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Silva Fennica 1926-1997
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Acta Forestalia Fennica
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Articles containing the keyword 'wood'.

Category: Research article

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 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 10001, category Research article
Karoliina Hämäläinen, Teemu Tahvanainen, Kaisa Junninen. (2018). Characteristics of boreal and hemiboreal herb-rich forests as habitats for polypore fungi. Silva Fennica vol. 52 no. 5 article id 10001. https://doi.org/10.14214/sf.10001
Highlights: Polypore species richness and diversity were affected positively by dead-wood diversity, and negatively by increasing latitude; Red-listed species responded only to the abundance of large-diameter dead wood; Main factor determining composition of polypore assemblages was host-tree species; High proportion of deciduous dead-wood in herb-rich forests provides complementary effect on polypore assemblages in boreal forest landscapes.

Herb-rich forests are often considered biodiversity hotspots in the boreal zone but their fungal assemblages, particularly those of wood-decaying fungi, remain poorly known. We studied herb-rich forests as habitats for polypores, a distinct group of wood-decaying fungi, and assessed the importance of tree- and stand-scale variables for polypore species richness, abundance, and diversity, including red-listed species. The data include 71 herb-rich forest stands in Finland and 4797 dead wood items, on which we made 2832 observations of 101 polypore species. Dead-wood diversity was the most important variable explaining polypore species richness and diversity, whereas increasing latitude had a negative effect. Red-listed species showed a positive response to the abundance of large-diameter dead wood, which, especially birch, supported also high general abundance of polypores. The composition of polypore assemblages reflected their host-tree species. The red-listed species did not show explicit patterns in the ordination space. Compared to old-growth spruce forests, herb-rich forests seem to host lower polypore species richness and less red-listed species. However, because of high proportion of deciduous trees in the dead wood profile, herb-rich forests have a clear complementary effect on polypore assemblages in boreal forest landscapes.

  • Hämäläinen, School of Forest Sciences, University of Eastern Finland, P.O. Box 111, FI-80101 Joensuu, Finland ORCID ID:E-mail: karoham@uef.fi (email)
  • Tahvanainen, Department of Environmental and Biological Sciences, University of Eastern Finland, P.O. Box 111, FI-80101 Joensuu, Finland ORCID ID:E-mail: teemu.tahvanainen@uef.fi
  • Junninen, Metsähallitus Parks & Wildlife Finland, c/o UEF/Borealis, P.O. Box 111, FI-80101 Joensuu, Finland ORCID ID:E-mail: kaisa.junninen@metsa.fi
article id 10001, category Research article
Karoliina Hämäläinen, Teemu Tahvanainen, Kaisa Junninen. (2018). Characteristics of boreal and hemiboreal herb-rich forests as habitats for polypore fungi. Silva Fennica vol. 52 no. 5 article id 10001. https://doi.org/10.14214/sf.10001
Highlights: Polypore species richness and diversity were affected positively by dead-wood diversity, and negatively by increasing latitude; Red-listed species responded only to the abundance of large-diameter dead wood; Main factor determining composition of polypore assemblages was host-tree species; High proportion of deciduous dead-wood in herb-rich forests provides complementary effect on polypore assemblages in boreal forest landscapes.

Herb-rich forests are often considered biodiversity hotspots in the boreal zone but their fungal assemblages, particularly those of wood-decaying fungi, remain poorly known. We studied herb-rich forests as habitats for polypores, a distinct group of wood-decaying fungi, and assessed the importance of tree- and stand-scale variables for polypore species richness, abundance, and diversity, including red-listed species. The data include 71 herb-rich forest stands in Finland and 4797 dead wood items, on which we made 2832 observations of 101 polypore species. Dead-wood diversity was the most important variable explaining polypore species richness and diversity, whereas increasing latitude had a negative effect. Red-listed species showed a positive response to the abundance of large-diameter dead wood, which, especially birch, supported also high general abundance of polypores. The composition of polypore assemblages reflected their host-tree species. The red-listed species did not show explicit patterns in the ordination space. Compared to old-growth spruce forests, herb-rich forests seem to host lower polypore species richness and less red-listed species. However, because of high proportion of deciduous trees in the dead wood profile, herb-rich forests have a clear complementary effect on polypore assemblages in boreal forest landscapes.

  • Hämäläinen, School of Forest Sciences, University of Eastern Finland, P.O. Box 111, FI-80101 Joensuu, Finland ORCID ID:E-mail: karoham@uef.fi (email)
  • Tahvanainen, Department of Environmental and Biological Sciences, University of Eastern Finland, P.O. Box 111, FI-80101 Joensuu, Finland ORCID ID:E-mail: teemu.tahvanainen@uef.fi
  • Junninen, Metsähallitus Parks & Wildlife Finland, c/o UEF/Borealis, P.O. Box 111, FI-80101 Joensuu, Finland ORCID ID:E-mail: kaisa.junninen@metsa.fi
article id 9938, category Research article
Jyrki Hytönen, Egbert Beuker, Anneli Viherä-Aarnio. (2018). Clonal variation in basic density, moisture content and heating value of wood, bark and branches in hybrid aspen. Silva Fennica vol. 52 no. 2 article id 9938. https://doi.org/10.14214/sf.9938
Highlights: Hybrid aspen clones differed in their moisture content, ash content, basic density and heating value; Stem wood had lower ash content, basic density and effective heating value than stem bark; There was significant vertical variation in wood and bark along the stem in moisture content and basic density.

Hybrid aspen (Populus tremula × P. tremuloides) is one of the fastest growing tree species in Finland. During the mid-1990s, a breeding programme was started with the aim of selecting clones that were superior in producing pulpwood. Hybrid aspen can also be grown as a short-rotation crop for bioenergy. To study clonal variation in wood and bark properties, seven clones were selected from a 12-year-old field trial located in southern Finland. From each clone, five trees were harvested and samples were taken from stem wood, stem bark and branches to determine basic density, effective heating value, moisture and ash content. Vertical within-tree variation in moisture content and basic density was also studied. The differences between clones were significant for almost all studied properties. For all studied properties there was a significant difference between wood and bark. Wood had lower ash content (0.5% vs. 3.9%), basic density (378 kg m–3 vs. 450 kg m–3) and effective heating value (18.26 MJ kg–1 vs. 19.24 MJ kg–1), but higher moisture content (55% vs. 49%) than bark. The values for branches were intermediate. These results suggest that the properties of hybrid aspen important for energy use could be improved by clonal selection. However, selecting clones based on fast growth only may be challenging since it may lead to a decrease in hybrid aspen wood density.

  • Hytönen, Natural Resources Institute Finland (Luke), Natural resources, Teknologiakatu 7, FI-67100 Kokkola, Finland ORCID ID:E-mail: jyrki.hytonen@luke.fi (email)
  • Beuker, Natural Resources Institute Finland (Luke), Production systems, Vipusenkuja 6, FI-57200 Savonlinna, Finland ORCID ID:E-mail: egbert.beuker@luke.fi
  • Viherä-Aarnio, Natural Resources Institute Finland (Luke), Production systems, Latokartanonkaari 9, FI-00790 Helsinki, Finland ORCID ID:E-mail: anneli.vihera-aarnio@luke.fi
article id 9914, category Research article
Jun Tanabe, Futoshi Ishiguri, Akira Tamura, Yuya Takashima, Jyunichi Ohshima, Kazuya Iizuka, Shinso Yokota. (2018). Within-tree radial and among-family variations in wood density, microfibril angle, and mechanical properties in Picea glehnii. Silva Fennica vol. 52 no. 2 article id 9914. https://doi.org/10.14214/sf.9914
Highlights: The modulus of elasticity was affected by both microfibril angle and wood density, whereas the modulus of rupture was mainly affected by wood density in Picea glehnii; A larger degree of among-family variation in wood properties was detected in juvenile wood than in mature wood, indicating that genetic improvements in the mechanical properties may be more effective for juvenile wood.

Genetic improvements in the mechanical properties of wood are important in forestry species used for lumber, such as Picea. The within-tree radial and among-family variations for the modulus of elasticity (MOE), modulus of rupture (MOR), and their related traits [i.e., microfibril angle (MFA) of the S2 layer in latewood tracheid and air-dry density (AD)] were evaluated in nine open-pollinated families of Picea glehnii (F. Schmidt) Mast. The radial variation in MOR was mainly affected by AD, whereas MOE was affected by MFA and AD. Higher F-values obtained by analysis of variance and coefficient of variation were observed for all properties at the 6th–15th annual ring, except for AD at the 6th–10th annual ring. This result suggests that the contribution of genetic effect is larger in these highly variable regions. In addition, positive correlation coefficients were obtained between wood properties at the 6th–15th annual ring and mean values of these properties. Therefore, genetic improvements for MOE, MOR, and their related traits in P. glehnii is likely to be more effective in juvenile wood, specifically at the 6th–15th annual ring from the pith.

  • Tanabe, Faculty of Education, Chiba University, Chiba, 263-8522, Japan ORCID ID:E-mail: tanabe_j@chiba-u.jp (email)
  • Ishiguri, Faculty of Agriculture, Utsunomiya University, Utsunomiya 321-8505, Japan ORCID ID:E-mail: ishiguri@cc.utsunomiya-u.ac.jp
  • Tamura, Forest Tree Breeding Center, Forestry and Forest Products Research Institute, Hitachi, 319-1301, Japan ORCID ID:E-mail: akirat@affrc.go.jp
  • Takashima, Forest Tree Breeding Center, Forestry and Forest Products Research Institute, Hitachi, 319-1301, Japan ORCID ID:E-mail: ytakashima@ffpri.affrc.go.jp
  • Ohshima, Faculty of Agriculture, Utsunomiya University, Utsunomiya 321-8505, Japan ORCID ID:E-mail: joshima@cc.utsunomiya-u.ac.jp
  • Iizuka, Faculty of Agriculture, Utsunomiya University, Utsunomiya 321-8505, Japan ORCID ID:E-mail: kiizuka@cc.utsunomiya-u.ac.jp
  • Yokota, Faculty of Agriculture, Utsunomiya University, Utsunomiya 321-8505, Japan ORCID ID:E-mail: yokotas@cc.utsunomiya-u.ac.jp
article id 9902, category Research article
Perttu Anttila, Vesa Nivala, Olli Salminen, Markus Hurskainen, Janne Kärki, Tomi J. Lindroos, Antti Asikainen. (2018). Regional balance of forest chip supply and demand in Finland in 2030. Silva Fennica vol. 52 no. 2 article id 9902. https://doi.org/10.14214/sf.9902
Highlights: The impact of increasing forest chip demand in 2030 was analyzed in Finland; Demand of small trees may exceed potential at the national level; Surplus potential will remain in logging residues and stumps; Hot spots of demand call for efficient logistical solutions.

According to the National Energy and Climate Strategy of Finland in 2016, the demand for forest chips, that is, wood chips made of forest biomass directly for energy use, could even double by 2030 compared to the present situation. A spatially explicit impact analysis of regional supply and demand balances for forest chips was carried out. The balances were calculated as the difference between technical harvesting potentials and demand. First, the technical potentials were estimated based on the national forest inventory data. Secondly, three demand scenarios were defined for 2030 and subsequently deducted from the potentials. The results suggested that there would be increasing competition for feedstock in southern and western Finland, whereas in eastern and northern Finland there would still be surplus potential. Moreover, due to the remarkable deficit of small trees in southern Finland, there might be pressure towards using more pulpwood-sized and/or imported wood in energy production. The results also showed that, in particular, large new plants consuming substantial amounts of forest chips could have a significant effect on the regional availability of forest chips. Moreover, with increasing transport distances, new logistical solutions will be needed.

  • Anttila, Natural Resources Institute Finland (Luke), Yliopistokatu 6, FI-80100 Joensuu, Finland ORCID ID: http://orcid.org/0000-0002-6131-392X E-mail: perttu.anttila@luke.fi (email)
  • Nivala, Natural Resources Institute Finland (Luke), Eteläranta 55, FI-96300 Rovaniemi, Finland ORCID ID:E-mail: vesa.nivala@luke.fi
  • Salminen, Natural Resources Institute Finland (Luke), Latokartanonkaari 9, FI-00790 Helsinki, Finland ORCID ID:E-mail: olli.salminen@luke.fi
  • Hurskainen, VTT Technical Research Centre of Finland Ltd, Koivurannantie 1, FI-40400 Jyväskylä, Finland ORCID ID:E-mail: markus.hurskainen@vtt.fi
  • Kärki, VTT Technical Research Centre of Finland Ltd, Koivurannantie 1, FI-40400 Jyväskylä, Finland ORCID ID:E-mail: janne.karki@vtt.fi
  • Lindroos, VTT Technical Research Centre of Finland Ltd, Vuorimiehentie 3 (Espoo), P.O. Box 1000, FI-02044 VTT, Finland ORCID ID:E-mail: tomi.j.lindroos@vtt.fi
  • Asikainen, Natural Resources Institute Finland (Luke), Yliopistokatu 6, FI-80100 Joensuu, Finland ORCID ID:E-mail: antti.asikainen@luke.fi
article id 7830, category Research article
Jari Lindblad, Johanna Routa, Johanna Ruotsalainen, Marja Kolström, Ari Isokangas, Lauri Sikanen. (2018). Weather based moisture content modelling of harvesting residues in the stand. Silva Fennica vol. 52 no. 2 article id 7830. https://doi.org/10.14214/sf.7830
Highlights: Weather data used for estimating the moisture content of energy wood; The validation of the weather based models performed based on the field data.

Harvesting residues collected from the final cuttings of boreal forests are an important source of solid biofuel for energy production in Finland and Sweden. In the Finnish supply chain, the measurement of residues is performed by scales integrated in forwarders. The mass of residues is converted to volume by conversion factors. In this study, weather based models for defining the moisture content of residues were developed and validated. Models were also compared with the currently used fixed tables of conversion factors. The change of the moisture content of residues is complex, and an exact estimation was challenging. However, the model predicting moisture change for three hour periods was found to be the most accurate. The main improvement compared to fixed tables was the lack of a systematic error. It can be assumed that weather based models will give more reliable estimates for the moisture in varying climate conditions and the further development of models should be focused on obtaining more appropriate data from varying drying conditions in different geographical and microclimatological locations.

  • Lindblad, ORCID ID:E-mail: jari.lindblad@luke.fi (email)
  • Routa, Natural Resources Institute Finland (Luke), Production systems, Yliopistokatu 6, FI-80100 Joensuu, Finland ORCID ID:E-mail: johanna.routa@luke.fi
  • Ruotsalainen, Finnish Meteorological Institute, Aviation and Military Weather Services, P.O. Box 1627, FI-70211 Kuopio, Finland ORCID ID:E-mail: johanna.ruotsalainen@fmi.fi
  • Kolström, University of Eastern Finland, School of Forest Sciences, P.O. Box 111, FI-80101 Joensuu, Finland ORCID ID:E-mail: marja.kolstrom@uef.fi
  • Isokangas, University of Oulu, Control Engineering, P.O. Box 8000, FI-90014 University of Oulu, Finland ORCID ID:E-mail: ari.isokangas@oulu.fi
  • Sikanen, Natural Resources Institute Finland (Luke), Production systems, Yliopistokatu 6, FI-80100 Joensuu, Finland ORCID ID:E-mail: lauri.sikanen@luke.fi
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 7003, category Research article
Poje Anton, Raffaele Spinelli, Natascia Magagnotti, Matevz Mihelic. (2018). The effect of feedstock, knife wear and work station on the exposure to noise and vibrations in wood chipping operations. Silva Fennica vol. 52 no. 1 article id 7003. https://doi.org/10.14214/sf.7003
Highlights: Exposure to noise and vibration is higher when chipping branches rather than logs; Noise levels are higher in the separate cab, especially at some frequencies; Vibration is higher for the Z axis in the separate cab, for the X axis in the truck; Noise is higher when working with blunt knives, rather than new knives; Knife wear has no significant effect on exposure to whole-body vibration.

Industrial chipping is becoming increasingly popular, as the result of a growing demand for woody biomass. Industrial chippers are large, powerful machines that generate much noise and vibration. This study explored some factors that may affect exposure to noise and vibration, namely: feedstock type (branches vs. logs), work station characteristics (truck cab vs. separate cab) and knife wear (new knives vs. blunt knives). Exposure to noise was significantly affected by all three factors, and it was higher for branch feedstock, separate cabs and blunt knives. The higher exposure levels recorded for the separate cab were especially insidious, because they were below and above the hearing threshold and would elude immediate perception. Exposure to whole-body vibration (WBV) was significantly higher for branch feedstock and for the separate cab. Knife wear seemed to determine an increase in WBV, but this effect had no statistical significance and the result could not be taken as conclusive. Among the three factors studied, work station characteristics had the strongest effect. Further studies may extend the comparison to a wider range of options, as well as explore the use of exposure variation for machine diagnostics.

  • Anton, University of Ljubljana, Dept. of Forestry and Renewable Resources, Večna pot 83, 1000 Ljubljana, Slovenia ORCID ID:E-mail: anton.poje@bf.uni-lj.si
  • Spinelli, CNR IVALSA, Via Madonna del Piano 10, I-50019 Sesto Fiorentino, Italy; AFORA, University of the Sunshine Coast, Locked Bag 4, Maroochydore DC, Queensland, 4558 Australia ORCID ID: http://orcid.org/0000-0001-9545-1004 E-mail: spinelli@ivalsa.cnr.it (email)
  • Magagnotti, CNR IVALSA, Via Madonna del Piano 10, I-50019 Sesto Fiorentino, Italy; AFORA, University of the Sunshine Coast, Locked Bag 4, Maroochydore DC, Queensland, 4558 Australia ORCID ID:E-mail: magagnotti@ivalsa.cnr.it
  • Mihelic, University of Ljubljana, Dept. of Forestry and Renewable Resources, Večna pot 83, 1000 Ljubljana, Slovenia ORCID ID:E-mail: matevz.mihelic@bf.uni-lj.si
article id 6999, category Research article
Virginia Morales Olmos, Jacek P. Siry. (2018). The Law of One Price in global coniferous sawlog markets. Silva Fennica vol. 52 no. 1 article id 6999. https://doi.org/10.14214/sf.6999
Highlights: The Law of One Price did not hold for North American, European and South American sawlog markets between 1995–2012; There are long-term relationships between some of the analyzed sawlog prices in these markets; The Law of One Price may hold between sawlogs traded in Sweden and Norway, Norway and Finland, and Canada West and US Northwest.

With progressing globalization of forest production, roundwood prices in different countries may follow similar trends. The Law of One Price (LOP) postulates that the price of a similar product should be the same in different markets when expressed in the same currency. The objectives of this research were (1) to test the LOP in selected coniferous sawlog markets, and (2) to analyze whether a common market – the European Union – leads to the existence of a single sawlog market. The analysis included Brazil, Chile, Finland, Germany, Norway, Poland, Russia Northwest, Sweden, the US South, the US Northwest, Canada East, and Canada West. The results suggest that some of the coniferous sawlog markets were cointegrated which means that they shared a long-term relationship even if in the short-term they do not necessarily adjust to each other. The LOP may hold between coniferous sawlog markets in Sweden and Norway from 1995 through 2012 when sawlog prices were expressed in USD, and in Norway and Finland for 2001–2012 for prices in EUR. Furthermore, the LOP may hold for North American markets in the West for 2004–2012.

  • Morales Olmos, Universidad de la República-Sede Tacuarembó, Ruta 5. km, 386.200, Tacuarembó, CP 45000, Uruguay ORCID ID:E-mail: vmolmos@gmail.com (email)
  • Siry, Warnell School of Forestry and Natural Resources, University of Georgia, 180 E. Green Street, Athens, GA 30602-2152, USA ORCID ID:E-mail: jsiry@uga.edu
article id 7731, category Research article
Anneli Viherä-Aarnio, Pirkko Velling. (2017). Growth, wood density and bark thickness of silver birch originating from the Baltic countries and Finland in two Finnish provenance trials. Silva Fennica vol. 51 no. 4 article id 7731. https://doi.org/10.14214/sf.7731
Highlights: Baltic origins of silver birch had significantly thicker bark than the Finnish ones; In terms of wood density, no consistent difference was detected between the Baltic and Finnish origins; Incidence of darkened core wood increased with increasing seed origin latitude; Frost cracks were most common in south Latvian origins grown in central Finland.

Silver birch (Betula pendula Roth) seed origins from the Baltic countries and from Finland were compared in terms of growth, wood density, bark thickness and the incidence of darkened core wood, frost cracks and decay, and the effect of seed origin latitude was examined in two Finnish provenance trials. The material consisted of 21 stand and single tree origins ranging from latitudes 54° to 63°N from the Baltic countries and Finland. The trials, measured at the age of 22 years, were located at Tuusula (60°21´N), southern Finland and at Viitasaari (63°11´N), central Finland. The Baltic origins were superior to the Finnish ones in the southern trial regarding height, whereas in central Finland the Finnish origins grew better. There was no consistent difference between the Baltic and the Finnish group of origins in wood density. Bark thickness decreased with increasing seed origin latitude. The Baltic origins had significantly thicker bark than the Finnish origins. A moderate positive correlation was detected between the seed origin latitude and the incidence of darkened core wood in the southern trial, where the darkened core wood was more common in the Finnish origins than in the Baltic ones. The highest proportion of trees with frost cracks was detected in the south-western Latvian origins growing in central Finland. Seed transfers from the Baltic would have an increasing effect on the bark thickness of birch logs, but no or only minor effects on wood density. Based on our results, there is no reason to recommend the use of non-native Baltic seed origins in Finland instead of the native locally adapted seed sources.

  • Viherä-Aarnio, Natural Resources Institute Finland (Luke), Green technology, P.O. Box 2, FI-00791 Helsinki, Finland ORCID ID:E-mail: anneli.vihera-aarnio@luke.fi (email)
  • Velling, ORCID ID:E-mail: pike.velling@phnet.fi
article id 7731, category Research article
Anneli Viherä-Aarnio, Pirkko Velling. (2017). Growth, wood density and bark thickness of silver birch originating from the Baltic countries and Finland in two Finnish provenance trials. Silva Fennica vol. 51 no. 4 article id 7731. https://doi.org/10.14214/sf.7731
Highlights: Baltic origins of silver birch had significantly thicker bark than the Finnish ones; In terms of wood density, no consistent difference was detected between the Baltic and Finnish origins; Incidence of darkened core wood increased with increasing seed origin latitude; Frost cracks were most common in south Latvian origins grown in central Finland.

Silver birch (Betula pendula Roth) seed origins from the Baltic countries and from Finland were compared in terms of growth, wood density, bark thickness and the incidence of darkened core wood, frost cracks and decay, and the effect of seed origin latitude was examined in two Finnish provenance trials. The material consisted of 21 stand and single tree origins ranging from latitudes 54° to 63°N from the Baltic countries and Finland. The trials, measured at the age of 22 years, were located at Tuusula (60°21´N), southern Finland and at Viitasaari (63°11´N), central Finland. The Baltic origins were superior to the Finnish ones in the southern trial regarding height, whereas in central Finland the Finnish origins grew better. There was no consistent difference between the Baltic and the Finnish group of origins in wood density. Bark thickness decreased with increasing seed origin latitude. The Baltic origins had significantly thicker bark than the Finnish origins. A moderate positive correlation was detected between the seed origin latitude and the incidence of darkened core wood in the southern trial, where the darkened core wood was more common in the Finnish origins than in the Baltic ones. The highest proportion of trees with frost cracks was detected in the south-western Latvian origins growing in central Finland. Seed transfers from the Baltic would have an increasing effect on the bark thickness of birch logs, but no or only minor effects on wood density. Based on our results, there is no reason to recommend the use of non-native Baltic seed origins in Finland instead of the native locally adapted seed sources.

  • Viherä-Aarnio, Natural Resources Institute Finland (Luke), Green technology, P.O. Box 2, FI-00791 Helsinki, Finland ORCID ID:E-mail: anneli.vihera-aarnio@luke.fi (email)
  • Velling, ORCID ID:E-mail: pike.velling@phnet.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 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 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 1713, category Research article
Lars-Göran Stener, Lars Rytter, Gunnar Jansson. (2017). Effects of pruning on wood properties of planted silver birch in southern Sweden. Silva Fennica vol. 51 no. 2 article id 1713. https://doi.org/10.14214/sf.1713
Highlights: Pruning silver birch trees increased the production of defect-free wood outside the knots; Most wood defects were found inside the knots; Pruned birch trees provide butt logs with higher value than unpruned trees.

Pruning was performed at midsummer in two genetically homogenous and managed planted silver birch stands in southern Sweden – one aged 9 and one aged 10 years. Wood defects were analysed 10 years thereafter, using the five uppermost twigs of the stems up to a height of 30 dm. The number of trees examined at each site was around 70, of which half were pruned. The main findings were that: a) compared to unpruned trees, pruned trees produced more defect-free wood outside the knots; b) most wood defects were found inside the knots; and c) wood defects like rot and bark ingrowth were similar for pruned and unpruned trees, while discolouration was marginally higher for pruned trees inside knots but similar outside knots. Overall, the results confirm previous findings that pruned birch trees will provide butt logs with higher value than unpruned trees.

  • Stener, The Forestry Research Institute of Sweden, Ekebo 2250, 268 90 Svalöv, Sweden ORCID ID:E-mail: lars-goran.stener@skogforsk.se (email)
  • Rytter, The Forestry Research Institute of Sweden, Ekebo 2250, 268 90 Svalöv, Sweden ORCID ID:E-mail: lars.rytter@skogforsk.se
  • Jansson, The Forestry Research Institute of Sweden, Uppsala Science Park, 751 83 Uppsala, Sweden ORCID ID:E-mail: gunnar.jansson@skogforsk.se
article id 1599, category Research article
Andrew McEwan, Michal Brink, Raffaele Spinelli. (2017). Factors affecting the productivity and work quality of chain flail delimbing and debarking. Silva Fennica vol. 51 no. 2 article id 1599. https://doi.org/10.14214/sf.1599
Highlights: Machine productivity averaged 59 m3 ub SMH–1, with a 19% incidence of delay time; Productivity increased 70% if tree volume increased from 0.1 to 0.4 m3 ub; Debarking quality was good for 58% of the trees, medium for 29% and poor for 13%; The more trees in a bunch and the higher BWBS, the lower debarking quality.

Chain flail delimbing and debarking may improve value recovery from small tree harvests, without renouncing the benefits of multi-tree processing. The technology is mature and capable of excellent performance, which has been documented in many benchmark studies. This paper offers new insights into the relationship between the performance of chain flail delimbing and debarking and such factors as tree volume, load volume, tree form and bark-wood bond strength (BWBS). The study was conducted in Chile, during the commercial harvesting of a Eucalyptus globulus Labill. plantation. In an observational study, researchers collected production data from over 780 work cycles, and work quality data from over 1000 individual trees. The analysis of these data shows that productivity is affected primarily by load volume. Work quality is affected by BWBS and by the number of trees in a load. Work quality degrades with increasing BWBS and tree number, since more trees tend to shield each other. Tree form has no effect on either productivity or work quality. Regression and probability functions are provided, and can be used for predictive purposes when trying to optimize current operations or to prospect the introduction of chain flail technology to new work environments.

  • McEwan, Postgraduate Forest Programme, Faculty of Natural and Agricultural Sciences, University of Pretoria, Private Bag X20 Hatfield, Pretoria, 0028, South Africa ORCID ID:E-mail: Andrew.McEwan@nmmu.ac.za
  • Brink, Postgraduate Forest Programme, Faculty of Natural and Agricultural Sciences, University of Pretoria, Private Bag X20 Hatfield, Pretoria, 0028, South Africa ORCID ID:E-mail: michal@cmo.co.za
  • Spinelli, CNR IVALSA, Via Madonna del Piano 10, I-50019 Sesto Fiorentino (FI), Italy ORCID ID: http://orcid.org/0000-0001-9545-1004 E-mail: spinelli@ivalsa.cnr.it (email)
article id 1694, category Research article
Katri Luostarinen, Katja Hakkarainen, Henri Kaksonen. (2017). Wood anatomy of seed and basal bud originated downy birches (Betula pubescens Ehrh.) grown at four different sites. Silva Fennica vol. 51 no. 1 article id 1694. https://doi.org/10.14214/sf.1694
Highlights: Young xylem of sprouts did not clearly show more mature characteristics than that of seedlings; Marked differences in xylem structure could be observed between growing sites.

In trees, xylem must fulfil three important tasks: conducting water to leaves, storing nutrients and water, and supporting the trunk. The origin of the trunk, i.e., seed or basal bud that forms sprouts, and the growth site may affect xylem anatomy, differences of which can affect successful growth of trees. Both seedlings and sprouts of downy birch (Betula pubescens Ehrh.) from four different growth sites with two different soil media, peat and mineral soil, were studied. The diameter of fibres and vessels and the thickness of the double fibre wall were measured, and the number of vessels, rays and axial parenchyma cells was counted. The fibre wall:lumen ratio, vessel percentage area and vessel size:number ratio were calculated. Xylem from sprouts showed only occasionally more mature characteristics than that of seedlings. The number of rays was similar at all four sites, but differences were observed in all other studied characteristics between sites, particularly if soil type was different. The vessel size and number correlated with the number of axial parenchyma cells in juvenile wood, which emphasises the importance of their connections with storage cells particularly at this stage of growth. Good water conductivity was connected with weaker wood, particularly in maturing wood.

  • Luostarinen, School of Forest Sciences, University of Eastern Finland, P.O. Box 111, FI-80101 Joensuu, Finland ORCID ID:E-mail: katri.luostarinen@uef.fi (email)
  • Hakkarainen, Natural Resources Institute of Finland (Luke), Yliopistokatu 6, FI-80100 Joensuu, Finland ORCID ID:E-mail: katjahak@gmail.com
  • Kaksonen, School of Forest Sciences, University of Eastern Finland, P.O. Box 111, FI-80101 Joensuu, Finland ORCID ID:E-mail: hkaksone@gmail.com
article id 1611, category Research article
Ilpo Ervasti. (2016). Wood fiber contents of different materials in the paper industry material chain expressed in roundwood equivalents (RWEs). Silva Fennica vol. 50 no. 4 article id 1611. https://doi.org/10.14214/sf.1611
Highlights: The paper industry material recycling chain consists of different material streams; Consumed paper products form a huge fiber source for industry. However, a reliable measuring system should be developed to quantify these fiber volumes; Converting factors are introduced to quantify the wood fiber contents of different paper industry-related materials of the chain, namely, wood pulp, paper and recovered paper; By using these conversion factors it is possible to convert for example global recovered paper utilization volumes into wood fiber volumes expressed in roundwood equivalents (RWEs).

At present, there are no means for reliably comparing the wood fiber contents of different material streams within the paper industry material chain with each other. The aim of this article is to introduce conversion factors that make it possible to quantify the volume of wood expressed in roundwood equivalent (RWE) values for different paper industry-related materials in the material chain. These conversion factors apply to wood pulp, paper, and recovered paper. European data are used in quantifying the paper industry material streams and calculating the RWE conversion factors. The introduced conversion factors can be used to estimate RWE volumes at a global scale. With assumption that paper recycling did not occur and that paper production volume remained unchanged, an additional volume of 666 million m3 RWEs would be required globally per annum to produce 167 million tons of virgin wood pulp to replace 222 million tons of recovered paper utilized by the paper industry in 2010. This volume is approximately the same as 1.6 times the total removal of wood in Europe (EU27), or the total annual removal of wood in the USA, Canada, and Brazil combined.

  • Ervasti, Aalto University, Industrial Engineering and Management, Maarintie 8, 02150 Espoo, Finland ORCID ID:E-mail: ilervasti@gmail.com (email)
article id 1611, category Research article
Ilpo Ervasti. (2016). Wood fiber contents of different materials in the paper industry material chain expressed in roundwood equivalents (RWEs). Silva Fennica vol. 50 no. 4 article id 1611. https://doi.org/10.14214/sf.1611
Highlights: The paper industry material recycling chain consists of different material streams; Consumed paper products form a huge fiber source for industry. However, a reliable measuring system should be developed to quantify these fiber volumes; Converting factors are introduced to quantify the wood fiber contents of different paper industry-related materials of the chain, namely, wood pulp, paper and recovered paper; By using these conversion factors it is possible to convert for example global recovered paper utilization volumes into wood fiber volumes expressed in roundwood equivalents (RWEs).

At present, there are no means for reliably comparing the wood fiber contents of different material streams within the paper industry material chain with each other. The aim of this article is to introduce conversion factors that make it possible to quantify the volume of wood expressed in roundwood equivalent (RWE) values for different paper industry-related materials in the material chain. These conversion factors apply to wood pulp, paper, and recovered paper. European data are used in quantifying the paper industry material streams and calculating the RWE conversion factors. The introduced conversion factors can be used to estimate RWE volumes at a global scale. With assumption that paper recycling did not occur and that paper production volume remained unchanged, an additional volume of 666 million m3 RWEs would be required globally per annum to produce 167 million tons of virgin wood pulp to replace 222 million tons of recovered paper utilized by the paper industry in 2010. This volume is approximately the same as 1.6 times the total removal of wood in Europe (EU27), or the total annual removal of wood in the USA, Canada, and Brazil combined.

  • Ervasti, Aalto University, Industrial Engineering and Management, Maarintie 8, 02150 Espoo, Finland ORCID ID:E-mail: ilervasti@gmail.com (email)
article id 1611, category Research article
Ilpo Ervasti. (2016). Wood fiber contents of different materials in the paper industry material chain expressed in roundwood equivalents (RWEs). Silva Fennica vol. 50 no. 4 article id 1611. https://doi.org/10.14214/sf.1611
Highlights: The paper industry material recycling chain consists of different material streams; Consumed paper products form a huge fiber source for industry. However, a reliable measuring system should be developed to quantify these fiber volumes; Converting factors are introduced to quantify the wood fiber contents of different paper industry-related materials of the chain, namely, wood pulp, paper and recovered paper; By using these conversion factors it is possible to convert for example global recovered paper utilization volumes into wood fiber volumes expressed in roundwood equivalents (RWEs).

At present, there are no means for reliably comparing the wood fiber contents of different material streams within the paper industry material chain with each other. The aim of this article is to introduce conversion factors that make it possible to quantify the volume of wood expressed in roundwood equivalent (RWE) values for different paper industry-related materials in the material chain. These conversion factors apply to wood pulp, paper, and recovered paper. European data are used in quantifying the paper industry material streams and calculating the RWE conversion factors. The introduced conversion factors can be used to estimate RWE volumes at a global scale. With assumption that paper recycling did not occur and that paper production volume remained unchanged, an additional volume of 666 million m3 RWEs would be required globally per annum to produce 167 million tons of virgin wood pulp to replace 222 million tons of recovered paper utilized by the paper industry in 2010. This volume is approximately the same as 1.6 times the total removal of wood in Europe (EU27), or the total annual removal of wood in the USA, Canada, and Brazil combined.

  • Ervasti, Aalto University, Industrial Engineering and Management, Maarintie 8, 02150 Espoo, Finland ORCID ID:E-mail: ilervasti@gmail.com (email)
article id 1461, category Research article
Ludmila Novitskaya, Nadezhda Nikolaeva, Natalia Galibina, Tatiana Tarelkina, Ludmila Semenova. (2016). The greatest density of parenchyma inclusions in Karelian birch wood occurs at confluences of phloem flows. Silva Fennica vol. 50 no. 3 article id 1461. https://doi.org/10.14214/sf.1461
Highlights: Dark-colored inclusions creating the figured pattern in Karelian birch wood consist of storage parenchyma cells; Their greatest density is formed above branch attachments and below forks; In these zones, the sucrose content is elevated since photoassimilate flows of the trunk and branches merge into one pathway; A high level of sucrose enhances the differentiation of parenchyma cells.

The specific pattern of the wood of Karelian birch (Betula pendula Roth var. carelica (Merckl.) Hämet-Ahti), is created mainly by dark-coloured inclusions of parenchyma tissue. Our study revealed that the greatest density of parenchyma inclusions in Karelian birch wood is observed above branch attachments to the trunk and below forks. In the place of branch attachment, phloem flows of photoassimilates (sucrose) from the branch and along the trunk merge into one pathway, causing a rise in sucrose content in tissues there. In the area below the fork, sucrose flows from two (or more) trunk axes are combined. Many studies have demonstrated that elevated sucrose level is associated with the differentiation of parenchyma. We believe that where large phloem fluxes merge a high level of sucrose promotes mass differentiation of parenchyma cells instead of fibers and vessels. As a result, the density of the figured pattern in the wood increases. The obtained data have a practical value and can be used in developing recommendations for Karelian birch cultivation.

  • Novitskaya, Forest Research Institute, Karelian Research Center, Russian Academy of Sciences, Pushkinskaya str. 11, 185910, Petrozavodsk, Russia ORCID ID:E-mail: ludnovits@rambler.ru (email)
  • Nikolaeva, Forest Research Institute, Karelian Research Center, Russian Academy of Sciences, Pushkinskaya str. 11, 185910, Petrozavodsk, Russia ORCID ID:E-mail: kar-birch@mail.ru
  • Galibina, Forest Research Institute, Karelian Research Center, Russian Academy of Sciences, Pushkinskaya str. 11, 185910, Petrozavodsk, Russia ORCID ID:E-mail: galibina@krc.karelia.ru
  • Tarelkina, Forest Research Institute, Karelian Research Center, Russian Academy of Sciences, Pushkinskaya str. 11, 185910, Petrozavodsk, Russia ORCID ID:E-mail: karelina.t.v@gmail.com
  • Semenova, Forest Research Institute, Karelian Research Center, Russian Academy of Sciences, Pushkinskaya str. 11, 185910, Petrozavodsk, Russia ORCID ID:E-mail: mi7enova@gmail.com
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 1521, category Research article
Kalle Karttunen, Juha Laitila, Tapio Ranta. (2016). First-thinning harvesting alternatives for industrial or energy purposes based on regional Scots pine stand simulations in Finland. Silva Fennica vol. 50 no. 2 article id 1521. https://doi.org/10.14214/sf.1521
Highlights: Small-diameter delimbed wood from Scots pine stands delivered directly for energy use was the most cost-efficient option in terms of the total supply-chain cost in comparison with corresponding industrial use or a whole-tree supply chain for energy use; Forest-management and harvesting decisions influenced the removal of forest biomass and stumpage price as well as the total supply-chain costs for forest biomass; The greatest cost-reduction potential (10.0%, 4.00 € m–3) was achieved for the delimbed energy wood’s supply chain in the regional case of South Savo in eastern Finland.

Combining research into forest management stand conditions and wood supply chain processes has been missing from earlier forestry studies. There is a clear need to develop more cost-efficient small-diameter wood production, harvesting and transportation methods from first thinning, which could be used for either industrial or energy wood purposes. This study considers the total cost for small-diameter wood originating from young Scots pine (Pinus sylvestris L.) dominated stands. Pine pulpwood is the most harvested and most used roundwood assortment, use of which is expected to rise following new pulp-mill investments in Finland. In addition, utilisation of small-diameter trees directly for energy purposes has been increasing steadily in recent years. The aim of the study was to determine the cost-reduction potential of alternative forest management options and supply chains for small diameter-wood in the regional case of South Savo in eastern Finland. The total costs of three distinct scenarios were studied on the basis of forest management, first-thinning harvesting methods, and transportation: 1) industrial wood, 2) delimbed energy wood, and 3) whole trees for energy purposes. The cost-reduction potential for energy-wood supply chains from first thinning was compared to the industrial supply chain. Small-diameter delimbed wood delivered straight for energy purposes was found to be the most cost-efficient as far as the total cost of the supply chain is concerned. More cost-efficient small-diameter wood processes can be found by linking forest stand simulations with supply chain analysis.

  • Karttunen, Lappeenranta University of Technology, LUT School of Energy Systems, Laboratory of Bioenergy, Lönnrotinkatu 7, FI-50100 Mikkeli, Finland ORCID ID:E-mail: kalle.karttunen@lut.fi
  • 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
  • Ranta, Lappeenranta University of Technology, LUT School of Energy Systems, Laboratory of Bioenergy, Lönnrotinkatu 7, FI-50100 Mikkeli, Finland ORCID ID:E-mail: tapio.ranta@lut.fi (email)
article id 1521, category Research article
Kalle Karttunen, Juha Laitila, Tapio Ranta. (2016). First-thinning harvesting alternatives for industrial or energy purposes based on regional Scots pine stand simulations in Finland. Silva Fennica vol. 50 no. 2 article id 1521. https://doi.org/10.14214/sf.1521
Highlights: Small-diameter delimbed wood from Scots pine stands delivered directly for energy use was the most cost-efficient option in terms of the total supply-chain cost in comparison with corresponding industrial use or a whole-tree supply chain for energy use; Forest-management and harvesting decisions influenced the removal of forest biomass and stumpage price as well as the total supply-chain costs for forest biomass; The greatest cost-reduction potential (10.0%, 4.00 € m–3) was achieved for the delimbed energy wood’s supply chain in the regional case of South Savo in eastern Finland.

Combining research into forest management stand conditions and wood supply chain processes has been missing from earlier forestry studies. There is a clear need to develop more cost-efficient small-diameter wood production, harvesting and transportation methods from first thinning, which could be used for either industrial or energy wood purposes. This study considers the total cost for small-diameter wood originating from young Scots pine (Pinus sylvestris L.) dominated stands. Pine pulpwood is the most harvested and most used roundwood assortment, use of which is expected to rise following new pulp-mill investments in Finland. In addition, utilisation of small-diameter trees directly for energy purposes has been increasing steadily in recent years. The aim of the study was to determine the cost-reduction potential of alternative forest management options and supply chains for small diameter-wood in the regional case of South Savo in eastern Finland. The total costs of three distinct scenarios were studied on the basis of forest management, first-thinning harvesting methods, and transportation: 1) industrial wood, 2) delimbed energy wood, and 3) whole trees for energy purposes. The cost-reduction potential for energy-wood supply chains from first thinning was compared to the industrial supply chain. Small-diameter delimbed wood delivered straight for energy purposes was found to be the most cost-efficient as far as the total cost of the supply chain is concerned. More cost-efficient small-diameter wood processes can be found by linking forest stand simulations with supply chain analysis.

  • Karttunen, Lappeenranta University of Technology, LUT School of Energy Systems, Laboratory of Bioenergy, Lönnrotinkatu 7, FI-50100 Mikkeli, Finland ORCID ID:E-mail: kalle.karttunen@lut.fi
  • 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
  • Ranta, Lappeenranta University of Technology, LUT School of Energy Systems, Laboratory of Bioenergy, Lönnrotinkatu 7, FI-50100 Mikkeli, Finland ORCID ID:E-mail: tapio.ranta@lut.fi (email)
article id 1474, category Research article
Cedric A. Goussanou, Sabin Guendehou, Achille E. Assogbadjo, Maguette Kaire, Brice Sinsin, Aida Cuni-Sanchez. (2016). Specific and generic stem biomass and volume models of tree species in a West African tropical semi-deciduous forest. Silva Fennica vol. 50 no. 2 article id 1474. https://doi.org/10.14214/sf.1474
Highlights: Non-destructive sampling approach applied to derive ground truth observations and generate robust basic wood densities; Species-specific and generic allometric equations; Specific equations have better predictive capabilities than generic models.

The quantification of the contribution of tropical forests to global carbon stocks and climate change mitigation requires availability of data and tools such as allometric equations. This study made available volume and biomass models for eighteen tree species in a semi-deciduous tropical forest in West Africa. Generic models were also developed for the forest ecosystem, and basic wood density determined for the tree species. Non-destructive sampling approach was carried out on five hundred and one sample trees to analyse stem volume and biomass. From the modelling of volume and biomass as functions of diameter at breast height (Dbh) and stem height, logarithmic models had better predictive capabilities. The model validation showed that in absence of data on height, models using Dbh only as variable was an alternative. The comparison of basic wood densities to data published in literature enabled to conclude that the non-destructive sampling was a good approach to determining reliable basic wood density. The comparative analysis of species-specific models in this study with selected generic models for tropical forests indicated low probability to identify effective generic models with good predictive ability for biomass. Given tree species richness of tropical forests, the study demonstrated the hypothesis that species-specific models are preferred to generic models, and concluded that further research should be oriented towards development of specific models to cover the full range of dominant tree species of African forests.

  • Goussanou, Laboratory of Applied Ecology, Faculty of Agronomic Sciences, University of Abomey-Calavi, 01 BP 526 Cotonou, Benin ORCID ID:E-mail: cedricgoussanou@gmail.com (email)
  • Guendehou, Laboratory of Applied Ecology, Faculty of Agronomic Sciences, University of Abomey-Calavi, 01 BP 526 Cotonou, Benin; Benin Centre for Scientific and Technical Research, 03 BP 1665 Cotonou, Benin ORCID ID:E-mail: sguendehou@yahoo.fr
  • Assogbadjo, Laboratory of Applied Ecology, Faculty of Agronomic Sciences, University of Abomey-Calavi, 01 BP 526 Cotonou, Benin ORCID ID:E-mail: assogbadjo@yahoo.fr
  • Kaire, Centre Régional AGRHYMET, Département Formation et Recherche, BP 11011 Niamey, Niger ORCID ID:E-mail: m.kaire@agrhymet.ne
  • Sinsin, Laboratory of Applied Ecology, Faculty of Agronomic Sciences, University of Abomey-Calavi, 01 BP 526 Cotonou, Benin ORCID ID:E-mail: bsinsin@gmail.com
  • Cuni-Sanchez, University of Copenhagen, Center for Macroecology, Evolution and Climate, Nørregade 10, P.O. Box 2177, 1017 Copenhagen K, Denmark ORCID ID:E-mail: aidacuni@hotmail.com
article id 1428, category Research article
Gernot Erber, Franz Holzleitner, Maximilian Kastner, Karl Stampfer. (2016). Effect of multi-tree handling and tree-size on harvester performance in small-diameter hardwood thinnings. Silva Fennica vol. 50 no. 1 article id 1428. https://doi.org/10.14214/sf.1428
Highlights: Harvesting with the accumulating energy wood head EF28 was studied under small tree dimension (8 dm3) in hardwood thinnings; Reasonable productivity was achieved; Maximum achieved cutting diameter in hornbeam stand was 23 cm and 15% lower than in softwood stands; Head has potential under such conditions.

Early thinnings are laborious and costly. Thus forest companies are searching for cost and time efficient ways to carry out this task. The study’s purpose was to determine the productivity of the EF28 accumulating energy wood harvesting head in harvesting small-diameter hornbeam (Carpinus betulus L.) undergrowth trees and evaluate the effect of its multi-tree handling (MTH) capacity on time consumption. The harvester was a wheeled, three-axle Komatsu 911. A time study of 7.1 hours on 19 plots, with a total area of 0.76 ha was conducted. On average, the harvested tree volume was 8 dm³ and the stand density was 2666 trees/ha. The productivity was modelled with MTH conduction, mean diameter at breast height and the number of trees handled per cycle as independent variables. On average, MTH took 27% longer per cycle, increased extracted volume per cycle by 33% and consequently increased productivity with 5.0%. In 71.9% of the cycles more than one tree was handled and if so, dimensions were smaller than in single-tree handling (5.8 cm vs. 12.0 cm). Maximum felling diameter of 23 cm was about 15% smaller than in softwood (according to the manufacturer’s specifications) and the driver didn’t exploit the EF28’s theoretical potential in terms of trees handled per cycle. It can be concluded that the head could significantly improve productivity in small-diameter wood procurement.

  • Erber, Addresses University of Natural Resources and Life Sciences Vienna, Department of Forest and Soil Sciences, Institute of Forest Engineering, Peter-Jordan Straße 82/3, A-1190 Vienna, Austria ORCID ID:E-mail: gernot.erber@boku.ac.at (email)
  • Holzleitner, Addresses University of Natural Resources and Life Sciences Vienna, Department of Forest and Soil Sciences, Institute of Forest Engineering, Peter-Jordan Straße 82/3, A-1190 Vienna, Austria ORCID ID:E-mail: franz.holzleitner@boku.ac.at
  • Kastner, Addresses University of Natural Resources and Life Sciences Vienna, Department of Forest and Soil Sciences, Institute of Forest Engineering, Peter-Jordan Straße 82/3, A-1190 Vienna, Austria ORCID ID:E-mail: maximilian.kastner@boku.ac.at
  • Stampfer, Addresses University of Natural Resources and Life Sciences Vienna, Department of Forest and Soil Sciences, Institute of Forest Engineering, Peter-Jordan Straße 82/3, A-1190 Vienna, Austria ORCID ID:E-mail: karl.stampfer@boku.ac.at
article id 1393, category Research article
Werner Poschenrieder, Andreas Rais, Jan-Willem G. van de Kuilen, Hans Pretzsch. (2016). Modelling sawn timber volume and strength development at the individual tree level – essential model features by the example of Douglas fir. Silva Fennica vol. 50 no. 1 article id 1393. https://doi.org/10.14214/sf.1393
Highlights: An individual tree timber growth and quality model toolbox was designed; It realistically predicts an increase of bending strength with planting density; Prediction was shown to be based on consideration of essential intrinsic variables; Height‑diameter‑allometry depending on planting density was effective; Consideration of cambial age and knot area ratio was crucial.

We designed a streamlined timber growth and quality model that aims at the effect of stand management on the efficiency of wood resource use. Applying the R based module toolbox to experimental plots of Douglas fir (Pseudotsuga menziesii [Mirb.] Franco) we analysed essential model features for reflecting the influence of planting density on board strength. The current version realistically predicted a significant increase of centre board bending strength at tree age 40 with initial stand density. Model performance gained clear advantage from a) parameterisation of height to diameter allometry as dependent on planting density b) consideration of cambial age and cross‑sectional knot area in board strength computation. Crown shape was less decisive. The model produced a significant effect of planting density even after a whole rotation period of 70 years as well as a realistic spectrum of board bending strength.

