of northeastern Québec, one in the balsam fir-white birch domain (southern region) and one in the spruce-mosses domain (northern region). We then sampled and characterized snags and live trees in 30 stands from each of these two chronosequences. We also looked for nest cavities on all sampled snags, performed bird inventories by point counts, and calculated tree mortality rate from permanent sample plots. Results show that mortality rates follow a U-shaped pattern, with more snags of large diameter (> 20 cm DBH) in young (< 50 years) and in old (> 200 years) forests. In the latter, we also found more nest cavities than in any other age classes. Although abundance of primary cavity nesters (excavating species) did not vary among age classes, secondary cavity nesters (using cavities already available) tend to be more numerous in older forests. Our results highlight the capacity for young and old-growth forests to provide quality habitat for species that are dependent on large snags. Proper forest management should maintain a mosaic of different age forest stands, including snags, to promote biodiversity and provide important resources for resident bird species.
  • Lowe, Centre d’étude de la foret, Département des sciences du bois et de la foret, Pavillon Abitibi-Price, 2405 rue de la Terrasse, Université Laval, Québec, Québec, G1V 0A6, Canada ORCID ID:E-mail: jeovannalowe@gmail.com (email)
  • Pothier, Centre d’étude de la foret, Département des sciences du bois et de la foret, Pavillon Abitibi-Price, 2405 rue de la Terrasse, Université Laval, Québec, Québec, G1V 0A6, Canada ORCID ID:E-mail:
  • Savard, Wildlife Research, Science and Technology, Québec Region, 1141 Route de l’Église, P.O. Box 10100, Québec, Québec, G1V 4H5, Canada ORCID ID:E-mail:
  • Rompré, Centre d’étude de la foret, Département des sciences du bois et de la foret, Pavillon Abitibi-Price, 2405 rue de la Terrasse, Université Laval, Québec, Québec, G1V 0A6, Canada & Department of Biology and Health Sciences, 84 West South Street, Wilkes University, PA 18766, USA ORCID ID:E-mail:
  • Bouchard, Ministère des Ressources naturelles et de la Faune, Direction de l’Environnement et de la Protection des Forets, 880 Chemin Ste-Foy, Quebec, Québec, G1S 4X4, Canada ORCID ID:E-mail:
article id 127, category Research article
Mika Rekola, Annukka Valkeapää, Tapio Rantala. (2010). Nordic forest professionals’ values. Silva Fennica vol. 44 no. 5 article id 127. https://doi.org/10.14214/sf.127
The present study analyses the values held by forest professionals in three Nordic countries: Finland, Norway, and Sweden. The data is from a large (n = 1113) internet survey that used cognitive mapping as a research tool, which is a novelty in value measurement. The questionnaire is based on the organisational value theory of Schein (1992), supplemented with relevant forest-related and environmental values. The forest-related main value factors were in the following order of importance: Expertise, Private forestry, Forest production, Nature conservation, and Tradition. The measurement included two kinds of cases: action values, referring to present decision-making, and ideal values, referring to decisions concerning future ideals. Most of the values’ scores were similar. Almost all values received higher scores of importance in the ideal cases compared to action cases, a fact that can probably be explained by constraints related to the professionals’ current working environment. Some international differences were also found: Sweden and Norway were closer to each other and both differed from Finland, where private forestry, forest production, and traditions are highly valued. Moreover, respondents working in industry were found to be slightly more production-oriented than other forest professionals. The study also revealed several weaknesses of the cognitive mapping method in measuring values.
  • Rekola, University of Helsinki, Department of Forest Sciences, P.O. Box 27, FI-00014 University of Helsinki ORCID ID:E-mail: mika.rekola@helsinki.fi (email)
  • Valkeapää, University of Helsinki, Department of Forest Sciences, P.O. Box 27, FI-00014 University of Helsinki ORCID ID:E-mail:
  • Rantala, University of Helsinki, Department of Forest Sciences, P.O. Box 27, FI-00014 University of Helsinki ORCID ID:E-mail: tapio.rantala@helsinki.fi
article id 124, category Research article
Johannes Windisch, Lauri Sikanen, Dominik Röser, David Gritten. (2010). Supply chain management applications for forest fuel procurement – cost or benefit? Silva Fennica vol. 44 no. 5 article id 124. https://doi.org/10.14214/sf.124
It is commonly agreed that logistics is very demanding in forest fuel business. Even though logistics and supply chain management (SCM) tools already have found their way into forestry business, for example, in roundwood operations, they are not yet very widespread in the field of forest fuel procurement. The present study investigates if modern supply chain management applications are capable of increasing the profitability of forest fuel procurement operations. Since margins are low, decreasing the provision costs could boost wood-based bioenergy business. The study is based on the investigation of two Finnish forest owners associations (FOA) involved in forest fuel procurement using a modern SCM tool. The investigation is done by cost-benefit analysis (CBA) using the net present value (NPV) methodology to determine the profitability. According to the estimates made by the staff, which are based on data such as work time records and delivery notes from before and after introduction of the new system, in both FOAs, the benefits far outweigh the costs over a considered timespan of ten years. However, the amount of the NPV varied significantly. For FOA1, with an annual chip production of 150 000 loose m3, the NPV is 212 739 euro, while for FOA2, with an annual chip production of 37 000 loose m3, the NPV is 969 841 euro. Even if the NPV of FOA2 seems to be very high, the profitability of SCM tools in forest fuel procurement is clearly demonstrated. Additionally, the results indicate that a considerable cost saving potential in forest fuel procurement is attainable through improving work flows and thus reduce the work input.