  • Poschenrieder, Technische Universität München, Chair of Forest Growth and Yield Science, Hans Carl von Carlowitz Platz 2, 85354 Freising, Germany ORCID ID: http://orcid.org/0000-0002-9028-8583 E-mail: Werner.Poschenrieder@lrz.tum.de (email)
  • Rais, Technische Universität München, Chair of Forest Growth and Yield Science, Hans Carl von Carlowitz Platz 2, 85354 Freising, Germany; Technische Universität München, Holzforschung München, Winzererstrasse 45, 80797 Munich, Germany ORCID ID:E-mail: Andreas.Rais@hfm.tum.de
  • van de Kuilen, Technische Universität München, Holzforschung München, Winzererstrasse 45, 80797 Munich, Germany ORCID ID:E-mail: vandekuilen@hfm.tum.de
  • Pretzsch, Technische Universität München, Chair of Forest Growth and Yield Science, Hans Carl von Carlowitz Platz 2, 85354 Freising, Germany ORCID ID:E-mail: Hans.Pretzsch@lrz.tum.de
article id 1341, category Research article
Přemysl Humplík, Petr Čermák, Tomáš Žid. (2016). Electrical impedance tomography for decay diagnostics of Norway spruce (Picea abies): possibilities and opportunities. Silva Fennica vol. 50 no. 1 article id 1341. https://doi.org/10.14214/sf.1341
Highlights: Statistical parameters of EIT datasets with values of electrical resistance of heartwood are possible to employ in refining heartwood rot diagnostics; Sapwood proportion is decreasing as the proportion of decay on the radial cut expands; Using EIT datasets and sapwood proportion, trees with rot can be split into two groups as per proportion of decay: [< 35%] and [> 35%].

The paper aimed at testing the potential of refining tree rot diagnostics carried out by means of electrical impedance tomography (EIT). Examined was the use of EIT datasets with electrical resistance values and sapwood proportion determined on the basis of tomograms. Making use of datasets with resistance values in EIT rot diagnostics is not a default method, although datasets stay unaffected by a fixed colour scale and subsequent subjective evaluation unlike tomograms. Tomography measurement was carried out for 27 individuals of Norway spruce (Picea abies [L.] Karst.) in two stands north-east of Brno, Czech Republic. Once felled down, radial cut-outs were sampled at the measurement site and used for localising rot and determining the extent of the area of decay. The results were subsequently compared with tomograms. EIT datasets containing values of electrical resistance found by measuring were statistically processed and compared with the extent of rot area identified within the cuts. Sapwood proportion values were also detected using the tomograms. The baseline assumption that sapwood proportion decreases as the rot area in the radial cut expands was confirmed. In trees with rot percentage to 35% approximately, sapwood proportion was exceeding 30% except one tree. In trees with rot percentage exceeding 35%, sapwood proportion was below 30%. On the basis of interpreted datasets, the trees can be split into three characteristic groups that correspond to the occurrence, extent and nature of the rot.

  • Humplík, Mendel University in Brno, Faculty of Forestry and Wood Technology, Zemědělská 1665/3, 613 00 Brno, Czech Republic ORCID ID:E-mail: premysl.humplik@mendelu.cz (email)
  • Čermák, Mendel University in Brno, Faculty of Forestry and Wood Technology, Zemědělská 1665/3, 613 00 Brno, Czech Republic ORCID ID:E-mail: petr.cermak@mendelu.cz
  • Žid, Mendel University in Brno, Faculty of Forestry and Wood Technology, Zemědělská 1665/3, 613 00 Brno, Czech Republic ORCID ID:E-mail: tomas.zid@mendelu.cz
article id 1341, category Research article
Přemysl Humplík, Petr Čermák, Tomáš Žid. (2016). Electrical impedance tomography for decay diagnostics of Norway spruce (Picea abies): possibilities and opportunities. Silva Fennica vol. 50 no. 1 article id 1341. https://doi.org/10.14214/sf.1341
Highlights: Statistical parameters of EIT datasets with values of electrical resistance of heartwood are possible to employ in refining heartwood rot diagnostics; Sapwood proportion is decreasing as the proportion of decay on the radial cut expands; Using EIT datasets and sapwood proportion, trees with rot can be split into two groups as per proportion of decay: [< 35%] and [> 35%].

The paper aimed at testing the potential of refining tree rot diagnostics carried out by means of electrical impedance tomography (EIT). Examined was the use of EIT datasets with electrical resistance values and sapwood proportion determined on the basis of tomograms. Making use of datasets with resistance values in EIT rot diagnostics is not a default method, although datasets stay unaffected by a fixed colour scale and subsequent subjective evaluation unlike tomograms. Tomography measurement was carried out for 27 individuals of Norway spruce (Picea abies [L.] Karst.) in two stands north-east of Brno, Czech Republic. Once felled down, radial cut-outs were sampled at the measurement site and used for localising rot and determining the extent of the area of decay. The results were subsequently compared with tomograms. EIT datasets containing values of electrical resistance found by measuring were statistically processed and compared with the extent of rot area identified within the cuts. Sapwood proportion values were also detected using the tomograms. The baseline assumption that sapwood proportion decreases as the rot area in the radial cut expands was confirmed. In trees with rot percentage to 35% approximately, sapwood proportion was exceeding 30% except one tree. In trees with rot percentage exceeding 35%, sapwood proportion was below 30%. On the basis of interpreted datasets, the trees can be split into three characteristic groups that correspond to the occurrence, extent and nature of the rot.

  • Humplík, Mendel University in Brno, Faculty of Forestry and Wood Technology, Zemědělská 1665/3, 613 00 Brno, Czech Republic ORCID ID:E-mail: premysl.humplik@mendelu.cz (email)
  • Čermák, Mendel University in Brno, Faculty of Forestry and Wood Technology, Zemědělská 1665/3, 613 00 Brno, Czech Republic ORCID ID:E-mail: petr.cermak@mendelu.cz
  • Žid, Mendel University in Brno, Faculty of Forestry and Wood Technology, Zemědělská 1665/3, 613 00 Brno, Czech Republic ORCID ID:E-mail: tomas.zid@mendelu.cz
article id 1394, category Research article
Sari Karvinen, Tuomas Nummelin. (2015). Finnish wood harvesting contractors’ risks in Russia. Silva Fennica vol. 49 no. 5 article id 1394. https://doi.org/10.14214/sf.1394
Highlights: Disagreements on wood measurement and payment delays were the most important economic risks; Dependency on a few clients created risk for unfavourable agreements and work interruptions; Fires in site huts caused the risk of personal injury; Inadequate professional skills were serious economic and work interruption risks; Unhealthy competition, the functioning of the authorities, and infrastructure were important external risk factors.

Finnish wood harvesting contractors have been working in Russia since the 1990s and new entrepreneurs are still interested in starting operations there, even though Russia is not an easy business environment. This study identifies the most significant risks in contracting in Russia. Risks were identified through expert evaluation and a risk analysis was conducted by using a risk matrix. Possible preventative measures were assessed for the identified risks. Some risks were found to be common in Russia and Finland, for example a limited number of clients, dependency on a few clients, and weak negotiating positions. A stable amount of work, i.e. the availability of stands for harvesting, was also a challenge on the both sides of border. Typical problems in Russia were breaches of contract, especially disagreements on wood measurement and payment delays, potentially causing serious economic losses. Specific to Russia were problems related to machine service and spare parts, as well as security issues. The professional skills of machine operators, as well as changing work motivation were risks in Russia. Cultural differences lead to more challenging supervision and management of staff. Among the external factors, the most challenging in Russia were unhealthy competition in the marketplace and non-transparent and the unpredictable procedures of the authorities. In Russia problems caused by seasonality are amplified by the sparse road network and longer downtime. The revealed specific features of the Russian business environment can help Finnish wood harvesting companies to plan a risk management process for operations in Russia.

  • Karvinen, Natural Resources Institute Finland (Luke), Economics and society, P.O. Box 68, FI-80101 Joensuu, Finland ORCID ID:E-mail: sari.karvinen@luke.fi (email)
  • Nummelin, Natural Resources Institute Finland (Luke), Green technology, P.O. Box 18, FI-01301 Vantaa, Finland ORCID ID:E-mail: tuomas.nummelin@luke.fi
article id 1382, category Research article
Juha Laitila, Johanna Routa. (2015). Performance of a small and a medium sized professional chippers and the impact of storage time on Scots pine (Pinus sylvestris) stem wood chips characteristics. Silva Fennica vol. 49 no. 5 article id 1382. https://doi.org/10.14214/sf.1382
Highlights: The storage time of pulpwood had no significant effect on particle size distribution in any chip size classes; The study confirms the knowledge that chipping time consumption is inversely proportional to engine power and grapple load size in feeding; The use of an narrower 80 mm × 80 mm sieve on Scots pine material does not seem to offer any benefit compared to a 100 mm × 100 mm sieve from the perspective of chip quality.

The primary aim of this study was to clarify the chipping productivity and fuel consumption of tractor-powered and truck-mounted drum chippers when chipping pine pulpwood at a terminal. The secondary aim was to evaluate the impact of wood storage time on the chemical and physical technical specifications of wood chips by chipping pulpwood from eight different storage time groups, using Scots pine (Pinus sylvestris) pulpwood stems logged between 2 and 21 months previously at the terminal with the above-mentioned chippers. Thirdly, the impact of sieve mesh size on the particle size distribution of wood chips from different age groups was compared by using an 80 mm × 80 mm sieve for a tractor-powered chipper and a 100 mm × 100 mm sieve for a truck-mounted chipper. With both chippers, the chipping productivity grew as a function of grapple load weight. The average chipping productivity of the tractor-powered chipper unit was 19 508 kg (dry mass) per effective hour (E0h), and for the truck-mounted chipper the average productivity was 31 184 kg E0h–1. The tractor-powered drum chipper’s fuel consumption was 3.1 litres and for the truck-mounted chipper 3.3 litres per chipped 1000 kg (dry mass). The amount of extractives or volatiles did not demonstrate any statistically significant differences between storage time groups. The particle size distributions with both chippers were quite uniform, and the storage time of pulpwood did not have a significant effect on the particle size distribution in any chip size classes. One reason for this might be that the basic density of chipped wood was homogenous and there was no statistical difference between different storage times. The use of new sharp knives is likely to have affected chip quality, as witnessed by the absence of oversized particles and the moderate presence of fines. The use of narrower 80 mm × 80 mm sieves on Scots pine material does not seem to offer any benefit compared to 100 mm × 100 mm from the chip quality point of view.

  • 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)
  • 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 1377, category Research article
Raul Fernandez-Lacruz, Fulvio Di Fulvio, Dimitris Athanassiadis, Dan Bergström, Tomas Nordfjell. (2015). Distribution, characteristics and potential of biomass-dense thinning forests in Sweden. Silva Fennica vol. 49 no. 5 article id 1377. https://doi.org/10.14214/sf.1377
Highlights: Biomass-dense thinning forests (BDTF) cover 2.1–9.8 M ha in Sweden, which represents 9–44% of the country’s productive forest land area, depending on the constraints applied; 65% of BDTF area is found in northern Sweden; Analyses revealed a yearly harvesting potential of at least 4.3 M OD t of undelimbed whole trees (3.0 M OD t of delimbed stemwood including tops).

Understanding the characteristics of unutilized biomass resources, such as small-diameter trees from biomass-dense thinning forests (BDTF) (non-commercially-thinned forests), can provide important information for developing a bio-based economy. The aim of this study was to describe the areal distribution, characteristics (biomass of growing stock, tree height, etc.) and harvesting potential of BDTF in Sweden. A national forest inventory plot dataset was imported into a geographical information system and plots containing BDTF were selected by applying increasingly stringent constraints. Results show that, depending on the constraints applied, BDTF covers 9–44% (2.1–9.8 M ha) of the productive forest land area, and contains 7–34% of the total growing stock (119–564 M OD t), with an average biomass density of 57 OD t ha–1. Of the total BDTF area, 65% is located in northern Sweden and 2% corresponds to set-aside farmlands. Comparisons with a study from 2008 indicate that BDTF area has increased by at least 4% (about 102 000 ha), in line with general trends for Sweden and Europe. Analyses revealed that the technical harvesting potential of delimbed stemwood (over bark, including tops) from BDTF ranges from 3.0 to 6.1 M OD t yr–1 (7.5 to 15.1 M m3 yr–1), while the potential of whole-tree harvesting ranges from 4.3 to 8.7 M OD t yr–1 (10.2 to 20.6 M m3 yr–1) depending on the scenario considered. However, further technological developments of the harvest and supply systems are needed to utilize the full potential of BDTF.

  • Fernandez-Lacruz, Swedish University of Agricultural Sciences (SLU), Department of Forest Biomaterials and Technology (SBT), Skogsmarksgränd, SE-901 83 Umeå, Sweden ORCID ID: http://orcid.org/0000-0001-9284-8911 E-mail: raul.fernandez@slu.se (email)
  • Di Fulvio, Swedish University of Agricultural Sciences (SLU), Department of Forest Biomaterials and Technology (SBT), Skogsmarksgränd, SE-901 83 Umeå, Sweden; International Institute for Applied Systems Analysis (IIASA), Ecosystems Services and Management Program (ESM), Schlossplatz 1, A-2361 Laxenburg, Austria ORCID ID:E-mail: Fulvio.di.Fulvio@slu.se
  • Athanassiadis, Swedish University of Agricultural Sciences (SLU), Department of Forest Biomaterials and Technology (SBT), Skogsmarksgränd, SE-901 83 Umeå, Sweden ORCID ID:E-mail: Dimitris.Athanassiadis@slu.se
  • Bergström, Swedish University of Agricultural Sciences (SLU), Department of Forest Biomaterials and Technology (SBT), Skogsmarksgränd, SE-901 83 Umeå, Sweden ORCID ID:E-mail: Dan.Bergstrom@slu.se
  • Nordfjell, Swedish University of Agricultural Sciences (SLU), Department of Forest Biomaterials and Technology (SBT), Skogsmarksgränd, SE-901 83 Umeå, Sweden ORCID ID:E-mail: Tomas.Nordfjell@slu.se
article id 1342, category Research article
Blas Mola-Yudego, Gianni Picchi, Dominik Röser, Raffaele Spinelli. (2015). Assessing chipper productivity and operator effects in forest biomass operations. Silva Fennica vol. 49 no. 5 article id 1342. https://doi.org/10.14214/sf.1342
Highlights: A model is constructed to assess the productivity in chipping of wood biomass at roadside; The data includes 172 trials and 67 operators in Italy; The operator effect was included in a mixed model approach; The R2 were 0.76 (fixed part) and 0.88 (incl. operator effects).

The present research focuses on the productivity of energy wood chipping operations at several sites in Italy. The aim was to assess the productivity and specifically the effect attributed to the operator in the chipping of wood biomass. The research included 172 trials involving 67 operators across the country that were analysed using a mixed model approach, in order to assess productivity, and to isolate the operator effect from other potential variables. The model was constructed using different predictors aiming to explain the variability due to the machines and the raw-materials. The final model included the average piece weight of raw material chipped as well as the power of the machine. The coefficients of determination (R2) were 0.76 for the fixed part of the model, and 0.88 when the effects due to the operators were included. The operators’ performance compared to their peers was established, and it was compared to a subjective classification based on the operator’s previous experience. The results of this study can help to the planning and logistics of raw material supply for bioenergy, as well as to a more effective training of future forest operators.

  • Mola-Yudego, School of Forest Sciences, University of Eastern Finland, P.O. Box 111, FI-80101 Joensuu, Finland; NIBIO Norwegian Institute of Bioeconomy Research, P.O. Box 115, 1431 Ås, Norway ORCID ID: http://orcid.org/0000-0003-0286-0170 E-mail: blas.mola@uef.fi (email)
  • Picchi, CNR IVALSA, Via Madonna del Piano 10, I-50019 Sesto Fiorentino, Italy ORCID ID:E-mail: picchi@ivalsa.cnr.it
  • Röser, Forest Feedstocks Group, FPInnovations, Vancouver, British Columbia, Canada ORCID ID:E-mail: dominik.roser@fpinnovations.ca
  • Spinelli, CNR IVALSA, Via Madonna del Piano 10, I-50019 Sesto Fiorentino, Italy ORCID ID:E-mail: spinelli@ivalsa.cnr.it
article id 1391, category Research article
Roberts Matisons, Jānis Jansons, Juris Katrevičs, Āris Jansons. (2015). Relation of tree-ring width and earlywood vessel size of alien Quercus rubra L. with climatic factors in Latvia. Silva Fennica vol. 49 no. 4 article id 1391. https://doi.org/10.14214/sf.1391
Highlights: Climate-growth relationships of red oak from three sites in Latvia were studied; Tree-ring width was mainly affected by temperature and precipitation in late summer; Vessel size was correlated with temperature parameters in autumn–spring; Sets of climatic factors significant for growth of red oak differed between sites; Changes in climate-growth relationships occurred during 20th century.

The effect of climatic factors on wood anatomy of the alien red oak (Quercus rubra L.) growing in three experimental plantations in Latvia was assessed by classical dendrochronological techniques. Two tree-ring proxies – tree-ring width (TRW) and mean area of earlywood vessel lumen (VLA) – were studied on 33 trees. Annual variation of TRW amongst trees was similar (mean r = 0.46), but there was more individuality in VLA (mean r = 0.26); nevertheless, chronologies of both proxies had rather synchronous variation amongst the sites. Annual variation of TRW was affected by factors related to water deficit in late summer, as suggested by the negative effect of temperature and positive effect of precipitation that have intensified during the 20th century, likely due to warming. Although weather conditions during the dormant period did not directly affect TRW, temperature during the autumn-spring period has been the main climatic determinant of VLA likely via influence on overwintering and hence vigour of tree. This suggests that conductive properties of wood and hence the susceptibility to water deficit have been affected by weather conditions before the formation of tree rings. During the 20th century, sensitivity of VLA has shifted from temperature in winter to temperature in autumn likely due to climate change. Still, the positive effect of these factors suggests that warming of climate would increase VLA and hence the risk of embolism and xylem disfunction. Therefore, the importance of availability of water for growth of red oak in Latvia is increasing.

  • Matisons, LSFRI “Silava”, Rigas str. 111, Salaspils, Latvia, LV2169 ORCID ID:E-mail: robism@inbox.lv (email)
  • Jansons, Latvian Forest Competence Centre, Dzērbenes str. 27, Riga, Latvia, LV 1006 ORCID ID:E-mail: janis.jansons@silava.lv
  • Katrevičs, LSFRI “Silava”, Rigas str. 111, Salaspils, Latvia, LV2169 ORCID ID:E-mail: juris.katrevics@silava.lv
  • Jansons, LSFRI “Silava”, Rigas str. 111, Salaspils, Latvia, LV2169 ORCID ID:E-mail: aris.jansons@silava.lv
article id 1391, category Research article
Roberts Matisons, Jānis Jansons, Juris Katrevičs, Āris Jansons. (2015). Relation of tree-ring width and earlywood vessel size of alien Quercus rubra L. with climatic factors in Latvia. Silva Fennica vol. 49 no. 4 article id 1391. https://doi.org/10.14214/sf.1391
Highlights: Climate-growth relationships of red oak from three sites in Latvia were studied; Tree-ring width was mainly affected by temperature and precipitation in late summer; Vessel size was correlated with temperature parameters in autumn–spring; Sets of climatic factors significant for growth of red oak differed between sites; Changes in climate-growth relationships occurred during 20th century.

The effect of climatic factors on wood anatomy of the alien red oak (Quercus rubra L.) growing in three experimental plantations in Latvia was assessed by classical dendrochronological techniques. Two tree-ring proxies – tree-ring width (TRW) and mean area of earlywood vessel lumen (VLA) – were studied on 33 trees. Annual variation of TRW amongst trees was similar (mean r = 0.46), but there was more individuality in VLA (mean r = 0.26); nevertheless, chronologies of both proxies had rather synchronous variation amongst the sites. Annual variation of TRW was affected by factors related to water deficit in late summer, as suggested by the negative effect of temperature and positive effect of precipitation that have intensified during the 20th century, likely due to warming. Although weather conditions during the dormant period did not directly affect TRW, temperature during the autumn-spring period has been the main climatic determinant of VLA likely via influence on overwintering and hence vigour of tree. This suggests that conductive properties of wood and hence the susceptibility to water deficit have been affected by weather conditions before the formation of tree rings. During the 20th century, sensitivity of VLA has shifted from temperature in winter to temperature in autumn likely due to climate change. Still, the positive effect of these factors suggests that warming of climate would increase VLA and hence the risk of embolism and xylem disfunction. Therefore, the importance of availability of water for growth of red oak in Latvia is increasing.

  • Matisons, LSFRI “Silava”, Rigas str. 111, Salaspils, Latvia, LV2169 ORCID ID:E-mail: robism@inbox.lv (email)
  • Jansons, Latvian Forest Competence Centre, Dzērbenes str. 27, Riga, Latvia, LV 1006 ORCID ID:E-mail: janis.jansons@silava.lv
  • Katrevičs, LSFRI “Silava”, Rigas str. 111, Salaspils, Latvia, LV2169 ORCID ID:E-mail: juris.katrevics@silava.lv
  • Jansons, LSFRI “Silava”, Rigas str. 111, Salaspils, Latvia, LV2169 ORCID ID:E-mail: aris.jansons@silava.lv
article id 1337, category Research article
Leszek Bujoczek, Małgorzata Bujoczek, Jan Banaś, Stanisław Zięba. (2015). Spruce regeneration on woody microsites in a subalpine forest in the western Carpathians. Silva Fennica vol. 49 no. 3 article id 1337. https://doi.org/10.14214/sf.1337
Highlights: The occurrence probability of Picea abies seedlings on fallen deadwood was found to increase with diameter and decay stage of deadwood and with the volume of living trees, and to decrease with the density of living trees, sapling density, and land slope. It was also higher on stumps with greater diameter and in plots with higher sapling density, but decreased with increasing stump height.

The density of Picea abies [L.] Karst. regeneration on different microsites, the quantity and quality of woody microsites, and seedling occurrence probability on stumps and fallen deadwood were studied in a subalpine forest that has been under protection for approximately 30–40 years (Gorce Mountains in the western Carpathians). Thirty percent of seedlings and 29% of saplings grew on stumps and fallen deadwood, while the remaining regeneration occurred on soil surface and mounds created by uprooted trees. The occurrence probability of Picea seedlings on fallen deadwood increased with deadwood diameter and decay stage and with the volume of living trees, and decreased with increased density of living trees, sapling density, and land slope. Furthermore, seedlings were more likely to grow on stumps with a greater diameter and in plots with higher sapling density, but less likely to grow on higher stumps. Stumps and fallen deadwood covered about 4% of the forest floor, but the material that is most important for promoting regeneration (strongly decomposed logs and those of a diameter exceeding 30 cm) took up only about 22 m2 ha-1. We have concluded that in a subalpine forest that has been protected for 30–40 years regeneration processes take place mostly on soil surface and stumps. The role of fallen deadwood increases over time as a greater number of suitable logs (in terms of size and decay stage) become available.

  • Bujoczek, University of Agriculture in Krakow, ORCID ID:E-mail: lbujoczek@gmail.com (email)
  • Bujoczek, University of Agriculture in Krakow, ORCID ID:E-mail: bujoczek.m@gmail.com
  • Banaś, University of Agriculture in Krakow, ORCID ID:E-mail: rlbanas@cyf-kr.edu.pl
  • Zięba, University of Agriculture in Krakow, ORCID ID:E-mail: rlzieba@cyf-kr.edu.pl
article id 1337, category Research article
Leszek Bujoczek, Małgorzata Bujoczek, Jan Banaś, Stanisław Zięba. (2015). Spruce regeneration on woody microsites in a subalpine forest in the western Carpathians. Silva Fennica vol. 49 no. 3 article id 1337. https://doi.org/10.14214/sf.1337
Highlights: The occurrence probability of Picea abies seedlings on fallen deadwood was found to increase with diameter and decay stage of deadwood and with the volume of living trees, and to decrease with the density of living trees, sapling density, and land slope. It was also higher on stumps with greater diameter and in plots with higher sapling density, but decreased with increasing stump height.

The density of Picea abies [L.] Karst. regeneration on different microsites, the quantity and quality of woody microsites, and seedling occurrence probability on stumps and fallen deadwood were studied in a subalpine forest that has been under protection for approximately 30–40 years (Gorce Mountains in the western Carpathians). Thirty percent of seedlings and 29% of saplings grew on stumps and fallen deadwood, while the remaining regeneration occurred on soil surface and mounds created by uprooted trees. The occurrence probability of Picea seedlings on fallen deadwood increased with deadwood diameter and decay stage and with the volume of living trees, and decreased with increased density of living trees, sapling density, and land slope. Furthermore, seedlings were more likely to grow on stumps with a greater diameter and in plots with higher sapling density, but less likely to grow on higher stumps. Stumps and fallen deadwood covered about 4% of the forest floor, but the material that is most important for promoting regeneration (strongly decomposed logs and those of a diameter exceeding 30 cm) took up only about 22 m2 ha-1. We have concluded that in a subalpine forest that has been protected for 30–40 years regeneration processes take place mostly on soil surface and stumps. The role of fallen deadwood increases over time as a greater number of suitable logs (in terms of size and decay stage) become available.

  • Bujoczek, University of Agriculture in Krakow, ORCID ID:E-mail: lbujoczek@gmail.com (email)
  • Bujoczek, University of Agriculture in Krakow, ORCID ID:E-mail: bujoczek.m@gmail.com
  • Banaś, University of Agriculture in Krakow, ORCID ID:E-mail: rlbanas@cyf-kr.edu.pl
  • Zięba, University of Agriculture in Krakow, ORCID ID:E-mail: rlzieba@cyf-kr.edu.pl
article id 1293, category Research article
Jukka Malinen, Mika Haring, Harri Kilpeläinen, Erkki Verkasalo. (2015). Comparison of alternative roundwood pricing systems – a simulation approach. Silva Fennica vol. 49 no. 3 article id 1293. https://doi.org/10.14214/sf.1293
Highlights: A discrete event simulation model was developed for studying roundwood pricing systems; For a single buyer, pricing based on residual value appraisal produced (RVA) 4.87 per cent higher wood paying capability and 3.70 per cent higher stumpage price than pricing based on average unit prices; As the number of buyers using RVA increases, the competition increased and the advantage decreased.

In a closed market, roundwood buyers pricing system affect the roundwood flow from the stands to different roundwood users. If a buyer is capable to discriminate higher value stands from low quality stands better than its competitors, the buyer should be able to buy better raw material. In the study, a discrete event simulation was used to examine the effect of residual value appraisal (RVA) -based pricing of roundwood by log dimensions and grades compared to the traditional pricing based on average unit prices (UP) of roundwood assortments on roundwood flow. The core of the simulation model was the data containing 51 pine dominated stands from southern Finland. Sample trees were theoretically bucked by the bucking simulator in order to estimate the volumes, dimensions and grades of the logs and roundwood assortments. The simulation model of roundwood markets included four roundwood buyers, two corporations and two saw milling enterprises. The main finding of the study was that the buyers who use RVA gains an advantage and receives better quality compared to buyers who use UP. As the number of buyers using RVA increases, the competition increased and the advantage decreased.

  • Malinen, University of Eastern Finland, School of Forest Sciences, P.O. Box 111, FI-80101 Joensuu, Finland ORCID ID:E-mail: jukka.malinen@uef.fi (email)
  • Haring, University of Eastern Finland, School of Forest Sciences, P.O. Box 111, FI-80101 Joensuu, Finland ORCID ID:E-mail: mika.haring@gmail.com
  • Kilpeläinen, Natural Resources Institute Finland (Luke), Bio-based business and industry, P.O. Box 68, FI-80101 Joensuu, Finland ORCID ID:E-mail: harri.kilpelainen@luke.fi
  • Verkasalo, Natural Resources Institute Finland (Luke), Bio-based business and industry, P.O. Box 68, FI-80101 Joensuu, Finland ORCID ID:E-mail: erkki.verkasalo@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 1124, category Research article
Āris Jansons, Mārtiņš Zeps, Juris Rieksts-Riekstiņš, Roberts Matisons, Oskars Krišāns. (2014). Height increment of hybrid aspen Populus tremuloides x P. tremula as a function of weather conditions in central part of Latvia. Silva Fennica vol. 48 no. 5 article id 1124. https://doi.org/10.14214/sf.1124
Highlights: Intra-annual height growth of hybrid aspen was monitored; Clones with early leaf flushing dates showed faster height growth; Height growth was generally controlled by temperature; Fast-growing hybrids were more robust to weather conditions than slow-growing ones; Potential evapotranspiration (moisture regime) negatively affected height growth of clones with delayed phenology.
Height growth of young hybrid aspen (Populus tremula L. × P. tremuloides Michx.) was studied in relation to weather conditions. Height of clones with different leaf flushing phenology (early, intermediate and late) was monitored during the growing periods of 2010 and 2011 in a plantation established on former agricultural land. Mean daily height increment (HI) was calculated. Multiple linear regression was used to determine which weather factors (variables) had significant effect on HI. Mean seasonal height growth (mean seasonal HI) between clones (groups) was compared by ANOVA. In both years, HI was significantly higher for clones with early and intermediate leaf flushing compared to clones with late leaf flushing. The effect of weather factors also differed between clones according to their leaf flushing phenology; it was the weakest for HI of clones with early leaf flushing compared to clones with intermediate and late leaf flushing. Mean temperature was the main factor, which positively affected HI of all clones, suggesting that warmer climate might be beneficial for height growth of young hybrid aspen in Latvia. Nevertheless, significant negative relationship between HI and potential evapotranspiration (PET) was observed for clones with delayed leaf flushing, suggesting negative effect of increasing variability of precipitation on growth. Thus, the differences in height growth intensity might be related to growth sensitivity to weather conditions. On the other hand, such differences in height growth between clones might be caused by competition (i.e. with herbs), as trees with early leaf flushing might conquer more resources and become more robust against the environmental fluctuation.
  • Jansons, LSFRI „SILAVA”, Rigas Str. 111, Salaspils, Latvia, LV2169 ORCID ID:E-mail: aris.jansons@silava.lv
  • Zeps, LSFRI „SILAVA”, Rigas Str. 111, Salaspils, Latvia, LV2169 ORCID ID:E-mail: martins.zeps@silava.lv
  • Rieksts-Riekstiņš, LSFRI „SILAVA”, Rigas Str. 111, Salaspils, Latvia, LV2169 ORCID ID:E-mail: Juris.Riekstins@silava.lv
  • Matisons, LSFRI „SILAVA”, Rigas Str. 111, Salaspils, Latvia, LV2169 ORCID ID:E-mail: robism@inbox.lv (email)
  • Krišāns, LSFRI „SILAVA”, Rigas Str. 111, Salaspils, Latvia, LV2169 ORCID ID:E-mail: oskars.krisans@silava.lv
article id 1107, category Research article
Arvo Tullus, Arne Sellin, Priit Kupper, Reimo Lutter, Linnar Pärn, Anna K. Jasinska, Meeli Alber, Maarja Kukk, Tea Tullus, Hardi Tullus, Krista Lõhmus, Anu Sõber. (2014). Increasing air humidity – a climate trend predicted for northern latitudes – alters the chemical composition of stemwood in silver birch and hybrid aspen. Silva Fennica vol. 48 no. 4 article id 1107. https://doi.org/10.14214/sf.1107
Highlights: Hybrid aspen and silver birch trees grew more slowly under increased air humidity conditions and had higher concentrations of N and P and a lower K to N ratio in stemwood; Minor species-specific changes were detected in stemwood concentrations of cellulose and hemicellulose; Density, calorific value and concentrations of lignin and ash in stemwood were not affected by elevated humidity.
We studied the physicochemical properties of stemwood in saplings of silver birch (Betula pendula Roth) and hybrid aspen (Populus tremula L. × P. tremuloides Michx.), grown for four years under artificially elevated relative air humidity (on average by 7%) in field conditions, using the Free Air Humidity Manipulation (FAHM) research facility in Estonia. Altogether 91 sample trees from three experimental plots with manipulated air humidity and from three control plots were cut in the dormant season and sampled for the analysis of cellulose, hemicellulose, acid detergent lignin, macronutrients (N, P, K), ash content, density, and calorific value of wood. The analysed trees grew significantly more slowly under elevated humidity conditions, with a more pronounced effect on aspens. Significantly higher concentrations of N and P were observed in the stemwood of both aspens and birches grown under elevated humidity. This could be the result of a change in the content of living parenchyma cells and/or enhanced retranslocation of nutrients into wood parenchyma. Additionally, humidification resulted in a significantly higher concentration of cellulose and a lower concentration of hemicellulose in aspen stemwood, and in significantly lower concentrations of cellulose and K in birch stemwood. Elevated humidity did not affect lignin concentration, ash content, basic density and calorific value of stemwood. Results from the FAHM experiment suggest that the increasing air humidity accompanying global warming at northern latitudes will affect the growth and functioning of deciduous trees and forests, with obvious consequences also for forest management and industry.
  • Tullus, Department of Botany, Institute of Ecology and Earth Sciences, Faculty of Science and Technology, University of Tartu, Lai 40, Tartu 51005, Estonia ORCID ID:E-mail: arvo.tullus@ut.ee (email)
  • Sellin, Department of Botany, Institute of Ecology and Earth Sciences, Faculty of Science and Technology, University of Tartu, Lai 40, Tartu 51005, Estonia ORCID ID:E-mail: arne.sellin@ut.ee
  • Kupper, Department of Botany, Institute of Ecology and Earth Sciences, Faculty of Science and Technology, University of Tartu, Lai 40, Tartu 51005, Estonia ORCID ID:E-mail: priit.kupper@ut.ee
  • Lutter, Institute of Forestry and Rural Engineering, Estonian University of Life Sciences, Kreutzwaldi 5, Tartu 51014, Estonia ORCID ID:E-mail: reimo.lutter@emu.ee
  • Pärn, Institute of Forestry and Rural Engineering, Estonian University of Life Sciences, Kreutzwaldi 5, Tartu 51014, Estonia ORCID ID:E-mail: linnar.parn@emu.ee
  • Jasinska, Department of Botany, Institute of Ecology and Earth Sciences, Faculty of Science and Technology, University of Tartu, Lai 40, Tartu 51005, Estonia & Institute of Dendrology, Polish Academy of Sciences, Parkowa 5, 62-035 Kórnik, Poland ORCID ID:E-mail: jasiak9@wp.pl
  • Alber, Department of Botany, Institute of Ecology and Earth Sciences, Faculty of Science and Technology, University of Tartu, Lai 40, Tartu 51005, Estonia ORCID ID:E-mail: meeli.alber@ut.ee
  • Kukk, Department of Botany, Institute of Ecology and Earth Sciences, Faculty of Science and Technology, University of Tartu, Lai 40, Tartu 51005, Estonia ORCID ID:E-mail: maarja.kukk@ut.ee
  • Tullus, Institute of Forestry and Rural Engineering, Estonian University of Life Sciences, Kreutzwaldi 5, Tartu 51014, Estonia ORCID ID:E-mail: tea.tullus@emu.ee
  • Tullus, Institute of Forestry and Rural Engineering, Estonian University of Life Sciences, Kreutzwaldi 5, Tartu 51014, Estonia ORCID ID:E-mail: hardi.tullus@emu.ee
  • Lõhmus, Department of Botany, Institute of Ecology and Earth Sciences, Faculty of Science and Technology, University of Tartu, Lai 40, Tartu 51005, Estonia ORCID ID:E-mail: krista.lohmus@ut.ee
  • Sõber, Department of Botany, Institute of Ecology and Earth Sciences, Faculty of Science and Technology, University of Tartu, Lai 40, Tartu 51005, Estonia ORCID ID:E-mail: anu.sober@ut.ee
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 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 962, category Research article
Paul A. Klockow, Anthony W. D'Amato, John B. Bradford, Shawn Fraver. (2014). Nutrient concentrations in coarse and fine woody debris of Populus tremuloides Michx.-dominated forests, northern Minnesota, USA. Silva Fennica vol. 48 no. 1 article id 962. https://doi.org/10.14214/sf.962
Highlights: We examine effects of size, species, and decay on woody debris nutrient concentrations; Results indicate wide variation in nutrient concentrations across the factors examined; Fine woody debris nutrient concentrations were greater than in coarse woody debris; Coarse woody debris nutrient concentrations generally increased as decay progressed; Results suggest high fine woody debris stocks can represent an important nutrient source.
Contemporary forest harvesting practices, specifically harvesting woody biomass as a source of bioenergy feedstock, may remove more woody debris from a site than conventional harvesting. Woody debris, particularly smaller diameter woody debris, plays a key role in maintaining ecosystem nutrient stores following disturbance. Understanding nutrient concentrations within woody debris is necessary for assessing the long-term nutrient balance consequences of altered woody debris retention, particularly in forests slated for use as bioenergy feedstocks. Nutrient concentrations in downed woody debris of various sizes, decay classes, and species were characterized within one such forest type, Populus tremuloides Michx.-dominated forests of northern Minnesota, USA. Nutrient concentrations differed significantly between size and decay classes and generally increased as decay progressed. Fine woody debris (≤ 7.5 cm diameter) had higher nutrient concentrations than coarse woody debris (> 7.5 cm diameter) for all nutrients examined except Na and Mn, and nutrient concentrations varied among species. Concentrations of N, Mn, Al, Fe, and Zn in coarse woody debris increased between one and three orders of magnitude, while K decreased by an order of magnitude with progressing decay. The variations in nutrient concentrations observed here underscore the complexity of woody debris nutrient stores in forested ecosystems and suggest that retaining fine woody debris at harvest may provide a potentially important source of nutrients following intensive removals of bioenergy feedstocks.
  • Klockow, Department of Forest Resources, University of Minnesota, St. Paul, MN 55108, USA ORCID ID:E-mail: klock039@umn.edu (email)
  • D'Amato, Department of Forest Resources, University of Minnesota, St. Paul, MN 55108, USA ORCID ID:E-mail: damato@umn.edu
  • Bradford, US Geological Survey, Southwest Biological Science Center, Flagstaff, AZ 86001, USA ORCID ID:E-mail: jbradford@usgs.gov
  • Fraver, School of Forest Resources, University of Maine, Orono, ME 04469, USA ORCID ID:E-mail: shawn.fraver@maine.edu
article id 962, category Research article
Paul A. Klockow, Anthony W. D'Amato, John B. Bradford, Shawn Fraver. (2014). Nutrient concentrations in coarse and fine woody debris of Populus tremuloides Michx.-dominated forests, northern Minnesota, USA. Silva Fennica vol. 48 no. 1 article id 962. https://doi.org/10.14214/sf.962
Highlights: We examine effects of size, species, and decay on woody debris nutrient concentrations; Results indicate wide variation in nutrient concentrations across the factors examined; Fine woody debris nutrient concentrations were greater than in coarse woody debris; Coarse woody debris nutrient concentrations generally increased as decay progressed; Results suggest high fine woody debris stocks can represent an important nutrient source.
Contemporary forest harvesting practices, specifically harvesting woody biomass as a source of bioenergy feedstock, may remove more woody debris from a site than conventional harvesting. Woody debris, particularly smaller diameter woody debris, plays a key role in maintaining ecosystem nutrient stores following disturbance. Understanding nutrient concentrations within woody debris is necessary for assessing the long-term nutrient balance consequences of altered woody debris retention, particularly in forests slated for use as bioenergy feedstocks. Nutrient concentrations in downed woody debris of various sizes, decay classes, and species were characterized within one such forest type, Populus tremuloides Michx.-dominated forests of northern Minnesota, USA. Nutrient concentrations differed significantly between size and decay classes and generally increased as decay progressed. Fine woody debris (≤ 7.5 cm diameter) had higher nutrient concentrations than coarse woody debris (> 7.5 cm diameter) for all nutrients examined except Na and Mn, and nutrient concentrations varied among species. Concentrations of N, Mn, Al, Fe, and Zn in coarse woody debris increased between one and three orders of magnitude, while K decreased by an order of magnitude with progressing decay. The variations in nutrient concentrations observed here underscore the complexity of woody debris nutrient stores in forested ecosystems and suggest that retaining fine woody debris at harvest may provide a potentially important source of nutrients following intensive removals of bioenergy feedstocks.
  • Klockow, Department of Forest Resources, University of Minnesota, St. Paul, MN 55108, USA ORCID ID:E-mail: klock039@umn.edu (email)
  • D'Amato, Department of Forest Resources, University of Minnesota, St. Paul, MN 55108, USA ORCID ID:E-mail: damato@umn.edu
  • Bradford, US Geological Survey, Southwest Biological Science Center, Flagstaff, AZ 86001, USA ORCID ID:E-mail: jbradford@usgs.gov
  • Fraver, School of Forest Resources, University of Maine, Orono, ME 04469, USA ORCID ID:E-mail: shawn.fraver@maine.edu
article id 1047, category Research article
Kalle Karttunen, Lauri Lättilä, Olli-Jussi Korpinen, Tapio Ranta. (2013). Cost-efficiency of intermodal container supply chain for forest chips. Silva Fennica vol. 47 no. 4 article id 1047. https://doi.org/10.14214/sf.1047
Highlights: The combined availability and simulation study method obtains more realistic results for use in practical decision-making in supply chain management; The total costs of forest chips with intermodal composite container supply chains were lower than traditional options in all scenarios; The most advantageous way to expand the procurement area for forest chips is either to use composite container trucks or start using train transportation instead of trucks for procurement from longer distances.
Cost-efficient solutions of supply chains for energy wood are required as part of endeavors to reach targets for renewable energy utilization. Long-distance railway transportation is an interesting area of research, especially for high-volume sites where the forest-to-site distance is considerable and rail facilities already exist. The aim of the study was to compare the cost-efficiency of an intermodal container supply chain and traditional multi-modal supply chain with corresponding direct truck logistics for long-distance transportation of forest chips. In the study, site-dependent information for forest biomass transport was integrated into a simulation model to calculate the cost-efficiency of logistic operations related to forest chips transportation in central Finland. The model was tested with several truck and railway transportation scenarios for varying demand of forest chips at the case power plant. The total costs of traditional supply chains were found to be 5–19% more expensive than container supply chain scenarios. The total unit costs of forest chips varied between 15.3 and 20.0 €/MWh depending on the scenario. It is concluded on the basis of the scenario study that intermodal light-structure container logistics and railway transportation could be developed as a viable option for large-scale supply of forest chips.
  • Karttunen, Lappeenranta University of Technology, LUT Savo Sustainable Technologies, Sammonkatu 12, FI-50130 Mikkeli, Finland ORCID ID:E-mail: kalle.karttunen@lut.fi (email)
  • Lättilä, Lappeenranta University of Technology, LUT Savo Sustainable Technologies, Sammonkatu 12, FI-50130 Mikkeli, Finland ORCID ID:E-mail: lauri.lattila@lut.fi
  • Korpinen, Lappeenranta University of Technology, LUT Savo Sustainable Technologies, Sammonkatu 12, FI-50130 Mikkeli, Finland ORCID ID:E-mail: olli-jussi.korpinen@lut.fi
  • Ranta, Lappeenranta University of Technology, LUT Savo Sustainable Technologies, Sammonkatu 12, FI-50130 Mikkeli, Finland ORCID ID:E-mail: tapio.ranta@lut.fi
article id 1002, category Research article
Pentti Niemistö. (2013). Effect of growing density on biomass and stem volume growth of downy birch stands on peatland in Western and Northern Finland. Silva Fennica vol. 47 no. 4 article id 1002. https://doi.org/10.14214/sf.1002
Highlights: The thinning response in young downy birch stands was low and the mortality of merchantable stems was tolerable even in dense unthinned thickets during the rotation of 50 years; The production of above-ground woody biomass and stem volume or even the production of pulpwood increased with stand density, with these values being greatest for unthinned or very lightly thinned plots.
The objective of the study was to ascertain the relationship of thinning intensity of downy birch (Betula pubescens Ehrh.) stands with height, crown, and diameter development as well as pulpwood, stem volume, and biomass increment using long-term (20−30 years) field experiments. Diameter growth of birches increased with thinning intensity during the first 15 years from thinning in all development phases, though after that it did so only for the youngest stands. The thinning response was low. Thinning intensity had no influence on increase in height. In terms of stem volume with bark, the mortality in unthinned stands during the study period was 30–45 m3 ha-1. The mean stem number in unthinned birch thickets fell from 25 000 ha-1 at a dominant height of 7 m to 3000 ha-1 at 18 m. The stem volume increment over the first 15 years was highest (5–6 m3 ha-1 a-1) on the very lightly thinned or unthinned plots, but later there was no significant difference between initial thinning intensities. The maximum above-ground leafless biomass (over 100 Mg ha-1) was achieved on very lightly thinned plots. Also, the total production (including thinning removal) of biomass or stem volume or even the production of pulpwood increased with stand density, with these values being greatest for very lightly thinned or unthinned plots. During 50-year rotation, the highest leafless above-ground biomass production was 2.5 Mg ha-1 a-1 as a mean value from the experiments. The highest mean annual production of pulpwood (d > 6.5 cm) was 3.2 m3 ha-1 a-1, and, in practice, no saw timber or veneer timber was produced, because of the small size and low quality of the stems. A thinning in downy birch stands increased slightly the size of stems to be removed in future cuttings, but with exception for very light thinning it decreased the production of biomass and merchantable wood.
  • Niemistö, Finnish Forest Research Institute, Parkano Unit, FI-39700 Parkano, Finland ORCID ID:E-mail: pentti.niemisto@metla.fi (email)
article id 1002, category Research article
Pentti Niemistö. (2013). Effect of growing density on biomass and stem volume growth of downy birch stands on peatland in Western and Northern Finland. Silva Fennica vol. 47 no. 4 article id 1002. https://doi.org/10.14214/sf.1002
Highlights: The thinning response in young downy birch stands was low and the mortality of merchantable stems was tolerable even in dense unthinned thickets during the rotation of 50 years; The production of above-ground woody biomass and stem volume or even the production of pulpwood increased with stand density, with these values being greatest for unthinned or very lightly thinned plots.
The objective of the study was to ascertain the relationship of thinning intensity of downy birch (Betula pubescens Ehrh.) stands with height, crown, and diameter development as well as pulpwood, stem volume, and biomass increment using long-term (20−30 years) field experiments. Diameter growth of birches increased with thinning intensity during the first 15 years from thinning in all development phases, though after that it did so only for the youngest stands. The thinning response was low. Thinning intensity had no influence on increase in height. In terms of stem volume with bark, the mortality in unthinned stands during the study period was 30–45 m3 ha-1. The mean stem number in unthinned birch thickets fell from 25 000 ha-1 at a dominant height of 7 m to 3000 ha-1 at 18 m. The stem volume increment over the first 15 years was highest (5–6 m3 ha-1 a-1) on the very lightly thinned or unthinned plots, but later there was no significant difference between initial thinning intensities. The maximum above-ground leafless biomass (over 100 Mg ha-1) was achieved on very lightly thinned plots. Also, the total production (including thinning removal) of biomass or stem volume or even the production of pulpwood increased with stand density, with these values being greatest for very lightly thinned or unthinned plots. During 50-year rotation, the highest leafless above-ground biomass production was 2.5 Mg ha-1 a-1 as a mean value from the experiments. The highest mean annual production of pulpwood (d > 6.5 cm) was 3.2 m3 ha-1 a-1, and, in practice, no saw timber or veneer timber was produced, because of the small size and low quality of the stems. A thinning in downy birch stands increased slightly the size of stems to be removed in future cuttings, but with exception for very light thinning it decreased the production of biomass and merchantable wood.
  • Niemistö, Finnish Forest Research Institute, Parkano Unit, FI-39700 Parkano, Finland ORCID ID:E-mail: pentti.niemisto@metla.fi (email)
article id 938, category Research article
Lars Karlsson, Tommy Mörling, Urban Bergsten. (2013). Influence of silvicultural regimes on the volume and proportion of juvenile and mature wood in boreal Scots pine. Silva Fennica vol. 47 no. 4 article id 938. https://doi.org/10.14214/sf.938
Highlights: Initial stand densities have a large impact on the proportion of mature wood within trees throughout most of their life cycle; The difference between regimes in volume of long fibres in crop trees could be substantial; Long-term silvicultural strategies implemented at juvenile stand ages can be important tools in order to produce wood raw material suited for specific end-uses.
Trees from 48 to 78 years old, exposed to three different long-term silvicultural regimes, were examined for transition ages between juvenile (JW), transition (TW) and mature wood (MW), total wood volume and proportions of the same wood types, as defined by fibre length. Twenty one sample trees were collected at sites with similar growing conditions within the same geographical area. Stem discs and fibre samples from breast height (BRH), 20% of tree height, green crown height and 70% of tree height were analysed. Trees growing in an environment with few neighboring trees (Sparse regime) started to produce MW, on average, five years later at BRH and six to nine years later at 20% of total tree height than trees in stands with high stem numbers (Dense regime) and trees growing in stands where the stem number had been heavily reduced after an initial high stand density (Dense/Sparse regime). For all regimes, the greatest mean fibre length was found below the green crown and high initial stem numbers were found to positively influence fibre length. The proportion of MW in the whole stem was 34% at Sparse regime sites, 57–69% at Dense/Sparse sites and 63–64% in sites where there was a Dense regime. The proportion of MW was significantly lower for trees from the Sparse regime on each stem section compared. In conclusion, the results suggest that the initial condition a tree faces affects the stem wood properties and quality output at the end of the rotation period.
  • Karlsson, Department of Forest Biomaterials and Technology, Swedish University of Agricultural Sciences, SE-901 83 Umeå, Sweden ORCID ID:E-mail: lars.karlsson@slu.se (email)
  • Mörling, Department of Forest Ecology and Management, Swedish University of Agricultural Sciences, SE-901 83 Umeå, Sweden ORCID ID:E-mail: tommy.morling@slu.se
  • Bergsten, Department of Forest Biomaterials and Technology, Swedish University of Agricultural Sciences, SE-901 83 Umeå, Sweden ORCID ID:E-mail: urban.bergsten@slu.se
article id 954, category Research article
Anna-Maria Eriksson, Jörgen Olsson, Bengt Gunnar Jonsson, Sara Toivanen, Mattias Edman. (2013). Effects of restoration fire on dead wood heterogeneity and availability in three Pinus sylvestris forests in Sweden. Silva Fennica vol. 47 no. 2 article id 954. https://doi.org/10.14214/sf.954
Restoration fires are increasingly used as a conservation tool in Sweden to recreate forests with characteristics of previous forests that were periodically disturbed by fires and promote fire-dependent species. Restoration fires can result in large inputs of fresh dead wood, but there are risks of losing some of the existing, pre-fire dead wood. To assess these counteracting effects we studied the heterogeneity and availability of dead wood before and after three restoration fires in boreal Scots pine forests. Specifically, we studied volumes of stumps, high stumps, snags and logs. The fires decreased the total volume of pre-fire dead wood (23-41%) and consumed logs in late decay stages (26-54%) to a higher extent than logs in earlier stages. The input of new fresh dead wood after the fires exceeded losses of pre-fire dead wood and resulted in a net increase of dead wood in all three sites. The added dead wood consisted of fresh snags killed by the fires. Fire also affected log characteristics: reducing their vegetation coverage (60-98%), decreasing their ground contact (4-50%) and increasing their surface area of charred wood (>50%). Such changes have important consequences for the micro environmental conditions inside logs, but have been rarely studied in relation to restoration fires. Our results show that restoration fire causes changes in dead wood availability and characteristics of logs. The results imply that ideally stands with low abundance of rare and heavily decayed wood substrates should be burned to optimize dead wood values. Alternatively, management practices should include protection of these substrates during restoration fires.
  • Eriksson, Department of Natural Sciences, Mid Sweden University, SE-851 70, Sundsvall, Sweden ORCID ID:E-mail: anna-maria.eriksson@miun.se (email)
  • Olsson, Department of Ecology and Environmental Science, Umeå University, SE-901 87, Umeå, Sweden ORCID ID:E-mail: jorgen.m.olsson@slu.se
  • Jonsson, Department of Natural Sciences, Mid Sweden University, SE-851 70, Sundsvall, Sweden ORCID ID:E-mail: bengt-gunnar.jonsson@miun.se
  • Toivanen, Department of Natural Sciences, Mid Sweden University, SE-851 70, Sundsvall, Sweden ORCID ID:E-mail: sara.toivanen@lansstyrelsen.se
  • Edman, Department of Natural Sciences, Mid Sweden University, SE-851 70, Sundsvall, Sweden ORCID ID:E-mail: mattias.edman@miun.se
article id 930, category Research article
Raffaele Spinelli, Eugenio Cavallo, Lars Eliasson, Alessio Facello. (2013). Comparing the efficiency of drum and disc chippers. Silva Fennica vol. 47 no. 2 article id 930. https://doi.org/10.14214/sf.930
The study compared the effect of chipper type on productivity, power demand, fuel consumption and product quality. Tests were conducted on two commercial chipper models, a disc and a drum chipper. Both chippers had the same diameter capacity, were applied to the same tractor and fed with the same feedstock types. Fifteen replications were conducted per machine and for each of four different feedstock types, reaching a total of 120 tests. The disc chipper had a higher energy efficiency and used 19% less fuel per unit product, possibly due to its simpler design, integrating comminuting and discharge system in one synergic device. In contrast, the drum chipper was 8% more productive, since it cut with the same energy all along the length of its knives. The drum chipper produced smaller chips, with a higher incidence of fines. Feedstock type had a strong effect on productivity, energy efficiency and product quality. The effect of feedstock type was mainly related to piece size, and may be stronger than the effect of chipper type. Further studies should determine the effect of blade wear on the relative performance of the two chipper types.
  • Spinelli, CNR IVALSA, Via Madonna del Piano 10, Sesto Fiorentino (FI), Italy ORCID ID:E-mail: spinelli@ivalsa.cnr.it (email)
  • Cavallo, CNR IVALSA, Via Madonna del Piano 10, Sesto Fiorentino (FI), Italy ORCID ID:E-mail: e.cavallo@imamoter.cnr.it
  • Eliasson, Skogforsk, Uppsala Science Park, SE-751 83 Uppsala, Sweden ORCID ID:E-mail: lars.eliasson@skogforsk.se
  • Facello, CNR IVALSA, Via Madonna del Piano 10, Sesto Fiorentino (FI), Italy ORCID ID:E-mail: a.facello@ima.to.cnr.it
article id 904, category Research article
Raul Fernandez-Lacruz, Fulvio Di Fulvio, Dan Bergström. (2013). Productivity and profitability of harvesting power line corridors for bioenergy. Silva Fennica vol. 47 no. 1 article id 904. https://doi.org/10.14214/sf.904
Trees growing under the wires and around the pylons carrying power lines (PL) represent a significant threat to the power supply because they can cause power outages and damage. The vegetation in these PL corridors is cleared motor-manually on a regular basis, which represents about 50% of the PL maintenance costs. In Sweden, PL corridors account for 140 000 ha of productive forest land, with an estimated bioenergy potential of 3 TWh/year. The aim of this study was to measure the productivity of a harvester (with an accumulating felling head) and a forwarder, performing PL corridor clearing (with the collection of whole trees for energy use) and to calculate how the cost and economic profitability is dependent on tree height, biomass removal, harvested area, forwarding distance and wood fuel price. The study also compared the economic profitability of the mechanized harvesting system with motor-manual clearing. Experimental units were inventoried along a PL corridor in central Sweden and a time study of one harvester and one forwarder (with a single operator per machine), working in those units, was carried out. The results showed that if the tree height was greater than about 6 m, the mechanized harvesting system became a more cost-efficient alternative, when compared to motor-manual clearing, but it was also found that mechanized clearing is not always the most cost-effective option. Nevertheless, mechanization of PL clearing has a huge potential for expansion, requiring further research in the combined management of the PL corridors and side areas.
  • Fernandez-Lacruz, Department of Forest Biomaterials and Technology, Swedish University of Agricultural Sciences, SE-901 83 Umeå, Sweden ORCID ID:E-mail: raul.fernandez@slu.se (email)
  • Di Fulvio, Department of Forest Biomaterials and Technology, Swedish University of Agricultural Sciences, SE-901 83 Umeå, Sweden ORCID ID:E-mail: fulvio.di.fulvio@slu.se
  • Bergström, Department of Forest Biomaterials and Technology, Swedish University of Agricultural Sciences, SE-901 83 Umeå, Sweden ORCID ID:E-mail: dan.bergstrom@slu.se
article id 901, category Research article
Luis A. Apiolaza, Rosa M. Alzamora. (2013). Building deployment portfolios for genotypes under performance instability. Silva Fennica vol. 47 no. 1 article id 901. https://doi.org/10.14214/sf.901
We used portfolio theory to analyze the tradeoffs between returns and performance instability of deployment units for Pinus radiata D. Don. We considered three groups of 34 trees each grown to produce appearance lumber, structural lumber, or both. Risk was based on the variability of tree returns in scenarios of changing volume, wood stiffness and presence of resin defects due to genotype by environment interaction inducing both changes of scale and differential tree response to environmental scenarios. The return of structural trees was highly variable with a mean of 3.11 NZ $/stem/year, followed by appearance-structural trees (3.48 NZ $/stem/year). In contrast, appearance trees had the lowest returns (1.99 NZ $/stem/year) and variability. The portfolio model selected structural trees in high-risk scenarios, but selection was apportioned between structural and appearance-structural trees as the risk decreased. The model selected only appearance trees for high-risk aversion. The analysis also considered silvicultural regimes, where the appearance-structural regime was selected under high variability. As risk decreased the appearance grades regime was also selected. The structural regime was rarely selected due to the variability of stiffness between trees. Using genotypes improved for stiffness could increase the expected value and reduce variability for structural purposes, making the structural regime more appealing.
  • Apiolaza, School of Forestry, University of Canterbury, Private Bag 4800, 8042 Canterbury, New Zealand ORCID ID:E-mail: luis.apiolaza@canterbury.ac.nz (email)
  • Alzamora, Instituto de Manejo Forestal, Universidad Austral, Valdivia, Chile ORCID ID:E-mail: ralzamor@uach.cl
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 921, category Research article
Katri Luostarinen. (2012). Tracheid wall thickness and lumen diameter in different axial and radial locations in cultivated Larix sibirica trunks. Silva Fennica vol. 46 no. 5 article id 921. https://doi.org/10.14214/sf.921
In Larix trunks the properties of wood differ clearly radially, but the axial differences are smaller as well as being less studied. Wood anatomy is in particular poorly studied, even though all other wood properties derive from cell and tissue structure. The aim of this study was to chart variation in tracheid size (double wall thickness (2CWT), diameter of lumen (RD)) within fast grown cultivated Siberian larch (Larix sibirica Ledeb.) trunks. The differences in 2CWT and RD were clear between earlywood (EW) and latewood (LW), 2CWT increasing clearly less in EW than in LW towards the bark, while RD stayed quite stable in LW but in EW increased markedly towards the bark. The difference in 2CWT between EW and LW increased towards the upper trunk. In conclusion, the radial variation in RD and 2CWT was different between the butt and other studied heights. As the difference in 2CWT between EW and LW was smaller at the butt than the upper portion of the trunk, the wood was the most homogenous at the butt.
  • Luostarinen, University of Eastern Finland, School of Forest Sciences, P.O. Box 111, FI-80101 Joensuu, Finland ORCID ID:E-mail: katri.luostarinen@uef.fi (email)
article id 921, category Research article
Katri Luostarinen. (2012). Tracheid wall thickness and lumen diameter in different axial and radial locations in cultivated Larix sibirica trunks. Silva Fennica vol. 46 no. 5 article id 921. https://doi.org/10.14214/sf.921
In Larix trunks the properties of wood differ clearly radially, but the axial differences are smaller as well as being less studied. Wood anatomy is in particular poorly studied, even though all other wood properties derive from cell and tissue structure. The aim of this study was to chart variation in tracheid size (double wall thickness (2CWT), diameter of lumen (RD)) within fast grown cultivated Siberian larch (Larix sibirica Ledeb.) trunks. The differences in 2CWT and RD were clear between earlywood (EW) and latewood (LW), 2CWT increasing clearly less in EW than in LW towards the bark, while RD stayed quite stable in LW but in EW increased markedly towards the bark. The difference in 2CWT between EW and LW increased towards the upper trunk. In conclusion, the radial variation in RD and 2CWT was different between the butt and other studied heights. As the difference in 2CWT between EW and LW was smaller at the butt than the upper portion of the trunk, the wood was the most homogenous at the butt.
  • Luostarinen, University of Eastern Finland, School of Forest Sciences, P.O. Box 111, FI-80101 Joensuu, Finland ORCID ID:E-mail: katri.luostarinen@uef.fi (email)
article id 921, category Research article
Katri Luostarinen. (2012). Tracheid wall thickness and lumen diameter in different axial and radial locations in cultivated Larix sibirica trunks. Silva Fennica vol. 46 no. 5 article id 921. https://doi.org/10.14214/sf.921
In Larix trunks the properties of wood differ clearly radially, but the axial differences are smaller as well as being less studied. Wood anatomy is in particular poorly studied, even though all other wood properties derive from cell and tissue structure. The aim of this study was to chart variation in tracheid size (double wall thickness (2CWT), diameter of lumen (RD)) within fast grown cultivated Siberian larch (Larix sibirica Ledeb.) trunks. The differences in 2CWT and RD were clear between earlywood (EW) and latewood (LW), 2CWT increasing clearly less in EW than in LW towards the bark, while RD stayed quite stable in LW but in EW increased markedly towards the bark. The difference in 2CWT between EW and LW increased towards the upper trunk. In conclusion, the radial variation in RD and 2CWT was different between the butt and other studied heights. As the difference in 2CWT between EW and LW was smaller at the butt than the upper portion of the trunk, the wood was the most homogenous at the butt.
  • Luostarinen, University of Eastern Finland, School of Forest Sciences, P.O. Box 111, FI-80101 Joensuu, Finland ORCID ID:E-mail: katri.luostarinen@uef.fi (email)
article id 910, category Research article
Gernot Erber, Christian Kanzian, Karl Stampfer. (2012). Predicting moisture content in a pine logwood pile for energy purposes. Silva Fennica vol. 46 no. 4 article id 910. https://doi.org/10.14214/sf.910
Determining the moisture content of naturally dried fuel stock without frequent measuring is a problem still unsolved. Modelling moisture content based on automatically captured meteorological data could provide a solution. An accurate model would allow the drying period and the point of chipping to be optimised. For the experimental study, a metal frame supported by load sensors and loaded with 17 tons of logwood was set up next to a meteorological station. A multiple linear regression model was used to link meteorological and load data to provide a formula for determining the moisture content. The pile dried for a period of 14 months (average temperature of 7.3 °C, a humidity of 81%, and 777 mm of rainfall). The overall moisture content dropped from 50.1% to 32.2%. The regression model, which based on daily means and sums of meteorological parameters, provided a mean deviance from the observed curve of –0.51%±0.71% within the period of investigation. Relative humidity was found to be most important parameter in drying. Increased moisture content resulting from rainfall greater than 30 mm per day reverted back to pre-rainfall values within two to three days, if no other rainfall events followed. Covering the pile would have a positive effect on the drying performance. In terms of economic benefit it could be shown that natural drying is beneficial. Overall this study shows that meteorological data used in site specific drying models can adequately predict the moisture content of naturally dried logwood.
  • Erber, University of Natural Resources and Life Sciences, Peter Jordan-Strasse 82, 1190 Wien, Austria ORCID ID:E-mail: gernot.erber@boku.ac.at (email)
  • Kanzian, University of Natural Resources and Life Sciences, Peter Jordan-Strasse 82, 1190 Wien, Austria ORCID ID:E-mail: christian.kanzian@boku.ac.at
  • Stampfer, University of Natural Resources and Life Sciences, Peter Jordan-Strasse 82, 1190 Wien, Austria ORCID ID:E-mail: karl.stampfer@boku.ac.at
article id 51, category Research article
Sanna Hautamäki, Antti Mutanen, Jari Viitanen. (2012). Substitution in the Finnish forest industry’s roundwood procurement. Silva Fennica vol. 46 no. 3 article id 51. https://doi.org/10.14214/sf.51
In this study, the interaction and substitution between domestic and imported roundwood in the Finnish forest industry’s wood procurement is analysed by timber assortments. The results from the translog cost function approach and quarterly data of the total wood procurement and its components during the euro regime indicate that, to a certain extent, the Finnish forest industry has had the possibility of substituting imported roundwood volumes between countries in the Baltic Sea region. Contrary to earlier studies, also in the case of Russian birch pulpwood, the most important imported timber assortment, the results suggest that Russian birch pulpwood has rather substituted for than complemented the domestic supply in Finland. The increase in roundwood export duties in Russia has had a statistically significant effect on the trade in birch pulpwood and spruce sawlogs. Moreover, the results confirm the earlier findings of a rigid demand for roundwood in Finnish roundwood markets.
  • Hautamäki, Finnish Forest Research Institute, Joensuu Unit, P.O. Box 68, FI-80101 Joensuu, Finland ORCID ID:E-mail:
  • Mutanen, Finnish Forest Research Institute, Joensuu Unit, P.O. Box 68, FI-80101 Joensuu, Finland ORCID ID:E-mail: antti.mutanen@metla.fi (email)
  • Viitanen, Finnish Forest Research Institute, Joensuu Unit, P.O. Box 68, FI-80101 Joensuu, Finland ORCID ID:E-mail:
article id 48, category Research article
Jyrki Hytönen, Lasse Aro. (2012). Biomass and nutrition of naturally regenerated and coppiced birch on cutaway peatland during 37 years. Silva Fennica vol. 46 no. 3 article id 48. https://doi.org/10.14214/sf.48
Biomass production and nutrient use of birch thickets with a mixture of willow on a cut away peatland in southern Finland over a period of 37 years was studied. Dense, naturally regenerated 16-year-old birch stands were cut down, fertilized with either wood ash (P 108 and K 339 kg ha–1) or PK fertilizer (P 50 and K 95 kg ha–1) or left unfertilized. The biomass production of the coppiced stands and one uncut stand was monitored for a period of 21 years. Soil nutrient and foliar nutrient concentrations were analyzed several times during the study period. Ash fertilization supplied more nutrients than PK fertilization and increased the soil nutrient amounts more. The foliar phosphorus concentration of birch on control plots indicated a severe phosphorus deficiency which was removed by PK and ash fertilization. Fertilization did not increase nutrient concentrations of the stem (wood + bark) nor the amount of nutrients bound in the biomass. Two energy wood rotations (16+21 years) produced 124–158 Mg ha–1 of leafless, above-ground biomass altogether corresponding to 61–78 Mg ha–1 of carbon. The highest biomass yield was achieved with a rotation of 37 years in the uncut stand (211 Mg ha–1). Corresponding values for mean annual increment (MAI) were 3.4–4.3 Mg ha–1 and 5.7 Mg ha–1. This study shows that the length of the rotation for birch in energy wood production should be longer than 21 years. PK and ash fertilization increased the biomass of coppiced 21-year-old birch by 23 Mg ha–1 and 33 Mg ha–1, respectively.
  • Hytönen, Finnish Forest Research Institute, Kannus, Finland ORCID ID:E-mail: jyrki.hytonen@metla.fi (email)
  • Aro, Finnish Forest Research Institute, Kannus, Finland ORCID ID:E-mail: lasse.aro@metla.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 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 43, category Research article
Anni Markkanen, Panu Halme. (2012). Polypore communities in broadleaved boreal forests. Silva Fennica vol. 46 no. 3 article id 43. https://doi.org/10.14214/sf.43
The cover and extent of boreal broadleaved forests have been decreasing due to modern forest management practices and fire suppression. As decomposers of woody material, polypores are ecologically important ecosystem engineers. The ecology and conservation biology of polypores have been studied intensively in boreal coniferous forests. However, only a few studies have focused on the species living on broadleaved trees. To increase knowledge on this species group we conducted polypore surveys in 27 broadleaved forests and 303 forest compartments (539 ha) on the southern boreal zone in Finland and measured dead wood and forest characteristics. We detected altogether 98 polypore species, of which 13 are red-listed in Finland. 60% of the recorded species are primarily associated with broadleaved trees. The number of species in a local community present in a broadleaved forest covered approximately 50 species, of which 30–40 were primarily associated with broadleaved trees. The size of the inventoried area explained 67% of the variation in the species richness, but unlike in previous studies conducted in coniferous forests, dead wood variables as well as forest structure had very limited power in explaining polypore species richness on forest stand level. The compartments occupied by red listed Protomerulius caryae had an especially high volume of living birch, but otherwise the occurrences of red-listed species could not be predicted based on the forest structure.
  • Markkanen, Department of Biological and Environmental Science, P.O. Box 35, FI-40014 University of Jyväskylä, Finland ORCID ID:E-mail: anni.e.markkanen@gmail.com (email)
  • Halme, Department of Biological and Environmental Science, P.O. Box 35, FI-40014 University of Jyväskylä, Finland ORCID ID:E-mail:
article id 87, category Research article
Radek Bace, Miroslav Svoboda, Pavel Janda. (2011). Density and height structure of seedlings in subalpine spruce forests of Central Europe: logs vs. stumps as a favourable substrate. Silva Fennica vol. 45 no. 5 article id 87. https://doi.org/10.14214/sf.87
Decaying logs and stumps provide an important seedling substrate in natural subalpine forests. However, only stumps present such a role in managed forests. The aim of this study was to assess the differences in the process of seedling colonization between logs and stumps. The study was carried out in the Czech Republic, in two old-growth subalpine spruce forests located in the Bohemian Forest and Ash Mts., dominated by Athyrium distentifolium Opiz and Vaccinium myrtillus L. undergrowth, respectively. Norway spruce (Picea abies (L.) Karst.) regeneration growing on logs, stumps and non-coarse woody debris (CWD) microsites was surveyed. Regeneration (height 0–2.0 m) densities exceeded 5000 individuals per ha on both sites. The average density of P. abies regeneration per square meter of substrate was 0.3-5.7-19.6 and 0.5-3.8-11.0 on non-CWD microsites, logs and stumps, located in A. distentifolium and V. myrtillus undergrowth, respectively. Stumps and non-CWD microsites dominated by V. myrtillus, supported a higher proportion of taller seedlings per plot compared to the small seedlings growing on logs and non-CWD dominated by A. distentifolium ground-cover. The disproportion in regeneration densities between the stumps and the original logs decreased with increasing stages of decay. The tallest regeneration growing on stumps (root-soil plates) was significantly older than that growing on the logs (stems). Based on these two latter findings, the stumps appeared to provide suitable seedling substrates several years earlier than the logs did. Therefore, we conclude that the stumps play a more important role (relative to their covered area, 21–28 m2 ha–1) in terms of suitable microsites for regeneration, than the logs do.
  • Bace, Czech University of Life Sciences, Faculty of Forestry and Wood Sciences, Prague, Czech Republic ORCID ID:E-mail: bace@fld.czu.cz (email)
  • Svoboda, Czech University of Life Sciences, Faculty of Forestry and Wood Sciences, Prague, Czech Republic ORCID ID:E-mail:
  • Janda, Czech University of Life Sciences, Faculty of Forestry and Wood Sciences, Prague, Czech Republic 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 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 78, category Research article
Kris Vandekerkhove, Luc De Keersmaeker, Ruben Walleyn, Frank Köhler, Luc Crevecoeur, Leen Govaere, Arno Thomaes, Kris Verheyen. (2011). Reappearance of old-growth elements in lowland woodlands in northern Belgium: Do the associated species follow? Silva Fennica vol. 45 no. 5 article id 78. https://doi.org/10.14214/sf.78
The forest cover of the western European lowland plain has been very low for centuries. Remaining forests were intensively managed, and old-growth elements like veteran trees and coarse woody debris became virtually absent. Only over the last decades have these old-growth elements progressively redeveloped in parks, lanes and forests, and have now reached their highest level over the last 500–1000 years. Biodiversity associated with these old-growth elements makes up an important part of overall forest biodiversity. The ability of species to recolonise the newly available habitat is strongly determined by limitations in their dispersal and establishment. We analyse the current status and development of old-growth elements in Flanders (northern Belgium) and the process of recolonisation by means of specific cases, focussing on saproxylic fungi and saproxylic beetles. Our results show that ‘hotspots’ of secondary old growth, even isolated small patches, may have more potential for specialised biodiversity than expected, and may provide important new strongholds for recovery and recolonisation of an important share of old-growth related species.
  • Vandekerkhove, INBO, Gaverstraat 4, B-9500 Geraardsbergen, Belgium ORCID ID:E-mail: kris.vandekerkhove@inbo.be (email)
  • De Keersmaeker, INBO, Gaverstraat 4, B-9500 Geraardsbergen, Belgium ORCID ID:E-mail:
  • Walleyn, INBO, Gaverstraat 4, B-9500 Geraardsbergen, Belgium ORCID ID:E-mail:
  • Köhler, Koleopterologisches Forschungsbüro, Bornheim, Germany ORCID ID:E-mail:
  • Crevecoeur, Genk, Belgium ORCID ID:E-mail:
  • Govaere, Agency of Nature and Forests, Brussels, Belgium ORCID ID:E-mail:
  • Thomaes, INBO, Gaverstraat 4, B-9500 Geraardsbergen, Belgium ORCID ID:E-mail:
  • Verheyen, Ghent University, Laboratory of Forestry, Gontrode, Belgium ORCID ID:E-mail:
article id 447, category Research article
Jim Kiser. (2011). Histochemical and geometric alterations of sapwood in coastal Douglas-fir following mechanical damage during commercial thinning. Silva Fennica vol. 45 no. 4 article id 447. https://doi.org/10.14214/sf.447
Histochemical and geometric alterations to sapwood in mechanically damaged Douglas-fir (Pseudotsuga menziesii [Mirbel] Franco) trees were quantified 14 years after thinning. Discoloration and decay were measured in felled damaged and undamaged trees. Compartmentalized walls were identified and measured macroscopically. Sapwood to heartwood ratio was measured incrementally along the boles. Results showed a distinct reaction zone forming at the time of injury. Compartmentalized walls 1–3 were less distinct and heavily resinous streaking was evident in extant tissues, particularly in the axial direction. Post-damaged sapwood was burl-like for 4–6 years and tracheids contained resin-filled lumina. Damaged wood volumes were modeled by multiple regression. Wound depth, wound area, and diameter inside bark (DIB) accounted for 73% of the discolored volume (p = 0.02). DIB alone accounted for just over 55% of the response. Post-damaged sapwood averaged 15 mm (SE = 2.3 mm) greater in width on the side opposite the damage along the length of the boards. Wound area explained just over 65% of this response (p = 0.003). Sapwood area was not significantly different between damaged and control trees (p = 0.56). Results indicate that wounded Douglas-fir trees may slow conversion of sapwood to heartwood on the bole side opposite the wound, possibly as a response to maintain sapwood area necessary for physiological maintenance of the existing crown. About 19% of the lower bole volume in damaged trees was affected by discoloration and secondarily by structural changes. Reduction in value of the lower log can be as high as 19% by conventional bucking practices. Alternatives are presented to reduce the value loss to between 2.5% to 3.5%.
  • Kiser, P.O. Box 3729, Pagosa Springs, Colorado, USA ORCID ID:E-mail: jim.kiser@parelli.com (email)
article id 110, category Research article
Erlend Nybakk, Pablo Crespell, Eric Hansen. (2011). Climate for innovation and innovation strategy as drivers for success in the wood industry: moderation effects of firm size, industry sector, and country of operation. Silva Fennica vol. 45 no. 3 article id 110. https://doi.org/10.14214/sf.110
This study examines the relationships between firm financial performance and a) the climate for innovation and b) innovation strategy in the wood products industry. The focus is on the moderator effects of firm size, country of operation, and industry sector. Using a sample of 460 responses from chief executive officers and top managers of Norwegian and US firms, we conducted a regression analysis to probe for interaction effects. The sample included primary and secondary manufacturers of various sizes. Consistent with previous studies, we found a positive impact for both a climate for innovation and an innovation strategy on firm performance. In terms of moderation, only one interaction was found to be significant, representing a moderator effect of industry size on the climate-performance relationship. Further testing showed that secondary, large manufacturers exhibited a weaker, yet still positive, relationship between climate for innovation and performance. This low level of significant interactions suggests stability of the relationship among the main factors depicted in the model, with important implications for managers and future research. These findings indicate that a positive climate for innovation and a management committed to innovation through an innovation strategy have a positive effect on the bottom line of wood products firms. This effect holds true regardless of industry, size, or country, so most firms can benefit from the implementation of these pro-innovation practices.
  • Nybakk, Norwegian Forest and Landscape Institute, P.O. Box 115, N-1431 Ås, Norway ORCID ID:E-mail: nye@skogoglandskap.no (email)
  • Crespell, FPInnovations (Forintek Division), Vancouver, BC, Canada ORCID ID:E-mail:
  • Hansen, Oregon State University, College of Forestry, OR, USA 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 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 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 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 34, category Research article
Natalie Macias, Chris Knowles. (2011). Examining the effect of environmental certification, wood source, and price on architects’ preferences of hardwood flooring. Silva Fennica vol. 45 no. 1 article id 34. https://doi.org/10.14214/sf.34
This article examines the importance architects place on three factors, environmental certification, wood source, and price, when specifying hardwood flooring. Architects were presented with nine flooring scenarios, in which the three factors were present in varying levels. They were asked to rank the scenarios from the least preferred to the most preferred. Data were obtained from a mail survey of architects in Oregon and Washington, U.S.A. (n = 402). Conjoint analyses determined that architects consider price and wood source to be the most important factors when specifying hardwood flooring. Interestingly, environmental certification was considered the least important factor. The respondents were then separated into three groups for further analysis based on whether they identified themselves as more influenced by environmental factors (biocentric) or human needs (anthropocentric). This analysis showed that the biocentric group favored wood source over price and environmental certification, while the anthropocentric group favored price.
  • Macias, Oregon State University, Department of Wood Science and Engineering, 119 Richardson Hall, Corvallis, OR 97331, USA ORCID ID:E-mail: natalie.macias@gmail.com
  • Knowles, Oregon State University, Department of Wood Science and Engineering, 119 Richardson Hall, Corvallis, OR 97331, USA ORCID ID:E-mail: chris.knowles@oregonstate.edu (email)
article id 34, category Research article
Natalie Macias, Chris Knowles. (2011). Examining the effect of environmental certification, wood source, and price on architects’ preferences of hardwood flooring. Silva Fennica vol. 45 no. 1 article id 34. https://doi.org/10.14214/sf.34
This article examines the importance architects place on three factors, environmental certification, wood source, and price, when specifying hardwood flooring. Architects were presented with nine flooring scenarios, in which the three factors were present in varying levels. They were asked to rank the scenarios from the least preferred to the most preferred. Data were obtained from a mail survey of architects in Oregon and Washington, U.S.A. (n = 402). Conjoint analyses determined that architects consider price and wood source to be the most important factors when specifying hardwood flooring. Interestingly, environmental certification was considered the least important factor. The respondents were then separated into three groups for further analysis based on whether they identified themselves as more influenced by environmental factors (biocentric) or human needs (anthropocentric). This analysis showed that the biocentric group favored wood source over price and environmental certification, while the anthropocentric group favored price.
  • Macias, Oregon State University, Department of Wood Science and Engineering, 119 Richardson Hall, Corvallis, OR 97331, USA ORCID ID:E-mail: natalie.macias@gmail.com
  • Knowles, Oregon State University, Department of Wood Science and Engineering, 119 Richardson Hall, Corvallis, OR 97331, USA ORCID ID:E-mail: chris.knowles@oregonstate.edu (email)
article id 454, category Research article
Paula Jylhä, Olli Dahl, Juha Laitila, Kalle Kärhä. (2010). The effect of supply system on the wood paying capability of a kraft pulp mill using Scots pine harvested from first thinnings. Silva Fennica vol. 44 no. 4 article id 454. https://doi.org/10.14214/sf.454
The efficiencies of wood supply systems based on cut-to-length (CTL) harvesting, the harvesting of loose whole trees, and whole-tree bundling were compared using the relative wood paying capabilities (WPC) of a kraft pulp mill as decisive criteria. The WPCs from mill to stump were calculated for three first-thinning stands of Scots pine (Pinus sylvestris L.) with mean breast-height diameter of the removal of 6, 8, and 12 cm. Pulp price had a strong effect on the WPC, and the CTL system resulted in the highest WPC per m3 at stump. The savings in procurement costs and gains in energy generation from additional raw material acquired with the harvesting of loose whole trees did not compensate the losses in pulp production. Considering removal per hectare, loose whole trees gave the highest WPCs at stump in the two stands with the smallest trees and the highest proportion of additional raw material. Decrease in pulp price and increase in energy price improved the competitiveness of the whole-tree systems. In the case of whole-tree bundling, savings in transportation costs did not balance the high cutting and compaction costs, and the bundling system was the least competitive alternative.
  • Jylhä, Finnish Forest Research Institute, Kannus, Finland ORCID ID:E-mail: paula.jylha@metla.fi (email)
  • Dahl, Aalto University School of Science and Technology, Department of Forest Products Technology, Espoo, Finland ORCID ID:E-mail:
  • Laitila, Finnish Forest Research Institute, Joensuu, Finland ORCID ID:E-mail:
  • Kärhä, Metsäteho Oy, Helsinki, Finland ORCID ID:E-mail:
article id 134, category Research article
Dan Bergström, Urban Bergsten, Tomas Nordfjell. (2010). Comparison of boom-corridor thinning and thinning from below harvesting methods in young dense Scots pine stands. Silva Fennica vol. 44 no. 4 article id 134. https://doi.org/10.14214/sf.134
At present, only a small proportion of the potential extractable bioenergy from young dense forests in Sweden is utilized. The conventional mechanized first thinning systems used in such stands suffer from low productivity, so the operation is only profitable in stands with bigger trees and high standing volumes. Conventional harvesters are used for this operation equipped with accumulating felling heads designed for handling several trees during each crane cycle. In thinning from below the felling and bunching work requires many time-consuming non-linear crane movements to avoid felling or damaging of future crop trees. However, higher productivity can be achieved when trees between strip roads are harvested in about 1 m-wide corridors with a length corresponding to the reach of the crane. We refer to this operation as boom-corridor thinning. The objective of this study was to compare felling and bunching productivity in young dense stands when employing thinning from below or boom-corridor thinning. Experiments were performed using a randomized block design involving between 4400 and 18 600 trees x ha-1 with a corresponding average tree size of 7.2 and 3.2 cm dbh, respectively. Based on the average tree being removed at a dbh of 5.7 cm, the productivity (ODt x PW-hour-1) was significant (almost 16%) higher for the boom-corridor thinning than for thinning from below treatment. At the same time, the time taken for the work element “Crane in-between” (the period between the loaded crane starting to move towards a tree and the felling head rapidly slowing down for positioning) was significantly reduced, by almost 17%. The positive results were achieved even though the operator was new to the method. To achieve a significantly higher efficiency during the felling and bunching operation, development of new harvesting equipment and operating techniques seems crucial.
  • Bergström, Swedish University of Agricultural Sciences, Dept of Forest Resource Management, Section of Planning and Operations Management, Umeå, Sweden ORCID ID:E-mail: dan.bergstrom@srh.slu.se (email)
  • Bergsten, Swedish University of Agricultural Sciences, Dept of Forest Resource Management, Section of Planning and Operations Management, Umeå, Sweden ORCID ID:E-mail:
  • Nordfjell, Swedish University of Agricultural Sciences, Dept of Forest Resource Management, Section of Planning and Operations Management, Umeå, Sweden ORCID ID:E-mail:
article id 144, category Research article
Markku Oikari, Kalle Kärhä, Teijo Palander, Heikki Pajuoja, Heikki Ovaskainen. (2010). Analyzing the views of wood harvesting professionals related to the approaches for increasing the cost-efficiency of wood harvesting from young stands. Silva Fennica vol. 44 no. 3 article id 144. https://doi.org/10.14214/sf.144
A lot of viable guidelines are currently available for more cost-effective harvesting of energy wood and industrial roundwood (i.e. pulpwood) from young stands. The study ranked the proposed potential approaches for increasing the cost-efficiency of small-diameter (d1.3 < 10 cm) energy wood and industrial roundwood harvesting from early thinnings. Research data, based on a total of 40 personal interviews, was collected in early 2008. The interviewees were divided into four wood harvesting professional groups: 1) Managers in wood procurement organizations, 2) Forest machine contractors, 3) Forest machine manufacturers and vendors, and 4) Wood harvesting researchers. In the opinion of the respondents, there is great potential to increase the cost-efficiency of wood harvesting through improving harvesting conditions (i.e. effective tending of seedling stands, delaying harvesting operations, and pre-clearance of dense undergrowth). The interviewees also underlined that harvesting methods can be rationalized, e.g. multiple-tree handling in industrial roundwood cuttings, crane scale measurement, integrated wood harvesting, and careful selection of stands for harvesting. The strong message given by the interviewees was that the education of forest machine operators must be made more effective in the future. There would be significant possibilities for cost savings in young stands, if methods and techniques with the most potential were utilized completely in wood harvesting.
  • Oikari, Karelwood, Kontiolahti, Finland ORCID ID:E-mail: markku.oikari@karelwood.com (email)
  • Kärhä, Metsäteho Oy, Helsinki, Finland ORCID ID:E-mail:
  • Palander, University of Eastern Finland, Faculty of Science and Forestry, Joensuu, Finland ORCID ID:E-mail:
  • Pajuoja, Metsäteho Oy, Helsinki, Finland ORCID ID:E-mail:
  • Ovaskainen, University of Eastern Finland, Faculty of Science and Forestry, Joensuu, Finland ORCID ID:E-mail:
article id 144, category Research article
Markku Oikari, Kalle Kärhä, Teijo Palander, Heikki Pajuoja, Heikki Ovaskainen. (2010). Analyzing the views of wood harvesting professionals related to the approaches for increasing the cost-efficiency of wood harvesting from young stands. Silva Fennica vol. 44 no. 3 article id 144. https://doi.org/10.14214/sf.144
A lot of viable guidelines are currently available for more cost-effective harvesting of energy wood and industrial roundwood (i.e. pulpwood) from young stands. The study ranked the proposed potential approaches for increasing the cost-efficiency of small-diameter (d1.3 < 10 cm) energy wood and industrial roundwood harvesting from early thinnings. Research data, based on a total of 40 personal interviews, was collected in early 2008. The interviewees were divided into four wood harvesting professional groups: 1) Managers in wood procurement organizations, 2) Forest machine contractors, 3) Forest machine manufacturers and vendors, and 4) Wood harvesting researchers. In the opinion of the respondents, there is great potential to increase the cost-efficiency of wood harvesting through improving harvesting conditions (i.e. effective tending of seedling stands, delaying harvesting operations, and pre-clearance of dense undergrowth). The interviewees also underlined that harvesting methods can be rationalized, e.g. multiple-tree handling in industrial roundwood cuttings, crane scale measurement, integrated wood harvesting, and careful selection of stands for harvesting. The strong message given by the interviewees was that the education of forest machine operators must be made more effective in the future. There would be significant possibilities for cost savings in young stands, if methods and techniques with the most potential were utilized completely in wood harvesting.
  • Oikari, Karelwood, Kontiolahti, Finland ORCID ID:E-mail: markku.oikari@karelwood.com (email)