  • Windisch, Finnish Forest Research Institute, Joensuu Research Unit, Yliopistokatu 6, P.O. Box 68, FI-80101 Joensuu, Finland ORCID ID:E-mail: johannes.windisch@metla.fi (email)
  • Sikanen, University of Eastern Finland, School of Forest Science, Yliopistokatu 7, P.O. Box 111, FI-80101 Joensuu, Finland ORCID ID:E-mail:
  • Röser, Finnish Forest Research Institute, Joensuu Research Unit, Yliopistokatu 6, P.O. Box 68, FI-80101 Joensuu, Finland ORCID ID:E-mail:
  • Gritten, University of Eastern Finland, School of Forest Science, Yliopistokatu 7, P.O. Box 111, FI-80101 Joensuu, Finland ORCID ID:E-mail:
article id 123, category Research article
Staffan Jacobson, Folke Pettersson. (2010). An assessment of different fertilization regimes in three boreal coniferous stands. Silva Fennica vol. 44 no. 5 article id 123. https://doi.org/10.14214/sf.123
In 1981–82 three field experiments were established with the aim of elucidating (i) the growth response of middle-aged coniferous stands at different fertilization intensities and, hence, the economic outcomes; and (ii) the need to add nutrients other than nitrogen (N). Nutrient additions were performed at intervals of two, four, six and eight years. The experiments were established on typical podzolized and N-limited mor-humus sites, two in Scots pine (Pinus sylvestris L.) stands and one in a Norway spruce (Picea abies (L.) Karst.) stand, at three different locations in Sweden. The ages of the stands were 65–70 years at the time of establishment. Growth responses were calculated after a 22-year study period. The growth responses were significant in all treatments. The addition of nutrients other than N did not affect stem growth at any of the sites. The growth response tended to increase with decreasing application interval. The results also revealed that the efficiency of fertilization is reduced as the interval between fertilizations is shortened. Accordingly, the growth effect per kg of added N was negatively correlated to fertilization intensity. The least intensive fertilization regime (an eight-year interval) resulted in an average net increase in C sequestration of 35 kg per kg N added. The profitability, in terms of internal rate of return, the present net value at different interest rates and the cost of production, i.e. the cost to produce one extra m3 under the different N regimes, are presented and discussed.
  • Jacobson, Skogforsk, Uppsala Science Park, SE-75183 Uppsala, Sweden ORCID ID:E-mail: staffan.jacobson@skogforsk.se (email)
  • Pettersson, Skogforsk, Uppsala Science Park, SE-75183 Uppsala, Sweden ORCID ID:E-mail:
article id 122, category Research article
Benoit Lafleur, Nicole J. Fenton, David Paré, Martin Simard, Yves Bergeron. (2010). Contrasting effects of season and method of harvest on soil properties and the growth of black spruce regeneration in the boreal forested peatlands of eastern Canada. Silva Fennica vol. 44 no. 5 article id 122. https://doi.org/10.14214/sf.122
It has been suggested that without sufficient soil disturbance, harvest in boreal forested peatlands may accelerate paludification and reduce forest productivity. The objectives of this study were to compare the effects of harvest methods (clearcutting vs. careful logging) and season (summer vs. winter harvest) on black spruce regeneration and growth in boreal forested peatlands of eastern Canada, and to identify the soil variables that favour tree growth following harvest. Moreover, we sought to determine how stand growth following harvest compared with that observed following fire. The average tree height of summer clearcuts was greater than that of summer carefully logged stands and that of all winter harvested sites. Summer clearcutting also resulted in a higher density of t