  • Kärhä, Metsäteho Oy, Helsinki, Finland ORCID ID:E-mail:
  • Palander, University of Eastern Finland, Faculty of Science and Forestry, Joensuu, Finland ORCID ID:E-mail:
  • Pajuoja, Metsäteho Oy, Helsinki, Finland ORCID ID:E-mail:
  • Ovaskainen, University of Eastern Finland, Faculty of Science and Forestry, Joensuu, Finland ORCID ID:E-mail:
article id 143, category Research article
Juha Laitila, Jani Heikkilä, Perttu Anttila. (2010). Harvesting alternatives, accumulation and procurement cost of small-diameter thinning wood for fuel in Central Finland. Silva Fennica vol. 44 no. 3 article id 143. https://doi.org/10.14214/sf.143
This study compared harvesting alternatives, accumulation and procurement costs of small-diameter thinning wood chips for fuel, when trees were harvested either as delimbed stemwood or whole trees. The calculation was made for a hypothetical plant located in Central Finland and the radius of the procurement area was 100 km via the existing road network. Cutting was done with conventional harvester head equipped with multi-tree-handling (MTH) accessories, with the logged trees being chipped at the roadside storage. The cost of delimbed stemwood chips at heating plant was 24% higher compared to the cost of whole tree chips. The availability analysis attested that delimbing lowered the regional cutting removal by 42% compared to the whole tree harvesting, when the minimum accumulation for the fuel fraction at the stand was set at 25 m3/ha. Delimbing diminishes the recovery rate at the site, resulting in a diminishing number of potential recovery sites meeting the threshold volume. However, the study showed that the forest energy potential is increased and procurement costs are reduced, if delimbed stemwood is harvested from stands where the whole tree harvesting is not acceptable due to nutrient loss or for other ecological reasons. Intelligent selection of cutting methods for different stands enables minimization of transport distance and control of procurement cost.
  • Laitila, The Finnish Forest Research Institute, Joensuu, Finland ORCID ID:E-mail: juha.laitila@metla.fi (email)
  • Heikkilä, L&T Biowatti Oy, Seinäjoki, Finland ORCID ID:E-mail:
  • Anttila, The Finnish Forest Research Institute, Joensuu, Finland ORCID ID:E-mail:
article id 140, category Research article
Jussi Laurila, Risto Lauhanen. (2010). Moisture content of Norway spruce stump wood at clear cutting areas and roadside storage sites. Silva Fennica vol. 44 no. 3 article id 140. https://doi.org/10.14214/sf.140
Norway spruce (Picea abies (L.) Karst.) stump wood is a potential source of bioenergy in Finland. The heating value of stump wood depends on, among other things, the moisture, carbon and ash content of the wood. In this study the moisture content of Norway spruce stump wood was examined immediately after harvesting at the clear cutting area and after different drying times at the roadside storage sites. Immediately after stump harvesting the average moisture content (wet basis) was 53%. The stump wood dried fairly fast during spring and summer. One month after stump harvesting, the average moisture content was about 31%. If the stump wood had dried well once, water absorption became very weak and the moisture content increased only slightly in the late autumn. Each spring and summer the moisture content of the stumps was lower than during the previous year. Annually the lowest moisture content was observed at the beginning of July and the highest at both the beginning and the end of the year. The moisture content of stump wood followed an upwards opening parabola over a one year period and was repeated each year. Three years after harvesting the heating value of the stump wood was still 5.241 MWh/ton. Overall, when harvesting took place in the spring or early summer, the stump wood was combustible after a one month drying period immediately after harvesting.
  • Laurila, Seinäjoki University of Applied Sciences, School of Agriculture and Forestry, FI-63700 Ähtäri, Finland ORCID ID:E-mail: jussi.laurila@seamk.fi (email)
  • Lauhanen, Seinäjoki University of Applied Sciences, School of Agriculture and Forestry, FI-63700 Ähtäri, Finland ORCID ID:E-mail:
article id 139, category Research article
Ulf Sikström, Curt Almqvist, Gunnar Jansson. (2010). Growth of Pinus sylvestris after the application of wood ash or P and K fertilizer to a peatland in southern Sweden. Silva Fennica vol. 44 no. 3 article id 139. https://doi.org/10.14214/sf.139
The effects of the application of wood ash and of fertilizer regimes including phosphorus (P) and potassium (K), with and without simultaneous addition of nitrogen (N), were investigated on a stand of Scots pine (Pinus sylvestris L.) saplings growing on a drained oligotrophic peatland site in southern Sweden. A randomized block design was used. Tree growth and concentrations of various elements in the needles were measured. The addition of similar doses of P (approx. 40 kg P ha–1) from different sources resulted in similar growth responses, amounting to 1.6–1.9 m3 ha–1 yr–1 of stem wood over the 26-year study. The P source was either wood ash (2500 kg d.w. ha–1) or PK-fertilizer (raw phosphate and potassium chloride). In response to several treatments there were both increased numbers of trees and increased growth of individual trees. The high PK-dose (40 kg P ha–1 and 80 kg K ha–1) appeared to result in a larger growth increase than the low dose (20 kg P ha–1 and 40 kg K ha–1). The N treatment had no additional effect on growth. In the control plots, tree growth was more or less negligible (0.04 m3 ha–1 yr–1). After almost 26 years, concentrations of P and K in the needles of treated plants were still higher than in the untreated control plants. Nevertheless, in spite of the elevated P concentration, P appears to limit the growth of Scots pine. In conclusion, after sufficient drainage of this type of peatland site, it is possible for a forest stand to develop to the pole stage if wood ash or PK-fertilizer is applied.
  • Sikström, Skogforsk (The Forestry Research Institute of Sweden), Uppsala Science Park, SE-751 83 Uppsala, Sweden ORCID ID:E-mail: ulf.sikstrom@skogforsk.se (email)
  • Almqvist, Skogforsk (The Forestry Research Institute of Sweden), Uppsala Science Park, SE-751 83 Uppsala, Sweden ORCID ID:E-mail:
  • Jansson, Skogforsk (The Forestry Research Institute of Sweden), Uppsala Science Park, SE-751 83 Uppsala, Sweden ORCID ID:E-mail:
article id 153, category Research article
Dirk Bieker, Steffen Rust. (2010). Non-destructive estimation of sapwood and heartwood width in Scots pine (Pinus sylvestris L.). Silva Fennica vol. 44 no. 2 article id 153. https://doi.org/10.14214/sf.153
Accurate estimates of the water conducting sapwood area are necessary to scale sapflow measurements to tree and stand level transpiration. We tested a non-destructive method, electric resistivity tomography (ERT), to estimate the area of conductive sapwood in 9 Pinus sylvestris L. trees in lower Saxony, Germany. Tomograms were compared to cross-sections stained with benzidine after harvesting. All tomograms displayed a distinct pattern of low resistivity at the stem perimeter and high resistivity in the stem centre with a steep increase in resistivity in between, assumed to indicate the transition from sapwood to heartwood. The tomograms showed a sapwood width 2 cm smaller than the staining method. This indicates that staining methods overestimate the amount of active sapwood because when heartwood is formed, moisture content decreases before extractive contents reach levels visible by staining. The ERT method is a new powerful method for the non-destructive estimation of sapwood and heartwood width.
  • Bieker, University of Applied Sciences and Arts, Faculty of Resource Management, Büsgenweg 1a, D-37077 Göttingen, Germany ORCID ID:E-mail:
  • Rust, University of Applied Sciences and Arts, Faculty of Resource Management, Büsgenweg 1a, D-37077 Göttingen, Germany ORCID ID:E-mail: rust@hawk-hhg.de (email)
article id 150, category Research article
Sini Eräjää, Panu Halme, Janne S. Kotiaho, Anni Markkanen, Tero Toivanen. (2010). The volume and composition of dead wood on traditional and forest fuel harvested clear-cuts. Silva Fennica vol. 44 no. 2 article id 150. https://doi.org/10.14214/sf.150
Logging residue and cut stumps are increasingly used as a renewable energy source known as forest fuel. Forest fuel harvesting obviously reduces the volume of dead wood and is likely to alter the dead wood composition, but the magnitude of the change is not known. Such information is important for the evaluation of the effects of forest fuel harvesting on biodiversity because a large proportion of forest dwelling species are directly dependent on dead wood. We measured the volume and characteristics of all dead wood units with a minimum diameter of 2 cm and a minimum length of 20 cm on 10 forest-fuel harvested and 10 traditional (control) clear-cuts. The total volume of dead wood at forest fuel harvested and control clear-cuts was 26.0 and 42.3 m3/ha, respectively. The volumes were much greater than expected suggesting that the volume of dead wood on clear-cuts has been underestimated in previous studies. Forest fuel harvested clear-cuts had 42% less branches and 81% less cut stumps than control clear-cuts but there were no differences in the volume of logs and pieces of logs, snags or roots. The volume of fine woody debris was negatively affected by forest fuel harvesting. We conclude that fine woody debris and cut stumps form a considerable resource on clear-cuts that is reduced by forest fuel harvesting. These components of dead wood have potential to be of importance in managed forests and thus deserve more attention in future biodiversity studies.
  • Eräjää, Department of Biological and Environmental Science, P.O. Box 35, FI-40014 University of Jyväskylä, Finland ORCID ID:E-mail:
  • 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 (email)
  • Kotiaho, Department of Biological and Environmental Science, P.O. Box 35, FI-40014 University of Jyväskylä, Finland ORCID ID:E-mail:
  • Markkanen, Department of Biological and Environmental Science, P.O. Box 35, FI-40014 University of Jyväskylä, Finland ORCID ID:E-mail:
  • Toivanen, Department of Biological and Environmental Science, P.O. Box 35, FI-40014 University of Jyväskylä, Finland ORCID ID:E-mail:
article id 150, category Research article
Sini Eräjää, Panu Halme, Janne S. Kotiaho, Anni Markkanen, Tero Toivanen. (2010). The volume and composition of dead wood on traditional and forest fuel harvested clear-cuts. Silva Fennica vol. 44 no. 2 article id 150. https://doi.org/10.14214/sf.150
Logging residue and cut stumps are increasingly used as a renewable energy source known as forest fuel. Forest fuel harvesting obviously reduces the volume of dead wood and is likely to alter the dead wood composition, but the magnitude of the change is not known. Such information is important for the evaluation of the effects of forest fuel harvesting on biodiversity because a large proportion of forest dwelling species are directly dependent on dead wood. We measured the volume and characteristics of all dead wood units with a minimum diameter of 2 cm and a minimum length of 20 cm on 10 forest-fuel harvested and 10 traditional (control) clear-cuts. The total volume of dead wood at forest fuel harvested and control clear-cuts was 26.0 and 42.3 m3/ha, respectively. The volumes were much greater than expected suggesting that the volume of dead wood on clear-cuts has been underestimated in previous studies. Forest fuel harvested clear-cuts had 42% less branches and 81% less cut stumps than control clear-cuts but there were no differences in the volume of logs and pieces of logs, snags or roots. The volume of fine woody debris was negatively affected by forest fuel harvesting. We conclude that fine woody debris and cut stumps form a considerable resource on clear-cuts that is reduced by forest fuel harvesting. These components of dead wood have potential to be of importance in managed forests and thus deserve more attention in future biodiversity studies.
  • Eräjää, Department of Biological and Environmental Science, P.O. Box 35, FI-40014 University of Jyväskylä, Finland ORCID ID:E-mail:
  • 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 (email)
  • Kotiaho, Department of Biological and Environmental Science, P.O. Box 35, FI-40014 University of Jyväskylä, Finland ORCID ID:E-mail:
  • Markkanen, Department of Biological and Environmental Science, P.O. Box 35, FI-40014 University of Jyväskylä, Finland ORCID ID:E-mail:
  • Toivanen, Department of Biological and Environmental Science, P.O. Box 35, FI-40014 University of Jyväskylä, Finland ORCID ID:E-mail:
article id 166, category Research article
Kim Pingoud, Johanna Pohjola, Lauri Valsta. (2010). Assessing the integrated climatic impacts of forestry and wood products. Silva Fennica vol. 44 no. 1 article id 166. https://doi.org/10.14214/sf.166
Managed forests serve as a store of carbon (C) and a renewable source of energy and materials. By using forest products as substitutes for fossil fuels or non-renewable materials, emissions from fossil C sources can be displaced. The efficiency of emissions displacement depends on the product, its lifecycle and the fossil-fuel based reference system that is substituted. Forest management practices have an impact on C stocks in biomass and on the annual supply of products and their mix. There are trade-offs between sequestering C stocks in forests and the climatic benefits obtained by sustainable forest harvesting and using wood products to displace fossil C emissions. This article presents an integrated, steady-state analysis comparing various equilibrium states of managed forests and wood product pools that represent sustainable long-term forestry and wood-use strategies. Two climatic indicators are used: the combined C stock in forests and wood products and the fossil C emissions displaced annually by harvested wood products. The study indicates that long-term strategies could be available that are better according to both indicators than forestry practices based on the existing silvicultural guidelines in Finland. These strategies would involve increasing the basal area and prolonging rotations to produce more sawlogs. Further, the climate benefits appear to be highest in case the sawlog supply is directed to production of long-lived materials substituting for fossil-emission and energy intensive materials and recycled after their useful life to bioenergy.
  • Pingoud, VTT Technical Research Centre of Finland, P.O. Box 1000, FI-02044 VTT, Espoo, Finland ORCID ID:E-mail: kim.pingoud@vtt.fi (email)
  • Pohjola, University of Helsinki, Department of Forest Sciences, P.O. Box 27, FI-00014 University of Helsinki, Finland ORCID ID:E-mail:
  • Valsta, University of Helsinki, Department of Forest Sciences, P.O. Box 27, FI-00014 University of Helsinki, Finland ORCID ID:E-mail:
article id 460, category Research article
Hong Ling, Sandhya Samarasinghe, G. Don Kulasiri. (2009). Modelling variability in full-field displacement profiles and Poisson ratio of wood in compression using stochastic neural networks. Silva Fennica vol. 43 no. 5 article id 460. https://doi.org/10.14214/sf.460
Vertical and horizontal displacement profiles in compression parallel-to-grain in a 20 x 20 mm area (30 x 21 or 630 points) in the Tangential–Longitudinal (T–L) and Radial Longitudinal (R–L) sections of small wood columns were obtained from digital image correlation applied to simultaneously captured images of the two surfaces. These consisted of 21 displacement realisations of 30 points along the length of the specimen. They revealed considerable local variations. Stochastic neural networks were successfully developed to simulate trends and noise across and along a specimen in both displacements as well as Poisson ratios in T–L and R–L sections for two selected load levels of 20kN and 40kN. These networks specifically embed noise characteristics extracted from data to generate realistic displacement and Poisson ratio realisations with inherent variability. Models were successfully validated using independent data extracted based on bootstrapping method with high accuracy with R2 ranging from 0.79 to 0.91. The models were further validated successfully using a second approach involving Confidence Intervals generated from the data extracted from the models. Models and experimental results revealed that for 20kN load, both vertical and horizontal displacements in T–L section were less heterogeneous across the specimen (smaller vertical shearing and horizontal strain, respectively) than those in the R–L section. For the 40kN load, both displacement profiles in the T–L section were less noisy and more compact than those for the 20kN load indicating less heterogeneity due to compaction of structure. In the R–L section, larger vertical shearing and horizontal strains persisted at 40 kN load. Poisson ratio decreased with load and it was nonlinear in both sections but T–L section showed much less noise across the specimen than the R–L section.
  • Ling, Centre for Advanced Computational Solutions (C-fACS), Lincoln University, Canterbury, New Zealand ORCID ID:E-mail:
  • Samarasinghe, Centre for Advanced Computational Solutions (C-fACS), Lincoln University, Canterbury, New Zealand ORCID ID:E-mail: sandhya.samarasinghe@lincoln.ac.nz (email)
  • Kulasiri, Centre for Advanced Computational Solutions (C-fACS), Lincoln University, Canterbury, New Zealand ORCID ID:E-mail:
article id 190, category Research article
Katri Luostarinen, Veikko Möttönen. (2009). Effect of felling season, storage and drying on colour of silver birch (Betula pendula) wood from four different growing sites. Silva Fennica vol. 43 no. 4 article id 190. https://doi.org/10.14214/sf.190
Darkening of birch wood during artificial drying is a significant problem regarding the use of its timber as raw material by the mechanical wood industry. In the future, an increasing proportion of birch timber will be obtained from plantation forests, which differ from natural forests in many respects. In this investigation sample boards of Betula pendula, both from naturally regenerated stands and plantations, were sawn into the dimensions used as raw material for parquet billets. Growing site, felling season, and storage of logs were taken into account as possible factors affecting wood colour changes during drying. The wood of birches from fertile plantations remained lighter-coloured during conventional drying than the wood of naturally regenerated birches from low- and medium-fertile stands. The reason may be the difference in tree age and growth rate between natural and planted stands. Thus, it could be beneficial to grow birch in fertile stands so that the trees reach log size as young as possible. The results of this study emphasise the good quality of the birch wood from planted stands compared to natural stands with regard to its colour.
  • Luostarinen, Faculty of Forest Sciences, University of Joensuu, P.O. Box 111, FI-80101 Joensuu, Finland ORCID ID:E-mail: katri.luostarinen@joensuu.fi (email)
  • Möttönen, Department of Mechanical Engineering, Lappeenranta University of Technology, P.O. Box 20, FI-53851 Lappeenranta, Finland ORCID ID:E-mail:
article id 189, category Research article
Lars Rytter, Gunnar Jansson. (2009). Influence of pruning on wood characters in hybrid aspen. Silva Fennica vol. 43 no. 4 article id 189. https://doi.org/10.14214/sf.189
Fast-growing hybrid aspens (Populus tremula L. x P. tremuloides Michx.) are currently of great interest in Sweden since they can produce biomass at high rates and, at the same time, can be used to produce higher value wood products. This study focuses on the effects of pruning hybrid aspen to improve its wood quality. About 50% of the trees in the experimental stand were pruned by removing twigs, at heights up to 4 m, when they were 7–8 years old. Ten years later, 20 pruned and 20 unpruned trees, representing four clones, were randomly selected. Ten knots or twig/stem junctions, respectively, per tree were exposed for inspection using a chain saw and examined. The results revealed that pruned trees cicatrised the knots within about three years and thereafter produced substantial amounts of faultless wood. In contrast, unpruned trees (which had retained almost 80% of their twigs, often as dry twigs with bark pockets) had produced small uneven amounts of quality wood. Removal of twigs with acute angles and/or large diameters resulted in greater colour defects and rot in annual rings outside the pruning position, but the time of cicatrisation was not significantly affected. The results show that pruning can be used to enhance the wood quality of hybrid aspen over a short time period, and that pruning should be performed early during the rotation period when branches are small, in order to minimize discolouration and rot in the new annual rings.
  • Rytter, The Forestry Research Institute of Sweden (Skogforsk), Ekebo 2250, SE-26890 Svalöv ORCID ID:E-mail: lars.rytter@skogforsk.se (email)
  • Jansson, The Forestry Research Institute of Sweden (Skogforsk), Uppsala Science Park, SE-751 83 Uppsala ORCID ID:E-mail:
article id 187, category Research article
Tobias Biechele, Leif Nutto, Gero Becker. (2009). Growth strain in Eucalyptus nitens at different stages of development. Silva Fennica vol. 43 no. 4 article id 187. https://doi.org/10.14214/sf.187
Eucalypts are renowned for their high growth stress levels. These stresses cause splitting, warping and dimensional instability when cutting, processing and drying the wood. In Chile, large Eucalyptus nitens plantations can be found, which, due to these problems, are scarcely utilised for solid wood products (veneer, sawn wood). This study aims to determine the factors influencing growth stress at different stages of tree’s development, and to identify whether the factors influencing growth stress change over time. In five stands of different ages, growth strain, as an indicator of growth stress, was measured at different tree heights with the single hole drilling method. The tree variables DBH, tree height, slenderness (height/diameter ratio) and crown parameters also were measured. A correlation analysis of tree variables and growth strains was undertaken. The results obtained indicate a high variability in growth strain values. It was concluded that growth strain is not correlated with a single growth parameter, but with a combination of factors that variously influence it at different ages and tree heights.
  • Biechele, University of Freiburg, Institute of Forest Utilisation and Work Science, Werthmannstr. 6, DE-79085 Freiburg, Germany ORCID ID:E-mail: tobias.biechele@fobawi.uni-freiburg.de (email)
  • Nutto, University of Freiburg, Institute of Forest Utilisation and Work Science, Werthmannstr. 6, DE-79085 Freiburg, Germany ORCID ID:E-mail:
  • Becker, University of Freiburg, Institute of Forest Utilisation and Work Science, Werthmannstr. 6, DE-79085 Freiburg, Germany ORCID ID:E-mail:
article id 204, category Research article
Gaby Deckmyn, Bostjan Mali, Hojka Kraigher, Niko Torelli, Maarten Op de Beeck, Reinhart Ceulemans. (2009). Using the process-based stand model ANAFORE including Bayesian optimisation to predict wood quality and quantity and their uncertainty in Slovenian beech. Silva Fennica vol. 43 no. 3 article id 204. https://doi.org/10.14214/sf.204
The purpose of this study was to expand an existing semi-mechanistic forest model, ANAFORE (ANAlysing Forest Ecosystems), to allow for the prediction of log quality and the accompanying uncertainty as influenced by climate and management. The forest stand is described as consisting of trees of different cohorts, either of the same or of different species (deciduous or coniferous). In addition to photosynthesis, transpiration, total growth and yield, the model simulates the daily evolution in vessel biomass and radius, parenchyma and branch development. From these data early and latewood biomass, wood tissue composition, knot formation and density are calculated. The new version presented here, includes the description of log quality, including red heart formation of beeches. A Bayesian optimisation routine for the species parameters was added to the stand model. From a given range of input parameters (prior), the model calculates an optimised range for the parameters (posterior) based on given output data, as well as an uncertainty on the predicted values. A case study was performed for Slovenian beech forests to illustrate the main model functioning and more in particular the simulation of the wood quality. The results indicate that the ANAFORE model is a useful tool for analyzing wood quality development and forest ecosystem functioning in response to management, climate and stand characteristics. However, the Bayesian optimization showed that the remaining uncertainty on the input parameters for the chosen stand was very large, due to the large number of input parameters in comparison to the limited stand data.
  • Deckmyn, Research Group Plant and Vegetation Ecology, University of Antwerpen, Universiteitsplein 1, 2610 Antwerpen, Belgium ORCID ID:E-mail: gaby.deckmyn@ua.ac.be (email)
  • Mali, Slovenian Forestry Institute, Vecna pot 2, 1000 Ljubljana, Slovenia ORCID ID:E-mail:
  • Kraigher, Slovenian Forestry Institute, Vecna pot 2, 1000 Ljubljana, Slovenia ORCID ID:E-mail:
  • Torelli, Slovenian Forestry Institute, Vecna pot 2, 1000 Ljubljana, Slovenia ORCID ID:E-mail:
  • Op de Beeck, Research Group Plant and Vegetation Ecology, University of Antwerpen, Universiteitsplein 1, 2610 Antwerpen, Belgium ORCID ID:E-mail:
  • Ceulemans, Research Group Plant and Vegetation Ecology, University of Antwerpen, Universiteitsplein 1, 2610 Antwerpen, Belgium ORCID ID:E-mail:
article id 202, category Research article
Tuula Nuutinen, Antti Kilpeläinen, Hannu Hirvelä, Kari Härkönen, Veli-Pekka Ikonen, Reetta Lempinen, Heli Peltola, Lars Wilhelmsson, Seppo Kellomäki. (2009). Future wood and fibre sources – case North Karelia in eastern Finland. Silva Fennica vol. 43 no. 3 article id 202. https://doi.org/10.14214/sf.202
Information on the potential wood supply is important for the wood industry. In this study, the future development of growing stock, cutting potential and wood properties corresponding to the regional scenario of North Karelian Forest Programme 2006–2010 was analysed. The simulations were performed by employing the Finnish MELA system together with the sample plot and tree data of the 9th Finnish National Forest Inventory (NFI9) as initial data for the simulations. Disc-based models for basic wood density, proportion of latewood and fibre length of Norway spruce and Scots pine in Sweden were calibrated and integrated into the MELA system. The wood properties at breast height of both harvested and standing trees were analysed in different strata (age, site type and cutting method) during the scenario period of 50 years (2002–2052). The average wood properties within the same strata varied only slightly over time. However, the results for different strata differed considerably. In general, wood density, fibre length and proportion of latewood increased, on average, as a function of tree age and along with a decrease in site fertility (excl. wood density and proportion of latewood in harvested Norway spruce in the first case and fibre length in the latter case for both species). For trees less than 80 years, properties in harvested trees were equal to or slightly greater than those of standing trees. The values for clear-cuttings were greater or equal to those of thinnings (excl. wood density and proportion of latewood in Norway spruce). The study demonstrates the value of model-based analyses utilising NFI tree measurements in regions that are considered to be sources of raw material.
  • Nuutinen, European Forest Institute, Torikatu 34, FI-80100 Joensuu, Finland ORCID ID:E-mail: tuula.nuutinen@efi.int (email)
  • Kilpeläinen, University of Joensuu, Faculty of Forest Sciences, P.O. Box 111, FI-80101 Joensuu, Finland ORCID ID:E-mail:
  • Hirvelä, Finnish Forest Research Institute, P.O. Box 18, FI-01301 Vantaa, Finland ORCID ID:E-mail:
  • Härkönen, Finnish Forest Research Institute, P.O. Box 18, FI-01301 Vantaa, Finland ORCID ID:E-mail:
  • Ikonen, University of Joensuu, Faculty of Forest Sciences, P.O. Box 111, FI-80101 Joensuu, Finland ORCID ID:E-mail:
  • Lempinen, Finnish Forest Research Institute, P.O. Box 68, FI-80101 Joensuu, Finland ORCID ID:E-mail:
  • Peltola, University of Joensuu, Faculty of Forest Sciences, P.O. Box 111, FI-80101 Joensuu, Finland ORCID ID:E-mail:
  • Wilhelmsson, Skogforsk, Uppsala Science Park, SE-751 83 Uppsala, Sweden ORCID ID:E-mail:
  • Kellomäki, University of Joensuu, Faculty of Forest Sciences, P.O. Box 111, FI-80101 Joensuu, Finland ORCID ID:E-mail:
article id 202, category Research article
Tuula Nuutinen, Antti Kilpeläinen, Hannu Hirvelä, Kari Härkönen, Veli-Pekka Ikonen, Reetta Lempinen, Heli Peltola, Lars Wilhelmsson, Seppo Kellomäki. (2009). Future wood and fibre sources – case North Karelia in eastern Finland. Silva Fennica vol. 43 no. 3 article id 202. https://doi.org/10.14214/sf.202
Information on the potential wood supply is important for the wood industry. In this study, the future development of growing stock, cutting potential and wood properties corresponding to the regional scenario of North Karelian Forest Programme 2006–2010 was analysed. The simulations were performed by employing the Finnish MELA system together with the sample plot and tree data of the 9th Finnish National Forest Inventory (NFI9) as initial data for the simulations. Disc-based models for basic wood density, proportion of latewood and fibre length of Norway spruce and Scots pine in Sweden were calibrated and integrated into the MELA system. The wood properties at breast height of both harvested and standing trees were analysed in different strata (age, site type and cutting method) during the scenario period of 50 years (2002–2052). The average wood properties within the same strata varied only slightly over time. However, the results for different strata differed considerably. In general, wood density, fibre length and proportion of latewood increased, on average, as a function of tree age and along with a decrease in site fertility (excl. wood density and proportion of latewood in harvested Norway spruce in the first case and fibre length in the latter case for both species). For trees less than 80 years, properties in harvested trees were equal to or slightly greater than those of standing trees. The values for clear-cuttings were greater or equal to those of thinnings (excl. wood density and proportion of latewood in Norway spruce). The study demonstrates the value of model-based analyses utilising NFI tree measurements in regions that are considered to be sources of raw material.
  • Nuutinen, European Forest Institute, Torikatu 34, FI-80100 Joensuu, Finland ORCID ID:E-mail: tuula.nuutinen@efi.int (email)
  • Kilpeläinen, University of Joensuu, Faculty of Forest Sciences, P.O. Box 111, FI-80101 Joensuu, Finland ORCID ID:E-mail:
  • Hirvelä, Finnish Forest Research Institute, P.O. Box 18, FI-01301 Vantaa, Finland ORCID ID:E-mail:
  • Härkönen, Finnish Forest Research Institute, P.O. Box 18, FI-01301 Vantaa, Finland ORCID ID:E-mail:
  • Ikonen, University of Joensuu, Faculty of Forest Sciences, P.O. Box 111, FI-80101 Joensuu, Finland ORCID ID:E-mail:
  • Lempinen, Finnish Forest Research Institute, P.O. Box 68, FI-80101 Joensuu, Finland ORCID ID:E-mail:
  • Peltola, University of Joensuu, Faculty of Forest Sciences, P.O. Box 111, FI-80101 Joensuu, Finland ORCID ID:E-mail:
  • Wilhelmsson, Skogforsk, Uppsala Science Park, SE-751 83 Uppsala, Sweden ORCID ID:E-mail:
  • Kellomäki, University of Joensuu, Faculty of Forest Sciences, P.O. Box 111, FI-80101 Joensuu, Finland ORCID ID:E-mail:
article id 201, category Research article
Rui Qi, Véronique Letort, Mengzhen Kang, Paul-Henry Cournède, Philippe de Reffye, Thierry Fourcaud. (2009). Application of the GreenLab model to simulate and optimize wood production and tree stability: a theoretical study. Silva Fennica vol. 43 no. 3 article id 201. https://doi.org/10.14214/sf.201
The GreenLab model was used to study the interaction between source-sink dynamics at the whole tree level, wood production and distribution within the stem, and tree mechanical stability through simulation and optimization. In this first promising numerical attempt, two GreenLab parameters were considered in order to maximize wood production: the sink strength for cambial growth and a coefficient that determines the way the biomass assigned to cambial growth is allocated to each metamer, through optimization and simulation respectively. The optimization procedure that has been used is based on a heuristic optimization algorithm called Particle Swarm Optimization (PSO). In the first part of the paper, wood production was maximized without considering the effect of wood distribution on tree mechanical stability. Contrary to common idea that increasing sink strength for cambial growth leads to increasing wood production, an optimal value can be found. The optimization results implied that an optimal source and sink balance should be considered to optimize wood production. In a further step, the mechanical stability of trees submitted to their self weight was taken into account based on simplified mechanical assumptions. Simulation results revealed that the allocation of wood at the stem base strongly influenced its global deformation. Such basic mechanical criterion can be an indicator of wood quality if we consider further the active biomechanical processes involved in tree gravitropic responses, e.g. formation of reaction wood.
  • Qi, Ecole Centrale Paris, Laboratory of Applied Mathematics, Grande Voie des Vignes, 92295 Chatenay-Malabry, France; Institute of Automation, Chinese Academy of Sciences, LIAMA/NLPR, P.O.Box 2728, Beijing, China ORCID ID:E-mail: qiruitree@gmail.com (email)
  • Letort, Ecole Centrale Paris, Laboratory of Applied Mathematics, Grande Voie des Vignes, 92295 Chatenay-Malabry, France ORCID ID:E-mail:
  • Kang, Institute of Automation, Chinese Academy of Sciences, LIAMA/NLPR, P.O.Box 2728, Beijing, China ORCID ID:E-mail:
  • Cournède, Ecole Centrale Paris, Laboratory of Applied Mathematics, Grande Voie des Vignes, 92295 Chatenay-Malabry, France; INRIA saclay Ile-de-France, EPI Digiplant, Parc Orsay Université, 91893 Orsay cedex, France ORCID ID:E-mail:
  • Reffye, INRIA saclay Ile-de-France, EPI Digiplant, Parc Orsay Université, 91893 Orsay cedex, France; CIRAD, UMR AMAP, Montpellier, F-34000 France ORCID ID:E-mail:
  • Fourcaud, CIRAD, UMR AMAP, Montpellier, F-34000 France ORCID ID:E-mail:
article id 199, category Research article
R. Edward Thomas. (2009). Modeling the relationships among internal defect features and external Appalachian hardwood log defect indicators. Silva Fennica vol. 43 no. 3 article id 199. https://doi.org/10.14214/sf.199
As a hardwood tree grows and develops, surface defects such as branch stubs and wounds are overgrown. Evidence of these defects remain on the log surface for decades and in many instances for the life of the tree. As the tree grows the defect is encapsulated or grown over by new wood. During this process the appearance of the defect in the tree’s bark changes. The defect becomes flatter and its dimension changes. This progressional change in appearance is predictable, permitting the size and location of the internal defect to be reliably estimated. This paper concerns the development and analysis of models for the prediction of internal features. With the advent of surface scanning and external detection systems, the prediction of internal features promises to significantly improve the quality, yield, and value of sawn wood products.
  • Thomas, USDA Forest Service, 241 Mercer Springs Road, Princeton, WV 24740, USA ORCID ID:E-mail: edthomas@gmail.com (email)
article id 195, category Research article
John R. Moore, Andrew J. Lyon, Gregory J. Searles, Leena E. Vihermaa. (2009). The effects of site and stand factors on the tree and wood quality of Sitka spruce growing in the United Kingdom. Silva Fennica vol. 43 no. 3 article id 195. https://doi.org/10.14214/sf.195
The extent and sources of variation in the wood quality of Sitka spruce (Picea sitchensis (Bong.) Carr.) were quantified using data collected from 64 stands in northern Britain. These stands were selected on the basis of elevation, latitude, longitude, yield class, initial spacing and the presence or absence of thinning. Dynamic modulus of elasticity (MOE) was calculated from measurements of stress wave velocity made on standing trees and qualitative descriptions were made of stem form. Dynamic MOE of individual trees ranged from 3.81 kN/mm2 up to 12.29 kN/mm2, with a mean of 7.71 kN/mm2. Approximately 55 percent of the variation in dynamic MOE was due to differences between individual trees within a site, while 35 percent was due to differences between sites. The remaining 10 percent was due to differences between the measurements made on opposite sides of each tree. Variation in dynamic MOE at the site level was significantly influenced by yield class, elevation as well as by a number of the interactions between these factors and latitude, longitude and initial spacing. A multiple regression model incorporating these variables was able to explain 45 percent of the variation in dynamic MOE. Ramicorn branches were the most commonly recorded defect (37.2% of all live trees), followed by stem scarring and basal sweep (6.9% and 6.3%, respectively). Dynamic MOE was not influenced by stem straightness (p = 0.10) which indicates the utility of stress wave velocity measurements for segregating Sitka spruce stands based on potential grade recovery.
  • Moore, Centre for Timber Engineering, Napier University, 10 Colinton Road, Edinburgh EH10 5DT, United Kingdom ORCID ID:E-mail: j.moore@napier.ac.uk (email)
  • Lyon, Centre for Timber Engineering, Napier University, 10 Colinton Road, Edinburgh EH10 5DT, United Kingdom ORCID ID:E-mail:
  • Searles, Centre for Timber Engineering, Napier University, 10 Colinton Road, Edinburgh EH10 5DT, United Kingdom ORCID ID:E-mail:
  • Vihermaa, Department of Analytical and Environmental Chemistry, University of Glasgow, Glasgow, UK ORCID ID:E-mail:
article id 195, category Research article
John R. Moore, Andrew J. Lyon, Gregory J. Searles, Leena E. Vihermaa. (2009). The effects of site and stand factors on the tree and wood quality of Sitka spruce growing in the United Kingdom. Silva Fennica vol. 43 no. 3 article id 195. https://doi.org/10.14214/sf.195
The extent and sources of variation in the wood quality of Sitka spruce (Picea sitchensis (Bong.) Carr.) were quantified using data collected from 64 stands in northern Britain. These stands were selected on the basis of elevation, latitude, longitude, yield class, initial spacing and the presence or absence of thinning. Dynamic modulus of elasticity (MOE) was calculated from measurements of stress wave velocity made on standing trees and qualitative descriptions were made of stem form. Dynamic MOE of individual trees ranged from 3.81 kN/mm2 up to 12.29 kN/mm2, with a mean of 7.71 kN/mm2. Approximately 55 percent of the variation in dynamic MOE was due to differences between individual trees within a site, while 35 percent was due to differences between sites. The remaining 10 percent was due to differences between the measurements made on opposite sides of each tree. Variation in dynamic MOE at the site level was significantly influenced by yield class, elevation as well as by a number of the interactions between these factors and latitude, longitude and initial spacing. A multiple regression model incorporating these variables was able to explain 45 percent of the variation in dynamic MOE. Ramicorn branches were the most commonly recorded defect (37.2% of all live trees), followed by stem scarring and basal sweep (6.9% and 6.3%, respectively). Dynamic MOE was not influenced by stem straightness (p = 0.10) which indicates the utility of stress wave velocity measurements for segregating Sitka spruce stands based on potential grade recovery.
  • Moore, Centre for Timber Engineering, Napier University, 10 Colinton Road, Edinburgh EH10 5DT, United Kingdom ORCID ID:E-mail: j.moore@napier.ac.uk (email)
  • Lyon, Centre for Timber Engineering, Napier University, 10 Colinton Road, Edinburgh EH10 5DT, United Kingdom ORCID ID:E-mail:
  • Searles, Centre for Timber Engineering, Napier University, 10 Colinton Road, Edinburgh EH10 5DT, United Kingdom ORCID ID:E-mail:
  • Vihermaa, Department of Analytical and Environmental Chemistry, University of Glasgow, Glasgow, UK ORCID ID:E-mail:
article id 194, category Research article
Ane Zubizarreta Gerendiain, Heli Peltola, Pertti Pulkkinen. (2009). Growth and wood property traits in narrow crowned Norway spruce (Picea abies f. pendula) clones grown in southern Finland. Silva Fennica vol. 43 no. 3 article id 194. https://doi.org/10.14214/sf.194
We investigated the growth, yield, wood density traits and fibre properties in 13 narrow crowned Norway spruce (Picea abies f. pendula) clones grown at a spacing of 2 m x 1.5 m (about 3300 seedlings/ha) in a field trial established in 1988 in southern Finland on a forest soil. For comparison, we used 3 normal crowned Norway spruce (Picea abies (L.) Karst.) genetic entries grown as a mixture in the same trial representing southern Finnish breeding regions. We found that wood density traits and fibre properties showed, on average, lower phenotypic variation than growth and yield traits regardless of crown type. Narrow crowned clones also had, on average, lower stem volume and fibre length, but higher overall wood density. More over, the phenotypic correlations between studied growth and wood properties ranged, on average, from moderate (normal crown) to high (narrow crown). These results were opposite to previous findings for narrow and normal crowned genetic entries grown in narrower spacing (1 m x 1 m) in southern Finland. Thus, this indicates lower plasticity of narrow crowned clones to the increasing growing space compared to normal crowned ones, so, they should be grown at denser spacing in order to fully utilise its space efficiency capacity. However, this field trial was established as a mixture of normal and narrow crown trees, so that 90% of genetic entries were narrow crowned ones, and therefore the crown competition would be much higher for normal crowned trees when the whole trial would consist of that entry alone. In the latter case, we could expect significantly lower productivity of normal crowned genetic entries with this spacing.
  • Zubizarreta Gerendiain, University of Joensuu, Faculty of Forest Sciences, P.O. Box 111, FI-80101 Joensuu, Finland ORCID ID:E-mail: ane.zubizarreta@joensuu.fi (email)
  • Peltola, University of Joensuu, Faculty of Forest Sciences, P.O. Box 111, FI-80101 Joensuu, Finland ORCID ID:E-mail:
  • Pulkkinen, Finnish Forest Research Institute, Haapastensyrjä Breeding Station, FI-12600 Läyliäinen, Finland ORCID ID:E-mail:
article id 194, category Research article
Ane Zubizarreta Gerendiain, Heli Peltola, Pertti Pulkkinen. (2009). Growth and wood property traits in narrow crowned Norway spruce (Picea abies f. pendula) clones grown in southern Finland. Silva Fennica vol. 43 no. 3 article id 194. https://doi.org/10.14214/sf.194
We investigated the growth, yield, wood density traits and fibre properties in 13 narrow crowned Norway spruce (Picea abies f. pendula) clones grown at a spacing of 2 m x 1.5 m (about 3300 seedlings/ha) in a field trial established in 1988 in southern Finland on a forest soil. For comparison, we used 3 normal crowned Norway spruce (Picea abies (L.) Karst.) genetic entries grown as a mixture in the same trial representing southern Finnish breeding regions. We found that wood density traits and fibre properties showed, on average, lower phenotypic variation than growth and yield traits regardless of crown type. Narrow crowned clones also had, on average, lower stem volume and fibre length, but higher overall wood density. More over, the phenotypic correlations between studied growth and wood properties ranged, on average, from moderate (normal crown) to high (narrow crown). These results were opposite to previous findings for narrow and normal crowned genetic entries grown in narrower spacing (1 m x 1 m) in southern Finland. Thus, this indicates lower plasticity of narrow crowned clones to the increasing growing space compared to normal crowned ones, so, they should be grown at denser spacing in order to fully utilise its space efficiency capacity. However, this field trial was established as a mixture of normal and narrow crown trees, so that 90% of genetic entries were narrow crowned ones, and therefore the crown competition would be much higher for normal crowned trees when the whole trial would consist of that entry alone. In the latter case, we could expect significantly lower productivity of normal crowned genetic entries with this spacing.
  • Zubizarreta Gerendiain, University of Joensuu, Faculty of Forest Sciences, P.O. Box 111, FI-80101 Joensuu, Finland ORCID ID:E-mail: ane.zubizarreta@joensuu.fi (email)
  • Peltola, University of Joensuu, Faculty of Forest Sciences, P.O. Box 111, FI-80101 Joensuu, Finland ORCID ID:E-mail:
  • Pulkkinen, Finnish Forest Research Institute, Haapastensyrjä Breeding Station, FI-12600 Läyliäinen, Finland ORCID ID:E-mail:
article id 194, category Research article
Ane Zubizarreta Gerendiain, Heli Peltola, Pertti Pulkkinen. (2009). Growth and wood property traits in narrow crowned Norway spruce (Picea abies f. pendula) clones grown in southern Finland. Silva Fennica vol. 43 no. 3 article id 194. https://doi.org/10.14214/sf.194
We investigated the growth, yield, wood density traits and fibre properties in 13 narrow crowned Norway spruce (Picea abies f. pendula) clones grown at a spacing of 2 m x 1.5 m (about 3300 seedlings/ha) in a field trial established in 1988 in southern Finland on a forest soil. For comparison, we used 3 normal crowned Norway spruce (Picea abies (L.) Karst.) genetic entries grown as a mixture in the same trial representing southern Finnish breeding regions. We found that wood density traits and fibre properties showed, on average, lower phenotypic variation than growth and yield traits regardless of crown type. Narrow crowned clones also had, on average, lower stem volume and fibre length, but higher overall wood density. More over, the phenotypic correlations between studied growth and wood properties ranged, on average, from moderate (normal crown) to high (narrow crown). These results were opposite to previous findings for narrow and normal crowned genetic entries grown in narrower spacing (1 m x 1 m) in southern Finland. Thus, this indicates lower plasticity of narrow crowned clones to the increasing growing space compared to normal crowned ones, so, they should be grown at denser spacing in order to fully utilise its space efficiency capacity. However, this field trial was established as a mixture of normal and narrow crown trees, so that 90% of genetic entries were narrow crowned ones, and therefore the crown competition would be much higher for normal crowned trees when the whole trial would consist of that entry alone. In the latter case, we could expect significantly lower productivity of normal crowned genetic entries with this spacing.
  • Zubizarreta Gerendiain, University of Joensuu, Faculty of Forest Sciences, P.O. Box 111, FI-80101 Joensuu, Finland ORCID ID:E-mail: ane.zubizarreta@joensuu.fi (email)
  • Peltola, University of Joensuu, Faculty of Forest Sciences, P.O. Box 111, FI-80101 Joensuu, Finland ORCID ID:E-mail:
  • Pulkkinen, Finnish Forest Research Institute, Haapastensyrjä Breeding Station, FI-12600 Läyliäinen, Finland ORCID ID:E-mail:
article id 193, category Research article
Jaume Gort, Ane Zubizarreta Gerendiain, Heli Peltola, Pertti Pulkkinen, Johanna Routa, Raimo Jaatinen. (2009). Differences in fibre properties in Scots pine (Pinus sylvestris L.) genetic entries grown at different spacing and sites. Silva Fennica vol. 43 no. 3 article id 193. https://doi.org/10.14214/sf.193
In forest breeding, stem volume growth and sawn timber quality indicators have been used as the most important selection traits for Scots pine, whereas less attention has been given to characteristics such as fibre properties. In the above context, we investigated the differences in fibre properties (i.e. fibre length, fibre width and coarseness) in 20 year old Scots pine (Pinus sylvestris L.) genetic entries as affected by spacing and site, but also the phenotypic correlations between fibre properties, yield and wood density. The study was based on materials harvested from 10 genetic entries grown in a spacing trial (site 1) in central Finland, with a current stand density of 2000 (spacing 1), 2000–2500 (spacing 2) and 4000 trees/ha (spacing 3). In order to study the effects of site, we harvested additional material (4 of 7 genetic entries same as on site 1) from a trial located in southern Finland with a corresponding stand density of 2000 trees/ha (site 2). On site 1, spacing 1 and 3, all average values for analysed fibre properties were similar. In spacing 2 average values were slightly higher. On site 2, the average values for different fibre properties were similar compared to the corresponding spacing 1 on site 1. Spacing affected (p < 0.05) all average fibre properties on site 1; as did also site, when comparing same genetic entries grown on both sites. Regardless of spacing and site, the phenotypic correlations between average fibre length, fibre width and coarseness showed, on average, moderate to strong correlation (p < 0.05). Fibre width showed, in general, low and positive phenotypic correlation with diameter at breast height, stem volume and wood density on site 1. However, as a whole, the ranking of genetic entries changed depending on the trait and spacing considered. Thus, no overall ranking between genetic entries was possible.
  • Gort, University of Joensuu, Faculty of Forest Sciences, FI-80101 Joensuu, Finland ORCID ID:E-mail: jaume.gort@joensuu.fi (email)
  • Zubizarreta Gerendiain, University of Joensuu, Faculty of Forest Sciences, FI-80101 Joensuu, Finland ORCID ID:E-mail:
  • Peltola, University of Joensuu, Faculty of Forest Sciences, FI-80101 Joensuu, Finland ORCID ID:E-mail:
  • Pulkkinen, Finnish Forest Research Institute, Haapastensyrjä Breeding Station, Karkkilantie ORCID ID:E-mail:
  • Routa, University of Joensuu, Faculty of Forest Sciences, FI-80101 Joensuu, Finland ORCID ID:E-mail:
  • Jaatinen, Finnish Forest Research Institute, Haapastensyrjä Breeding Station, Karkkilantie ORCID ID:E-mail:
article id 192, category Research article
Heli Peltola, Jaume Gort, Pertti Pulkkinen, Ane Zubizarreta Gerendiain, Jouni Karppinen, Veli-Pekka Ikonen. (2009). Differences in growth and wood density traits in Scots pine (Pinus sylvestris L.) genetic entries grown at different spacing and sites. Silva Fennica vol. 43 no. 3 article id 192. https://doi.org/10.14214/sf.192
In forest breeding, stem volume has typically taken as the most important selection trait, whereas less attention has been given to wood density traits. In this work, we investigated the effects of spacing and genetic entry on the growth, yield and wood density traits in 20 year old Scots pines (Pinus sylvestris L.) based on 10 genetic entries harvested from a spacing trial (stand density range 2000–4000 trees/ha) in central Finland. In order to study also the site effects, we harvested additional material from a trial located in southern Finland (stand density of 2000 trees/ha). Compared to growth and yield properties, wood density traits showed a lower phenotypic variation. Phenotypic correlations among different traits were negative, and mostly moderate to high, suggesting that selection for one trait would simultaneously affect the others. In addition, moderate to strong phenotypic correlations were found among different wood density traits. Stem volume (V) and breast height diameter (DBH) were the largest in widest spacing, whereas in the densest one tree height (H) and latewood percentage were the highest. Genetic entry affected H and wood density traits regardless of spacing. When comparing two sites (with same stand density), genetic entry affected H, whereas site affected DBH and wood density traits. Ranking between genetic entries changed depending on the trait, spacing or site considered. Therefore, no overall ranking was possible. However, we could identify genetic entries having a high V and a relatively high wood density, showing potential for future forest regeneration material.
  • Peltola, University of Joensuu, Faculty of Forest Sciences, FI-80101 Joensuu, Finland ORCID ID:E-mail: heli.peltola@joensuu.fi (email)
  • Gort, University of Joensuu, Faculty of Forest Sciences, FI-80101 Joensuu, Finland ORCID ID:E-mail:
  • Pulkkinen, Finnish Forest Research Institute, Haapastensyrjä Breeding Station, Karkkilantie 247, FI-12600 Läyliäinen, Finland ORCID ID:E-mail:
  • Zubizarreta Gerendiain, University of Joensuu, Faculty of Forest Sciences, FI-80101 Joensuu, Finland ORCID ID:E-mail:
  • Karppinen, University of Joensuu, Faculty of Forest Sciences, FI-80101 Joensuu, Finland ORCID ID:E-mail:
  • Ikonen, University of Joensuu, Faculty of Forest Sciences, FI-80101 Joensuu, Finland ORCID ID:E-mail:
article id 191, category Research article
Katri Luostarinen, Noora Huotari, Eila Tillman-Sutela. (2009). Effect of regeneration method on growth, wood density and fibre properties of downy birch (Betula pubescens Ehrh.). Silva Fennica vol. 43 no. 3 article id 191. https://doi.org/10.14214/sf.191
Short rotation tree stands, established by coppicing, are nowadays used mainly for energy purposes in Fennoscandia, but their usage for pulp raw material may increase in the future. Downy birch (Betula pubescens), which is commonly used for pulp production in boreal zone, has good sprouting capacity. However, it is not known if the fibre properties of sprout-originated downy birches differ from those of seed-originated ones. Therefore, fibre length and width of sprout- and seed-originated downy birches grown on fertile soil were measured at a stand age of 25 years. Additionally annual ring width, stem height and diameter, and wood density were studied to compare the growth and wood properties of sprout- and seed-originated birches. Annual rings were slightly wider in sprout- than in seed-originated birches, whereas no differences were observed in wood density. Fibres, too, were slightly longer and wider in sprout- than in seed-originated trees. Still these minor differences observed here are hardly significant for the industries using birch wood. Consequently downy birch wood from coppiced stands is well suited for pulp. The advantages of coppice, i.e. rapidity and low costs of establishment, productivity, and the ability of downy birch to grow on untypical forest sites, may even increase the importance of the wood coming from coppiced birch stands in the future.
  • Luostarinen, Faculty of Forest Sciences, University of Joensuu, P.O. Box 111, FI-80101, Joensuu, Finland ORCID ID:E-mail: katri.luostarinen@joensuu.fi (email)
  • Huotari, Finnish Forest Research Institute, Muhos Research Unit, Kirkkosaarentie, FI-91500 Muhos, Finland ORCID ID:E-mail:
  • Tillman-Sutela, Finnish Forest Research Institute, Muhos Research Unit, Kirkkosaarentie, FI-91500 Muhos, Finland ORCID ID:E-mail:
article id 212, category Research article
Sandhya Samarasinghe. (2009). Exploration of fracture dynamics properties and predicting fracture toughness of individual wood beams using neural networks. Silva Fennica vol. 43 no. 2 article id 212. https://doi.org/10.14214/sf.212
In this study, the time to crack initiation (Tinit), duration of crack propagation (Tfrac), crack initiation stress, peak stress as well as crack speed and fracture toughness were investigated for three Rates of Loading (ROL) and four sizes of notched wood beams using high-speed video imaging and neural networks. Tinit was consistent for all volumes and the average Tinit was nonlinearly related to volume and ROL. For the smallest ROL, there was a distinct volume effect on Tinit and the effect was negligble at the largest ROL. However, the stress at crack initiation was not consistent. Contrasting these, Tfrac for all volumes appeared to be highly variable but the peak stress carried prior to catastrophic failure was consistent. The crack propagation was a wave phenomenon with positive and negative (crack closure) speeds that varied with the ROL. As accurate estimation of crack initiation load (or stress) and its relationship to peak load (or stress) is important for determining fracture toughness, Artificial Neural Networks (ANN) models were developed for predicting them from volume, Young’s modulus, face and grain angles, density, moisture content and ROL. Models for crack initiation load and peak load showed much higher predictive power than those for the stresses with correlation coefficients of 0.85 and 0.97, respectively, between the actual and predicted loads. Neural networks were also developed for predicting fracture toughness of individual wood specimens and the best model produced a statistically significant correlation of 0.813 between the predicted and actual fracture toughness on a validation dataset. The inputs captured 62% of variability of fracture toughness. Volume and Young’s modulus were the top two contributing variables with others providing lesser contributions.
  • Samarasinghe, Centre for Advanced Computational Solutions (C-fACS), Lincoln University, Canterbury, New Zealand ORCID ID:E-mail: sandhya.samarasinghe@lincoln.ac.nz (email)
article id 464, category Research article
Christian Kanzian, Franz Holzleitner, Karl Stampfer, Sarah Ashton. (2009). Regional energy wood logistics – optimizing local fuel supply. Silva Fennica vol. 43 no. 1 article id 464. https://doi.org/10.14214/sf.464
The promotion of electric energy production from solid biomass by the Austrian government has lead to a boom in the construction of new combined heat and power plants. The current total demand for wood chips in the research area for energy purposes is 70 400 m3 of loose volume chips per year. The expected increase in demand due to these new plants is more than 4 times greater than current demand: up to 302 700 m3 of loose volume per year. Even if the energy wood feedstock potential is satisfactory, the design of the supply chain is still unresolved. The aim of this study is to give decision-makers a base for further development. To accomplish this, we designed and tested four different supply scenarios: one for 9 plants and one for 16 plants. The scenarios were developed using a combination of geographic information systems (GIS) and linear programming methods. The results indicate that direct transport of solid fuel wood as round wood and chipping at the plant is the cheapest supply system with a resulting cost of 5.6–6.6 EUR/m3 loose. Using harvesting residues can only be recommended for large plants because of poor fuel quality. In this case, residues would be chipped at or near the landing, piled and transported via self-loading trucks at a cost between 8.4 and 9.1 EUR/m3 loose. In order to meet increasing demand and to ensure a continuous supply, especially during the winter and spring seasons it is necessary to optimize the supply chain by including storage terminals. However, using terminals and increased demand both lead to higher logistical costs. For example, if the total volume is handled via terminals, the average supply costs including storage will increase by 26%. Higher demand increases the costs by 24%.
  • Kanzian, University of Applied Life Sciences Vienna, Institute of Forest Engineering, Peter Jordan Strasse 82, A-1190 Vienna, Austria ORCID ID:E-mail: christian.kanzian@boku.ac.at (email)
  • Holzleitner, University of Applied Life Sciences Vienna, Institute of Forest Engineering, Peter Jordan Strasse 82, A-1190 Vienna, Austria ORCID ID:E-mail:
  • Stampfer, University of Applied Life Sciences Vienna, Institute of Forest Engineering, Peter Jordan Strasse 82, A-1190 Vienna, Austria ORCID ID:E-mail:
  • Ashton, Southern Regional Extension Forestry, Forestry Bldg. 4-420, University of Georgia, Athens, GA 30602, USA ORCID ID:E-mail:
article id 221, category Research article
Glen Murphy, Rod Brownlie, Mark Kimberley, Peter Beets. (2009). Impacts of forest harvesting related soil disturbance on end-of-rotation wood quality and quantity in a New Zealand radiata pine forest. Silva Fennica vol. 43 no. 1 article id 221. https://doi.org/10.14214/sf.221
The long-term effect of soil disturbance (litter removal, topsoil removal and compaction) from forest harvesting on wood quality and quantity of second-rotation Pinus radiata growing on a clay loam soil, was assessed at the end the rotation, 26 years after planting. Relative to Control plots, average tree and stand total volume at rotation end was not significantly affected by litter removal and nil or light compaction, but was significantly reduced by 28% by litter and topsoil removal and moderate subsoil compaction, and further reduced by 38% by heavy compaction. Wood density at breast height in the inner rings of trees in the most disturbed treatments was elevated by up to 30 kg m–3. This occurred because these treatments were more N deficient as reflected by foliar N levels during the first 11 years of growth relative to the Control. However, no treatment differences in wood density were evident in outer rings, and by rotation age overall mean density did not differ significantly between treatments. Neither acoustic velocity of standing trees, nor acoustic velocity of logs, was significantly affected by soil disturbance, indicating that stiffness of lumber cut from trees in the trial was likely to be similar for all treatments. Economic impacts of soil disturbance and compaction on this soil type will therefore result largely from the considerable negative impacts on final tree size, with little or no compensation from improved wood properties.
  • Murphy, Forest Engineering, Resources and Management Department, Oregon State University, Corvallis, Oregon, USA ORCID ID:E-mail: glen.murphy@oregonstate.edu (email)
  • Brownlie, Scion Research, Rotorua, New Zealand ORCID ID:E-mail:
  • Kimberley, Scion Research, Rotorua, New Zealand ORCID ID:E-mail:
  • Beets, Scion Research, Rotorua, New Zealand ORCID ID:E-mail:
article id 220, category Research article
Jani Heikkilä, Matti Sirén, Anssi Ahtikoski, Jari Hynynen, Tiina Sauvula, Mika Lehtonen. (2009). Energy wood thinning as a part of stand management of Scots pine and Norway spruce. Silva Fennica vol. 43 no. 1 article id 220. https://doi.org/10.14214/sf.220
The effects of combined production of industrial and energy wood on yield and harvesting incomes, as well as the feasibility of energy wood procurement, were studied. Data for 22 Scots pine (Pinus sylvestris L.) and 21 Norway spruce (Picea abies (L.) Karst.) juvenile stands in Central and Southern Finland were used to compare six combined production regimes to conventional industrial wood production. The study was based on simulations made by the MOTTI stand simulator, which produces growth predictions for alternative management regimes under various site and climatic conditions. The combined production regimes included precommercial thinning at 4–8 m dominant height to a density of 3000–4000 stems ha–1 and energy wood harvesting at 8, 10 or 12 m dominant height. Combined production did not decrease the total yield of industrial wood during the rotation period. Differences in the mean annual increment (MAI) were small, and the rotation periods varied only slightly between the alternatives. Combined production regime can be feasible for a forest owner if the price of energy wood is 3–5 EUR m–3 in pine stands, and 8–9 EUR m–3 in spruce stands. Energy wood procurement was not economically viable at the current energy price (12 EUR MWh–1) without state subsidies. Without subsidies a 15 EUR MWh–1 energy price would be needed. Our results imply that the combined production of industrial and energy wood could be a feasible stand management alternative.
  • Heikkilä, L&T Biowatti Oy, P.O. Box 738, FI-60101 Seinäjoki, Finland ORCID ID:E-mail: jani.heikkila@biowatti.fi (email)
  • Sirén, Finnish Forest Research Institute, Vantaa Research Unit, P.O.Box 18, FI-01301 Vantaa, Finland ORCID ID:E-mail:
  • Ahtikoski, Finnish Forest Research Institute, Rovaniemi Research Unit, P.O.Box 16, FI-96301 Rovaniemi, Finland ORCID ID:E-mail:
  • Hynynen, Finnish Forest Research Institute, Vantaa Research Unit, P.O.Box 18, FI-01301 Vantaa, Finland ORCID ID:E-mail:
  • Sauvula, Seinäjoki University of Applied Sciences, School of Agriculture and Forestry, Tuomarniementie 55, FI-63700 Ähtäri, Finland ORCID ID:E-mail:
  • Lehtonen, Finnish Forest Research Institute, Vantaa Research Unit, P.O.Box 18, FI-01301 Vantaa, Finland ORCID ID:E-mail:
article id 216, category Research article
Juha Siitonen, Jenni Hottola, Auli Immonen. (2009). Differences in stand characteristics between brook-side key habitats and managed forests in southern Finland. Silva Fennica vol. 43 no. 1 article id 216. https://doi.org/10.14214/sf.216
Preservation of small habitat patches termed as “woodland key habitats” or “especially important habitats” in the Finnish Forest Act has become an integral part of biodiversity-oriented forest management. Forest Act habitats belong to particular habitat types defined in the act, and they are supposed to have natural-like stand characteristics. However, very little is known about the actual stand structure in the designated habitats. Our aim was to compare stand characteristics between brook-side key habitats and comparable managed forests as controls. Seven study areas were selected from four regions across southern Finland. Within each study area ten key habitats and ten controls (140 stands) were randomly selected. Living and dead trees and cut stumps were measured in each stand within a 0.2 ha plot. The average degree of previous cutting was significantly lower whereas the volume of dead wood, volume of deciduous trees, and stand diversity were each significantly higher in key habitats than controls. The average volume of dead wood was 11.7 m3 ha–1 in key habitats and 6.5 m3 ha–1 in controls. However, there was considerable variation among individual stands, and a large part of key habitats could not be distinguished from randomly selected control stands with respect to stand characteristics. The preservation of natural brook channels with their immediate surroundings is undoubtedly important for maintaining aquatic and semiaquatic biodiversity. Nevertheless, when complementing the forest conservation network in the future, main emphasis in selecting potentially valuable stands should be placed on important structural features such as dead wood and old trees.
  • Siitonen, Finnish Forest Research Institute, Vantaa Research Unit, P.O. Box 18, FI-01301 Vantaa, Finland ORCID ID:E-mail: juha.siitonen@metla.fi (email)
  • Hottola, Finnish Forest Research Institute, Vantaa Research Unit, P.O. Box 18, FI-01301 Vantaa, Finland ORCID ID:E-mail:
  • Immonen, Finnish Forest Research Institute, Vantaa Research Unit, P.O. Box 18, FI-01301 Vantaa, Finland ORCID ID:E-mail:
article id 216, category Research article
Juha Siitonen, Jenni Hottola, Auli Immonen. (2009). Differences in stand characteristics between brook-side key habitats and managed forests in southern Finland. Silva Fennica vol. 43 no. 1 article id 216. https://doi.org/10.14214/sf.216
Preservation of small habitat patches termed as “woodland key habitats” or “especially important habitats” in the Finnish Forest Act has become an integral part of biodiversity-oriented forest management. Forest Act habitats belong to particular habitat types defined in the act, and they are supposed to have natural-like stand characteristics. However, very little is known about the actual stand structure in the designated habitats. Our aim was to compare stand characteristics between brook-side key habitats and comparable managed forests as controls. Seven study areas were selected from four regions across southern Finland. Within each study area ten key habitats and ten controls (140 stands) were randomly selected. Living and dead trees and cut stumps were measured in each stand within a 0.2 ha plot. The average degree of previous cutting was significantly lower whereas the volume of dead wood, volume of deciduous trees, and stand diversity were each significantly higher in key habitats than controls. The average volume of dead wood was 11.7 m3 ha–1 in key habitats and 6.5 m3 ha–1 in controls. However, there was considerable variation among individual stands, and a large part of key habitats could not be distinguished from randomly selected control stands with respect to stand characteristics. The preservation of natural brook channels with their immediate surroundings is undoubtedly important for maintaining aquatic and semiaquatic biodiversity. Nevertheless, when complementing the forest conservation network in the future, main emphasis in selecting potentially valuable stands should be placed on important structural features such as dead wood and old trees.
  • Siitonen, Finnish Forest Research Institute, Vantaa Research Unit, P.O. Box 18, FI-01301 Vantaa, Finland ORCID ID:E-mail: juha.siitonen@metla.fi (email)
  • Hottola, Finnish Forest Research Institute, Vantaa Research Unit, P.O. Box 18, FI-01301 Vantaa, Finland ORCID ID:E-mail:
  • Immonen, Finnish Forest Research Institute, Vantaa Research Unit, P.O. Box 18, FI-01301 Vantaa, Finland ORCID ID:E-mail:
article id 227, category Research article
Ola Lindroos. (2008). The effects of increased mechanization on time consumption in small-scale firewood processing. Silva Fennica vol. 42 no. 5 article id 227. https://doi.org/10.14214/sf.227
Firewood, which is mainly processed by the consumer, is still an important source of energy for heating houses in industrialised countries. Possibilities to compare the mechanization’s impact on efficiency of firewood processing are limited, due to variations between working conditions in previous studies. Therefore, the objective was to compare time consumption for two small-scale firewood processing systems with different levels of mechanisation under identical conditions. The systems were tested on two classes of wood: one with a homogeneous and medium-sized diameter of logs and one with a mixture of small and large-diameter-logs. Differences in time consumption were analysed for correlations with physical workloads, deviations to routine operations, operator influences and operator perceptions. Twelve operators (60–79 years old) were studied and they showed large variation in time consumption. However, the within-operator time consumption patterns were consistent. In other words, operators all responded similarly to the different combinations of systems and wood classes, but at different absolute levels. The time required to process a unit volume of wood was 25–33% lower when the more highly mechanised system was used, and the time required was 13–22% lower for the homogeneous wood class. Physical work load, deviations and perceptions of the work varied between operators, but were weakly correlated with time consumption. The results’ implications for analyses of investments in equipment for firewood-processing for self-sufficiency purposes are discussed.
  • Lindroos, Swedish University of Agricultural Sciences, Department of Forest Resource Management, SE-901 83 Umeå, Sweden ORCID ID:E-mail: ola.lindroos@srh.slu.se (email)
article id 225, category Research article
Johan Bergh, Urban Nilsson, Harald Grip, Per-Ola Hedwall, Tomas Lundmark. (2008). Effects of frequency of fertilisation on production, foliar chemistry and nutrient leaching in young Norway spruce stands in Sweden. Silva Fennica vol. 42 no. 5 article id 225. https://doi.org/10.14214/sf.225
Keywords: sludge; wood-ash; boreal; N; P; K
There is a great need to increase the production in Swedish forests to meet future demand from the forest industry and the bio-energy sector. One option to increase the production is to supply nutrients to young stands of Norway spruce. For the practical application it is important to develop and optimise fertilisation regimes in terms of production, economy and leaching of nutrients. The frequency of fertilisation is one important variable in the fertilisation regime, and this study aimed to study effects of different fertilisation frequencies on production and leaching of nitrogen. In 2001, five field experiments were established in southern, central and northern Sweden. Young stands of Norway spruce were fertilised every year, every second year and every third year. In addition, fertilisation with sludge pellets and wood-ash combined with nitrogen was investigated. The current annual increment after five years of treatment was significantly larger in fertilised than in unfertilised treatments. The difference in production between fertilisation every year and every second year was insignificant, while fertilisation every third year resulted in lower production. Sludge pellets and wood-ash fertilisation gave significantly lower production than fertilisation every second year even though approximately the same amount of nitrogen was applied. There was relatively little leaching of nitrate to ground water in all treatments; 0.6–1 kg N ha–1 a–1 from plots with fertilisation every year or every second year; and 2.7 kg N ha–1 a–1 from plots with fertilisation every third year. Most of the leaching was after the first fertilisation, in all treatments at all sites.
  • Bergh, Swedish University of Agricultural Sciences, Southern Swedish Forest Research Centre, P.O. Box 49, SE-230 53 Alnarp, Sweden ORCID ID:E-mail: johan.bergh@ess.slu.se (email)
  • Nilsson, Swedish University of Agricultural Sciences, Southern Swedish Forest Research Centre, P.O. Box 49, SE-230 53 Alnarp, Sweden ORCID ID:E-mail:
  • Grip, Swedish University of Agricultural Sciences, Southern Swedish Forest Research Centre, P.O. Box 49, SE-230 53 Alnarp, Sweden ORCID ID:E-mail:
  • Hedwall, Swedish University of Agricultural Sciences, Southern Swedish Forest Research Centre, P.O. Box 49, SE-230 53 Alnarp, Sweden ORCID ID:E-mail:
  • Lundmark, Swedish University of Agricultural Sciences, Southern Swedish Forest Research Centre, P.O. Box 49, SE-230 53 Alnarp, Sweden ORCID ID:E-mail:
article id 248, category Research article
Tuula Jyske, Harri Mäkinen, Pekka Saranpää. (2008). Wood density within Norway spruce stems. Silva Fennica vol. 42 no. 3 article id 248. https://doi.org/10.14214/sf.248
We studied the variation in average wood density of annual rings, earlywood density, and latewood density in addition to ring width and latewood percentage within Norway spruce (Picea abies (L.) Karst.) stems from the pith to the bark, and from the stem base towards the stem apex. Moreover, the variation in wood density within annual rings was studied at the different heights and radial positions in the stem. The material consisted of 85 trees from central and south-eastern Finland. Variation between the annual rings accounted for 11–27% of the total variation in wood density. Only small differences (3–6%) in wood density were found between different heights in the stem. The largest (49–80%) variation in wood density was found within the annual rings. The difference in wood density between earlywood and latewood was smaller in the rings near the pith than in the outer rings. The increasing wood density from the pith outwards was related to increasing latewood density and latewood percentage, whereas the earlywood density increased only slightly from the pith outwards. In a given cambial age (i.e., given rings from the pith), the average wood density of annual rings increased with increasing stem height. In contrast, in the rings formed in the same calendar years (i.e., given rings from the bark), the average wood density of annual rings decreased with increasing stem height. The results of this study verify our knowledge of wood density variation and can further contribute to creating models to predict wood density.
  • Jyske, The Finnish Forest Research Institute, Vantaa Research Unit, P.O. Box 18, FI-01301 Vantaa, Finland ORCID ID:E-mail: tuula.jyske@metla.fi (email)
  • Mäkinen, The Finnish Forest Research Institute, Vantaa Research Unit, P.O. Box 18, FI-01301 Vantaa, Finland ORCID ID:E-mail:
  • Saranpää, The Finnish Forest Research Institute, Vantaa Research Unit, P.O. Box 18, FI-01301 Vantaa, Finland ORCID ID:E-mail:
article id 247, category Research article
Ane Zubizarreta Gerendiain, Heli Peltola, Pertti Pulkkinen, Veli-Pekka Ikonen, Raimo Jaatinen. (2008). Differences in growth and wood properties between narrow and normal crowned types of Norway spruce grown at narrow spacing in Southern Finland. Silva Fennica vol. 42 no. 3 article id 247. https://doi.org/10.14214/sf.247
In recent years there has been increased interest in the so called narrow crowned Norway spruce (Picea abies f. pendula), which is a rare mutant of Norway spruce (Picea abies (L.) Karsten), as a suitable wood raw material source for pulp and paper production. This is because it is less sensitive to competition than the normal crowned Norway spruce, and thus, could be more productive especially at dense spacing. In the above context, we investigated how the growth and yield (such as height, diameter, stem volume and ring width) in addition to wood density traits and fibre properties (such as wood density, fibre length and width, cell wall thickness and fibre coarseness) were affected in trees from 9 full-sib families representing narrow crowned Norway spruce grown at narrow spacing of 1 m 1 m in Southern Finland. For comparison, we used normal crowned Norway spruce trees from 6 breeding regions. We found that, compared to growth and yield traits, wood density traits and fibre properties showed, on average, lower phenotypic variations. In addition, these variations were smaller for narrow crowned families than for normal crowned genetic entries. Narrow crowned families also showed, on average, higher growth and yield and fibre length, but lower wood density. Moreover, the phenotypic correlations between growth, yield, wood density traits and fibre properties, ranged, on average, from moderate (narrow crowned) to high (normal crowned). As a whole, the growth and wood properties of narrow crowned families were found to be less sensitive to tree competition than the normal crowned genetic entries used as a comparison.
  • Zubizarreta Gerendiain, University of Joensuu, Faculty of Forest Sciences, Joensuu, Finland ORCID ID:E-mail: ane.zubizarreta@joensuu.fi (email)
  • Peltola, University of Joensuu, Faculty of Forest Sciences, Joensuu, Finland ORCID ID:E-mail:
  • Pulkkinen, Finnish Forest Research Institute, Haapastensyrjä Breeding Station, Läyliäinen, Finland ORCID ID:E-mail:
  • Ikonen, University of Joensuu, Faculty of Forest Sciences, Joensuu, Finland ORCID ID:E-mail:
  • Jaatinen, Finnish Forest Research Institute, Haapastensyrjä Breeding Station, Läyliäinen, Finland ORCID ID:E-mail:
article id 247, category Research article
Ane Zubizarreta Gerendiain, Heli Peltola, Pertti Pulkkinen, Veli-Pekka Ikonen, Raimo Jaatinen. (2008). Differences in growth and wood properties between narrow and normal crowned types of Norway spruce grown at narrow spacing in Southern Finland. Silva Fennica vol. 42 no. 3 article id 247. https://doi.org/10.14214/sf.247
In recent years there has been increased interest in the so called narrow crowned Norway spruce (Picea abies f. pendula), which is a rare mutant of Norway spruce (Picea abies (L.) Karsten), as a suitable wood raw material source for pulp and paper production. This is because it is less sensitive to competition than the normal crowned Norway spruce, and thus, could be more productive especially at dense spacing. In the above context, we investigated how the growth and yield (such as height, diameter, stem volume and ring width) in addition to wood density traits and fibre properties (such as wood density, fibre length and width, cell wall thickness and fibre coarseness) were affected in trees from 9 full-sib families representing narrow crowned Norway spruce grown at narrow spacing of 1 m 1 m in Southern Finland. For comparison, we used normal crowned Norway spruce trees from 6 breeding regions. We found that, compared to growth and yield traits, wood density traits and fibre properties showed, on average, lower phenotypic variations. In addition, these variations were smaller for narrow crowned families than for normal crowned genetic entries. Narrow crowned families also showed, on average, higher growth and yield and fibre length, but lower wood density. Moreover, the phenotypic correlations between growth, yield, wood density traits and fibre properties, ranged, on average, from moderate (narrow crowned) to high (normal crowned). As a whole, the growth and wood properties of narrow crowned families were found to be less sensitive to tree competition than the normal crowned genetic entries used as a comparison.
  • Zubizarreta Gerendiain, University of Joensuu, Faculty of Forest Sciences, Joensuu, Finland ORCID ID:E-mail: ane.zubizarreta@joensuu.fi (email)
  • Peltola, University of Joensuu, Faculty of Forest Sciences, Joensuu, Finland ORCID ID:E-mail:
  • Pulkkinen, Finnish Forest Research Institute, Haapastensyrjä Breeding Station, Läyliäinen, Finland ORCID ID:E-mail:
  • Ikonen, University of Joensuu, Faculty of Forest Sciences, Joensuu, Finland ORCID ID:E-mail:
  • Jaatinen, Finnish Forest Research Institute, Haapastensyrjä Breeding Station, Läyliäinen, Finland ORCID ID:E-mail:
article id 247, category Research article
Ane Zubizarreta Gerendiain, Heli Peltola, Pertti Pulkkinen, Veli-Pekka Ikonen, Raimo Jaatinen. (2008). Differences in growth and wood properties between narrow and normal crowned types of Norway spruce grown at narrow spacing in Southern Finland. Silva Fennica vol. 42 no. 3 article id 247. https://doi.org/10.14214/sf.247
In recent years there has been increased interest in the so called narrow crowned Norway spruce (Picea abies f. pendula), which is a rare mutant of Norway spruce (Picea abies (L.) Karsten), as a suitable wood raw material source for pulp and paper production. This is because it is less sensitive to competition than the normal crowned Norway spruce, and thus, could be more productive especially at dense spacing. In the above context, we investigated how the growth and yield (such as height, diameter, stem volume and ring width) in addition to wood density traits and fibre properties (such as wood density, fibre length and width, cell wall thickness and fibre coarseness) were affected in trees from 9 full-sib families representing narrow crowned Norway spruce grown at narrow spacing of 1 m 1 m in Southern Finland. For comparison, we used normal crowned Norway spruce trees from 6 breeding regions. We found that, compared to growth and yield traits, wood density traits and fibre properties showed, on average, lower phenotypic variations. In addition, these variations were smaller for narrow crowned families than for normal crowned genetic entries. Narrow crowned families also showed, on average, higher growth and yield and fibre length, but lower wood density. Moreover, the phenotypic correlations between growth, yield, wood density traits and fibre properties, ranged, on average, from moderate (narrow crowned) to high (normal crowned). As a whole, the growth and wood properties of narrow crowned families were found to be less sensitive to tree competition than the normal crowned genetic entries used as a comparison.
  • Zubizarreta Gerendiain, University of Joensuu, Faculty of Forest Sciences, Joensuu, Finland ORCID ID:E-mail: ane.zubizarreta@joensuu.fi (email)
  • Peltola, University of Joensuu, Faculty of Forest Sciences, Joensuu, Finland ORCID ID:E-mail:
  • Pulkkinen, Finnish Forest Research Institute, Haapastensyrjä Breeding Station, Läyliäinen, Finland ORCID ID:E-mail:
  • Ikonen, University of Joensuu, Faculty of Forest Sciences, Joensuu, Finland ORCID ID:E-mail:
  • Jaatinen, Finnish Forest Research Institute, Haapastensyrjä Breeding Station, Läyliäinen, Finland ORCID ID:E-mail:
article id 259, category Research article
Jani Laturi, Jarmo Mikkola, Jussi Uusivuori. (2008). Carbon reservoirs in wood products-in-use in Finland: current sinks and scenarios until 2050. Silva Fennica vol. 42 no. 2 article id 259. https://doi.org/10.14214/sf.259
This study addresses the question of how much carbon will be sequestered in wood products during the coming decades in Finland. Using sawnwood and other wood material consumption data since the 1950s and inventory data of carbon reservoirs of wood products in the Finnish construction and civil engineering sector, we first derive estimates for the carbon reservoirs in wood products-in-use in that sector. We then extend the estimate to include all wood products-in-use. We find that the carbon pool of wood products in the Finnish construction and civil engineering sector grew by about 12% since an inventory for 2000, and that the overall estimate for carbon reservoirs of Finnish wood products in 2004 was 26.6 million tons of carbon. In building the scenarios until 2050, econometric time series models accounting for the relationship between wood material consumption and the development of GDP were used. The results indicate that the range of carbon reservoirs of wood products in Finland will be 39.6–64.2 million tons of carbon in the year 2050. The impacts of different forms of the decay function on the time-path of a carbon sink and its value in wood products were also studied. When a logistic decay pattern is used, the discounted value of the predicted carbon sink of wood products in Finland is between EUR850 and EUR1380 million – at the price level of EUR15/CO2 ton – as opposed to 440–900 million euros, if a geometric decay pattern is used.
  • Laturi, Finnish Forest Research Institute, Vantaa Research Unit, P.O. Box 18, FI-01301 Vantaa, Finland ORCID ID:E-mail: jani.laturi@metla.fi (email)
  • Mikkola, Finnish Forest Research Institute, Vantaa Research Unit, P.O. Box 18, FI-01301 Vantaa, Finland ORCID ID:E-mail:
  • Uusivuori, Finnish Forest Research Institute, Vantaa Research Unit, P.O. Box 18, FI-01301 Vantaa, Finland ORCID ID:E-mail:
article id 257, category Research article
Nadir Ayrilmis. (2008). Effect of compression wood on dimensional stability of medium density fiberboard. Silva Fennica vol. 42 no. 2 article id 257. https://doi.org/10.14214/sf.257
This study evaluated the effect of compression wood on dimensional stability of medium density fiberboards (MDF) manufactured from fiber furnishes of pine (Pinus nigra Arnold var. pallasiana) containing compression wood. Two panel types were manufactured from two different compression wood (CW) portion / normal wood (NW) portions in the furnish, 75/25 and 10/90, respectively. Linear and thickness variations of the panels exposed to various relative humidites at 20 °C, linear expansion/contraction and thickness swelling/shrinkage, were measured according to the procedures defined by DIN EN 318 (2005) standard test method. Panels made from fiber furnish containing 75% the CW had higher linear expansion and linear contraction values with an average value of 0.286% and 0.247% than those of panels made from fiber furnish containing 10% the CW with an average value of 0.184% and 0.152%, respectively. As for thickness swelling and thickness shrinkage properties, panels made from fiber furnish containing 75% the CW had the thickness swelling and thickness shrinkage values with an average of 5.042% and 4.402% while panels made from fiber furnish containing 10% the CW had the values with 3.621% and 2.861%, respectively. Consequently, based on the findings obtained from this study, expansion and swelling properties of the MDF panels were negatively affected by compression wood increase.
  • Ayrilmis, University of Istanbul, Faculty of Forestry, Department of Wood Mechanics and Technology, Bahcekoy, TR-34473 Istanbul, Turkey ORCID ID:E-mail: nadiray@istanbul.edu.tr (email)
article id 256, category Research article
Juha Laitila. (2008). Harvesting technology and the cost of fuel chips from early thinnings. Silva Fennica vol. 42 no. 2 article id 256. https://doi.org/10.14214/sf.256
This study compared and analyzed the procurement cost of whole tree chips when using supply chains based on comminution at the roadside landing or at the terminal. It also identified the bottlenecks of the most common logging systems used in Finland. The study was done by using existing and published productivity parameters and models. The procurement cost calculations were made for a stand where the forwarding distance was 200 metres, removal of whole trees was 60 m per hectare and the area of the stand was 2.0 hectares. The average size of the removed whole trees was 30 litres. The direct transport distance from the stand to the terminal or to the end use facility was 40 km while the secondary distance from the terminal to the end use facility was 10 km. A stumpage price for the harvested raw material was not included in this study. According to the study the cost of whole trees chips were 31.9–41.6 euros/m at the plant, or 14.9–19.4 euros/MWh when the moisture content of chips was estimated to be 40%. The two-machine system was found to be the most cost competitive logging system in pre-commercial thinnings thanks to both efficient cutting and, especially, forwarding work. In the manual worker based logging, the costs of felling bunching were the same as the mechanised system, whereas in forwarding the costs were almost double. Using the harwarder system the logging costs were found to be the highest, but in the larger tree volumes and removals the costs were almost equal to the manual worker based logging. The supply chain based on chipping at the roadside landing was more cost efficient compared to the chipping at the terminal system. The lower comminution cost at the terminal was not enough to cover the higher transportation cost of unprocessed material to the terminal, handling cost of chips at the terminal or the delivery cost to the end use facility.
  • Laitila, Finnish Forest Research Institute, Joensuu Research Unit, Joensuu, Finland ORCID ID:E-mail: juha.laitila@metla.fi (email)
article id 254, category Research article
Johanna Joensuu, Kari Heliövaara, Eino Savolainen. (2008). Risk of bark beetle (Coleoptera, Scolytidae) damage in a spruce forest restoration area in central Finland. Silva Fennica vol. 42 no. 2 article id 254. https://doi.org/10.14214/sf.254
A beetle inventory using window traps was performed to examine the effect of forest restoration by artificial addition of dead wood on the abundance of beetles and to evaluate the risk of bark beetle damage in a forest restoration area. The number of beetle families was slightly increased, but no consistent differences were found in the abundance of families containing saproxylic Coleoptera between the restoration and control plots. The abundance and species number of bark beetles and longhorn beetles were significantly higher on the restoration plots. Ips typographus and Pityogenes chalcographus increased only slightly in abundance. In the regression models produced, the abundance of bark beetles was best explained by the volume of recently dead wood. However, the bark beetle species whose abundance increased most were secondary and the material also suggests an increase in the abundance of bark beetles’ natural enemies. The risk of bark beetle damage in the area is thus considered insignificant.
  • Joensuu, Dept. of Forest Ecology, University of Helsinki, Finland ORCID ID:E-mail: johanna.joensuu@metsanhoitajat.fi (email)
  • Heliövaara, Dept. of Forest Ecology, University of Helsinki, Finland ORCID ID:E-mail:
  • Savolainen, Kuopio Natural History Museum, Kuopio, Finland ORCID ID:E-mail:
article id 250, category Research article
Saara Lilja-Rothsten, Michelle de Chantal, Chris Peterson, Timo Kuuluvainen, Ilkka Vanha-Majamaa, Pasi Puttonen. (2008). Microsites before and after restoration in managed Picea abies stands in southern Finland: effects of fire and partial cutting with dead wood creation. Silva Fennica vol. 42 no. 2 article id 250. https://doi.org/10.14214/sf.250
Different types of microsites, e.g. CWD (coarse woody debris), mounds, and uprooting pits, are important for tree regeneration and biodiversity. However, microsite diversity is greatly reduced in managed stands. We studied how restoration treatments changed microsite distribution in mature managed Picea abies stands. Four cutting treatments were used: uncut, low-CWD (5 m3 ha–1 of down retention trees, DRT, and 50 m3 ha–1 of standing retention trees), intermediate-CWD (as previous but leaving 30 m3 ha–1 of DRT), and high-CWD (as previous but with 60 m3 ha–1 of DRT). Timber harvested from stands ranged from 108–168 m3 ha–1. Half of the stands were burned, and half remained unburned. Sampling was stratified into upland and paludified biotopes within each stand. The pre-treatment microsite distributions were dominated by level ground in both biotopes; mounds and microsites on or next to CWD or a stump were slightly more abundant in the paludified than in the upland biotopes. Microsites were more diverse after cutting, with and without fire. The cutting treatment increased the relative abundances of microsites on or next to CWD. Fire consumed small diameter dead wood and flattened mounds. Microsites were more diverse in paludified than in upland biotopes. The results demonstrate that microsite diversity can rapidly be restored to structurally impoverished managed Picea stands despite a large portion of wood volume being harvested.
  • Lilja-Rothsten, University of Helsinki, Dept. of Forest Ecology, Finland ORCID ID:E-mail: saara.lilja@helsinki.fi (email)
  • Chantal, University of Helsinki, Dept. of Forest Ecology, Finland ORCID ID:E-mail:
  • Peterson, Dept. of Plant Biology, University of Georgia, Athens, GA, USA ORCID ID:E-mail:
  • Kuuluvainen, University of Helsinki, Dept. of Forest Ecology, Finland ORCID ID:E-mail:
  • Vanha-Majamaa, The Finnish Forest Research Institute, Vantaa Unit, Finland ORCID ID:E-mail:
  • Puttonen, The Finnish Forest Research Institute, Vantaa Unit, Finland ORCID ID:E-mail:
article id 267, category Research article
Manfred Gronalt, Peter Rauch. (2008). Vendor managed inventory in wood processing industries – a case study. Silva Fennica vol. 42 no. 1 article id 267. https://doi.org/10.14214/sf.267
Solid structure timber (SST) is an important building material in the wood construction business, in which its production volume is largely related to that respective business. Due to the large variability in the demand and seasonal factors, SST producers’ inventories are likely to be simultaneously overstocked for one type of timber and out of stock of another. An inventory policy that ensures a high service level and relatively low stocks is required. In the present paper, we propose the vendor managed inventory (VMI) approach for controlling the stock of deals that are produced at a sawmill and delivered as raw material for SST-production. We evaluate two VMI implementations against the actual inventory management for three different market scenarios. Furthermore, we layout the necessities for reconfiguring the business processes, and subsequently set up an organisational framework within VMI, which is indeed applicable in this segment of the woodworking industry. In our application background, VMI as an inventory control system is able to reduce the overall raw material stock by more than 37% by simultaneously increasing the SST service level.
  • Gronalt, BOKU – University of Natural Resources and Applied Life Sciences, Feistmantelstr. 4, 1180 Vienna, Austria ORCID ID:E-mail:
  • Rauch, BOKU – University of Natural Resources and Applied Life Sciences, Feistmantelstr. 4, 1180 Vienna, Austria ORCID ID:E-mail: peter.rauch@boku.ac.at
article id 266, category Research article
Mikko Havimo, Juha Rikala, Jari Sirviö, Marketta Sipi. (2008). Distributions of tracheid cross-sectional dimensions in different parts of Norway spruce stems. Silva Fennica vol. 42 no. 1 article id 266. https://doi.org/10.14214/sf.266
Distributions of three cross-sectional dimensions: radial and tangential tracheid width, and cell wall thickness in different timber assortments of Norway spruce were investigated. Wood samples from a mature stand were measured with SilviScan. In the analysis, virtual trees were constructed from measurement data, and divided into three assortments: whole stem, top pulpwood and sawmill chips. Average values and distributions of the properties were calculated for all assortments, and distributions divided into earlywood and latewood across the whole tree assortment. There was considerable variation within latewood in all three cross-sectional dimensions, but variation in earlywood was slight in radial width and cell wall thickness. In earlywood, tangential tracheid width showed considerable internal variation, and the difference between earlywood and latewood in tangential width was small. Within-assortment variation of all three properties was larger than between assortments. We may conclude that only a moderate difference in pulp properties can be achieved by sorting raw material into sawmill chips and top pulpwood. Pulp fractionation into earlywood and latewood seems to be a more efficient method, since it gives classes with small within-class variation and distinct average properties. However, it should be kept in mind that the results are valid only in mature stands, where growth rate variation and juvenile wood content are small.
  • Havimo, University of Helsinki, Department of Forest Resource Management, P.O. Box 27, FI-00014 University of Helsinki, Finland ORCID ID:E-mail: mikko.havimo@helsinki.fi (email)
  • Rikala, University of Helsinki, Department of Forest Resource Management, P.O. Box 27, FI-00014 University of Helsinki, Finland ORCID ID:E-mail:
  • Sirviö, KCL, P.O. Box 70, FI-02151 Espoo, Finland ORCID ID:E-mail:
  • Sipi, University of Helsinki, Department of Forest Resource Management, P.O. Box 27, FI-00014 University of Helsinki, Finland ORCID ID:E-mail:
article id 266, category Research article
Mikko Havimo, Juha Rikala, Jari Sirviö, Marketta Sipi. (2008). Distributions of tracheid cross-sectional dimensions in different parts of Norway spruce stems. Silva Fennica vol. 42 no. 1 article id 266. https://doi.org/10.14214/sf.266
Distributions of three cross-sectional dimensions: radial and tangential tracheid width, and cell wall thickness in different timber assortments of Norway spruce were investigated. Wood samples from a mature stand were measured with SilviScan. In the analysis, virtual trees were constructed from measurement data, and divided into three assortments: whole stem, top pulpwood and sawmill chips. Average values and distributions of the properties were calculated for all assortments, and distributions divided into earlywood and latewood across the whole tree assortment. There was considerable variation within latewood in all three cross-sectional dimensions, but variation in earlywood was slight in radial width and cell wall thickness. In earlywood, tangential tracheid width showed considerable internal variation, and the difference between earlywood and latewood in tangential width was small. Within-assortment variation of all three properties was larger than between assortments. We may conclude that only a moderate difference in pulp properties can be achieved by sorting raw material into sawmill chips and top pulpwood. Pulp fractionation into earlywood and latewood seems to be a more efficient method, since it gives classes with small within-class variation and distinct average properties. However, it should be kept in mind that the results are valid only in mature stands, where growth rate variation and juvenile wood content are small.
  • Havimo, University of Helsinki, Department of Forest Resource Management, P.O. Box 27, FI-00014 University of Helsinki, Finland ORCID ID:E-mail: mikko.havimo@helsinki.fi (email)
  • Rikala, University of Helsinki, Department of Forest Resource Management, P.O. Box 27, FI-00014 University of Helsinki, Finland ORCID ID:E-mail:
  • Sirviö, KCL, P.O. Box 70, FI-02151 Espoo, Finland ORCID ID:E-mail:
  • Sipi, University of Helsinki, Department of Forest Resource Management, P.O. Box 27, FI-00014 University of Helsinki, Finland ORCID ID:E-mail:
article id 278, category Research article
Katri Luostarinen. (2007). The effect of annual ring orientation and drying method on deformations, casehardening and colour of silver birch (Betula pendula) boards. Silva Fennica vol. 41 no. 4 article id 278. https://doi.org/10.14214/sf.278
Deformations of timber, caused mainly by anisotropic shrinkage, can be partially directed by controlling annual ring orientation through different sawing patterns. Ring orientation also affects the movement of water from within the board to its surface, with rapidity of drying having implications for the wood colour. Here sawn silver birch (Betula pendula Roth) timber was classed into two groups according to ring orientation. Two drying methods were used. The final moisture content was lower and the colour lighter in dried boards with radial than with tangential flats, but deformations were larger in radial than in tangential boards. Both drying and ring orientation affected the final moisture content and moisture gradient of the boards. Very small differences in board sizes or shape had an effect on both colour and deformations. The results support the need for accurate sawing and for classing silver birch timber sawn into parquet billets according to ring orientation in order to optimise the drying quality.
  • Luostarinen, University of Joensuu, Faculty of Forest Sciences, P.O. Box 111, FI-80101 Joensuu, Finland ORCID ID:E-mail: katri.luostarinen@joensuu.fi (email)
article id 273, category Research article
Stefan Mattson, Urban Bergsten, Tommy Mörling. (2007). Pinus contorta growth in boreal Sweden as affected by combined lupin treatment and soil scarification. Silva Fennica vol. 41 no. 4 article id 273. https://doi.org/10.14214/sf.273
Effects of combining lupin (Lupinus nootkatensis L.) establishment and soil scarification on stem volume and stem biomass yield of lodgepole pine (Pinus contorta Dougl. var. latifolia Engelm.) were studied on a poor boreal site in Sweden 18 years after plantation. A field randomized block experiment was established with three different scarification techniques (disc trenching, moulding and ploughing) followed by establishment of lupins by either seeds or roots. There were three blocks without and two blocks with lupins. Overall, on average for the three soil scarification techniques, the lupin treatment significantly increased the volume per hectare by 102%.The lupin treatment significantly increased the stem volume per hectare by 236% for mounding and 139% for disc trenching, whereas the 55% increase for ploughing was not significant. The increase in the total stem biomass yield per tree was more pronounced for larger trees; 46% for average trees and 106% for dominant trees. However, there were no significant differences between scarification techniques for the lupin treatment in total stem biomass yield. Over the 18-year period, the increased growth rate following the lupin treatment resulted in a significantly decreased average stem basic wood density (on average 6%) for the sample trees. Because lupin is a nitrogen-fixing plant species, the large increase in tree growth following the lupin treatment was probably an effect of increased amount of nitrogen in the soil. The results indicate that use of lupin is a possible alternative to increase site productivity of lodgepole pine on poor boreal sites.
  • Mattson, Swedish University of Agricultural Sciences, Dept of Forest Ecology and Management, SE-901 83 Umeå, Sweden ORCID ID:E-mail:
  • Bergsten, Swedish University of Agricultural Sciences, Dept of Forest Ecology and Management, SE-901 83 Umeå, Sweden ORCID ID:E-mail:
  • Mörling, Swedish University of Agricultural Sciences, Dept of Forest Ecology and Management, SE-901 83 Umeå, Sweden ORCID ID:E-mail: tommy.morling@ssko.slu.se (email)
article id 286, category Research article
Riitta Hänninen, A. Maarit I. Kallio. (2007). Economic impacts on the forest sector of increasing forest biodiversity conservation in Finland. Silva Fennica vol. 41 no. 3 article id 286. https://doi.org/10.14214/sf.286
In the next coming years, political decisions will be made upon future actions to safeguard forest biodiversity in Southern Finland. We address the economic consequences on the Finnish forest sector of conserving additional 0.5% to 5% of the old growth forest land in Southern Finland. The impacts on supply, demand and prices of wood and forest industry production are analysed employing a partial equilibrium model of the Finnish forest sector. An increase in conservation raises wood prices and thus the production costs of the forest industry. This makes sawnwood production fall, but does not affect paper and paperboard production. The forest owners’ aggregated wood sales income is unaffected or slightly increased, because an increase in stumpage prices offsets the decrease in the harvests. If conservation increases wood imports, negative effects on forest industry become smaller whereas aggregated forest owners’ income may decline depending on the magnitude of import substitution.
  • Hänninen, Finnish Forest Research Institute, Unioninkatu 40 A, FI-00170 Helsinki, Finland ORCID ID:E-mail: riitta.hanninen@metla.fi (email)
  • Kallio, Finnish Forest Research Institute, Unioninkatu 40 A, FI-00170 Helsinki, Finland ORCID ID:E-mail: maarit.kallio@metla.fi
article id 285, category Research article
Heli Peltola, Antti Kilpeläinen, Kari Sauvala, Tommi Räisänen, Veli-Pekka Ikonen. (2007). Effects of early thinning regime and tree status on the radial growth and wood density of Scots pine. Silva Fennica vol. 41 no. 3 article id 285. https://doi.org/10.14214/sf.285
In this work, we studied the effects of early thinning on the radial growth and wood density over a 12-year post-thinning period in Scots pine (Pinus sylvestris L.) trees grown on a site with a rather poor nutrient supply. Ring width, early and late wood width and early wood percentage, mean intra-ring wood density and early- and late wood density were analyzed in 98 sample trees using X-ray microdensitometry. For the analyses, ten different thinning plots with post-thinning stand density varying from 575 to 3400 stems ha–1 were grouped into four classes representing heavy thinning, moderate thinning, light thinning and no thinning. We found that the radial growth in the thinned treatments increased significantly compared to that of the unthinned treatment. Despite this, the mean intra-ring wood density did not decrease significantly as a result of heavy thinning, although it was 2% less, on average (with a range of 1–4% in large and small trees), compared to that of the unthinned treatment. In the lightly thinned treatment, the mean intra-ring wood density even increased by 5%, on average (with a range 4–7% in small and large trees), but in the moderately thinned treatment, the level of change was not as clear. The thinning response of trees representing different status in a stand differed significantly and was also affected by the post-thinning stand density. Altogether, observed simultaneous increases in early and late wood widths and late wood density, but a decrease in early wood density indicate that as a result of heavy thinning, especially, un-uniformity of wood density will increase. On the other hand, although heavy thinning increased tree growth by 9–20%, on average, compared to moderate thinning, which corresponds quite well with business-as-usual management, mean wood density decreased only 0–4% depending on tree status in a stand (from large to small trees). Thus, the decrease observed in wood density was less than expected as a result of heavy thinning at an early stage of stand development, which has recently been recommended as one possible management option in Scots pine in Finland.
  • Peltola, University of Joensuu, Faculty of Forest Sciences, P.O. Box 111, FI-80101 Joensuu, Finland ORCID ID:E-mail: heli.peltola@joensuu.fi (email)
  • Kilpeläinen, University of Joensuu, Faculty of Forest Sciences, P.O. Box 111, FI-80101 Joensuu, Finland ORCID ID:E-mail:
  • Sauvala, Finnish Forest Research Institute, P.O. Box 18, FI-01301 Vantaa, Finland ORCID ID:E-mail:
  • Räisänen, University of Joensuu, Faculty of Forest Sciences, P.O. Box 111, FI-80101 Joensuu, Finland ORCID ID:E-mail:
  • Ikonen, University of Joensuu, Faculty of Forest Sciences, P.O. Box 111, FI-80101 Joensuu, Finland ORCID ID:E-mail:
article id 285, category Research article
Heli Peltola, Antti Kilpeläinen, Kari Sauvala, Tommi Räisänen, Veli-Pekka Ikonen. (2007). Effects of early thinning regime and tree status on the radial growth and wood density of Scots pine. Silva Fennica vol. 41 no. 3 article id 285. https://doi.org/10.14214/sf.285
In this work, we studied the effects of early thinning on the radial growth and wood density over a 12-year post-thinning period in Scots pine (Pinus sylvestris L.) trees grown on a site with a rather poor nutrient supply. Ring width, early and late wood width and early wood percentage, mean intra-ring wood density and early- and late wood density were analyzed in 98 sample trees using X-ray microdensitometry. For the analyses, ten different thinning plots with post-thinning stand density varying from 575 to 3400 stems ha–1 were grouped into four classes representing heavy thinning, moderate thinning, light thinning and no thinning. We found that the radial growth in the thinned treatments increased significantly compared to that of the unthinned treatment. Despite this, the mean intra-ring wood density did not decrease significantly as a result of heavy thinning, although it was 2% less, on average (with a range of 1–4% in large and small trees), compared to that of the unthinned treatment. In the lightly thinned treatment, the mean intra-ring wood density even increased by 5%, on average (with a range 4–7% in small and large trees), but in the moderately thinned treatment, the level of change was not as clear. The thinning response of trees representing different status in a stand differed significantly and was also affected by the post-thinning stand density. Altogether, observed simultaneous increases in early and late wood widths and late wood density, but a decrease in early wood density indicate that as a result of heavy thinning, especially, un-uniformity of wood density will increase. On the other hand, although heavy thinning increased tree growth by 9–20%, on average, compared to moderate thinning, which corresponds quite well with business-as-usual management, mean wood density decreased only 0–4% depending on tree status in a stand (from large to small trees). Thus, the decrease observed in wood density was less than expected as a result of heavy thinning at an early stage of stand development, which has recently been recommended as one possible management option in Scots pine in Finland.
  • Peltola, University of Joensuu, Faculty of Forest Sciences, P.O. Box 111, FI-80101 Joensuu, Finland ORCID ID:E-mail: heli.peltola@joensuu.fi (email)
  • Kilpeläinen, University of Joensuu, Faculty of Forest Sciences, P.O. Box 111, FI-80101 Joensuu, Finland ORCID ID:E-mail:
  • Sauvala, Finnish Forest Research Institute, P.O. Box 18, FI-01301 Vantaa, Finland ORCID ID:E-mail:
  • Räisänen, University of Joensuu, Faculty of Forest Sciences, P.O. Box 111, FI-80101 Joensuu, Finland ORCID ID:E-mail:
  • Ikonen, University of Joensuu, Faculty of Forest Sciences, P.O. Box 111, FI-80101 Joensuu, Finland ORCID ID:E-mail:
article id 285, category Research article
Heli Peltola, Antti Kilpeläinen, Kari Sauvala, Tommi Räisänen, Veli-Pekka Ikonen. (2007). Effects of early thinning regime and tree status on the radial growth and wood density of Scots pine. Silva Fennica vol. 41 no. 3 article id 285. https://doi.org/10.14214/sf.285
In this work, we studied the effects of early thinning on the radial growth and wood density over a 12-year post-thinning period in Scots pine (Pinus sylvestris L.) trees grown on a site with a rather poor nutrient supply. Ring width, early and late wood width and early wood percentage, mean intra-ring wood density and early- and late wood density were analyzed in 98 sample trees using X-ray microdensitometry. For the analyses, ten different thinning plots with post-thinning stand density varying from 575 to 3400 stems ha–1 were grouped into four classes representing heavy thinning, moderate thinning, light thinning and no thinning. We found that the radial growth in the thinned treatments increased significantly compared to that of the unthinned treatment. Despite this, the mean intra-ring wood density did not decrease significantly as a result of heavy thinning, although it was 2% less, on average (with a range of 1–4% in large and small trees), compared to that of the unthinned treatment. In the lightly thinned treatment, the mean intra-ring wood density even increased by 5%, on average (with a range 4–7% in small and large trees), but in the moderately thinned treatment, the level of change was not as clear. The thinning response of trees representing different status in a stand differed significantly and was also affected by the post-thinning stand density. Altogether, observed simultaneous increases in early and late wood widths and late wood density, but a decrease in early wood density indicate that as a result of heavy thinning, especially, un-uniformity of wood density will increase. On the other hand, although heavy thinning increased tree growth by 9–20%, on average, compared to moderate thinning, which corresponds quite well with business-as-usual management, mean wood density decreased only 0–4% depending on tree status in a stand (from large to small trees). Thus, the decrease observed in wood density was less than expected as a result of heavy thinning at an early stage of stand development, which has recently been recommended as one possible management option in Scots pine in Finland.
  • Peltola, University of Joensuu, Faculty of Forest Sciences, P.O. Box 111, FI-80101 Joensuu, Finland ORCID ID:E-mail: heli.peltola@joensuu.fi (email)
  • Kilpeläinen, University of Joensuu, Faculty of Forest Sciences, P.O. Box 111, FI-80101 Joensuu, Finland ORCID ID:E-mail:
  • Sauvala, Finnish Forest Research Institute, P.O. Box 18, FI-01301 Vantaa, Finland ORCID ID:E-mail:
  • Räisänen, University of Joensuu, Faculty of Forest Sciences, P.O. Box 111, FI-80101 Joensuu, Finland ORCID ID:E-mail:
  • Ikonen, University of Joensuu, Faculty of Forest Sciences, P.O. Box 111, FI-80101 Joensuu, Finland ORCID ID:E-mail:
article id 322, category Research article
Jaakko Repola. (2006). Models for vertical wood density of Scots pine, Norway spruce and birch stems, and their application to determine average wood density. Silva Fennica vol. 40 no. 4 article id 322. https://doi.org/10.14214/sf.322
The purpose of this study was to investigate the vertical dependence of the basic density of Scots pine, Norway spruce, and birch stems, and how such dependence could be applied for determining the average stem wood density. The study material consisted of 38 Scots pine (Pinus sylvestris), 39 Norway spruce (Picea abies [L.] Karst.) and 15 birch (Betula pendula and Betula pubescens) stands located on mineral soil sites in southern Finland. The stem material mainly represented thinning removal from stands at different stages of development. The linear mixed model technique, with both fixed and random effects, was used to estimate the model. According to the fixed part of the model, wood density was dependent on the vertical location along the stem in all three tree species. Wood density in pine decreased from the butt to the top, and the gradient in wood density was steep at the butt but decreased in the upper part of the stem. The vertical dependence was similar in birch, but the density gradient was much smaller. For spruce the vertical dependence of the basic density was moderate. The model can be calibrated for a tree stem when one or more sample disks are measured at freely selected heights. Using treewise calibrated predictions of the vertical density dependence and measured stem diameters, almost unbiased estimates, and lower prediction errors than with traditional methods, were obtained for the average stem wood density. The advantages of the method were greater for pine with a strong vertical dependence in basic density, than for spruce and birch.
  • Repola, Finnish Forest Research Institute, Rovaniemi Research Unit, Eteläranta 55, FI-96300 Rovaniemi, Finland ORCID ID:E-mail: jaakko.repola@metla.fi (email)
article id 358, category Research article
Turgay Akbulut, Nadir Ayrilmis. (2006). Effect of compression wood on surface roughness and surface absorption of medium density fiberboard. Silva Fennica vol. 40 no. 1 article id 358. https://doi.org/10.14214/sf.358
Compression wood is undoubtedly one of the most important raw material variables in wood based panel manufacturing. This study evaluated effect of compression wood on surface roughness and surface absorption (flow distance) of medium density fiberboards (MDF) manufactured from furnishes of pine (Pinus nigra Arnold var. pallasiana) containing compression wood. Panels were manufactured from two different portions of the furnish, one of the portions having a compression wood/normal wood ratio of 75/25, and the other having a ratio of 10/90. Surface absorption and surface roughness were determined according to (EN 382-1) and (ISO 4287), respectively. It was found that panels made from furnish with a 75/25 ratio had a significantly lower surface absorption value (255.78 mm) than panels made from furnish with a 10/90 ratio (317.95 mm). Surface roughness measurements based on three roughness parameters, average roughness (Ra), mean peak-to-valley height (Rz), and maximum peak-to-valley height (Ry) were considered to evaluate the surface characteristics of the panels and supported the above findings as the panels made from furnish with a 75/25 ratio had slightly rougher surface with average values of 4.15 µm (Ra). From the tests performed, we conclude that increasing of the compression wood portion increased the surface roughness and decreased the surface absorption value.
  • Akbulut, Istanbul University, Faculty of Forestry, Bahcekoy, TR-34473 Istanbul, Turkey ORCID ID:E-mail:
  • Ayrilmis, Istanbul University, Faculty of Forestry, Bahcekoy, TR-34473 Istanbul, Turkey ORCID ID:E-mail: nadiray@istanbul.edu.tr (email)
article id 354, category Research article
Mervi Talvitie, Olli Leino, Markus Holopainen. (2006). Inventory of sparse forest populations using adaptive cluster sampling. Silva Fennica vol. 40 no. 1 article id 354. https://doi.org/10.14214/sf.354
In many studies, adaptive cluster sampling (ACS) proved to be a powerful tool for assessing rare clustered populations that are difficult to estimate by means of conventional sampling methods. During 2002 and 2003, severe drought-caused damage was observed in the park forests of the City of Helsinki, Finland, especially in barren site pine and spruce stands. The aim of the present study was to examine sampling and measurement methods for assessing drought damage by analysing the effectiveness of ACS compared with simple random sampling (SRS). Horvitz-Thompson and Hansen-Hurwitz estimators of the ACS method were used for estimating the population mean and variance of the variable of interest. ACS was considerably more effective than SRS in assessing rare clustered populations such as those resulting from drought damage. The variances in the ACS methods were significantly smaller and the inventory efficiency in the field better than in SRS.
  • Talvitie, University of Helsinki, Department of Forest Resource Management, P.O. Box 27, FI-00014 University of Helsinki, Finland ORCID ID:E-mail: mervi.talvitie@helsinki.fi (email)
  • Leino, University of Helsinki, Department of Forest Resource Management, P.O. Box 27, FI-00014 University of Helsinki, Finland ORCID ID:E-mail:
  • Holopainen, University of Helsinki, Department of Forest Resource Management, P.O. Box 27, FI-00014 University of Helsinki, Finland ORCID ID:E-mail:
article id 479, category Research article
Ken Olaf Storaunet, Jørund Rolstad, Ivar Gjerde, Vegard S. Gundersen. (2005). Historical logging, productivity, and structural characteristics of boreal coniferous forests in Norway. Silva Fennica vol. 39 no. 3 article id 479. https://doi.org/10.14214/sf.479
Conservation of forest biodiversity has brought about an interest in evaluating the naturalness of forests, and to locate and protect semi-natural and old-growth forests in the Fennoscandian countries. However, it is not always clear how natural these forests really are, and how the past management history has affected their present structural composition. We studied the relationships between cut stumps from historical logging activity (50–100 years ago) and forest structural characteristics of today in a total of 385 0.25 ha plots in three boreal coniferous forests which are parts of National Nature Reserves in Norway. We also studied how forest productivity influenced these relationships. In plots with negligible logging impact we found the amount of living trees, dead wood, and size of the oldest trees mainly to increase with increasing productivity, whereas the age of the oldest trees decreased. The amount of deciduous trees was generally low irrespective of productivity. The intensity of logging did not consistently influence most of these forest structural variables, neither at low- nor at high-productive sites. The only consistent relationship in all study areas was a decreasing amount of dead wood with increasing logging intensity at high-productive sites. Also, the decay class distribution of dead wood was more right-skewed (indicating on-going accumulation of dead wood) the more logging had occurred at high-productive sites. Except from the effects on dead wood, previous logging does not show up as a major determinant of other stand structures of today.
  • Storaunet, Norwegian Forest Research Institute, Høgskolevegen 8, NO-1432 Ås, Norway ORCID ID:E-mail: ken.storaunet@skogforsk.no (email)
  • Rolstad, Norwegian Forest Research Institute, Høgskolevegen 8, NO-1432 Ås, Norway ORCID ID:E-mail:
  • Gjerde, Norwegian Forest Research Institute, Fanaflaten 4, NO-5244 Fana, Norway ORCID ID:E-mail:
  • Gundersen, Norwegian Forest Research Institute, Fanaflaten 4, NO-5244 Fana, Norway ORCID ID:E-mail:
article id 375, category Research article
Edgar Víquez, Diego Pérez. (2005). Effect of pruning on tree growth, yield, and wood properties of Tectona grandis plantations in Costa Rica. Silva Fennica vol. 39 no. 3 article id 375. https://doi.org/10.14214/sf.375
Reduced plantation densities have the effect that obtaining natural pruning and stem straightness are less assured. The physiological process of self-pruning is replaced by manual pruning. Generally, plantations are denser and have more uniform spacing than natural forests. In many, if not most species, natural pruning is never a satisfactory option, even after branch senescence, if production of clear wood is a management objective. Natural pruning can only be considered on a species by species basis. This study reports on the first results of a pruning trial for Tectona grandis L.F. plantations in Costa Rica. The treatments consisted of pruning heights of 3.0, 4.0, and 5.0 meters, and the Control without pruning. Differences among treatments in DBH and total height were significant at 3.2, 5.2, and 6.1 years of age, but not at 7.3 years. Under an intensive pruning regime, a teak tree at rotation (20 years) may yield over 40% of knot-free volume (over 60% of the merchantable tree volume). Current findings open a scope for new management options, aiming at improving stem form and wood quality by means of an intensive pruning regime, without having a detrimental effect on tree growth and stand yield.
  • Víquez, Tropical Agricultural Research and Higher Education Center (CATIE), Apartado 7170 CATIE, Turrialba, Costa Rica ORCID ID:E-mail: eviquez@catie.ac.cr (email)
  • Pérez, Ambiente Tierra S.A., Apartado 733-2250, Tres Ríos, Cartago, Costa Rica ORCID ID:E-mail:
article id 375, category Research article
Edgar Víquez, Diego Pérez. (2005). Effect of pruning on tree growth, yield, and wood properties of Tectona grandis plantations in Costa Rica. Silva Fennica vol. 39 no. 3 article id 375. https://doi.org/10.14214/sf.375
Reduced plantation densities have the effect that obtaining natural pruning and stem straightness are less assured. The physiological process of self-pruning is replaced by manual pruning. Generally, plantations are denser and have more uniform spacing than natural forests. In many, if not most species, natural pruning is never a satisfactory option, even after branch senescence, if production of clear wood is a management objective. Natural pruning can only be considered on a species by species basis. This study reports on the first results of a pruning trial for Tectona grandis L.F. plantations in Costa Rica. The treatments consisted of pruning heights of 3.0, 4.0, and 5.0 meters, and the Control without pruning. Differences among treatments in DBH and total height were significant at 3.2, 5.2, and 6.1 years of age, but not at 7.3 years. Under an intensive pruning regime, a teak tree at rotation (20 years) may yield over 40% of knot-free volume (over 60% of the merchantable tree volume). Current findings open a scope for new management options, aiming at improving stem form and wood quality by means of an intensive pruning regime, without having a detrimental effect on tree growth and stand yield.
  • Víquez, Tropical Agricultural Research and Higher Education Center (CATIE), Apartado 7170 CATIE, Turrialba, Costa Rica ORCID ID:E-mail: eviquez@catie.ac.cr (email)
  • Pérez, Ambiente Tierra S.A., Apartado 733-2250, Tres Ríos, Cartago, Costa Rica ORCID ID:E-mail:
article id 389, category Research article
Ritva Toivonen, Eric Hansen, Erno Järvinen, Raija-Riitta Enroth. (2005). The competitive position of the Nordic wood industry in Germany – intangible quality dimensions. Silva Fennica vol. 39 no. 2 article id 389. https://doi.org/10.14214/sf.389
This study examines the importance of various intangible product quality dimensions as perceived by wood-trading retailer and wholesaler companies in Germany. Using perceived importance and perceived performance, the study first examines the dimensionality of intangible product quality and then compares Nordic wood product suppliers with suppliers from other major supply regions. Data was collected from 76 German companies during 2000–2001. Results indicate that intangible product quality can be described in three dimensions, “Behaviour and Image”, “Serviceability and Environment”, and “Reliability”. Results also show that Nordic suppliers do not have a strong competitive position in Germany in terms of intangible product quality dimensions. Thus, Nordic suppliers could improve their competitive position by enhancing their service, logistics and other dimensions of the intangible product offering.
  • Toivonen, Pellervo Economic Research Institute PTT, Eerikinkatu 28 A, FI-00180, Helsinki, Finland ORCID ID:E-mail: ritva.toivonen@dnainternet.net (email)
  • Hansen, Oregon State University, Dept. of Wood Science & Engineering, Richardson Hall 108, 97331-5751 Corvallis, OR, USA ORCID ID:E-mail:
  • Järvinen, Pellervo Economic Research Institute PTT, Eerikinkatu 28 A, FI-00180, Helsinki, Finland ORCID ID:E-mail:
  • Enroth, Finnish Forest Research Institute, Unioninkatu 40 A, FI-00170 Helsinki, Finland ORCID ID:E-mail:
article id 388, category Research article
Jacob Edlund, Mats Warensjö. (2005). Repeatability in automatic sorting of curved Norway spruce saw logs. Silva Fennica vol. 39 no. 2 article id 388. https://doi.org/10.14214/sf.388
Sawn wood from curved logs is prone to have cross grain and contain compression wood, both of which affect the dimensional stability. Different types of curvature can, however, have different effects on both the sawing process and board quality, which is why a standard measure of bow height alone is not enough to sort logs or set the log quality. The aim of this study was to evaluate the repeatability when sorting curved saw logs using a 3D log scanner. In the study, 56 logs were categorized into five different curvature types and four different degrees of curvature severity. The logs were run through a Rema 3D log scanner four times, and the external geometry was recorded. From the geometry data, variables describing log shapes were calculated and used to develop models using linear discriminant analysis, which was used to classify the logs according to curvature type. The accuracy and repeatability were evaluated for the classifications with Cohen’s simple Kappa coefficient. The results of this study showed that it is possible to sort logs by curve type using a 3D log scanner, although sorting by curve type was largely dependent on curve severity. The repeatability test determined that the chance of a curved log being graded identically two consecutive times was 0.40, measured as kappa.
  • Edlund, SLU, Department of Forest Products and Markets, P.O. Box 7060, SE-750 07 Uppsala, Sweden ORCID ID:E-mail: jacob.edlund@spm.slu.se (email)
  • Warensjö, SLU, Department of Forest Products and Markets, P.O. Box 7060, SE-750 07 Uppsala, Sweden ORCID ID:E-mail:
article id 385, category Research article
Diego Pérez, Markku Kanninen. (2005). Effect of thinning on stem form and wood characteristics of teak (Tectona grandis) in a humid tropical site in Costa Rica. Silva Fennica vol. 39 no. 2 article id 385. https://doi.org/10.14214/sf.385
The aim of the study was to evaluate the effects of thinning intensity on wood properties, such as heartwood proportion, wood basic density, and stem form of teak (Tectona grandis L.f.). The thinning trial was established on a teak plantation in a humid tropical site in northern Costa Rica. The moderate and heavy thinnings yielded the highest percentage of heartwood volume (25 to 30% of total stem volume). The differences between stem form factors under different treatments were not statistically significant after separating thinning effects from timing effects. Both the highest (> 0.65 g cm–3) and the lowest (< 0.50 g cm–3) wood density values were observed under light thinnings, making it difficult to establish a relationship. Large variations in wood properties found under different thinning regimes suggest that at early stages teak stands can be managed under different thinning programs without negatively affecting the quality of wood under humid tropical conditions.
  • Pérez, Ambiente Tierra S.A., Apartado 733-2250, Tres Ríos, Cartago, Costa Rica ORCID ID:E-mail: diegoperez@costarricense.cr (email)
  • Kanninen, Center for International Forestry Research (CIFOR), Bogor, Indonesia ORCID ID:E-mail:
article id 385, category Research article
Diego Pérez, Markku Kanninen. (2005). Effect of thinning on stem form and wood characteristics of teak (Tectona grandis) in a humid tropical site in Costa Rica. Silva Fennica vol. 39 no. 2 article id 385. https://doi.org/10.14214/sf.385
The aim of the study was to evaluate the effects of thinning intensity on wood properties, such as heartwood proportion, wood basic density, and stem form of teak (Tectona grandis L.f.). The thinning trial was established on a teak plantation in a humid tropical site in northern Costa Rica. The moderate and heavy thinnings yielded the highest percentage of heartwood volume (25 to 30% of total stem volume). The differences between stem form factors under different treatments were not statistically significant after separating thinning effects from timing effects. Both the highest (> 0.65 g cm–3) and the lowest (< 0.50 g cm–3) wood density values were observed under light thinnings, making it difficult to establish a relationship. Large variations in wood properties found under different thinning regimes suggest that at early stages teak stands can be managed under different thinning programs without negatively affecting the quality of wood under humid tropical conditions.
  • Pérez, Ambiente Tierra S.A., Apartado 733-2250, Tres Ríos, Cartago, Costa Rica ORCID ID:E-mail: diegoperez@costarricense.cr (email)
  • Kanninen, Center for International Forestry Research (CIFOR), Bogor, Indonesia ORCID ID:E-mail:
article id 400, category Research article
Antti Mutanen, Anne Toppinen. (2005). Finnish sawlog market under forest taxation reform. Silva Fennica vol. 39 no. 1 article id 400. https://doi.org/10.14214/sf.400
The stepwise transition in forest taxation from site productivity tax to taxation of profits from timber sales was one of the major institutional changes to impact Finnish non-industrial private forest owners in the 1990s. In this study the effect of the forest taxation reform on the aggregate supply of sawlogs was investigated using time series analysis and quarterly data. In particular, we estimated two simultaneous equations systems for the pine and the spruce sawlog markets. According to the results, the forest taxation reform strengthened the supply of spruce and pine sawlogs in the anticipatory stage of the taxation reform in 1992. Also during the fiscal transition period, which started in 1993, the supply effect of the taxation reform has clearly been positive. The strong own-price elasticity of sawlog supply found in this study indicates high sensitivity to actual and expected wood price changes in the determination of sawlog supply in Finland. Furthermore, the results indicate that the theoretical assumption of a competitive market is suitable for the Finnish sawlog market, but that separate analysis of pine and spruce sawlogs provides additional insights into market behaviour.
  • Mutanen, Finnish Forest Research Institute, Joensuu Research Centre, P.O. Box 68, FI-80101 Joensuu, Finland ORCID ID:E-mail: antti.mutanen@metla.fi (email)
  • Toppinen, Finnish Forest Research Institute, Joensuu Research Centre, P.O. Box 68, FI-80101 Joensuu, Finland ORCID ID:E-mail:
article id 399, category Research article
Torjus F. Bolkesjø. (2005). Projecting pulpwood prices under different assumptions on future capacities in the pulp and paper industry. Silva Fennica vol. 39 no. 1 article id 399. https://doi.org/10.14214/sf.399
Capacity changes in the pulp and paper industry affect demand for pulpwood and thus pulpwood prices. This paper analyzes the impacts on roundwood prices in Norway of two possible capacity changes (one new machine and one close-down) that currently are high on the agenda in the Norwegian paper industry, and assesses the generality of the results obtained from these case studies. The two cases are implemented exogenously into a regionalized partial equilibrium forest sector model, and the capacity change scenarios are compared with a business as usual scenario assuming no demand shocks. The projected pulpwood prices change significantly in regions near mills where capacity shifts, at least for the close-down case, but only moderately at an aggregated national level. The reduction in prices under the close-down studied is higher than the price increase from the possible capacity increase case. The asymmetric price responses projected for the two case studies are supported by sensitivity analyses on other regions and cases (technologies). For the capacity increase case it is shown that the level of the projected pulpwood price is sensitive to assumptions on base-year prices and transport costs of imported roundwood, but the magnitudes of the price increases projected as a result of increased demand are less affected by these assumptions.
  • Bolkesjø, Norwegian University of Life Sciences, Dept. of Ecology and Natural Resource Management, Høyskoleveien 14, NO-1432 Ås, Norway ORCID ID:E-mail: torjus.bolkesjo@umb.no (email)
article id 393, category Research article
Seppo Rouvinen, Anne Rautiainen, Jari Kouki. (2005). A relation between historical forest use and current dead woody material in a boreal protected old-growth forest in Finland. Silva Fennica vol. 39 no. 1 article id 393. https://doi.org/10.14214/sf.393
Assessing the human impact on the naturalness and vegetation characteristics of protected areas is one of the key issues when designing forest conservation networks in Fennoscandia. We studied the small-scale, detailed relationship between forest utilization history and the current availability of dead woody material in a protected old-growth forest area in North Karelia, eastern Finland. From the study area of 32.4 ha, all the stumps (diameter ≥ 5 cm and height < 1.3 m, classified as natural, man-made and of undetermined origin) were measured using 25 x 25 m sub-plots. Standing and fallen dead trees (dbh ≥ 5 cm) were measured on 50 x 50 m plots in an area of 7.8 ha. The average number of stumps was 130 per ha, and over half of the stumps were classified as man-made. However, the historical documents since the 1910s showed no logging in the area: some of the largest man-made stumps probably originated from an earlier time, but most of those stumps were made considerably later. The variation in the total number of stumps (per ha) was great (range 0–560/ha, 0–16 m2/ha), with no clear clustering in space. However, clustering of man-made stumps was detected. The average volume of pooled standing and fallen trees was 84 m3/ha, with a range of 37–146 m3/ha. The other noticeable man-made disturbance besides logging was notching of aspens, which has a scatteredly significant influence on the amount of dead trees. In conclusion, the protected old-growth forest was not as a whole in a natural state but showed different degrees of human impact from virtually untouched patches to quite heavily managed patches. The results suggest that the number of man-made stumps may be a relatively quick and easy method of assessing the naturalness of woody biomass structure in the Fennoscandian boreal forests.
  • Rouvinen, University of Joensuu, Faculty of Forestry, P.O. Box 111, FI-80101 Joensuu, Finland ORCID ID:E-mail: seppo.rouvinen@joensuu.fi (email)
  • Rautiainen, University of Joensuu, Faculty of Forestry, P.O. Box 111, FI-80101 Joensuu, Finland ORCID ID:E-mail:
  • Kouki, University of Joensuu, Faculty of Forestry, P.O. Box 111, FI-80101 Joensuu, Finland ORCID ID:E-mail:
article id 415, category Research article
Sandhya Samarasinghe, Don Kulasiri. (2004). Stress intensity factor of wood from crack-tip displacement fields obtained from digital image processing. Silva Fennica vol. 38 no. 3 article id 415. https://doi.org/10.14214/sf.415
Stress intensity factor of radiata pine (Pinus radiata) in Tangential-Longitudinal opening mode was determined from crack-tip displacement fields obtained from digital image correlation in conjunction with orthotropic fracture theory. For lower loads, experiments agreed with the linear elastic fracture theory but for higher loads, stress intensity factor and load relationship was nonlinear. For 41% of the specimens tested, tip-displacement based stress intensity factor agreed with that based on the ASTM standard formula for lower loads but deviated for higher loads closer to failure. The tip displacement plots showed that the nonlinear behaviour is due to large displacements which we attributed to large plastic deformations and/or micro-cracking in this region. The other 59% specimens showed a similar trend except that the crack-tip based stress intensity factor was consistently higher than the value obtained from the standard formula. The fracture toughness from tip displacements was larger than the standard values for all specimens and the two were related by a logarithmic function with an R2 of 0.61. The study also established that fracture toughness increases with the angle of inclination of the original crack plane to the Radial Longitudinal plane.
  • Samarasinghe, Lincoln University, P.O. Box 84, Canterbury, New Zealand ORCID ID:E-mail:
  • Kulasiri, Lincoln University, P.O. Box 84, Canterbury, New Zealand ORCID ID:E-mail: kulasird@lincoln.ac.nz (email)
article id 426, category Research article
Uwe Schmitt, Risto Jalkanen, Dieter Eckstein. (2004). Cambium dynamics of Pinus sylvestris and Betula spp. in the northern boreal forest in Finland. Silva Fennica vol. 38 no. 2 article id 426. https://doi.org/10.14214/sf.426
Wood formation dynamics of pine and birch along a south-north transect in Finnish Lapland were determined by the pinning technique. For all trees at all sites a more or less sigmoid shape of the wood formation intensity is characteristic with a slow beginning, a faster growth in the middle and a decreasing activity towards the end of the vegetation period. Wood formation of pine started at sites 1–3 (southern sites) in the second week of June and at sites 4 and 5 (northern sites) only in the last week of June, whereas wood formation ended within the first half of August. Wood formation of birch started in the second half of June and ended around the beginning of August. First cells were laid down by pine and birch when the temperature sum had reached the level of 85 to 90 degree days and 110 to 120 degree days, respectively. The intensity of wood formation in pine was highest in July, in birch within two weeks in the middle of July. Wood formation in pine lasted for about seven weeks at the southernmost and about six weeks at the northernmost site. In birch, the duration of wood formation was about five weeks at the southernmost site and around three weeks at the other sites.
  • Schmitt, Federal Research Centre for Forestry and Forest Products, Institute for Wood Biology and Wood Protection, and University of Hamburg, Chair for Wood Biology, Leuschnerstr. 91, P. O. Box 800209, D-21002 Hamburg, Germany ORCID ID:E-mail: u.schmitt@holz.uni-hamburg.de (email)
  • Jalkanen, Finnish Forest Research Institute, Rovaniemi Research Station, Box 16, FI-96301 Rovaniemi, Finland ORCID ID:E-mail:
  • Eckstein, Federal Research Centre for Forestry and Forest Products, Institute for Wood Biology and Wood Protection, and University of Hamburg, Chair for Wood Biology, Leuschnerstr. 91, P. O. Box 800209, D-21002 Hamburg, Germany ORCID ID:E-mail:
article id 424, category Research article
Mats Warensjö, Göran Rune. (2004). Stem straightness and compression wood in a 22-year-old stand of container-grown Scots pine trees. Silva Fennica vol. 38 no. 2 article id 424. https://doi.org/10.14214/sf.424
The distribution of compression wood in relation to eccentric growth and development of stem straightness was studied in a 22-year-old Scots pine (Pinus sylvestris L.) stand in central Sweden that was established with container-grown seedlings. Stem straightness was measured on the same 440 trees in 1986 and 1997. The number of stems with straight base sections increased from 60% in 1986 to 89% in 1997. Measurements of 72 sample trees in 2001 showed that 96% of the trees had developed straight stem bases. External geometry data of the logs was obtained with a Rema 3D log scanner. A sub-sample of 16 trees was randomly selected for analysis of compression wood distribution and eccentricity measurements. From each tree, 11 discs were cut at every 60 cm along the stem. All discs, except one, contained compression wood. Compression wood and pith eccentricity was most pronounced near the stem base but not significantly correlated to basal sweep. Severe compression wood content was correlated to pith eccentricity and bow height. In general, correlations were better for the basal sections of the logs. Even though most trees were straight, they contained large amounts of compression wood. It is evident that eccentric growth and compression wood formation play major roles in the development of stem straightness. In several stems, a spiral compression wood distribution pattern was found. Reasons for this are discussed.
  • Warensjö, Department of Forest Products and Markets, Swedish University of Agricultural Sciences, SE-901 83 Umeå, Sweden ORCID ID:E-mail: mats.warensjo@spm.slu.se (email)
  • Rune, Department of Forestry and Wood Technology, Dalarna University, SE-776 98 Garpenberg, Sweden ORCID ID:E-mail:
article id 439, category Research article
Christina Lundgren. (2004). Microfibril angle and density patterns of fertilized and irrigated Norway spruce. Silva Fennica vol. 38 no. 1 article id 439. https://doi.org/10.14214/sf.439
Two Norway spruce nutrient optimisation trials, one in the north of Sweden and one in the south, were used to study the effects of intensive growth and fertilization on wood density and microfibril angle. Three different treatments and a control were available; daily irrigation, daily liquid fertilization and solid fertilization. The nutrient optimisation was based on foliage analysis and the solid fertilization essentially comprised the same amount of nutrients but was applied annually in solid form. Measurements of density and microfibril angle (MFA) were performed using X-ray diffraction. Growth rate, expressed as a transformation of annual ring width, was very important at the southern site when the effect of cambial maturation had been taken into account. Effects of both fertilization and irrigation remained strong and significant for density, and irrigation was a significant factor explaining MFA. At the northern site distance from pith was the dominant factor but the effect of growth rate was also strong and the treatment effect was significant for both density and MFA. The combination of higher MFA and decrease in density for fertilized trees resulted in a lower calculated strength of the wood. An over 100% increase in ring width only corresponded to approximately a 20% decrease in wood density and the production of wood dry matter was hence increased by treatments.
  • Lundgren, SLU, Dept. of Forest Products and Markets, P.O. Box 7060, SE-750 07 Uppsala, Sweden ORCID ID:E-mail: christina.lundgren@spm.slu.se (email)
article id 438, category Research article
Christina Lundgren. (2004). Cell wall thickness and tangential and radial cell diameter of fertilized and irrigated Norway spruce. Silva Fennica vol. 38 no. 1 article id 438. https://doi.org/10.14214/sf.438
Two Norway spruce nutrient trials were used to evaluate the effects of fertilization and irrigation on transverse tracheid dimensions. Three different treatments and a control (C) were used; daily irrigation (I), daily liquid fertilization (IL) and an annual solid fertilization (F). The nutrient optimisation was based on foliage analysis and both liquid and solid fertilization essentially comprised the same amount of nutrients but the latter was applied annually in solid form. The cell measurements; cell wall thickness, radial and tangential cell widths, were obtained using image analysis (SilviScan at CSIRO, Melbourne, Australia). Mean annual cell wall thickness was decreased by fertilization (F and IL) on both sites whereas no effect of the irrigation on wall thickness could be detected. Radial cell width was increased by treatment at Flakaliden but at Asa the effect of irrigation and fertilization was reversed when the data structure i.e. development from pith and out and annual ring width was taken into account. Tangential cell width was not significantly affected by treatment at Flakaliden. At Asa fertilization caused a small increase on tangential cell width. Ring width was positively affected by treatment and is an important factor explaining the effects on primarily cell wall thickness and radial cell width.
  • Lundgren, SLU, Dept. of Forest Products and Markets, P.O. Box 7060, SE-750 07 Uppsala, Sweden ORCID ID:E-mail: christina.lundgren@spm.slu.se (email)
article id 434, category Research article
Igor Drobyshev, Mats Niklasson, Per Angelstam. (2004). Contrasting tree-ring data with fire record in a pine-dominated landscape in the Komi Republic (Eastern European Russia): recovering a common climate signal. Silva Fennica vol. 38 no. 1 article id 434. https://doi.org/10.14214/sf.434
For the period 1420–1960 we contrasted fire events reconstructed at 14 sites distributed over a 50 km x 50 km area in the central part of the Komi Republic (European Russia) with a set of tree-ring width chronologies of Scots pine (Pinus sylvestris L.), developed for the same area. Our aim was to infer common climatic information contained in tree-ring variables and independently dated fire events with the help of a superposed epoch analysis. The strongest weather–growth link was shown for the latewood width, which was positively correlated with the temperature in April–May and July–August of the current growth season and with previous year precipitation in July–August. Earlywood width was positively affected by previous year precipitation in May and November. The relationship between yearly ring variables and multiple-site fire events was dependent on the seasonal timing of fire events as recorded in the scars. In years with early-season fires (which made up 37% of all fires dated with seasonal resolution) total ring width was significantly narrower. In years with late-season fires (63%) total ring width, earlywood, and latewood width were significantly wider. Years with late-season fires tended to be associated with local highs of the latewood width chronologies over 1400–1960, which implied a link between decadal-scale climate variation and fire regime of the area.
  • Drobyshev, SUFOR Project, Department of Plant Ecology and Systematics, Ecology Building, Sölvegatan 37, Lund University, SE-223 62 Lund, Sweden ORCID ID:E-mail: igor.drobyshev@ekol.lu.se (email)
  • Niklasson, SUFOR Project, Southern Swedish Forest Research Centre, SLU, P.O. Box 49, SE-230 53 Alnarp, Sweden ORCID ID:E-mail:
  • Angelstam, Grimsö Wildlife Research Station, Department of Conservation Biology, Forest Faculty, SLU, SE-730 91 Riddarhyttan, Sweden ORCID ID:E-mail:
article id 434, category Research article
Igor Drobyshev, Mats Niklasson, Per Angelstam. (2004). Contrasting tree-ring data with fire record in a pine-dominated landscape in the Komi Republic (Eastern European Russia): recovering a common climate signal. Silva Fennica vol. 38 no. 1 article id 434. https://doi.org/10.14214/sf.434
For the period 1420–1960 we contrasted fire events reconstructed at 14 sites distributed over a 50 km x 50 km area in the central part of the Komi Republic (European Russia) with a set of tree-ring width chronologies of Scots pine (Pinus sylvestris L.), developed for the same area. Our aim was to infer common climatic information contained in tree-ring variables and independently dated fire events with the help of a superposed epoch analysis. The strongest weather–growth link was shown for the latewood width, which was positively correlated with the temperature in April–May and July–August of the current growth season and with previous year precipitation in July–August. Earlywood width was positively affected by previous year precipitation in May and November. The relationship between yearly ring variables and multiple-site fire events was dependent on the seasonal timing of fire events as recorded in the scars. In years with early-season fires (which made up 37% of all fires dated with seasonal resolution) total ring width was significantly narrower. In years with late-season fires (63%) total ring width, earlywood, and latewood width were significantly wider. Years with late-season fires tended to be associated with local highs of the latewood width chronologies over 1400–1960, which implied a link between decadal-scale climate variation and fire regime of the area.
  • Drobyshev, SUFOR Project, Department of Plant Ecology and Systematics, Ecology Building, Sölvegatan 37, Lund University, SE-223 62 Lund, Sweden ORCID ID:E-mail: igor.drobyshev@ekol.lu.se (email)
  • Niklasson, SUFOR Project, Southern Swedish Forest Research Centre, SLU, P.O. Box 49, SE-230 53 Alnarp, Sweden ORCID ID:E-mail:
  • Angelstam, Grimsö Wildlife Research Station, Department of Conservation Biology, Forest Faculty, SLU, SE-730 91 Riddarhyttan, Sweden ORCID ID:E-mail:
article id 487, category Research article
Åsa Gustafsson. (2003). Logistic services as a competitive means – segmenting the retail market for softwood lumber. Silva Fennica vol. 37 no. 4 article id 487. https://doi.org/10.14214/sf.487
Softwood lumber has been considered traditionally as commodity. Subsequently brand names and trademarks were of subordinate value and competition was based on price. Recently, retailers have grown substantially and are forcing their suppliers to improve the production and delivery of products. As retailers are getting more diverse and powerful, suppliers are forced to adapt to the retailers’ service requirements. The new situation also brings opportunities for the sawmills to develop their competitive advantage. The retail industry is continuously changing, and in order for sawmills to develop and offer what retailers are asking for, it is necessary that they understand and interpret retailers’ requirements correctly. One way for sawmills to be successful is to develop accurate service elements and to use the service elements as a segmentation base in order to structure their customer base. This study shows that retailers place considerable emphasis on delivery and value-added logistical services. It generates three hypotheses concerning the following potential retail segments; turnover, category, and customer base.
  • Gustafsson, School of Industrial Engineering (IPS), Växjö University, SE-351 95 Växjö, Sweden ORCID ID:E-mail: asa.gustafsson@ips.vxu.se (email)
article id 494, category Research article
Antero Varhimo, Soili Kojola, Timo Penttilä, Raija Laiho. (2003). Quality and yield of pulpwood in drained peatland forests: pulpwood properties of Scots pine in stands of first commercial thinnings. Silva Fennica vol. 37 no. 3 article id 494. https://doi.org/10.14214/sf.494
The inherent structural dynamics of drained peatland forests may result in a great variation in various wood and fiber properties. We examined variation in fiber and pulp properties i) among stands, ii) among trees within stands, and iii) within trees in young stands dominated by Scots pine (Pinus sylvestris L.). The stands, selected to cover a maximal range of the potential variation, were all at a stage of development where the first commercial thinnings would be feasible. Differences in the processability of the thinning removals were small. In similar kraft cooking conditions, a 5-unit variation in the kappa number of unbleached pulp was observed among the stands. Stand origin had no effect on pulp bleaching. The wood formed prior to drainage had a higher density, shorter fibers, was slightly slower delignified by cooking, and its yield was slightly lower than that of post-drainage wood. These properties, except for high density, are typical for juvenile wood in general, and at stand level they did not correlate with the proportion of pre-drainage wood. When the variation in fiber and pulp properties was broken down into its components, most of it was derived from tree-level in all the cases. On average, the fiber and pulp properties did not differ from those observed for first-thinning pulpwood from upland sites. Consequently, peatland-grown pulpwood may be mixed with other pulpwood in industrial processes. It would probably be best suited as the raw material for pulps with high bonding requirements, e.g. in the top ply of multi-ply board grades or in some specialty grades.
  • Varhimo, KCL, P.O. Box 70, FIN-02151 Espoo, Finland ORCID ID:E-mail: antero.varhimo@kcl.fi (email)
  • Kojola, Finnish Forest Research Institute, Vantaa Research Centre, P.O. Box 18, FIN-01301 Vantaa, Finland ORCID ID:E-mail:
  • Penttilä, Finnish Forest Research Institute, Vantaa Research Centre, P.O. Box 18, FIN-01301 Vantaa, Finland ORCID ID:E-mail:
  • Laiho, Department of Forest Ecology, P.O. Box 27, FIN-00014 University of Helsinki, Finland ORCID ID:E-mail: raija.laiho@helsinki.fi
article id 503, category Research article
Jyrki Hytönen. (2003). Effects of wood, peat and coal ash fertilization on Scots pine foliar nutrient concentrations and growth on afforested former agricultural peat soils. Silva Fennica vol. 37 no. 2 article id 503. https://doi.org/10.14214/sf.503
The effects of ash and commercial fertilizers on the foliar nutrient concentrations and stand growth of Scots pine were studied in four field experiments established on former cultivated peat soils. The aims were to compare ash types (wood, peat and coal ash), study the effects of ash treatment (pelletization), compare ash fertilization with commercial fertilizers, and to study the interaction between ash fertilization and weed control. Foliar samples were collected 1–3 years and 7–8 years after fertilization. In the unfertilized plots, the foliar nitrogen and phosphorus concentrations were fairly high, while those of potassium were low in all the experiments. The boron levels were low in three out of the four experiments. Application of either loose or pelletized wood ash, as well as of commercial fertilizers, increased foliar potassium and boron concentrations, and thus successfully remedied the existing nutrient imbalances and deficiencies. Since phosphorus deficiencies are rarely encountered on field afforestation sites, poor-quality wood ash with low phosphorus concentration could be used. Peat ash containing phosphorus, but only small amounts of potassium and boron, was not found to be very suitable for soil amelioration in connection with field afforestation. Coal ash, containing only small amounts of potassium, was a good source of boron for pine even when used in small amounts, and thus it can be used in cases where boron deficiencies alone are encountered. Wood ash significantly increased the height growth of Scots pines in two of the experiments, but peat ash and coal ash had no statistically significant effect. Wood ash increased the number of healthy seedlings. Vegetation control decreased seedling mortality by 24%, increased the growth of pine and decreased the proportion of trees damaged by elk and by deciduous trees.
  • Hytönen, Finnish Forest Research Institute, Kannus Research Station, P.O. Box 44, FIN-69101 Kannus, Finland ORCID ID:E-mail: jyrki.hytonen@metla.fi (email)
article id 516, category Research article
Celeste Lacuna-Richman. (2003). Ethnicity and the utilization of non-wood forest products: findings from three Philippine villages. Silva Fennica vol. 37 no. 1 article id 516. https://doi.org/10.14214/sf.516
The utilization and trade of non-wood forest products in three villages in the Philippines were compared in this study. Two villages were situated close to each other on the Island of Palawan. The Tagbanua, an indigenous people, inhabited one village; migrants from the Visayas Region of the Philippines populated the other. The third village is located on the Island of Leyte, in the Visayas Region, populated by native Visayan settlers. There was no significant difference in the number of NWFPs utilized by the indigenous people and the migrants. However, there was a wide disparity in income between the two groups, with migrants earning more, partly due to the marketing of commercial NWFPs. This gap could be decreased by fairer trading practices that are dependent in part on better educational opportunities, land rights, legal assistance and access to markets for the Tagbanua. Specific socioeconomic characteristics, such as the presence of a hunter within the household and size of the family were found to have a positive correlation with the use of NWFPs in some study villages. Income and the food expenditure of the household were inversely related with the use of NWFPs in the native Visayan village.
  • Lacuna-Richman, Faculty of Forestry, University of Joensuu, P.O. Box 111, FIN-80101 Joensuu, Finland ORCID ID:E-mail: celeste.lacuna-richman@forest.joensuu.fi (email)
article id 514, category Research article
Jukka Malinen. (2003). Locally adaptable non-parametric methods for estimating stand characteristics for wood procurement planning. Silva Fennica vol. 37 no. 1 article id 514. https://doi.org/10.14214/sf.514
The purpose of this study was to examine the use of the local adaptation of the non-parametric Most Similar Neighbour (MSN) method in estimating stand characteristics for wood procurement planning purposes. Local adaptation was performed in two different ways: 1) by selecting local data from a database with the MSN method and using that data as a database in the basic k-nearest neighbour (k-nn) MSN method, 2) by selecting a combination of neighbours from the neighbourhood where the average of the predictor variables was closest to the target stand predictor variables (Locally Adaptable Neighbourhood (LAN) MSN method). The study data used comprised 209 spruce dominated stands located in central Finland and was collected with harvesters. The accuracy of the methods was analysed by estimating the tree stock characteristics and the log length/diameter distribution produced by a bucking simulation. The local k-nn MSN method was not notably better than the k-nn MSN method, although it produced less biased estimates on the edges of the input space. The LAN MSN method was found to be a more accurate method than the k-nn methods.
  • Malinen, University of Joensuu, Faculty of Forestry, P.O. Box 111, FIN-80101 Joensuu, Finland ORCID ID:E-mail: jukka.malinen@joensuu.fi (email)
article id 525, category Research article
Thomas Knoke. (2002). Value of complete information on red heartwood formation in beech (Fagus sylvatica). Silva Fennica vol. 36 no. 4 article id 525. https://doi.org/10.14214/sf.525
Beech (Fagus sylvatica L.) is the most important deciduous tree species in Germany. The wood of beech shows normally a bright colour (white beech) as long as no coloured heartwood has been formed. The facultative heartwood formation is induced when oxygen enters central parts of older trees, where dead or at least less vital parenchyma exist. The coloured heartwood is usually called ‘red heartwood’. Beech without red heartwood can preferably be found in younger trees which show a high water content even in central parts of the stem. The presence of red heartwood is regarded as a severe reduction of timber quality. Numerous studies have investigated opportunities to derive information on the presence and characteristics of red heartwood of standing beech trees. But until now it has not been tested whether such information could be helpful to improve the economics of beech-silviculture. This paper investigates whether complete information on the heartwood of standing beech could be useful to control the proportion of discoloured timber harvested during one rotation. It is also examined, which kind of information on the heartwood could be used to improve the economic results. To verify this, simulations based on simple algorithms were conducted. The general assumption was made that all information on the heartwood would be available. The results show that information which is restricted on the mere existence of red heartwood is neither suited to significantly reduce the amount of coloured timber nor is it possible to improve economic results based on this information. Only based on information on the recent formation of red heartwood of beech, which is actually still white the amount of discoloured timber can be reduced significantly. Consequently the discounted cash flows can only be substantially improved based on information on an expected formation of recent red heartwood.
  • Knoke, Institute of Silviculture and Forest Management, Technische Universität München, Am Hochanger 13, D-85354 Freising, Germany ORCID ID:E-mail: knoke@wbfe.forst.tu-muenchen.de (email)
article id 542, category Research article
Håkan Lindström. (2002). Intra-tree models of juvenile wood in Norway spruce as an input to simulation software. Silva Fennica vol. 36 no. 2 article id 542. https://doi.org/10.14214/sf.542
Juvenile wood found in the first 5–25 growth rings of a conifer has a structure and properties that differ from mature wood. Juvenile wood is therefore said to influence processing and the end-use of sawn products. Consequently, models describing the juvenile wood content, within and between trees, could be useful in improving the utilisation and value of wood as an industrial raw material. The objective of the present study was to develop juvenile wood models, based on Norway spruce trees, which could be used within a model system for conversion simulation studies. Nineteen stands of Norway spruce (Picea abies [L.] Karst.) were selected throughout Sweden. Based on DBH, two small, two medium, and two large diameter timber trees were taken from each stand. DBH varied between 180–470 mm, tree height between 17–34 m, and total age between 51–152 years. Each selected tree was cross-cut into logs; discs were prepared from the large end of each log and from the top end of the top log. Image analysis was used to determine growth ring development on sampled discs. Using tree and growth variables, the juvenile core radius and the logarithmic value of juvenile wood percentage were modelled. The two models had an R2Adj of 0.71 and 0.88 respectively.
  • Lindström, University of Canterbury, School of Forestry, Private Bag 4800, Christchurch, New Zealand ORCID ID:E-mail: lindstromhakan@netscape.net (email)
article id 563, category Research article
Timo Pakkala, Ilkka Hanski, Erkki Tomppo. (2002). Spatial ecology of the three-toed woodpecker in managed forest landscapes. Silva Fennica vol. 36 no. 1 article id 563. https://doi.org/10.14214/sf.563
The effects of landscape structure and forestry on the abundance and dynamics of boreal forest bird species have been studied widely, but there are relatively few studies in which the spatial structure and quality of the landscape have been related to the spatial ecology of bird species. In this paper, we present methods to measure territory and landscape quality for the three-toed woodpecker (Picoides tridactylus) and similar territorial forest bird species based on data from the Finnish multi-source national forest inventory and metapopulation theory. The three-toed woodpecker was studied with territory mapping within an area of 340 square km in southern Finland in 1987–2000. Altogether 195 breeding territory sites were observed. The spatial occurrence of the territories was aggregated, and the highest densities were observed in spruce-dominated old-growth forest areas. Both territory and landscape quality had significant consequences for the occurrence of the three-toed woodpecker. The spatial patterning and permanence of breeding and non-breeding territories were influenced by a combination of spatial dynamics of the species and the quality of the landscape, the latter being much influenced by forestry. The landscape-level spatial occurrence of the three-toed woodpecker in the study area may represent source-sink dynamics. The results of this paper suggest the presence of threshold values at different spatial scales, which may determine the occurrence of the three-toed woodpecker and similar species in managed forest landscapes.
  • Pakkala, Finnish Museum of Natural History, University of Helsinki, P.O. Box 17, FIN-00014 University of Helsinki, Finland ORCID ID:E-mail: timo.pakkala@helsinki.fi (email)
  • Hanski, Department of Ecology and Systematics, University of Helsinki, P.O. Box 47, FIN-00014 University of Helsinki, Finland ORCID ID:E-mail:
  • Tomppo, Finnish Forest Research Institute, Unioninkatu 40 A, FIN-00170 Helsinki, Finland ORCID ID:E-mail:
article id 555, category Research article
Leena Karjalainen, Timo Kuuluvainen. (2002). Amount and diversity of coarse woody debris within a boreal forest landscape dominated by Pinus sylvestris in Vienansalo wilderness, eastern Fennoscandia. Silva Fennica vol. 36 no. 1 article id 555. https://doi.org/10.14214/sf.555
The amount, variability, quality and spatial pattern of coarse woody debris (CWD) on mineral soil sites was studied within a natural Pinus sylvestris L. dominated boreal forest landscape in Russian Viena Karelia. Data on the total CWD was collected on 27 sample plots (20 m x 100 m) and data on large CWD was surveyed along four transects (40 m wide and up to 1000 m long). The mean volume of CWD (standing and down combined) was 69.5 m3 ha–1, ranging from 22.2 m3 ha–1 to 158.7 m3 ha–1 from plot to plot. On average, 26.9 m3 ha–1 (39%) of CWD was standing dead wood and 42.7 m3 ha–1 (61%) down dead wood. The CWD displayed a wide range of variation in tree species, tree size, stage of decay, dead tree type and structural characteristics, creating a high diversity of CWD habitats for saproxylic organisms. Large CWD was almost continuously present throughout the landscape and its overall spatial distribution was close to random, although a weak autocorrelation pattern was found at distances less than about 50 m. On small spatial scales total CWD showed wide variation up to a sample area of about 0.1 ha, beyond which the variation stabilized. The fire history variables of the sample plots were not related to the amount of CWD. This and the spatial pattern of CWD suggest that the CWD dynamics in this landscape was not driven by fire, but by more or less random mortality of trees due to autogenic causes of death.
  • Karjalainen, Department of Forest Ecology, P.O. Box 24, FIN-00014 University of Helsinki, Finland ORCID ID:E-mail:
  • Kuuluvainen, Department of Forest Ecology, P.O. Box 24, FIN-00014 University of Helsinki, Finland ORCID ID:E-mail: timo.kuuluvainen@helsinki.fi (email)
article id 554, category Research article
Seppo Rouvinen, Timo Kuuluvainen, Juha Siitonen. (2002). Tree mortality in a Pinus sylvestris dominated boreal forest landscape in Vienansalo wilderness, eastern Fennoscandia. Silva Fennica vol. 36 no. 1 article id 554. https://doi.org/10.14214/sf.554
Tree mortality and its causes and spatial pattern were examined along four transects (width 40 m, length 2550–3960 m), with a total length of 12 190 m and area of 48.8 ha, in a Pinus sylvestris L. dominated, boreal forest landscape. Tree mortality was determined within a time window of 3 years by identifying those trees (dbh ≥ 10 cm) along the transects that fitted into one of the three categories: 1) current mortality: trees that had died during the year of survey (1998), 2) recent mortality: trees that had died during the year (1997) before the survey year, and 3) predicted mortality: trees that were expected to die during the year (1999) following the survey year. Long-term tree mortality was studied on 10 plots (20 m x 100 m) by dating 87 dead trees using dendrochronological methods. The mean current mortality was 1.4 m3 ha–1 (3.7 trees ha–1). Both the recent and predicted mortalities were also 1.4 m3 ha–1. Mortality was, on the average, higher on peatlands than on mineral soils. The highest mortality was found within an area recently flooded by beavers. Over half of the examined trees (52%) were judged to die without any visible signs of an external abiotic cause. At the landscape scale, tree mortality was continuous although somewhat aggregated in space. Of the 66 dated standing dead Pinus trees, 23 (35%) had died during the 19th century and two during the 18th century, demonstrating that dead Pinus can remain standing for long periods of time before falling. Our results show that autogenic mortality of individual trees or small groups of trees was the predominant mode of disturbance in this Pinus dominated landscape.
  • Rouvinen, University of Joensuu, Faculty of Forestry, P.O. Box 111, FIN-80101 Joensuu, Finland ORCID ID:E-mail: seppo.rouvinen@forest.joensuu.fi (email)
  • Kuuluvainen, University of Helsinki, Department of Forest Ecology, P.O. Box 27, FIN-00014 University of Helsinki, Finland ORCID ID:E-mail:
  • Siitonen, Finnish Forest Research Institute, P.O. Box 18, FIN-01301 Vantaa, Finland ORCID ID:E-mail: juha.siitonen@metla.fi
article id 582, category Research article
Kari Kangas, Pasi Markkanen. (2001). Factors affecting participation in wild berry picking by rural and urban dwellers. Silva Fennica vol. 35 no. 4 article id 582. https://doi.org/10.14214/sf.582
The purpose of this study was to examine the participation of urban and rural dwellers in the activity of berry-picking. The respondents in the study lived in the city of Joensuu and in the municipality of Ilomantsi, in eastern Finland. 68% of Joensuu households compared with 82% of those in Ilomantsi participated in berry-picking. These evident differences in the participation rates may be largely due to the higher costs incurred by urban dwellers in picking, since the probability of participation was not significantly higher for Ilomantsi households compared with those in Joensuu who had access to a summer-cottage which was likely to be located near the berry resources. In both municipalities, the participants were divided into two groups according to the nature of their participation in the activity. The larger group – termed ordinary pickers – were characteristically younger families with children, while the other group, termed active pickers, were distinctly more advanced in age. The quantities picked for home consumption by the groups of pickers in Ilomantsi were twice as large as those picked by the corresponding groups in Joensuu. In Joensuu, households were not significantly involved in commercial picking.
  • Kangas, University of Joensuu, Faculty of Forestry, P.O. Box 111, FIN-80101 Joensuu, Finland ORCID ID:E-mail: kari.kangas@joensuu.fi (email)
  • Markkanen, University of Joensuu, Faculty of Forestry, P.O. Box 111, FIN-80101 Joensuu, Finland ORCID ID:E-mail:
article id 590, category Research article
Anna Saarsalmi, Eino Mälkönen, Sirpa Piirainen. (2001). Effects of wood ash fertilization on forest soil chemical properties. Silva Fennica vol. 35 no. 3 article id 590. https://doi.org/10.14214/sf.590
The effects of wood ash fertilization on soil chemical properties were studied in three young Scots pine (Pinus sylvestris L.) plantations and a Norway spruce (Picea abies (L.) Karst.) plantation with different site fertility in southern Finland. The dose of 3 t ha–1 of loose wood ash was applied to 4 replicate plots (25 x 25 m) at each experiment. Humus layer and mineral soil samples were taken before the treatment and 7 and 16 years after wood ash application. Results showed that neutralization as well as fertilization effects of wood ash on forest soil were of long duration. An ash-induced pH increase of 0.6–1.0 pH units and exchangeable acidity (EA) decrease of 58–83% were detected in the humus layer 16 years after wood ash application. The decrease in acidity was most pronounced on the Calluna site with initially the lowest pH and highest EA. In the mineral soil the increase in pH was observed later than in the humus layer. After 16 years, the mineral soil pH was increased (0.2–0.3 pH units) on the Vaccinium and Myrtillus sites. A corresponding and in most cases a significant increase in the extractable Ca and Mg concentrations was detected in both the humus layer and in the mineral soil. Wood ash significantly increased the effective cation exchange capacity (CECe) and base saturation (BS) but decreased the concentration of exchangeable Al in both soil layers on all the sites. No response of N availability to wood ash application could be found.
  • Saarsalmi, Finnish Forest Research Institute, Vantaa Research Centre, P.O. Box 18, FIN-01301 Vantaa, Finland ORCID ID:E-mail: anna.saarsalmi@metla.fi (email)
  • Mälkönen, Finnish Forest Research Institute, Vantaa Research Centre, P.O. Box 18, FIN-01301 Vantaa, Finland ORCID ID:E-mail:
  • Piirainen, Finnish Forest Research Institute, Joensuu Research Station, P.O. Box 68, FIN-80101 Joensuu, Finland ORCID ID:E-mail:
article id 588, category Research article
Marjut Ihalainen, Timo Pukkala. (2001). Modelling cowberry (Vaccinium vitis-idaea) and bilberry (Vaccinium myrtillus) yields from mineral soils and peatlands on the basis of visual field estimates. Silva Fennica vol. 35 no. 3 article id 588. https://doi.org/10.14214/sf.588
This study presents new models for predicting bilberry and cowberry yields from site and stand characteristics. These models enable one to evaluate the future states of forests in terms of berry yields. The modelling data consisted of visual field estimates of site and tree stand characteristics, as well as berry yields from 627 forest stands. Berry yields were estimated using a scale from 0 to 10. Using these data, models were prepared which predict the berry yield scores from those site and stand characteristics which are usually known in forest planning calculations. The model predictions correlated positively and often quite strongly with earlier models. The results were in line with previous studies on the effects of site and tree cover on berry production. According to the models, sites of medium and rather poor fertility produce the highest bilberry yields. Increasing tree height increases, and the basal area of spruce and proportion of deciduous trees decrease, bilberry yield. With mineral soils, cowberry yields are best on poor sites. A high proportion of pine improves cowberry yields. The yields are the highest in open areas and very young stands, on the one hand, and in sparsely populated stands of large and old trees, on the other hand. In pine swamps, the yields are best on rather poor sites. Increasing basal area of deciduous trees decreases cowberry yields.
  • Ihalainen, University of Joensuu, Faculty of Forestry, P.O. Box 111, FIN-80101 Joensuu, Finland ORCID ID:E-mail: marjut.ihalainen@forest.joensuu.fi (email)
  • Pukkala, University of Joensuu, Faculty of Forestry, P.O. Box 111, FIN-80101 Joensuu, Finland ORCID ID:E-mail:
article id 598, category Research article
A. Maarit I. Kallio. (2001). Interdependence of the sawlog, pulpwood and sawmill chip markets: an oligopsony model with an application to Finland. Silva Fennica vol. 35 no. 2 article id 598. https://doi.org/10.14214/sf.598
The interdependence of the markets for pulpwood, sawlogs and sawmill chips is analysed using a short-run model, which accommodates the alternative competition structures of wood buyers. We propose that imperfect competition in the pulpwood market tends to make the sawmills owned by the pulp and paper companies larger than the independent ones, even in the absence of transactional economies of integration. The impact of the wood market competition pattern on the profits of the forest owners and forest industry firms depends upon a firm-capacity structure, wood supply elasticities, and business cycles in the output markets. The numerical application of the model to the Finnish softwood market suggests that inflexibility of production capacities tends to make the wood demand rather insensitive with respect to price. Only the large firms, which all produce both pulp and sawnwood, may have oligopsony power under some conditions. Integrated production can increase competition in the sawlog market via the wood chip market.
  • Kallio, Helsinki School of Economics, Department of Economics and Management Science, P.O. Box 1210, FIN-00101 Helsinki ORCID ID:E-mail: maarit.kallio@hkkk.fi (email)
article id 607, category Research article
Jurkka Kuusipalo. (2001). Plastic coating of plywood using extrusion technique. Silva Fennica vol. 35 no. 1 article id 607. https://doi.org/10.14214/sf.607
The target was to study and develop industrially suitable methods to apply thermoplastic coatings on plywood. Typically, wear and climatic resistance for wooden sheets, such as chip board and plywood, is achieved by thermosetting resin coating (e.g. phenol-formaldehyde). However, economical and environmental issues are driving towards thermoplastic coatings (e.g. polyethylene) in such products. Several technologies, such as film gluing and laminating, have been introduced, but the costs and processing are limiting factors. This study concentrates on direct coating of plywood with extruded molten plastic film, in other words extrusion coating of plywood. This technique provides fast coating process and cheap raw materials. In the study it was found that extrusion coating of plywood is difficult. The high heat energy of the molten plastic causes moisture evaporation of the top veneer, and the only possible escape direction of the evaporated moisture is through the plastic, which causes bubbling in the plastic coating. Another disadvantage of the plywood is its rigidity, which limits the development of the process. In this work, a new technique was applied for coating the flexible veneers with typical extrusion coating equipment, where the escape of the evaporated moisture was possible through the top veneer to the atmosphere. Another main issue was to reach sufficient adhesion between plastic and plywood. Target was achieved using either monolayer polyethylene (PE-LD) or 2-layer polypropylene/adhesion polymer plastic coatings.
  • Kuusipalo, Tampere University of Technology, Institute of Paper Converting, Korkeakoulunkatu 4 C, P.O. Box 541, FIN-33720 Tampere, Finland ORCID ID:E-mail: jurkka@cc.tut.fi (email)
article id 622, category Research article
Håkan Lindström. (2000). Intra-tree models of basic density in Norway spruce as an input to simulation software. Silva Fennica vol. 34 no. 4 article id 622. https://doi.org/10.14214/sf.622
Basic density is said to influence aspects of conversion, properties, and end-use of forest products. Consequently, it is argued that accurate models of basic density variation, within and between trees, could be used to improve the utilisation of wood as an industrial raw material. The objective of the present study was to develop basic density models based on Norway spruce trees, that could be used within a model system for conversion simulation studies. Nineteen stands of Norway spruce (Picea abies (L.) Karst.) were selected throughout Sweden. Based on dbh, two small, two moderate, and two large timber trees were taken from each stand. Dbh varied between 180–470 mm, tree height between 17–34 m, and total age between 51–152 years. Each selected tree was cross-cut into logs; discs were prepared from the butt end of each log and from the top end of the top log. Computed tomography scanning and image analysis were used to determine basic density and growth ring development on sampled discs. Basic density development in 20-mm segments from pith outwards was modelled in models based on ring width, tree and growth condition data. The resulting models had an adjusted R2 of 0.37–0.51 and a RMSE of 37–41 kg/m3.
  • Lindström, University of Canterbury, School of Forestry, Private Bag 4800, Christchurch, New Zealand ORCID ID:E-mail: lindstromhakan@netscape.net (email)
article id 630, category Research article
S. Samarasinghe, G. D. Kulasiri. (2000). Displacement fields of wood in tension based on image processing: Part 2. Crack-tip displacements in mode-I and mixed-mode fracture. Silva Fennica vol. 34 no. 3 article id 630. https://doi.org/10.14214/sf.630
Near tip displacement fields for tensile loaded cracked rubber and wood with a crack parallel-, perpendicular-to-grain, and a parallel-to-grain crack inclined 30°, 45°, and 60° to the load axis were obtained from digital image correlation (DIC). Theoretical displacements were also obtained for rubber and wood using isotropic and orthotropic fracture theory, respectively. The results showed that DIC can reveal fine details of the nature of displacements and the influences of crack tip in both rubber and wood. Experimental crack tip displacements for wood compare well with theory; particularly, when load is perpendicular-to-grain. Some anomalies were found in the tip displacements in the direction of the tracheids due to the unique nature of their behaviour not accounted for by theory. Mixed-mode crack tip displacement fields for wood clearly showed the increasing influence of crack angle on the displacements, and the displacements perpendicular to crack compared very well with theory. The displacements parallel to crack showed some variations owing to the involvement of tracheids.
  • Samarasinghe, Lincoln University, Appl. Computing, Mathematics and Statistics Group, P.O. Box 84, Canterbury, New Zealand ORCID ID:E-mail:
  • Kulasiri, Lincoln University, Appl. Computing, Mathematics and Statistics Group, P.O. Box 84, Canterbury, New Zealand ORCID ID:E-mail: kulasird@tui.lincoln.ac.nz (email)
article id 629, category Research article
S. Samarasinghe, G. D. Kulasiri. (2000). Displacement fields of wood in tension based on image processing: Part 1. Tension parallel- and perpendicular- to grain and comparisons with isotropic behaviour. Silva Fennica vol. 34 no. 3 article id 629. https://doi.org/10.14214/sf.629
Displacement fields for tensile loaded rubber and wood in parallel- and perpendicular-to-grain were obtained from digital image correlation. The results showed that the digital image correlation can reveal fine details of the nature of displacements in both rubber and wood. It was found that when load is perpendicular-to-grain, the lignin matrix produces uniform displacement fields similar to that of isotropic rubber. Uniform displacement fields also observed when lignin is involved in contraction due to Poisson effect in parallel-to-grain tension. However, when tracheids carry the load in parallel-to-grain loading, or are compressed in perpendicular-to-grain loading, a complex displacement pattern distorted by internal shear stress and slippage is produced.
  • Samarasinghe, Lincoln University, Appl. Computing, Mathematics and Statistics Group, P.O. Box 84, Canterbury, New Zealand ORCID ID:E-mail:
  • Kulasiri, Lincoln University, Appl. Computing, Mathematics and Statistics Group, P.O. Box 84, Canterbury, New Zealand ORCID ID:E-mail: kulasird@tui.lincoln.ac.nz (email)
article id 627, category Research article
Joseph Buongiorno, Audra Kolbe, Mike Vasievich. (2000). Economic and ecological effects of diameter-limit and BDq management regimes: simulation results for northern hardwoods. Silva Fennica vol. 34 no. 3 article id 627. https://doi.org/10.14214/sf.627
The long-term financial and ecological effects of diameter-limit regimes and basal-area-diameter-q-ratio (BDq) regimes were compared by simulation in the case of northern hardwood forests. Varying the cutting cycle between 10 and 20 years had little effect on returns or stand structure. A 28-cm diameter-limit cut gave the highest production and financial returns, and the highest species diversity, but considerably lower size diversity. A 38-cm diameter-limit cut and a heavy BDq selection harvest gave high returns, while maintaining high levels of diversity. On lands of equal site quality, Michigan’s stands were more productive than Wisconsin’s. The results suggest that it is possible to manage northern hardwood stands sustainably with diameter-limit cuts, combined with removal of poorly performing understory trees. Adjusting the diameter limit gave rise to stands similar in productivity and structure to those obtained by BDq cutting regimes. Given their simplicity of implementation and monitoring, more attention should be given to diameter-limit cutting regimes, with attendant stand improvement measures, as a practical means for uneven-aged management of northern hardwoods.
  • Buongiorno, Department of Forest Ecology and Management, University of Wisconsin-Madison, 1630 Linden Drive, Madison, WI 53705, USA ORCID ID:E-mail: Jbuongio@facstaff.wisc.edu (email)
  • Kolbe, Department of Forest Ecology and Management, University of Wisconsin-Madison, 1630 Linden Drive, Madison, WI 53705, USA ORCID ID:E-mail:
  • Vasievich, USDA Forest Service, North Central Forest Experiment Station, 1407 S. Harrison Road, Suite 220, East Lansing, MI 48823, USA ORCID ID:E-mail:
article id 636, category Research article
Tuula Nuutinen, Hannu Hirvelä, Jari Hynynen, Kari Härkönen, Hannu Hökkä, Kari T. Korhonen, Olli Salminen. (2000). The role of peatlands in Finnish wood production – an analysis based on large-scale forest scenario modelling. Silva Fennica vol. 34 no. 2 article id 636. https://doi.org/10.14214/sf.636
Using the Finnish MELA model, a set of scenarios were produced and used to map the possibilities and risks surrounding the utilisation of peatlands in wood production in Finland. One of the scenarios was an estimate of allowable-cut calculated by maximising the net present value of the future revenues using a four per cent interest rate subject to non-decreasing flow of wood, saw logs and net income over a 50-year period, and net present value after the 50 year period greater or equal than in the beginning. The estimate for maximum regionally sustained removal in 1996–2005 was 68 million m3 per year – approaching 74 million m3 during the next decades. In this scenario, 14 per cent of all cuttings during the period 1996–2005 would be made on peatlands, which comprise ca. 31 per cent of the total area of forestry land. By the year 2025, the proportion of peatland cuttings would increase to over 20 per cent. The increase in future cutting possibilities on peatlands compensated for a temporary decrease in cuttings and growing stock on mineral soils. The allowable-cut effect was especially pronounced in northern Finland, where peatlands play an important role in wood production. In addition, the sensitivity of cutting possibilities for assumptions related to growth and price were analysed. The estimate of maximum sustainable yield as defined here seems to be fairly robust on the whole, except in northern Finland where the cutting scenarios were sensitive to the changes in the price of birch pulpwood. The proportion of peatland stands that are profitable for timber production depends on the interest rate: the higher the rate of interest the less peatland stands are thinned. The effect of cutting profile on future logging conditions and resulting costs were analysed in two forestry centres. If clear cuttings on mineral soils are to be cut first, an increase in future logging costs is inevitable.
  • Nuutinen, Finnish Forest Research Institute, Joensuu Research Station, P.O. Box 68, FIN-80101 Joensuu, Finland ORCID ID:E-mail: tuula.nuutinen@metla.fi (email)
  • Hirvelä, Finnish Forest Research Institute, Joensuu Research Station, P.O. Box 68, FIN-80101 Joensuu, Finland ORCID ID:E-mail:
  • Hynynen, Finnish Forest Research Institute, Joensuu Research Station, P.O. Box 68, FIN-80101 Joensuu, Finland ORCID ID:E-mail:
  • Härkönen, Finnish Forest Research Institute, Joensuu Research Station, P.O. Box 68, FIN-80101 Joensuu, Finland ORCID ID:E-mail:
  • Hökkä, Finnish Forest Research Institute, Joensuu Research Station, P.O. Box 68, FIN-80101 Joensuu, Finland ORCID ID:E-mail:
  • Korhonen, Finnish Forest Research Institute, Joensuu Research Station, P.O. Box 68, FIN-80101 Joensuu, Finland ORCID ID:E-mail:
  • Salminen, Finnish Forest Research Institute, Joensuu Research Station, P.O. Box 68, FIN-80101 Joensuu, Finland ORCID ID:E-mail:
article id 643, category Research article
Pekka Eskelinen, Harri Eskelinen. (2000). A K-band microwave measuring system for the analysis of tree stems. Silva Fennica vol. 34 no. 1 article id 643. https://doi.org/10.14214/sf.643
The internal structure of growing trees and freshly cut logs can be characterized in real time by analysing the transmission and reflection of Ku- or K-band microwave energy injected with a horizontal polarization towards the material. Information about the moisture content, material bends, number and location of knots and sections of spoiled wood e.g. due to insects can be gathered in real time. Most sensitive test parameters are attenuation, group delay and the rotation of a linearly polarized wavefront. A simultaneous recording of reflection reduces errors caused by non-significant surface deformations. The spatial resolution, humidity equalization and noise immunity can be improved by applying a wideband frequency modulation. Commercial building blocks supplemented with a special antenna arrangement give possibilities also for the rough harvester environment.
  • Eskelinen, Lappeenranta University of Technology, Department of Electrical Engineering, P.O. Box 20, FIN-53851 Lappeenranta, Finland ORCID ID:E-mail: ari.eskelinen@pp.inet.fi (email)
  • Eskelinen, Lappeenranta University of Technology, Department of Electrical Engineering, P.O. Box 20, FIN-53851 Lappeenranta, Finland ORCID ID:E-mail:
article id 665, category Research article
Kari Kangas. (1999). Trade of main wild berries in Finland. Silva Fennica vol. 33 no. 2 article id 665. https://doi.org/10.14214/sf.665
The price trends and markets of the main wild berries, bilberry (Vaccinium myrtillus L.) and lingonberry (Vaccinium vitis-idaea L.), were analysed in this study, which covered both domestic use of berries, imports and exports. The periods considered were for bilberries from 1988 to 1997 and for lingonberries from 1979 to 1994. The results indicated that both exports and imports have increased and domestic berries have lost their market share to imports in domestic use. One possible explanation for this trend was found in price development. Both export and import prices have decreased, but export price has still been higher than the import price. Simultaneously the domestic price has decreased the fastest. The formation of the price of lingonberries paid to the pickers in the organised domestic markets was studied with a regression model. The results indicated that domestic price was negatively dependent on the amounts of lingonberries demanded in the domestic markets and positively dependent on the export price. Correlation analysis gave evidence on the same kind of relations concerning bilberries.
  • Kangas, University of Joensuu, Faculty of Forestry, P.O. Box 111, FIN-80101 Joensuu, Finland ORCID ID:E-mail: kari.kangas@forest.joensuu.fi (email)
article id 662, category Research article
Lars Björklund. (1999). Identifying heartwood-rich stands or stems of Pinus sylvestris by using inventory data. Silva Fennica vol. 33 no. 2 article id 662. https://doi.org/10.14214/sf.662
Variations in heartwood percentage, heartwood radius and sapwood width, within and between stands of Scots pine (Pinus sylvestris L.), were analysed using a database of 198 CT-scanned (computer tomography) stems from 33 research plots (stands) throughout Sweden. Heartwood percentage varied greatly both between individual trees and between stands, and correlated poorly to site, stand and tree variables. This implies that it seems unfeasible to identify heartwood-rich stands or stems, e.g., for production of heartwood products, by using inventory data. Heartwood formation expressed as the number of new heartwood rings formed each year was found to increase with increasing cambial age, from about 0.5 rings per year at a cambial age of 45 years, to about 0.8 rings per year at a cambial age of 115 years.
  • Björklund, Swedish University of Agricultural Sciences, Department of Forest Management and Products, S-750 07 Uppsala, Sweden ORCID ID:E-mail: lars.bjorklund@sh.slu.se (email)
article id 662, category Research article
Lars Björklund. (1999). Identifying heartwood-rich stands or stems of Pinus sylvestris by using inventory data. Silva Fennica vol. 33 no. 2 article id 662. https://doi.org/10.14214/sf.662
Variations in heartwood percentage, heartwood radius and sapwood width, within and between stands of Scots pine (Pinus sylvestris L.), were analysed using a database of 198 CT-scanned (computer tomography) stems from 33 research plots (stands) throughout Sweden. Heartwood percentage varied greatly both between individual trees and between stands, and correlated poorly to site, stand and tree variables. This implies that it seems unfeasible to identify heartwood-rich stands or stems, e.g., for production of heartwood products, by using inventory data. Heartwood formation expressed as the number of new heartwood rings formed each year was found to increase with increasing cambial age, from about 0.5 rings per year at a cambial age of 45 years, to about 0.8 rings per year at a cambial age of 115 years.
  • Björklund, Swedish University of Agricultural Sciences, Department of Forest Management and Products, S-750 07 Uppsala, Sweden ORCID ID:E-mail: lars.bjorklund@sh.slu.se (email)
article id 662, category Research article
Lars Björklund. (1999). Identifying heartwood-rich stands or stems of Pinus sylvestris by using inventory data. Silva Fennica vol. 33 no. 2 article id 662. https://doi.org/10.14214/sf.662
Variations in heartwood percentage, heartwood radius and sapwood width, within and between stands of Scots pine (Pinus sylvestris L.), were analysed using a database of 198 CT-scanned (computer tomography) stems from 33 research plots (stands) throughout Sweden. Heartwood percentage varied greatly both between individual trees and between stands, and correlated poorly to site, stand and tree variables. This implies that it seems unfeasible to identify heartwood-rich stands or stems, e.g., for production of heartwood products, by using inventory data. Heartwood formation expressed as the number of new heartwood rings formed each year was found to increase with increasing cambial age, from about 0.5 rings per year at a cambial age of 45 years, to about 0.8 rings per year at a cambial age of 115 years.
  • Björklund, Swedish University of Agricultural Sciences, Department of Forest Management and Products, S-750 07 Uppsala, Sweden ORCID ID:E-mail: lars.bjorklund@sh.slu.se (email)
article id 675, category Research article
Per Linder, Peter Jonsson, Mats Niklasson. (1998). Tree mortality after prescribed burning in an old-growth Scots pine forest in northern Sweden. Silva Fennica vol. 32 no. 4 article id 675. https://doi.org/10.14214/sf.675
Tree mortality and input of dead trees were studied after a prescribed burning in a forest reserve in northern Sweden. The stand was a multi-layered old-growth forest. The overstorey was dominated by Scots pine (Pinus sylvestris L.) and the understorey consisted of mixed Scots pine and Norway spruce (Picea abies L. Karst.). Ground vegetation was dominated by ericaceous dwarf-shrubs and feathermosses. The stand has been affected by six forest fires during the last 500 years. The prescribed burning was a low intensity surface fire that scorched almost 90% of the ground. Tree mortality for smaller pines and spruces (DBH < 10 cm) was over 80% in the burned parts of the reserve. For larger pines, 10–50 cm DBH, mortality showed a decreasing trend with increasing diameter, from 14% in class 10–20 cm DBH to 1.4% in class 40–50 cm DBH. However, pines with DBH ≥ 50 cm had a significantly higher mortality, 20%, since a high proportion of them had open fire scars containing cavities, caused by fungi and insects, which enabled the fire to burn inside the trunks and hollow them out. The fire-induced mortality resulted in a 21 m3 ha–1 input of dead trees, of which 12 m3 ha–1 consisted of trees with DBH ≥ 30 cm. An increased mortality among larger trees after low-intensity fires has not previously been described in Fennoscandian boreal forests, probably owing to a lack of recent fires in old-growth stands. However, since large pines with open fire scars were once a common feature in the natural boreal forest, we suggest that this type of tree mortality should be mimicked in forestry practices aiming to maintain and restore natural forest biodiversity.
  • Linder, Department of Forest Vegetation Ecology, SLU, S-901 83 Umeå, Sweden ORCID ID:E-mail:
  • Jonsson, Department of Forest Vegetation Ecology, SLU, S-901 83 Umeå, Sweden ORCID ID:E-mail:
  • Niklasson, Southern Swedish Forest Research Centre, SLU, Box 49, S-230 53 Alnarp, Sweden ORCID ID:E-mail:
article id 700, category Research article
Riitta H. Hänninen. (1998). Exchange rate changes and the Finnish sawnwood demand and price in the UK market. Silva Fennica vol. 32 no. 1 article id 700. https://doi.org/10.14214/sf.700
This paper examines the long-run influence of exchange rate changes on the Finnish sawnwood price in the United Kingdom (UK) using quarterly data for the period 1978–1994. The degree of influence was measured by a pass-through coefficient (PT) obtained from a markup pricing relation of a system model. The model, which included export demand and price equations, was estimated with the cointegration method of Johansen. The results indicated a large PT, which means that exchange rate changes are reflected almost proportionately in Finnish export price expressed in pounds sterling. Thus, the Finnish price of sawnwood in pounds has lowered as a result of depreciation of the Finnish markka (FIM). This has improved Finnish competitiveness and market share in the UK. Appreciation of the FIM has had the opposite effect. It seems that Finnish exporters have made use of depreciations and devaluations of the FIM to maintain and increase their market shares but not necessarily their markups. For Finland, which is in the process of joining the European economic and monetary union (EMU), knowing the size of the PT is also important in assessing the economic impact of membership.
  • Hänninen, Forest Research Institute, Helsinki Research Centre, Unioninkatu 40 A, 00170 Helsinki, Finland ORCID ID:E-mail: riitta.hanninen@metla.fi (email)

Category: Review article

article id 446, category Review article
Guntis Brumelis, Bengt Gunnar Jonsson, Jari Kouki, Timo Kuuluvainen, Ekaterina Shorohova. (2011). Forest naturalness in northern Europe: perspectives on processes, structures and species diversity. Silva Fennica vol. 45 no. 5 article id 446. https://doi.org/10.14214/sf.446
Saving the remaining natural forests in northern Europe has been one of the main goals to halt the ongoing decline of forest biodiversity. To facilitate the recognition, mapping and efficient conservation of natural forests, there is an urgent need for a general formulation, based on ecological patterns and processes, of the concept of “forest naturalness”. However, complexity, structural idiosyncracy and dynamical features of unmanaged forest ecosystems at various spatio-temporal scales pose major challenges for such a formulation. The definitions hitherto used for the concept of forest naturalness can be fruitfully grouped into three dimensions: 1) structure-based concepts of natural forest, 2) species-based concepts of natural forest and 3) process-based concepts of natural forest. We propose that explicit and simultaneous consideration of all these three dimensions of naturalness can better cope with the natural variability of forest states and also aid in developing strategies for forest conservation and management in different situations. To become operational, criteria and indicators of forest naturalness need to integrate the three dimensions by combining species (e.g. red-listed-, indicator- and umbrella species) with stand and landscape level structural features that are indicative of disturbance and succession processes.
  • Brumelis, Faculty of Biology, University of Latvia, Kronvalda bulv. 4, Riga, LV-1586, Latvia; ORCID ID:E-mail: guntis.brumelis@lu.lv (email)
  • Jonsson, Department of Natural Sciences, Engineering and Mathematics, Mid Sweden University, Sundsvall, Sweden ORCID ID:E-mail:
  • Kouki, School of Forest Sciences, University of Eastern Finland, Joensuu, Joensuu ORCID ID:E-mail:
  • Kuuluvainen, Department of Forest Sciences, University of Helsinki, Finland ORCID ID:E-mail:
  • Shorohova, Saint-Petersburg State Forest Academy, Saint-Petersburg, Russia & Finnish Forest Research Institute, Vantaa Research Unit, Vantaa, Finland ORCID ID:E-mail:
article id 38, category Review article
Matieu Henry, Nicolas Picard, Carlo Trotta, Raphaël J. Manlay, Riccardo Valentini, Martial Bernoux, Laurent Saint-André. (2011). Estimating tree biomass of sub-Saharan African forests: a review of available allometric equations. Silva Fennica vol. 45 no. 3B article id 38. https://doi.org/10.14214/sf.38
In response to the growing interest in estimating carbon stocks in forests, available allometric equations have been compiled for sub-Saharan Africa. Tree, sprout and stand volume and biomass equations were reviewed. The 850 equations and 125 related references were incorporated into an open-access database on the Carboafrica website (http://www.carboafrica.net). The collected information provides a basic tool for the estimation of biomass and carbon stocks and other purposes, such as bioenergy and fodder supply assessment. A Tier-method approach was developed to illustrate the possible use of the equations. Current available biomass expansion factors that are used to convert a volume to the total aboveground biomass appear to be limited; incomplete species-specific allometric equations are preferred to generalised equations. The analysis of the database highlighted important gaps in available tools to assess forest carbon stocks and changes in these stocks. A quality control assessment revealed that 22% of the equations were misreported and recommendations were proposed to guide further research. Further statistical analyses, such as the Bayesian approach, would help to produce more accurate biomass estimates.
  • Henry, IRD, UMR Eco&Sols, Montpellier SupAgro, 2 place Viala, 34060 Montpellier, France; Di.S.A.F.Ri, Università degli Studi della Tuscia, Viterbo, Italy; and AgroParisTech-ENGREF, GEEFT, Montpellier, France ORCID ID:E-mail: henry@unitus.it (email)
  • Picard, CIRAD, Montpellier, France ORCID ID:E-mail:
  • Trotta, Di.S.A.F.Ri, Università degli Studi della Tuscia, Viterbo, Italy ORCID ID:E-mail:
  • Manlay, IRD, UMR Eco&Sols, Montpellier SupAgro, 2 place Viala, 34060 Montpellier, France; and AgroParisTech-ENGREF, GEEFT, Montpellier, France ORCID ID:E-mail:
  • Valentini, Di.S.A.F.Ri, Università degli Studi della Tuscia, Viterbo, Italy ORCID ID:E-mail:
  • Bernoux, IRD, UMR Eco&Sols, Montpellier SupAgro, 2 place Viala, 34060 Montpellier, France ORCID ID:E-mail:
  • Saint-André, CIRAD, Montpellier, France; and INRA, UR1138, Biogeochimie des Ecosystèmes Forestiers, Champenoux, France ORCID ID:E-mail:
article id 312, category Review article
Katja Lähtinen. (2007). Linking resource-based view with business economics of woodworking industry: earlier findings and future insights. Silva Fennica vol. 41 no. 1 article id 312. https://doi.org/10.14214/sf.312
The business environment and sources of competitiveness in the woodworking industry have changed notably since the 1990s. Wood products are traded globally, and with the increase of trade, abundant forest resources are no longer the main source of sustainable competitiveness. Competition within the woodworking industry is increasing both between European and non-European enterprises, as well as within the EU. Capability to create value-added, making rational strategic choices, and creative usage of intangible and tangible resources have been emphasized as crucial for sustaining woodworking industry competitiveness in higher cost-level countries. Resource-based view (RBV) defines the availability of intangible assets, capabilities and tangible resources, and their heterogeneous combination to form the basis for company success. The objective of this review is to examine the possibilities to employ the RBV to the study of the woodworking industry by combining existing empirical results of the factors of companies’ competitiveness with assessment of the RBV. In the existing literature, strategies implemented in woodworking companies have been approached rather widely, while the role of intangible and tangible resources in building firm-level success has received less focus. In addition, a significant gap exists in linking firms’ financial accounting information with empirical data on their resource-usage and business strategies. In future studies, more information of the effects of these strategic elements on the actual business success of the firms would be needed.
  • Lähtinen, Finnish Forest Research Institute, Joensuu Research Unit, P.O. Box 68, FI-80101 Joensuu, Finland ORCID ID:E-mail: katja.lahtinen@metla.fi (email)
article id 390, category Review article
Bengt Gunnar Jonsson, Nicholas Kruys, Thomas Ranius. (2005). Ecology of species living on dead wood – lessons for dead wood management. Silva Fennica vol. 39 no. 2 article id 390. https://doi.org/10.14214/sf.390
Dead wood has been identified as a crucial component for forest biodiversity. Recent research has improved our understanding of habitat relations for many species associated with dead wood. However, the consequences for forest management are yet to be explored. In this review we build upon the growing volume of studies on dead wood dependent species, the dynamics of dead wood and ecological theory in order to identify the challenges for forest management at the landscape level. The review has a Fennoscandian focus, but the problems and challenges are similar in many forest ecosystems. We argue that it is necessary to 1) counteract the current shortage in availability of dead wood, 2) concentrate planning at the landscape level in order to minimize isolation and reduce edge effects, 3) create a variety of dead wood types, and 4) utilise available quantitative analytical tools. This calls for new approaches to management that to a large extent includes available knowledge, and to find platforms for planning forested landscapes with diverse holdings.
  • Jonsson, Mid Sweden University, Dept of Natural Sciences, SE-851 70 Sundsvall, Sweden ORCID ID:E-mail: bengt-gunnar.jonsson@miun.se (email)
  • Kruys, SLU, Dept of Forest Resource Management and Geomatics, SE-901 83 Umeå, Sweden ORCID ID:E-mail:
  • Ranius, SLU, Dept of Entomology, SE-750 07 Uppsala, Sweden ORCID ID:E-mail:
article id 390, category Review article
Bengt Gunnar Jonsson, Nicholas Kruys, Thomas Ranius. (2005). Ecology of species living on dead wood – lessons for dead wood management. Silva Fennica vol. 39 no. 2 article id 390. https://doi.org/10.14214/sf.390
Dead wood has been identified as a crucial component for forest biodiversity. Recent research has improved our understanding of habitat relations for many species associated with dead wood. However, the consequences for forest management are yet to be explored. In this review we build upon the growing volume of studies on dead wood dependent species, the dynamics of dead wood and ecological theory in order to identify the challenges for forest management at the landscape level. The review has a Fennoscandian focus, but the problems and challenges are similar in many forest ecosystems. We argue that it is necessary to 1) counteract the current shortage in availability of dead wood, 2) concentrate planning at the landscape level in order to minimize isolation and reduce edge effects, 3) create a variety of dead wood types, and 4) utilise available quantitative analytical tools. This calls for new approaches to management that to a large extent includes available knowledge, and to find platforms for planning forested landscapes with diverse holdings.
  • Jonsson, Mid Sweden University, Dept of Natural Sciences, SE-851 70 Sundsvall, Sweden ORCID ID:E-mail: bengt-gunnar.jonsson@miun.se (email)
  • Kruys, SLU, Dept of Forest Resource Management and Geomatics, SE-901 83 Umeå, Sweden ORCID ID:E-mail:
  • Ranius, SLU, Dept of Entomology, SE-750 07 Uppsala, Sweden ORCID ID:E-mail:
article id 688, category Review article
John A. Stanturf, Callie J. Schweitzer, Emile S. Gardiner. (1998). Afforestation of marginal agricultural land in the Lower Mississippi River Alluvial Valley, U.S.A. Silva Fennica vol. 32 no. 3 article id 688. https://doi.org/10.14214/sf.688
Afforestation of marginal agricultural land in the Lower Mississippi Alluvial Valley (LMAV) relies on native species, planted mostly in single-species plantations. Hard mast species such as oak and pecan are favored for their value to wildlife, especially on public land. Successful afforestation requires an understanding of site variation within floodplains and matching species preferences and tolerances to site characteristics, in particular to inundation regimes. Soil physical conditions, root aeration, nutrient availability, and moisture availability during the growing season also must be considered in matching species to site. Afforestation methods include planting seedlings or cuttings, and direct-seeding. Both methods can be done by hand or by machine. If good quality seedlings are planted properly and well cared for before planting, the chances for successful establishment are high but complete failures do occur. Mortality and poor growth are caused by many factors: extended post-planting drought or flooding; poor planting or seeding practices; poor quality seed or seedlings; animal depredation; or herbicide drift from aerial application to nearby cropland. More species can be planted, even on continuously flooded sites. Direct-seeding, while limited to heavy-seeded species (oaks and hickories), costs less than 50% of planting seedlings. Growth varies considerably by soil type; most bottomland hardwoods grow best on silt loam and less well on clay soils. Up to 200 000 ha of land in the LMAV subject to spring and early summer backwater flooding could be afforested over the next decade.
  • Stanturf, USDA Forest Service, Southern Research Station, P.O. Box 227, Stoneville, MS 38776, USA ORCID ID:E-mail: jstantur/srs_stoneville@fs.fed.us (email)
  • Schweitzer, USDA Forest Service, Southern Research Station, P.O. Box 227, Stoneville, MS 38776, USA ORCID ID:E-mail:
  • Gardiner, USDA Forest Service, Southern Research Station, P.O. Box 227, Stoneville, MS 38776, USA ORCID ID:E-mail:
article id 693, category Review article
Erik G. Ståhl. (1998). Changes in wood and stem properties of Pinus sylvestris caused by provenance transfer. Silva Fennica vol. 32 no. 2 article id 693. https://doi.org/10.14214/sf.693
Wood properties focused in forest tree breeding should be of economic importance, have a large total variation and a high heritability. The properties of interest are those that influence the strength and durability of sawn products or the amount and properties of pulp produced. The following wood properties are treated: width of the annual ring, juvenile wood, late wood content, heart wood, tracheid dimensions, basic density, stem straightness and branch diameter. The provenance variation in wood properties can be related to differences in growth phenology. In the northern part of distribution P. sylvestris (L.) provenances transferred a few degrees southwards have a high survival and yield but stem wood production is low. Trees from these provenances will be straight and with few spike knots or other injuries. The shoot elongation period will be short and the temperature sum required for wood formation sufficient. Provenances transferred southwards will form thin annual rings, few and thin branches, little early wood, high basic density and slender tracheids with thick cell walls in comparison to local provenances. An example of the effect of alternative transfers on the yield and wood properties is evaluated. In regions with deviating climatic patterns alternative provenance transfer patterns may be better. The objectives of the land owner should influence the provenance choice. The importance of integrating tree improvement with silvicultural management is discussed with reference to spacing.
  • Ståhl, College of Dalarna, CITU Centre for Industrial Technology and Development, S-781 88 Borlänge, Sweden ORCID ID:E-mail: esl@du.se (email)

Category: Research note

article id 7798, category Research note
Jānis Liepiņš, Jānis Ivanovs, Andis Lazdiņš, Jurģis Jansons, Kaspars Liepiņš. (2017). Mapping of basic density within European aspen stems in Latvia. Silva Fennica vol. 51 no. 5 article id 7798. https://doi.org/10.14214/sf.7798
Highlights: Stem bark is significantly denser than wood and does not follow the same variation patterns along the stem; The main trend in radial variation of wood density was the increase from pith to bark; There is a weak relationship between mean basic density and commonly measured stand and tree parameters.

The objective of this study was to investigate basic density and its within-stem variation by studying 84 European aspen stems from 28 forest stands in Latvia. The studied forest stands covered all age classes from young stands to matured forests in representative growth conditions of European aspen. The densities of 2722 wood and 1022 bark specimens were measured from the sampled trees. Only the knot-free wood specimens without obvious wood defects were chosen for analyses. A map of basic density summarizing its radial and axial variations was constructed to show species-specific, within-stem variability and the relationships between density and tree and stand variables were examined. Stem wood and bark of the European aspen show different patterns of basic density variation along the tree stem. Wood density increases from pith to bark up to certain dimensions and shows a slight decrease afterwards. The weighted basic density of bark (446 ± 39.6 kg m–3) was higher than stem wood density (393 ± 30.4 kg m–3). Our results suggest that wood and bark density measurements obtained at breast height can be used for reliable estimation of the densities of whole-tree stem components, while tree parameters such as diameter at breast height (DBH), tree height and social status or stand parameters, including number of trees, basal area and age, are weak predictors in this context.

  • Liepiņš, Latvian State Forest Research Institute “Silava”, 111 Rigas Str., LV 2169, Salaspils, Latvia ORCID ID:E-mail: janis.liepins@silava.lv (email)
  • Ivanovs, Latvian State Forest Research Institute “Silava”, 111 Rigas Str., LV 2169, Salaspils, Latvia ORCID ID:E-mail: janis.ivanovs@silava.lv
  • Lazdiņš, Latvian State Forest Research Institute “Silava”, 111 Rigas Str., LV 2169, Salaspils, Latvia ORCID ID:E-mail: andis.lazdins@silava.lv
  • Jansons, Latvian State Forest Research Institute “Silava”, 111 Rigas Str., LV 2169, Salaspils, Latvia ORCID ID:E-mail: jurgis.jansons@silava.lv
  • Liepiņš, Latvian State Forest Research Institute “Silava”, 111 Rigas Str., LV 2169, Salaspils, Latvia ORCID ID:E-mail: kaspars.liepins@silava.lv
article id 7798, category Research note
Jānis Liepiņš, Jānis Ivanovs, Andis Lazdiņš, Jurģis Jansons, Kaspars Liepiņš. (2017). Mapping of basic density within European aspen stems in Latvia. Silva Fennica vol. 51 no. 5 article id 7798. https://doi.org/10.14214/sf.7798
Highlights: Stem bark is significantly denser than wood and does not follow the same variation patterns along the stem; The main trend in radial variation of wood density was the increase from pith to bark; There is a weak relationship between mean basic density and commonly measured stand and tree parameters.

The objective of this study was to investigate basic density and its within-stem variation by studying 84 European aspen stems from 28 forest stands in Latvia. The studied forest stands covered all age classes from young stands to matured forests in representative growth conditions of European aspen. The densities of 2722 wood and 1022 bark specimens were measured from the sampled trees. Only the knot-free wood specimens without obvious wood defects were chosen for analyses. A map of basic density summarizing its radial and axial variations was constructed to show species-specific, within-stem variability and the relationships between density and tree and stand variables were examined. Stem wood and bark of the European aspen show different patterns of basic density variation along the tree stem. Wood density increases from pith to bark up to certain dimensions and shows a slight decrease afterwards. The weighted basic density of bark (446 ± 39.6 kg m–3) was higher than stem wood density (393 ± 30.4 kg m–3). Our results suggest that wood and bark density measurements obtained at breast height can be used for reliable estimation of the densities of whole-tree stem components, while tree parameters such as diameter at breast height (DBH), tree height and social status or stand parameters, including number of trees, basal area and age, are weak predictors in this context.

  • Liepiņš, Latvian State Forest Research Institute “Silava”, 111 Rigas Str., LV 2169, Salaspils, Latvia ORCID ID:E-mail: janis.liepins@silava.lv (email)
  • Ivanovs, Latvian State Forest Research Institute “Silava”, 111 Rigas Str., LV 2169, Salaspils, Latvia ORCID ID:E-mail: janis.ivanovs@silava.lv
  • Lazdiņš, Latvian State Forest Research Institute “Silava”, 111 Rigas Str., LV 2169, Salaspils, Latvia ORCID ID:E-mail: andis.lazdins@silava.lv
  • Jansons, Latvian State Forest Research Institute “Silava”, 111 Rigas Str., LV 2169, Salaspils, Latvia ORCID ID:E-mail: jurgis.jansons@silava.lv
  • Liepiņš, Latvian State Forest Research Institute “Silava”, 111 Rigas Str., LV 2169, Salaspils, Latvia ORCID ID:E-mail: kaspars.liepins@silava.lv
article id 1544, category Research note
Osmo Mattila, Kaisa Hämäläinen, Liina Häyrinen, Sami Berghäll, Katja Lähtinen, Anne Toppinen. (2016). Strategic business networks in the Finnish wood products industry: a case of two small and medium-sized enterprises. Silva Fennica vol. 50 no. 3 article id 1544. https://doi.org/10.14214/sf.1544
Highlights: Network-based business models are not yet common in the wood products industry; Further research is suggested on network-based co-operation to vitalize industry.

The use of network-based business models has been brought up as a means of creating com-petitive edge in the tightening global competition. In practice, adopting network-based models has not yet become common in the wood products industry. The objective of this study is to gain better understanding of types of network-based business models using a case study of two small and medium-sized wood industry companies in Finland (for a sake of anonymity named as A and B). The network of company A is found to consist of mostly of established actors with a new-in-the-market value creation system, whereas network for company B is more stable and has an established value system aiming at growth and incremental innovations. Both networks had experienced difficulties in finding partners and lacked some strategic resources. Via this example we wish to stimulate further research interest on the sources of network-based competitive advantage in the traditional wood product industry in a need of renewal of business models.

  • Mattila, University of Helsinki, Department of Forest Sciences, FI-00014 Helsingin yliopisto, Finland ORCID ID:E-mail: osmo.mattila@helsinki.fi
  • Hämäläinen, Siparila Oy, Varaslahdentie 1, FI-40800 Vaajakoski, Finland ORCID ID:E-mail: kaisa.hamalainen@siparila.fi
  • Häyrinen, University of Helsinki, Department of Forest Sciences, FI-00014 Helsingin yliopisto, Finland ORCID ID:E-mail: liina.hayrinen@helsinki.fi
  • Berghäll, University of Helsinki, Department of Forest Sciences, FI-00014 Helsingin yliopisto, Finland ORCID ID:E-mail: sami.berghall@helsinki.fi
  • Lähtinen, University of Helsinki, Department of Forest Sciences, FI-00014 Helsingin yliopisto, Finland ORCID ID:E-mail: katja.lahtinen@helsinki.fi
  • Toppinen, University of Helsinki, Department of Forest Sciences, FI-00014 Helsingin yliopisto, Finland ORCID ID:E-mail: anne.toppinen@helsinki.fi (email)
article id 1346, category Research note
Āris Jansons, Roberts Matisons, Oskars Krišāns, Baiba Džeriņa, Mārtiņš Zeps. (2016). Effect of initial fertilization on 34-year increment and wood properties of Norway spruce in Latvia. Silva Fennica vol. 50 no. 1 article id 1346. https://doi.org/10.14214/sf.1346
Highlights: The initial fertilization increased the productivity of Picea abies increasing stem volume by 17% at the age of 34 years; The tree-ring width was affected for up to15 years; The fertilization did not affect mean tree-ring density, although the latewood density was increased.

Initial fertilisation, when the fertilizer is supplied during the plantation, is applied to improve the competitive ability of the seedlings and hence to increase their growth and productivity; however, fertilization could also alter wood properties and timber quality. In this study, the dimensions and tree-ring parameters – width, proportion of latewood, maximum and mean density, mean earlywood and latewood density – of initially fertilized (by 14, 6 and 11 g of N, P and K per seedling, respectively) Norway spruce (Picea abies Karst.) growing in an experimental plantation in Kalsnava, Latvia (temperate climate region) were assessed. The fertilization significantly increased the dimensions of trees in long-term (ca. 17% increase of stemwood volume). The analysis of tree-ring width suggested that the duration of the effect was ca. 15 years. The maximum and latewood density were higher for the fertilized trees only in a few years. The mean and earlywood density of tree-rings were mainly similar for both treatments. Altogether, considering the one-time application of a limited amount of fertilizer, such treatment had notable and lasting effect on Norway spruce.

  • Jansons, LSRFI “Silava”, Rigas str. 111, Salaspils, Latvia, LV2169 ORCID ID:E-mail: aris.jansons@silava.lv
  • Matisons, LSRFI “Silava”, Rigas str. 111, Salaspils, Latvia, LV2169 ORCID ID:E-mail: robism@inbox.lv (email)
  • Krišāns, LSRFI “Silava”, Rigas str. 111, Salaspils, Latvia, LV2169 ORCID ID:E-mail: oskars.krisans@silava.lv
  • Džeriņa, LSRFI “Silava”, Rigas str. 111, Salaspils, Latvia, LV2169 ORCID ID:E-mail: baiba.dzerina@silava.lv
  • Zeps, LSRFI “Silava”, Rigas str. 111, Salaspils, Latvia, LV2169 ORCID ID:E-mail: martins.zeps@silava.lv
article id 1346, category Research note
Āris Jansons, Roberts Matisons, Oskars Krišāns, Baiba Džeriņa, Mārtiņš Zeps. (2016). Effect of initial fertilization on 34-year increment and wood properties of Norway spruce in Latvia. Silva Fennica vol. 50 no. 1 article id 1346. https://doi.org/10.14214/sf.1346
Highlights: The initial fertilization increased the productivity of Picea abies increasing stem volume by 17% at the age of 34 years; The tree-ring width was affected for up to15 years; The fertilization did not affect mean tree-ring density, although the latewood density was increased.

Initial fertilisation, when the fertilizer is supplied during the plantation, is applied to improve the competitive ability of the seedlings and hence to increase their growth and productivity; however, fertilization could also alter wood properties and timber quality. In this study, the dimensions and tree-ring parameters – width, proportion of latewood, maximum and mean density, mean earlywood and latewood density – of initially fertilized (by 14, 6 and 11 g of N, P and K per seedling, respectively) Norway spruce (Picea abies Karst.) growing in an experimental plantation in Kalsnava, Latvia (temperate climate region) were assessed. The fertilization significantly increased the dimensions of trees in long-term (ca. 17% increase of stemwood volume). The analysis of tree-ring width suggested that the duration of the effect was ca. 15 years. The maximum and latewood density were higher for the fertilized trees only in a few years. The mean and earlywood density of tree-rings were mainly similar for both treatments. Altogether, considering the one-time application of a limited amount of fertilizer, such treatment had notable and lasting effect on Norway spruce.

  • Jansons, LSRFI “Silava”, Rigas str. 111, Salaspils, Latvia, LV2169 ORCID ID:E-mail: aris.jansons@silava.lv
  • Matisons, LSRFI “Silava”, Rigas str. 111, Salaspils, Latvia, LV2169 ORCID ID:E-mail: robism@inbox.lv (email)
  • Krišāns, LSRFI “Silava”, Rigas str. 111, Salaspils, Latvia, LV2169 ORCID ID:E-mail: oskars.krisans@silava.lv
  • Džeriņa, LSRFI “Silava”, Rigas str. 111, Salaspils, Latvia, LV2169 ORCID ID:E-mail: baiba.dzerina@silava.lv
  • Zeps, LSRFI “Silava”, Rigas str. 111, Salaspils, Latvia, LV2169 ORCID ID:E-mail: martins.zeps@silava.lv
article id 1320, category Research note
Abbot Okotie Oghenekaro, Geoffrey Daniel, Fred O Asiegbu. (2015). The saprotrophic wood-degrading abilities of Rigidoporus microporus. Silva Fennica vol. 49 no. 4 article id 1320. https://doi.org/10.14214/sf.1320
Highlights: Rigidoporus microporus isolates displayed varying saprotrophic capabilities on wood blocks of Rubber tree (Hevea brasiliensis); Percentage mass loss of (Hevea brasiliensis) wood blocks caused by the pathogenic Rigidoporus microporus was significantly higher than that observed with the endophytic isolate; The endophytic isolate has very poor saprotrophic ability on Hevea brasiliensis wood blocks.

Saprotrophic wood-decaying abilities of Rigidoporus microporus (Polyporales, Basidiomycota) syn. Rigidoporus lignosus and the structural alterations induced in wood blocks of Hevea brasiliensis Muell. Arg were studied. Mass loss of wood blocks was analyzed after 3 and 6 months respectively and the patterns of decay by pathogenic and endophytic isolates of this fungus were investigated using light microscopy. Effects of temperature on growth of the isolates on malt extract agar were also investigated. The R. microporus isolated from a non-H. brasiliensis host caused the highest percentage mass loss (27.2% after 6 months), followed by isolates ED310 (21.1%) and M13 (15.7%), both collected from diseased H. brasiliensis plantations. The isolate initially identified as an endophyte showed very low saprotrophic wood decay capability (4.3% after 6 months). The optimal temperature for growth of the isolates was 30 °C; except for the endophytic isolate which showed highest growth at 25 °C. Wood samples degraded by the R. microporus isolates showed simultaneous attack of wood cell walls, typical of white rot fungi. Results of the study indicate variability in the wood degrading abilities of the isolates and the potential differences in their physiology are discussed. Our findings further support the need for a taxonomical revision of the Rigidoporus genus.

  • Oghenekaro, Department of Forest Sciences, University of Helsinki, P.O. Box 27, FI-00014 University of Helsinki, Finland ORCID ID:E-mail: abbot.oghenekaro@helsinki.fi (email)
  • Daniel, Department of Forest Products/Wood Science, Swedish University of Agricultural Sciences, P.O. Box 7008, SE-75007 Uppsala, Sweden ORCID ID:E-mail: geoffrey.daniel@slu.se
  • Asiegbu, Department of Forest Sciences, University of Helsinki, P.O. Box 27, FI-00014 University of Helsinki, Finland ORCID ID:E-mail: fred.asiegbu@helsinki.fi
article id 1305, category Research note
Israel Sánchez-Osorio, Luis Domínguez, Gloria López-Pantoja, Raúl Tapias. (2015). Antennal response of Prinobius myardi to synthetic tree volatiles. Silva Fennica vol. 49 no. 3 article id 1305. https://doi.org/10.14214/sf.1305
Highlights: Prinobius myardi is a wood borer considered a major threat for Mediterranean oaks, especially Quercus suber and Q. ilex; We performed electroantennographic bioassays to assess olfactory sensitivity of P. myardi to synthetic plant volatiles; P. myardi exhibits a broad sensitivity to common tree volatiles, including those emitted by oaks (α-pinene and β-pinene) or non-host volatiles (1,8-cineole).
Prinobius myardi Mulsant is a wood borer implicated in the decline of Mediterranean oaks, especially Quercus suber L. and Quercus ilex L. Plant volatiles play an important role in plant-insect interactions, and electroantennography (EAG) is an effective tool for exploring the electrophysiological activity of host plant volatiles on insects. To improve our understanding of the olfactory sensitivity of P. myardi, we recorded EAG responses to 20 tree volatiles, and analyzed the dose-dependent response to five doses (10–4:1 to 1:1 v/v) of the three most EAG-active compounds. Antennae of P. myardi responded to 13 chemicals, mainly monoterpenes and green leaf volatiles, with the strongest EAG responses being observed with β-pinene, (+)-α-pinene and 1,8-cineole. Dose–response profiles showed positive dose-dependent responses for all three compounds. Our results suggest a broad sensitivity of P. myardi to common tree volatiles, particularly some host-related compounds and volatiles associated with wounded trees; the olfactory recognition of ratios of these compounds could play a role in host selection by P. myardi.
  • Sánchez-Osorio, Departamento de Ciencias Agroforestales, ETSI La Rábida, University of Huelva, 21819 Palos de la Frontera (Huelva), Spain ORCID ID: http://orcid.org/0000-0002-6852-7699 E-mail: isanchez@uhu.es (email)
  • Domínguez, Departamento de Ciencias Agroforestales, ETSI La Rábida, University of Huelva, 21819 Palos de la Frontera (Huelva), Spain ORCID ID: http://orcid.org/0000-0002-0131-0057 E-mail: luis.dominguez@dcaf.uhu.es
  • López-Pantoja, Departamento de Ciencias Agroforestales, ETSI La Rábida, University of Huelva, 21819 Palos de la Frontera (Huelva), Spain ORCID ID: http://orcid.org/0000-0002-2659-6127 E-mail: pantoja@uhu.es
  • Tapias, Departamento de Ciencias Agroforestales, ETSI La Rábida, University of Huelva, 21819 Palos de la Frontera (Huelva), Spain ORCID ID:E-mail: rtapias@uhu.es
article id 1255, category Research note
Āris Jansons, Roberts Matisons, Līga Puriņa, Una Neimane, Jānis Jansons. (2015). Relationships between climatic variables and tree-ring width of European beech and European larch growing outside of their natural distribution area. Silva Fennica vol. 49 no. 1 article id 1255. https://doi.org/10.14214/sf.1255
Highlights: In western Latvia, variation of tree-ring width of European beech and European larch within stands was similar; Dry summers and cold winters caused common event years in tree-rings; Moisture availability at the end of summer was apparently the main limiting factor for tree-ring width; Winter and spring temperature did not have significant and lasting effect on variation of tree-ring width.
Relationships between climatic variables and tree-ring width (TRW) of dominant European larch (Larix decidua Mill.) and European beech (Fagus sylvatica L.) trees growing outside of their natural distribution area in western Latvia were studied. Chronologies of TRW, which covered the periods 1949–2012 and 1911–2012, were produced for beech and larch, respectively. Common signatures in TRW between both species were observed, but their amplitude differed. Correlation analysis showed that variation of TRW of both species was affected by drought related climatic variables. Tree-ring width of beech was affected by temperature in the previous July and August and the effect of spring and autumn temperature was observed. Since the 1980s, the effect of July precipitation has become significant. Summer precipitation was significant for larch in the mid-part of the previous century; however, temperature in the previous September has become a limiting factor since 1970s. The limiting effect of winter and spring temperature apparently lost its significance around the 1950s.
  • Jansons, LSFRI „SILAVA”, Rigas Str. 111, Salaspils, Latvia, LV2169 ORCID ID:E-mail: aris.jansons@silava.lv
  • Matisons, LSFRI „SILAVA”, Rigas Str. 111, Salaspils, Latvia, LV2169 ORCID ID:E-mail: robism@inbox.lv (email)
  • Puriņa, LSFRI „SILAVA”, Rigas Str. 111, Salaspils, Latvia, LV2169 ORCID ID:E-mail: liga.purina@silava.lv
  • Neimane, LSFRI „SILAVA”, Rigas Str. 111, Salaspils, Latvia, LV2169 ORCID ID:E-mail: una.neimane@silava.lv
  • Jansons, Forest Competence Centre, Dzerbenes str. 27, Riga, Latvia, LV1006 ORCID ID:E-mail: janis.jansons@mnkc.lv
article id 1026, category Research note
Leif Nutto, Ricardo A. Malinovski, Martin Brunsmeier, Felipe Schumacher Sant’Anna. (2013). Ergonomic aspects and productivity of different pruning tools for a first pruning lift of Eucalyptus grandis Hill ex Maiden. Silva Fennica vol. 47 no. 4 article id 1026. https://doi.org/10.14214/sf.1026
Highlights: Pruning of hardwoods coming from forest plantations is becoming more and more important in Brazil to replace scarce wood from tropical forests; Evaluating productivity of different pruning tools is essential for the economic output of plantations managed for high quality wood; Pruning activities of forest workers can be classified as “hard” or “very hard work”. Depending on the tools used physical long-term damages may be prevented.
For the substitution of wood from tropical rainforests pruning of Eucalyptus for producing valuable hardwoods in short rotation plantations has become important. Existing tools and ergonomic aspects of pruning were not yet well analysed under these conditions. The objective of the study is to evaluate the productivity and ergonomics of three different pruning tools in a pruning lift up to 3 m in height. The trees used in the study came from an 18-month-old clonal Eucalyptus grandis stand planted in a 5.0 x 2.8 m spacing. Two manual pruning tools and an electric shear were tested for productivity by using time studies. Ergonomic aspects were evaluated by two test persons using pulse meter equipment. The highest productivity could be shown for the electric shear (236 trees per working day), followed by the manual shear (196 trees/day) and the handsaw (180 trees/day). The heartbeat rate of the two test persons ranged from a level of “very hard work” for the manual tools to “middle hard” and “hard work” for the electric shear. The workload level to achieve the productivity currently reached in practice using purely manual tools is extremely high, exceeding the permanent working capacity of the operators and leading to physical degradation on the long run.
  • Nutto, Department for Forestry, Federal University of Paraná, Av. Pref. Lothário Meissner, 632, Curitiba, PR, Brazil ORCID ID:E-mail: lnutto.ufpr@gmail.com (email)
  • Malinovski, Department for Forestry, Laboratory of Forest Operations, Federal University of Paraná, Av. Prefeito Lothario Meissner, 900, Curitiba, PR, Brazil ORCID ID:E-mail: ricardo@colheitademadeira.com.br
  • Brunsmeier, Chair of Forest Utilization, University of Freiburg, Werthmannstraße 6, 79085 Freiburg, Germany ORCID ID:E-mail: martin.brunsmeier@fobawi.uni-freiburg.de
  • Schumacher Sant’Anna, Department for Forestry, Laboratory of Forest Operations, Federal University of Paraná, Av. Prefeito Lothario Meissner, 900, Curitiba, PR, Brazil ORCID ID:E-mail: felipe@colheitademadeira.com.br
article id 60, category Research note
Dominik Röser, Blas Mola-Yudego, Robert Prinz, Beatrice Emer, Lauri Sikanen. (2012). Chipping operations and efficiency in different operational environments. Silva Fennica vol. 46 no. 2 article id 60. https://doi.org/10.14214/sf.60
This research analyses the productivity of energy wood chipping operations at several sites in Austria and Finland. The aim of the work is to examine the differences in productivity and the effects of the operational environment for the chipping of bioenergy at the roadside. Furthermore, the study quantifies the effects of different variables such as forest energy assortments, tree species, sieve size and machines on the overall productivity of chipping. The results revealed that there are significant differences in the chipping productivity in Austria and Finland which are largely based on the use of different sieve sizes. Furthermore, the different operational environments in both countries, as well as the characteristics of the raw material also seem to have an effect on productivity. In order to improve the chipping productivity, particularly in Central European conditions, all relevant stakeholders need to work jointly to find solutions that will allow a greater variation of chip size. Furthermore, in the future more consideration has to be given to the close interlinkage between the chipper, crane and grapple. As a result, investments costs can be optimized and operational costs and stress on the machines reduced.
  • Röser, Finnish Forest Research Institute, P.O. Box 68, FI-80101 Joensuu, Finland ORCID ID:E-mail: dominik.roser@metla.fi (email)
  • Mola-Yudego, University of Eastern Finland, School of Forest Sciences, Joensuu, Finland ORCID ID:E-mail:
  • Prinz, Finnish Forest Research Institute, P.O. Box 68, FI-80101 Joensuu, Finland ORCID ID:E-mail:
  • Emer, University of Padova, Department of Land, Agriculture and Forest Systems, Legnaro (PD), Italy ORCID ID:E-mail:
  • Sikanen, University of Eastern Finland, School of Forest Sciences, Joensuu, Finland ORCID ID:E-mail:
article id 91, category Research note
Raisa Mäkipää, Tapio Linkosalo. (2011). A non-destructive field method for measuring wood density of decaying logs. Silva Fennica vol. 45 no. 5 article id 91. https://doi.org/10.14214/sf.91
Decaying dead wood density measurements are a useful indicator for multiple purposes, such as for estimating the amount of carbon in dead wood and making predictions of potential diversity of dead wood inhabiting fungi and insects. Currently, qualitative decay phases are used as wood density estimates in many applications, since measuring the density is laborious. A quantitative measure of density would, however, be preferred over the qualitative one. Penetrometers, which are commonly used for measuring the density of standing trees, might also be applicable to dead wood density measurements. We tested the device for making quick, quantitative measurements of decaying logs. The penetrometer measures the depth into which a pre-loaded spring forces a pin in the wood. We tested pins of 5 and 10 mm diameter together with an original 2.5 mm pin and compared the results with gravimetric density measurements of the sample logs. Our results suggest that the standard pin works for less decayed wood, but for more decomposed wood, the thicker 5 mm pin gave more reliable estimates when the penetration measures were converted to densities with a linear regression function (R2 = 0.62, F = 82.9, p = 0.000). The range of wood densities successfully measured with the 5 mm pin was from 180 to 510 kg m–3. With the 10 mm pin, the measuring resolution of denser wood was compromised, while the improvement at the other end of density scale was not large. As a conclusion, the penetrometer seems to be a promising tool for quick density testing of decaying logs in field, but it needs to be modified to use a thicker measuring pin than the standard 2.5 mm pin.
  • Mäkipää, The Finnish Forest Research Institute, Vantaa, Finland ORCID ID:E-mail: raisa.makipaa@metla.fi (email)
  • Linkosalo, The Finnish Forest Research Institute, Vantaa, Finland ORCID ID:E-mail:
article id 91, category Research note
Raisa Mäkipää, Tapio Linkosalo. (2011). A non-destructive field method for measuring wood density of decaying logs. Silva Fennica vol. 45 no. 5 article id 91. https://doi.org/10.14214/sf.91
Decaying dead wood density measurements are a useful indicator for multiple purposes, such as for estimating the amount of carbon in dead wood and making predictions of potential diversity of dead wood inhabiting fungi and insects. Currently, qualitative decay phases are used as wood density estimates in many applications, since measuring the density is laborious. A quantitative measure of density would, however, be preferred over the qualitative one. Penetrometers, which are commonly used for measuring the density of standing trees, might also be applicable to dead wood density measurements. We tested the device for making quick, quantitative measurements of decaying logs. The penetrometer measures the depth into which a pre-loaded spring forces a pin in the wood. We tested pins of 5 and 10 mm diameter together with an original 2.5 mm pin and compared the results with gravimetric density measurements of the sample logs. Our results suggest that the standard pin works for less decayed wood, but for more decomposed wood, the thicker 5 mm pin gave more reliable estimates when the penetration measures were converted to densities with a linear regression function (R2 = 0.62, F = 82.9, p = 0.000). The range of wood densities successfully measured with the 5 mm pin was from 180 to 510 kg m–3. With the 10 mm pin, the measuring resolution of denser wood was compromised, while the improvement at the other end of density scale was not large. As a conclusion, the penetrometer seems to be a promising tool for quick density testing of decaying logs in field, but it needs to be modified to use a thicker measuring pin than the standard 2.5 mm pin.
  • Mäkipää, The Finnish Forest Research Institute, Vantaa, Finland ORCID ID:E-mail: raisa.makipaa@metla.fi (email)
  • Linkosalo, The Finnish Forest Research Institute, Vantaa, Finland ORCID ID:E-mail:
article id 91, category Research note
Raisa Mäkipää, Tapio Linkosalo. (2011). A non-destructive field method for measuring wood density of decaying logs. Silva Fennica vol. 45 no. 5 article id 91. https://doi.org/10.14214/sf.91
Decaying dead wood density measurements are a useful indicator for multiple purposes, such as for estimating the amount of carbon in dead wood and making predictions of potential diversity of dead wood inhabiting fungi and insects. Currently, qualitative decay phases are used as wood density estimates in many applications, since measuring the density is laborious. A quantitative measure of density would, however, be preferred over the qualitative one. Penetrometers, which are commonly used for measuring the density of standing trees, might also be applicable to dead wood density measurements. We tested the device for making quick, quantitative measurements of decaying logs. The penetrometer measures the depth into which a pre-loaded spring forces a pin in the wood. We tested pins of 5 and 10 mm diameter together with an original 2.5 mm pin and compared the results with gravimetric density measurements of the sample logs. Our results suggest that the standard pin works for less decayed wood, but for more decomposed wood, the thicker 5 mm pin gave more reliable estimates when the penetration measures were converted to densities with a linear regression function (R2 = 0.62, F = 82.9, p = 0.000). The range of wood densities successfully measured with the 5 mm pin was from 180 to 510 kg m–3. With the 10 mm pin, the measuring resolution of denser wood was compromised, while the improvement at the other end of density scale was not large. As a conclusion, the penetrometer seems to be a promising tool for quick density testing of decaying logs in field, but it needs to be modified to use a thicker measuring pin than the standard 2.5 mm pin.
  • Mäkipää, The Finnish Forest Research Institute, Vantaa, Finland ORCID ID:E-mail: raisa.makipaa@metla.fi (email)
  • Linkosalo, The Finnish Forest Research Institute, Vantaa, Finland ORCID ID:E-mail:
article id 470, category Research note
Paula Jylhä, Juha Laitila. (2007). Energy wood and pulpwood harvesting from young stands using a prototype whole-tree bundler. Silva Fennica vol. 41 no. 4 article id 470. https://doi.org/10.14214/sf.470
The productivity of cutting and bundling whole trees using the first prototype of a bundle-harvester comprised of a harwarder as the base machine, an accumulating felling head, and a compacting device was studied in three young stands in order to facilitate the further development of the concept. In addition, the removal and its composition were studied as a means of laying the foundations for developing methods for work rating and measurement on delivery. Bundling enables in-depth integration of pulpwood and energy wood procurement. Both energy wood (crown biomass) and pulpwood can be incorporated into the same bundles, and the subsequent separation of these fractions takes place at the debarking phase at the pulpmill. Bundle-harvesting productivities were relatively low (2.8–3.7 m3/E0-h) when compared to current harvesting technology. Improving working techniques, machine structure, and components showed great potential for increasing the efficiency of the concept. The bundles were dimensionally uniform. Their solid volume varied between 0.350 m3 and 0.513 m3, depending on the bundle assortment and stand properties. Integrating energy wood harvesting with pulpwood harvesting increased removal even by 59 per cent.
  • Jylhä, Finnish Forest Research Institute, Kannus Research Unit, P.O. Box 44, FI-69101 Kannus, Finland ORCID ID:E-mail: paula.jylha@metla.fi (email)
  • Laitila, Finnish Forest Research Institute, Joensuu Research Unit, P.O. Box 68, FI-80101 Joensuu, Finland ORCID ID:E-mail:
article id 470, category Research note
Paula Jylhä, Juha Laitila. (2007). Energy wood and pulpwood harvesting from young stands using a prototype whole-tree bundler. Silva Fennica vol. 41 no. 4 article id 470. https://doi.org/10.14214/sf.470
The productivity of cutting and bundling whole trees using the first prototype of a bundle-harvester comprised of a harwarder as the base machine, an accumulating felling head, and a compacting device was studied in three young stands in order to facilitate the further development of the concept. In addition, the removal and its composition were studied as a means of laying the foundations for developing methods for work rating and measurement on delivery. Bundling enables in-depth integration of pulpwood and energy wood procurement. Both energy wood (crown biomass) and pulpwood can be incorporated into the same bundles, and the subsequent separation of these fractions takes place at the debarking phase at the pulpmill. Bundle-harvesting productivities were relatively low (2.8–3.7 m3/E0-h) when compared to current harvesting technology. Improving working techniques, machine structure, and components showed great potential for increasing the efficiency of the concept. The bundles were dimensionally uniform. Their solid volume varied between 0.350 m3 and 0.513 m3, depending on the bundle assortment and stand properties. Integrating energy wood harvesting with pulpwood harvesting increased removal even by 59 per cent.
  • Jylhä, Finnish Forest Research Institute, Kannus Research Unit, P.O. Box 44, FI-69101 Kannus, Finland ORCID ID:E-mail: paula.jylha@metla.fi (email)
  • Laitila, Finnish Forest Research Institute, Joensuu Research Unit, P.O. Box 68, FI-80101 Joensuu, Finland ORCID ID:E-mail:

Category: Discussion article

article id 119, category Discussion article
Markku Larjavaara, Helene C. Muller-Landau. (2011). Cross-section mass: an improved basis for woody debris necromass inventory. Silva Fennica vol. 45 no. 2 article id 119. https://doi.org/10.14214/sf.119
  • Larjavaara, Smithsonian Tropical Research Institute, Unit 9100 Box 0948, DPO AA 34002-9998, USA, and University of Helsinki, Department of Forest Sciences, Finland ORCID ID:E-mail: larjavaaram@si.edu (email)
  • Muller-Landau, Smithsonian Tropical Research Institute, Unit 9100 Box 0948, DPO AA 34002-9998, USA ORCID ID:E-mail:
article id 119, category Discussion article
Markku Larjavaara, Helene C. Muller-Landau. (2011). Cross-section mass: an improved basis for woody debris necromass inventory. Silva Fennica vol. 45 no. 2 article id 119. https://doi.org/10.14214/sf.119
  • Larjavaara, Smithsonian Tropical Research Institute, Unit 9100 Box 0948, DPO AA 34002-9998, USA, and University of Helsinki, Department of Forest Sciences, Finland ORCID ID:E-mail: larjavaaram@si.edu (email)
  • Muller-Landau, Smithsonian Tropical Research Institute, Unit 9100 Box 0948, DPO AA 34002-9998, USA ORCID ID:E-mail:
article id 119, category Discussion article
Markku Larjavaara, Helene C. Muller-Landau. (2011). Cross-section mass: an improved basis for woody debris necromass inventory. Silva Fennica vol. 45 no. 2 article id 119. https://doi.org/10.14214/sf.119
  • Larjavaara, Smithsonian Tropical Research Institute, Unit 9100 Box 0948, DPO AA 34002-9998, USA, and University of Helsinki, Department of Forest Sciences, Finland ORCID ID:E-mail: larjavaaram@si.edu (email)
  • Muller-Landau, Smithsonian Tropical Research Institute, Unit 9100 Box 0948, DPO AA 34002-9998, USA ORCID ID:E-mail:
article id 119, category Discussion article
Markku Larjavaara, Helene C. Muller-Landau. (2011). Cross-section mass: an improved basis for woody debris necromass inventory. Silva Fennica vol. 45 no. 2 article id 119. https://doi.org/10.14214/sf.119
  • Larjavaara, Smithsonian Tropical Research Institute, Unit 9100 Box 0948, DPO AA 34002-9998, USA, and University of Helsinki, Department of Forest Sciences, Finland ORCID ID:E-mail: larjavaaram@si.edu (email)
  • Muller-Landau, Smithsonian Tropical Research Institute, Unit 9100 Box 0948, DPO AA 34002-9998, USA ORCID ID:E-mail:

Category: Article

article id 7184, category Article
Bror-Anton Granvik. (1967). Havusahatavaran valmistus kenttäpyörösahalla : työtieteellinen tutkimus. Acta Forestalia Fennica vol. 84 no. 3 article id 7184. https://doi.org/10.14214/aff.7184
English title: The preparation of coniferous sawn goods using circular saws. A work study.

The objectives of the paper were to find out structure of the sawing time when using field circular saws, influence of the different factors on the sawing time and its structure, average sawing time per unit of raw material and sawn goods, and the fundamentals for the creation of an equitable system for the determination of the basis of payment in sawing work. The observations of the time study were made on both a single log and a work period basis. The material was collected using four saws of different brands.

The results showed that the season when the work was done, and top diameter of the logs to be sawn affected the constant times included in the total sawing time and the time used for sawing of center pieces. While the tree species did not affect the constant times, the grade of the logs of different tree species did have effect, especially in winter sawing. The factors affecting the different phases of the work are described in detail. The length of sawing time was longer in the winter than in the summer. The preparatory jobs in sawing required in average 82 cmin per log, and the time increased with increasing top diameter. The actual sawing is the most time-consuming part of the work, it took in average 132 cmin. 

The PDF includes a summary in English.

  • Granvik, ORCID ID:E-mail:
article id 7174, category Article
Pentti Alho. (1967). Pohjois-Pohjanmaan rannikkokuntien maanjako-olot metsätalouden kannalta. Acta Forestalia Fennica vol. 82 no. 1 article id 7174. https://doi.org/10.14214/aff.7174
English title: Influences of partitioning of land in forestry in the municipalities of northern Ostrobothnia in Finland.

Farm forestry in northern Ostrobothnia has met different kinds of obstacles that decrease its profitability, some national, some local. One of the later is partitioning of land. The purpose of this investigation was to survey the division of farm land in the coastal municipalities of northern Ostrobothnia in Finland, where the conditions are among the most unfavourable in the country in this respect. The material used in the investigation was collected in a previous study about the structure of the farms in the area. First part of the paper summarises the history of partitioning of land in Finland.

The results show that division of the woodlots of a farm are in the coastal municipalities of northern Ostrobothnia very disadvantageous for forestry. The average distance of a woodlot to the farmhouse is 8.3 km, but there is a great variation between the municipalities, and the distance varies from 30 to 1.9 km. The form of the lots, as the long ribbon-like woodlots in the municipality of Liminka, complicates often practical forestry. In addition, the number of separate woodlots is high, in average 9.2 per farm.

The great distance of the woodlots from the main farms hinders the use of forests and diminishes the financial result of forestry. Unfavourable form of the woodlots posts similar hindrances to harvesting of timber and forest management as the long distances and high number of separate plots. The problem is heightened by the abundance of peatlands in relation to productive forest lands in the area.

The PDF includes a summary in German.

  • Alho, ORCID ID:E-mail:
article id 7142, category Article
Seppo Ervasti. (1964). Suomen sahateollisuuden kausivaihtelu. 2. Tutkimustulokset. Acta Forestalia Fennica vol. 76 no. 2 article id 7142. https://doi.org/10.14214/aff.7142
English title: Seasonal variation in the sawmill industry of Finland II. Investigation results.

Seasonal variation in the sawmill industry of Finland was studied in an investigation based on questionnaires answered by a random sample of sawmills concerning the time period of 1958-1960. The method is described in detail in a separate article in Acta Forestalia Fennica issue 75 no. 1.

The seasonal variations in purchase of roundwood was largest in big sawmills, which purchase the main part of the timber as standing sales and buy most of the wood from the State Forest auctions at the end of September. Also, they can afford to reserve their material earlier than the smaller companies. The saw logs are mainly felled in the winter in Finland because the climatic conditions and availability of labour are best at that time. Small sawmills begin fellings a little earlier than the larger ones.

In long-transport of timber the proportion of floating decreased from 47% in 1958 to 38% in 1960. At the same time, proportion of truck transport increased from 48% to 55%. Small sawmills use almost exclusively land transport. They received almost three-fourths of their logs between January and May, because the sawing is concentrated in the first half of the year. Therefore, floating does not suit for their transport method. The larger the sawmill, the later is the seasonal peak of log deliveries. The output of the big sawmills is distributed more evenly thoughout the year. The smaller the sawmill, the quicker is the turnover of raw material and the smaller the sawlog inventories.

The seasonal variation in output is sharper at small sawmills where sawing is concentrated in the first half of the year. The seasonal peak of the early spring is due to the aim at getting the sawn wood to dry early enough for shipments in the summer. Air drying takes an average of 4 ½ months. Kiln drying is more common at the larger sawmills, and gives them more flexibility. Due to the large seasonal variation in operation, the capacity of the small mills is poorly utilized. Domestic sales of sawn wood levels up the seasonality of the deliveries. Export sales are concentrated at the end and turn of the year. Also, the seasonal peak of expenditure occurs in the winter, but that of income in the summer.

The PDF includes a summary in English.

  • Ervasti, ORCID ID:E-mail:
article id 7142, category Article
Seppo Ervasti. (1964). Suomen sahateollisuuden kausivaihtelu. 2. Tutkimustulokset. Acta Forestalia Fennica vol. 76 no. 2 article id 7142. https://doi.org/10.14214/aff.7142
English title: Seasonal variation in the sawmill industry of Finland II. Investigation results.

Seasonal variation in the sawmill industry of Finland was studied in an investigation based on questionnaires answered by a random sample of sawmills concerning the time period of 1958-1960. The method is described in detail in a separate article in Acta Forestalia Fennica issue 75 no. 1.

The seasonal variations in purchase of roundwood was largest in big sawmills, which purchase the main part of the timber as standing sales and buy most of the wood from the State Forest auctions at the end of September. Also, they can afford to reserve their material earlier than the smaller companies. The saw logs are mainly felled in the winter in Finland because the climatic conditions and availability of labour are best at that time. Small sawmills begin fellings a little earlier than the larger ones.

In long-transport of timber the proportion of floating decreased from 47% in 1958 to 38% in 1960. At the same time, proportion of truck transport increased from 48% to 55%. Small sawmills use almost exclusively land transport. They received almost three-fourths of their logs between January and May, because the sawing is concentrated in the first half of the year. Therefore, floating does not suit for their transport method. The larger the sawmill, the later is the seasonal peak of log deliveries. The output of the big sawmills is distributed more evenly thoughout the year. The smaller the sawmill, the quicker is the turnover of raw material and the smaller the sawlog inventories.

The seasonal variation in output is sharper at small sawmills where sawing is concentrated in the first half of the year. The seasonal peak of the early spring is due to the aim at getting the sawn wood to dry early enough for shipments in the summer. Air drying takes an average of 4 ½ months. Kiln drying is more common at the larger sawmills, and gives them more flexibility. Due to the large seasonal variation in operation, the capacity of the small mills is poorly utilized. Domestic sales of sawn wood levels up the seasonality of the deliveries. Export sales are concentrated at the end and turn of the year. Also, the seasonal peak of expenditure occurs in the winter, but that of income in the summer.

The PDF includes a summary in English.

  • Ervasti, ORCID ID:E-mail:
article id 7142, category Article
Seppo Ervasti. (1964). Suomen sahateollisuuden kausivaihtelu. 2. Tutkimustulokset. Acta Forestalia Fennica vol. 76 no. 2 article id 7142. https://doi.org/10.14214/aff.7142
English title: Seasonal variation in the sawmill industry of Finland II. Investigation results.

Seasonal variation in the sawmill industry of Finland was studied in an investigation based on questionnaires answered by a random sample of sawmills concerning the time period of 1958-1960. The method is described in detail in a separate article in Acta Forestalia Fennica issue 75 no. 1.

The seasonal variations in purchase of roundwood was largest in big sawmills, which purchase the main part of the timber as standing sales and buy most of the wood from the State Forest auctions at the end of September. Also, they can afford to reserve their material earlier than the smaller companies. The saw logs are mainly felled in the winter in Finland because the climatic conditions and availability of labour are best at that time. Small sawmills begin fellings a little earlier than the larger ones.

In long-transport of timber the proportion of floating decreased from 47% in 1958 to 38% in 1960. At the same time, proportion of truck transport increased from 48% to 55%. Small sawmills use almost exclusively land transport. They received almost three-fourths of their logs between January and May, because the sawing is concentrated in the first half of the year. Therefore, floating does not suit for their transport method. The larger the sawmill, the later is the seasonal peak of log deliveries. The output of the big sawmills is distributed more evenly thoughout the year. The smaller the sawmill, the quicker is the turnover of raw material and the smaller the sawlog inventories.

The seasonal variation in output is sharper at small sawmills where sawing is concentrated in the first half of the year. The seasonal peak of the early spring is due to the aim at getting the sawn wood to dry early enough for shipments in the summer. Air drying takes an average of 4 ½ months. Kiln drying is more common at the larger sawmills, and gives them more flexibility. Due to the large seasonal variation in operation, the capacity of the small mills is poorly utilized. Domestic sales of sawn wood levels up the seasonality of the deliveries. Export sales are concentrated at the end and turn of the year. Also, the seasonal peak of expenditure occurs in the winter, but that of income in the summer.

The PDF includes a summary in English.

  • Ervasti, ORCID ID:E-mail:
article id 7142, category Article
Seppo Ervasti. (1964). Suomen sahateollisuuden kausivaihtelu. 2. Tutkimustulokset. Acta Forestalia Fennica vol. 76 no. 2 article id 7142. https://doi.org/10.14214/aff.7142
English title: Seasonal variation in the sawmill industry of Finland II. Investigation results.

Seasonal variation in the sawmill industry of Finland was studied in an investigation based on questionnaires answered by a random sample of sawmills concerning the time period of 1958-1960. The method is described in detail in a separate article in Acta Forestalia Fennica issue 75 no. 1.

The seasonal variations in purchase of roundwood was largest in big sawmills, which purchase the main part of the timber as standing sales and buy most of the wood from the State Forest auctions at the end of September. Also, they can afford to reserve their material earlier than the smaller companies. The saw logs are mainly felled in the winter in Finland because the climatic conditions and availability of labour are best at that time. Small sawmills begin fellings a little earlier than the larger ones.

In long-transport of timber the proportion of floating decreased from 47% in 1958 to 38% in 1960. At the same time, proportion of truck transport increased from 48% to 55%. Small sawmills use almost exclusively land transport. They received almost three-fourths of their logs between January and May, because the sawing is concentrated in the first half of the year. Therefore, floating does not suit for their transport method. The larger the sawmill, the later is the seasonal peak of log deliveries. The output of the big sawmills is distributed more evenly thoughout the year. The smaller the sawmill, the quicker is the turnover of raw material and the smaller the sawlog inventories.

The seasonal variation in output is sharper at small sawmills where sawing is concentrated in the first half of the year. The seasonal peak of the early spring is due to the aim at getting the sawn wood to dry early enough for shipments in the summer. Air drying takes an average of 4 ½ months. Kiln drying is more common at the larger sawmills, and gives them more flexibility. Due to the large seasonal variation in operation, the capacity of the small mills is poorly utilized. Domestic sales of sawn wood levels up the seasonality of the deliveries. Export sales are concentrated at the end and turn of the year. Also, the seasonal peak of expenditure occurs in the winter, but that of income in the summer.

The PDF includes a summary in English.

  • Ervasti, ORCID ID:E-mail:
article id 7137, category Article
Yrjö Roitto. (1963). Ison-Saimaan yhteisuitto-ongelma. Acta Forestalia Fennica vol. 75 no. 3 article id 7137. https://doi.org/10.14214/aff.7137
English title: Problem of co-operative floating on the Iso-Saimaa in Eastern Finland.

In Finland roundwood is floated either privately or co-operatively. In the later, a co-operative floating association is established to operate floating. The association is compulsory association of those enterprises who want to have wood floated along the floating routes of the area. It is favoured when the number of enterprises and the wood to be floated is large. In addition, costs are lower than in private floating.

Floating in Lake Saimaa area in Central Finland can be divided into Iso-Saimaa, where floating is private, and into Saimaa Water System, where floating is operated by a co-operative floating association. It has been suggested that adoption of co-operative floating in Iso-Saimaa would be to the common interest. This study aimed at finding out if co-operative floating influences the transport costs, and if co-operative floating increases competition of roundwood by forest industry companies.

According to the study, the costs of most enterprises would decrease. The total decrease in costs would amount to 65 million Finnish marks annually, about 20% less than the present costs. The change of organization would not alter the competitive relationship in buying roundwood. On the other hand, it would seem that co-operative floating would be less flexible than private floating. The management of a large organization, whose effective operation time would cover only a part of the year, would meet with some difficulties. Also, co-operative floating would reduce competition among enterprises.

The PDF includes a summary in English.

  • Roitto, ORCID ID:E-mail:
article id 7127, category Article
Jouko Einola. (1961). Puutavaran hankintakustannusten ennakkolaskenta. Acta Forestalia Fennica vol. 73 no. 5 article id 7127. https://doi.org/10.14214/aff.7127
English title: Precalculation of logging costs.
English keywords: wood sales; costs; cost accounting

The investigation studies the whole logging operation from the stump to the consumption. The main purpose is to obtain a maximum profit. Proceeds and costs have been studied from the view point of precalculation. First, basic costs theory concepts are introduced. Second, the role of precalculation is described and finally a survey of the practical calculation problems and its results are described.

The purpose of precalculation is to achieve the best possible total financial result for the whole enterprise. The aim is to maximize the difference between future proceeds and the costs. When an alternative calculation is prepared, as many promising alternatives as possible is sought, and the most advantageous of these are selected after a rough survey. Since contributory factors are changing, precalculation is a continuous operation.

Logging operations can be handled in various alternative ways, of which the most advantageous has to be chosen. If there is a large number of different courses of action, the target must be maximum contribution margin per time unit. With labour, too, the aim is to maximize the differentiation between proceeds and costs of a long-term point of view. A working plan of the alternative selected can be formed into a target calculation with the aid of budgets and standards. When purchasing timber, procurement plans can be drawn up and priced for each consignment, and then combined and scrutinized to give target calculations. If the factors affecting them change, the targets must be altered.

The PDF includes a summary in English.

  • Einola, ORCID ID:E-mail:
article id 7126, category Article
Viljo Holopainen. (1960). On the price elasticity of the supply of sawn wood for export. Acta Forestalia Fennica vol. 73 no. 4 article id 7126. https://doi.org/10.14214/aff.7126

The present investigation is concerned with the price elasticity of sawn wood, concentrating on the price elasticity of sawn wood supply for export. The supply of sawn wood for export is referred to the joint attitude to price changes of all producers participating in the market.

The study concludes that producers cannot in the short- and medium-term view use the price parameter to increase total utilization in the sawn wood market. Demand holds a primary position in price formation. The capacity reserve of the sawmills permits great variations in output at the mill level, and thus elasticity in the supply of sawn wood. High timber costs are typical for the industry. Supply of roundwood can easily be adapted even to large variations in demand. The price elasticity of roundwood supply is rather great.

The long process of sawn wood production and the resulting relatively long lead-time of deliveries result in a long adaptation time of supply. Expansion and contraction of sawn wood exports cause, via the effect of exports, on income similar fluctuations in the domestic sales of sawn wood. This weakens the price elasticity of exports in some degree.

The ‘instantaneous elasticity’ upwards of sawn wood supply might be great, but speculation with stocks at the different levels of production often makes it ‘incalculable’. The price elasticity of a medium-long and long period can be expected to be relatively great upwards. The downward elasticity of a period of medium length is probably small. The elasticity of a prolonged period may be influenced by the substitution of other materials for sawn wood.

The PDF includes a summary in Finnish.

  • Holopainen, ORCID ID:E-mail:
article id 7125, category Article
L. Runeberg. (1960). European trade in raw wood during the 1950’s and prospects in the days of EEC and EFTA. Acta Forestalia Fennica vol. 73 no. 3 article id 7125. https://doi.org/10.14214/aff.7125

This paper concentrates on the roundwood commerce in Western Europe as seen from the point of view of Finland, considering the role of Eastern Europe. The first part analyses exports and imports both quantitatively and qualitatively, and the balance of the trade in the export countries. Second part covers the new market groups in Europe and the opportunities for a common market.

Arter the Second World War, a surprisingly large trade in roundwood reappeared in Europe. The European countries exported in average 11 million m3 of roundwood annually, of which 4.3 million m3 was pulpwood, and 2.8 million m3 pitprops. Finland leads exports during the 1950s with a yearly average of 4.2 million m3, followed by France and Sweden. Western Germany is the largest importing country with a negative balance of 2.8 million m3. It is concluded, from a theoretical point of view, that in Western Europe only Finland can maintain a large roundwood export. From a national point of view, however, it would be more favourable to expand the countries’ own refining industries.

On the whole, it seems as if the European roundwood trade should continue on a rather large scale during the 1960s, partly because the border trade can be expected to increase, with a freer trade, and partly because the European timber deficit needs filling from sources outside Europe. In addition, the pulp industries in the importing countries will compete more and more keenly with the exporting countries for pulpwood supplies.

The PDF includes a summary in Finnish.

  • Runeberg, ORCID ID:E-mail:
article id 7122, category Article
Kullervo Kuusela. (1960). Pinotavaraleimikon taksatoriset tunnukset ja niiden vaikutus leimikkoarvioinnin tarkkuuteen. Acta Forestalia Fennica vol. 72 no. 5 article id 7122. https://doi.org/10.14214/aff.7122
English title: Mensurational characteristics of cordwood stock market for felling and their effect on the precision of stock estimation.

The annual fellings and sales of pulpwood from the State Forests of Finland comprised 4.0–4.6 million m3 in 1955–1959. In order to improve the accuracy of the methods used in estimating the pulpwood stocks marked for felling, a pilot survey of 18 marked stocks was carried out in 1959. The stock area, average plot volume, variation of the plot volumes, size and shape of the plot and the distribution of the trees by diameter classes as factors affecting the precision have been studied in this paper.

The greater the mean volume of a plot the more homogenous is the structure of the marked stock. The same number of plots gives a better relative precision for the south Finnish marked stock than for the north Finnish ones, which are heterogenous and less valuable. Stocks smaller than 50 ha can often be estimated more advantageously by the strip method or visually than by the plot method. The proper size of plot in Southern Finland is 0.02–0.03 ha. In Northern Finland the plots should be larger due to the heterogenous stocks, about 0.05 ha. The shape can be either circular or rectangular. The former may be more practical and reliable in the field. The minimum number of sample trees is considered to be about 200 per 100 sample plots 0.03 ha in size.

The PDF includes a summary in English.

  • Kuusela, ORCID ID:E-mail:
article id 7122, category Article
Kullervo Kuusela. (1960). Pinotavaraleimikon taksatoriset tunnukset ja niiden vaikutus leimikkoarvioinnin tarkkuuteen. Acta Forestalia Fennica vol. 72 no. 5 article id 7122. https://doi.org/10.14214/aff.7122
English title: Mensurational characteristics of cordwood stock market for felling and their effect on the precision of stock estimation.

The annual fellings and sales of pulpwood from the State Forests of Finland comprised 4.0–4.6 million m3 in 1955–1959. In order to improve the accuracy of the methods used in estimating the pulpwood stocks marked for felling, a pilot survey of 18 marked stocks was carried out in 1959. The stock area, average plot volume, variation of the plot volumes, size and shape of the plot and the distribution of the trees by diameter classes as factors affecting the precision have been studied in this paper.

The greater the mean volume of a plot the more homogenous is the structure of the marked stock. The same number of plots gives a better relative precision for the south Finnish marked stock than for the north Finnish ones, which are heterogenous and less valuable. Stocks smaller than 50 ha can often be estimated more advantageously by the strip method or visually than by the plot method. The proper size of plot in Southern Finland is 0.02–0.03 ha. In Northern Finland the plots should be larger due to the heterogenous stocks, about 0.05 ha. The shape can be either circular or rectangular. The former may be more practical and reliable in the field. The minimum number of sample trees is considered to be about 200 per 100 sample plots 0.03 ha in size.

The PDF includes a summary in English.

  • Kuusela, ORCID ID:E-mail:
article id 7121, category Article
Viljo Holopainen. (1960). Marketing roundwood in Finland and the Scandinavian Countries. With special regard to marketing channels and trade customs. Acta Forestalia Fennica vol. 72 no. 4 article id 7121. https://doi.org/10.14214/aff.7121

The present investigation set out to find out the structures of supply and demand, channels and methods of marketing, developments in marketing methods, trade customs, similarities and differences in marketing of the private forest owners and the State, local features of the market of domestic roundwood trade in Finland, and compares marketing of unprocessed wood between Finland and Scandinavian countries. The study is based on statistics of various sections of trade and from the State Boards of Forestry.

The channels of marketing from private forests in Finland and the Scandinavian countries are different. In Norway the wood is primarily marketed through the forest owners’ associations, in Finland direct individual selling is applied, while in Sweden both channels are common. In Norway and in Sweden the forest owners’ marketing organizations were probably formed mainly to protect the forest owners’ interest in price formation. The price is determined on the organizational level, while in Finland the price formation mechanism has retained a competitive nature. In Sweden the creation of demand for roundwood has been one reason for establishment of the associations, which have established new forest industry particularly in areas of low demand.

The institutions affect also the trade customs in Norway and Sweden. For instance, measuring of roundwood is performed in Scandinavia according to detailed public regulations and often carried out by the officials of special measuring boards. The Forms Committee has also since 1950 brought significant unification in the trade customs of Finland. Greatest differences in trade customs between the State and private forestry is observed in Finland.

The producer’s role in marketing has increased since 1930s, which is demonstrated by the increasing activity in marketing by the forest owners’ associations in Norway and Sweden. Also, the relative importance of sales with contract for delivery has been growing. A second line of development appears in the more detailed norms in trade customs.

The PDF includes a summary in Finnish.

  • Holopainen, ORCID ID:E-mail:
article id 7121, category Article
Viljo Holopainen. (1960). Marketing roundwood in Finland and the Scandinavian Countries. With special regard to marketing channels and trade customs. Acta Forestalia Fennica vol. 72 no. 4 article id 7121. https://doi.org/10.14214/aff.7121

The present investigation set out to find out the structures of supply and demand, channels and methods of marketing, developments in marketing methods, trade customs, similarities and differences in marketing of the private forest owners and the State, local features of the market of domestic roundwood trade in Finland, and compares marketing of unprocessed wood between Finland and Scandinavian countries. The study is based on statistics of various sections of trade and from the State Boards of Forestry.

The channels of marketing from private forests in Finland and the Scandinavian countries are different. In Norway the wood is primarily marketed through the forest owners’ associations, in Finland direct individual selling is applied, while in Sweden both channels are common. In Norway and in Sweden the forest owners’ marketing organizations were probably formed mainly to protect the forest owners’ interest in price formation. The price is determined on the organizational level, while in Finland the price formation mechanism has retained a competitive nature. In Sweden the creation of demand for roundwood has been one reason for establishment of the associations, which have established new forest industry particularly in areas of low demand.

The institutions affect also the trade customs in Norway and Sweden. For instance, measuring of roundwood is performed in Scandinavia according to detailed public regulations and often carried out by the officials of special measuring boards. The Forms Committee has also since 1950 brought significant unification in the trade customs of Finland. Greatest differences in trade customs between the State and private forestry is observed in Finland.

The producer’s role in marketing has increased since 1930s, which is demonstrated by the increasing activity in marketing by the forest owners’ associations in Norway and Sweden. Also, the relative importance of sales with contract for delivery has been growing. A second line of development appears in the more detailed norms in trade customs.

The PDF includes a summary in Finnish.

  • Holopainen, ORCID ID:E-mail:
article id 7121, category Article
Viljo Holopainen. (1960). Marketing roundwood in Finland and the Scandinavian Countries. With special regard to marketing channels and trade customs. Acta Forestalia Fennica vol. 72 no. 4 article id 7121. https://doi.org/10.14214/aff.7121

The present investigation set out to find out the structures of supply and demand, channels and methods of marketing, developments in marketing methods, trade customs, similarities and differences in marketing of the private forest owners and the State, local features of the market of domestic roundwood trade in Finland, and compares marketing of unprocessed wood between Finland and Scandinavian countries. The study is based on statistics of various sections of trade and from the State Boards of Forestry.

The channels of marketing from private forests in Finland and the Scandinavian countries are different. In Norway the wood is primarily marketed through the forest owners’ associations, in Finland direct individual selling is applied, while in Sweden both channels are common. In Norway and in Sweden the forest owners’ marketing organizations were probably formed mainly to protect the forest owners’ interest in price formation. The price is determined on the organizational level, while in Finland the price formation mechanism has retained a competitive nature. In Sweden the creation of demand for roundwood has been one reason for establishment of the associations, which have established new forest industry particularly in areas of low demand.

The institutions affect also the trade customs in Norway and Sweden. For instance, measuring of roundwood is performed in Scandinavia according to detailed public regulations and often carried out by the officials of special measuring boards. The Forms Committee has also since 1950 brought significant unification in the trade customs of Finland. Greatest differences in trade customs between the State and private forestry is observed in Finland.

The producer’s role in marketing has increased since 1930s, which is demonstrated by the increasing activity in marketing by the forest owners’ associations in Norway and Sweden. Also, the relative importance of sales with contract for delivery has been growing. A second line of development appears in the more detailed norms in trade customs.

The PDF includes a summary in Finnish.

  • Holopainen, ORCID ID:E-mail:
article id 7119, category Article
Paavo J. Ollinmaa. (1960). Eräistä ojitetuilla soilla kasvavan puun fysikaalisista ominaisuuksista. Acta Forestalia Fennica vol. 72 no. 2 article id 7119. https://doi.org/10.14214/aff.7119
English title: Physical properties of wood growing on drained peatlands.

The objective of the investigation was to determine the differences between faultless timber grown on a peatland before and after draining, in respect of compressive strength to the grain, volume weight, and shrinkage. In addition, the influence of the boundary zone between the close-ringed wood formed before draining and the wide-ringed wood produced after draining on strength of the timber was studied. The material consisted of 15 sample trees of Scots pine (Pinus sylvestris L.), Norway spruce (Picea abies (L.) Karst.), white birch (Betula pubescens Ehrh.) and silver birch (B. Pendula Roth).

The volume weight of wood of the tree species in ascending order is; spruce, pine, white birch, silver birch. The volume weight of Scots pine seems to decrease from the butt end upwards, while no trend was revealed for spruce. In the coniferous trees, the wide-ringed wood formed subsequent to draining was slightly lighter than the close-ringed wood produced prior draining. No distinct trend was seen in the birch species. The volume weight of pine and spruce increased with decreasing width of the growth rings up to a certain limit, after which the conditions inverted.

The compressive strength of the different kinds of wood seems to increase from the butt end upwards, but after height of two meters it begins to decrease considerably. In birch, this point of inversion is in somewhat greater height. In spruce timber, the compressive strength parallel to the grain is lowest for wood which contains exclusively wide-ringed wood formed after draining. The boundary zone between the woods formed before and after draining is very distinguishable, but has no remarkable influence on the compressive strength parallel to the grain. Shrinkage of close-ringed wood is higher in all three principal directions than that of wide-ringed wood. This can be explained by the variations in volume weight and fibrillar orientation of the tracheid walls.

The PDF includes a summary in English.

  • Ollinmaa, ORCID ID:E-mail:
article id 7118, category Article
Paavo J. Ollinmaa. (1959). Reaktiopuututkimuksia. Acta Forestalia Fennica vol. 72 no. 1 article id 7118. https://doi.org/10.14214/aff.7118
English title: Study on reaction wood.

Compression wood of the tree species studied in this investigation, Scots pine (Pinus sylvestris L.), Norway spruce (Picea abies (L.) Karst.) and common juniper (Juniperus communis L.), was found to be characterized in its cross section by the thick walls and rounded shape of its tracheids and the profuse occurence of spaces. Tension wood of aspen (Populus tremula L.) and alder (Alnus incana (L.) Moench) was found in microscopic examination to be characterized by the gelatinous appearance of the wood fibres, by its small cell cavities and by the thickness and buckling of the inner layer of the cecondary wall. Tracheids of the compression wood were found to have shorter length than normal on an average, while the tension wood fibres were found to be longer.

The microchemical studies suggest a higher than normal lignin content in compression wood and lower than normal lignin content in tension wood, as compared to normal wood. The reverse would be true for the cellulose contents. Volume weight of absolute dry reaction wood was distinctly higher than that of normal wood. The longitudinal shrinkage of reaction wood, particularly of compression wood, is several times that of normal wood. Transversal shrinkage of compression wood is much less than normal wood. Swelling tests revealed pushing effect of compression wood on elongation and pulling effect on tension wood on constraction. Volume shrinkage of compression wood is less than that of normal wood, in contrast to tension wood. The strength of compression wood in absolutely dry condition was nearly same as that of normal wood.

The PDF includes a summary in English.

  • Ollinmaa, ORCID ID:E-mail:
article id 7118, category Article
Paavo J. Ollinmaa. (1959). Reaktiopuututkimuksia. Acta Forestalia Fennica vol. 72 no. 1 article id 7118. https://doi.org/10.14214/aff.7118
English title: Study on reaction wood.

Compression wood of the tree species studied in this investigation, Scots pine (Pinus sylvestris L.), Norway spruce (Picea abies (L.) Karst.) and common juniper (Juniperus communis L.), was found to be characterized in its cross section by the thick walls and rounded shape of its tracheids and the profuse occurence of spaces. Tension wood of aspen (Populus tremula L.) and alder (Alnus incana (L.) Moench) was found in microscopic examination to be characterized by the gelatinous appearance of the wood fibres, by its small cell cavities and by the thickness and buckling of the inner layer of the cecondary wall. Tracheids of the compression wood were found to have shorter length than normal on an average, while the tension wood fibres were found to be longer.

The microchemical studies suggest a higher than normal lignin content in compression wood and lower than normal lignin content in tension wood, as compared to normal wood. The reverse would be true for the cellulose contents. Volume weight of absolute dry reaction wood was distinctly higher than that of normal wood. The longitudinal shrinkage of reaction wood, particularly of compression wood, is several times that of normal wood. Transversal shrinkage of compression wood is much less than normal wood. Swelling tests revealed pushing effect of compression wood on elongation and pulling effect on tension wood on constraction. Volume shrinkage of compression wood is less than that of normal wood, in contrast to tension wood. The strength of compression wood in absolutely dry condition was nearly same as that of normal wood.

The PDF includes a summary in English.

  • Ollinmaa, ORCID ID:E-mail:
article id 7118, category Article
Paavo J. Ollinmaa. (1959). Reaktiopuututkimuksia. Acta Forestalia Fennica vol. 72 no. 1 article id 7118. https://doi.org/10.14214/aff.7118
English title: Study on reaction wood.

Compression wood of the tree species studied in this investigation, Scots pine (Pinus sylvestris L.), Norway spruce (Picea abies (L.) Karst.) and common juniper (Juniperus communis L.), was found to be characterized in its cross section by the thick walls and rounded shape of its tracheids and the profuse occurence of spaces. Tension wood of aspen (Populus tremula L.) and alder (Alnus incana (L.) Moench) was found in microscopic examination to be characterized by the gelatinous appearance of the wood fibres, by its small cell cavities and by the thickness and buckling of the inner layer of the cecondary wall. Tracheids of the compression wood were found to have shorter length than normal on an average, while the tension wood fibres were found to be longer.

The microchemical studies suggest a higher than normal lignin content in compression wood and lower than normal lignin content in tension wood, as compared to normal wood. The reverse would be true for the cellulose contents. Volume weight of absolute dry reaction wood was distinctly higher than that of normal wood. The longitudinal shrinkage of reaction wood, particularly of compression wood, is several times that of normal wood. Transversal shrinkage of compression wood is much less than normal wood. Swelling tests revealed pushing effect of compression wood on elongation and pulling effect on tension wood on constraction. Volume shrinkage of compression wood is less than that of normal wood, in contrast to tension wood. The strength of compression wood in absolutely dry condition was nearly same as that of normal wood.

The PDF includes a summary in English.

  • Ollinmaa, ORCID ID:E-mail:
article id 7488, category Article
Viljo Holopainen. (1959). The concept of a roundwood price level and its determination in forestry. Acta Forestalia Fennica vol. 68 no. 6 article id 7488. https://doi.org/10.14214/aff.7488

Roundwood statistics are essential in a country such as Finland, where the roundwood market costitutes one of the most important internal markets. Determining the price level of roundwood can, however, be problematic due to the difficulty of the empirical determination. The main difficulties are the many timber assortments, quality differcences within a timber assortment, large variation of local prices due to variations in demand and harvesting conditions and in sales methods. The article discusses these problems from the perspective of composing a roundwood statistics for different timber assortments that would allow local and temporal comparison of the prices. It seems impossible to compose price statistics that could eliminate totally the variation in the material, transport conditions and demand fluctuations caused by technical development. However, one can suffice to a compromise that would eliminate the major disturbances and take into account other factors that are not related with market when studying the price series. In addition, the paper discusses methods for calculation of price indices.

The PDF includes a summary in Finnish.

  • Holopainen, ORCID ID:E-mail:
article id 7488, category Article
Viljo Holopainen. (1959). The concept of a roundwood price level and its determination in forestry. Acta Forestalia Fennica vol. 68 no. 6 article id 7488. https://doi.org/10.14214/aff.7488

Roundwood statistics are essential in a country such as Finland, where the roundwood market costitutes one of the most important internal markets. Determining the price level of roundwood can, however, be problematic due to the difficulty of the empirical determination. The main difficulties are the many timber assortments, quality differcences within a timber assortment, large variation of local prices due to variations in demand and harvesting conditions and in sales methods. The article discusses these problems from the perspective of composing a roundwood statistics for different timber assortments that would allow local and temporal comparison of the prices. It seems impossible to compose price statistics that could eliminate totally the variation in the material, transport conditions and demand fluctuations caused by technical development. However, one can suffice to a compromise that would eliminate the major disturbances and take into account other factor