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Silva Fennica vol. 48 no. 1 | 2014

Category: Research article

article id 1077, category Research article
Göran Bergqvist, Roger Bergström & Märtha Wallgren. (2014). Recent browsing damage by moose on Scots pine, birch and aspen in young commercial forests – effects of forage availability, moose population density and site productivity. Silva Fennica vol. 48 no. 1 article id 1077. https://doi.org/10.14214/sf.1077
Highlights: Moose damage was most common on aspen and least common on Scots pine; Damage to Scots pine increased when the amount of pine browse decreased, moose index and site index increased and when birch was overtopping pine; Damage to birch increased when moose index increased and damage to aspen increased when the amount of pine and birch browse decreased.
Moose browsing damage from the winter preceding the study (recent damage) on Scots pine, birch and aspen was examined in relation to forage availability, an index of moose population density and site productivity in young forests in the hemiboreal zone. Recent damage was observed for 4.1 ± 0.54% (mean ± SE; Scots pine), 16.8 ± 1.89% (birch) and 67.6 ± 13.76% (aspen) of the trees. A multiple regression with five independent variables explained 19% (Scots pine) 14% (birch) and 33% (aspen) of the variation in recent damage. Cover of Scots pine browse was the most important variable for predicting damage to Scots pine and accounted for 44% of the explained variation. When birch was overtopping pine there was a significant increase in damage to pine. Moose index was the only significant variable to explain recent damage to birch, and accounted for 64% of the explained variation. For aspen, damage was negatively correlated to coverage of Scots pine and birch browse, each variable accounting for 38% of the explained variation. For Scots pine, increasing the number of pines ha–1 and performing pre-commercial thinning in such a way that pines are not overtopped may be efficient ways of reducing damage proportions, whereas birch needs to be protected from moose (by a reduction of the moose population or otherwise) in order to escape damage. Increased amounts of Scots pine browse and birch browse may also reduce damage levels to aspen, according to this study.
  • Bergqvist, Swedish Association for Hunting and Wildlife Management, Öster Malma, SE-611 91 Nyköping, Sweden ORCID ID:E-mail: goran.bergqvist@jagareforbundet.se (email)
  • Bergström, Forestry Research Institute of Sweden, Uppsala Science Park, SE-751 83 Uppsala, Sweden; (present) Gropgränd 2 A, SE-753 10 Uppsala, Sweden ORCID ID:E-mail: larsrogerbergstrom@yahoo.com
  • Wallgren, Forestry Research Institute of Sweden, Uppsala Science Park, SE-751 83 Uppsala, Sweden ORCID ID:E-mail: martha.wallgren@skogforsk.se
article id 1003, category Research article
Raffaele Spinelli, Carolina Lombardini & Natascia Magagnotti. (2014). The effect of mechanization level and harvesting system on the thinning cost of Mediterranean softwood plantations. Silva Fennica vol. 48 no. 1 article id 1003. https://doi.org/10.14214/sf.1003
Highlights: Whole-tree harvesting is 40–50% cheaper than cut-to-length harvesting; Mechanization reduced thinning cost by a factor 4; Between 1.5 and 6% of the residual trees were damaged; Mechanized cut-to-length harvesting allows controlled biomass release; Mechanized whole-tree harvesting is the cheapest option for energy chip production.
The study compared motor-manual cut-to-length (CTL) harvesting, motor-manual whole-tree (WT) harvesting, mechanized CTL harvesting and mechanized WT harvesting as applied to the production of energy chips from the second thinning of Mediterranean pine plantations in flat terrain. Mechanization increased productivity between 6 and 20 times, depending on process step. It also allowed reducing thinning cost by a factor 4. Shifting from CTL to WT harvesting resulted in a reduction of harvesting cost between 40 and 50%. Fuel consumption was between 40 and 100% higher for CTL harvesting than for WT harvesting. Mechanization entailed a reduction of fuel consumption between 10 and 40%. Stand damage was generally low, between 1.5 and 6%. Mechanized CTL harvesting resulted in the lowest incidence of wounding, and the difference between mechanized CTL and manual WT harvesting was statistically significant. Soil compaction was absent or very small, depending on treatment. Mechanized thinning may produce larger increases of soil bulk density, compared to motor-manual thinning, but the difference is small, although significant. CTL harvesting leaves a larger amount of biomass on the soil, which relieves possible concerns about soil nutrient depletion. On the other hand, heavy residue loads may increase fire risk especially in sensitive Mediterranean environments.
  • Spinelli, CNR IVALSA,Via Madonna del Piano 10, Sesto Fiorentino (FI), Italy ORCID ID:E-mail: spinelli@ivalsa.cnr.it (email)
  • Lombardini, CNR IVALSA,Via Madonna del Piano 10, Sesto Fiorentino (FI), Italy ORCID ID:E-mail: lombardini@ivalsa.cnr.it
  • Magagnotti, CNR IVALSA,Via Biasi 75, S. Michele all’Adige (TN), Italy ORCID ID:E-mail: magagnotti@ivalsa.cnr.it
article id 989, category Research article
Anna Saarsalmi, Pekka Tamminen & Mikko Kukkola. (2014). Effects of long-term fertilisation on soil properties in Scots pine and Norway spruce stands. Silva Fennica vol. 48 no. 1 article id 989. https://doi.org/10.14214/sf.989
Highlights: N fertilisation increased the amount of carbon in the organic layer; N fertilisation decreased the C/N ratio in the surface soil; N addition increased the amount of most nutrients in the organic layer; N fertilisation tended to lower pH, although only slightly.
The response of surface soil after 45- to 52-years to repeated nitrogen and phosphorus fertilisation was studied. This study included 30 factorial experiments established in young (5- to 30-year-old) stands using plots of 900 m2, on average, and by randomising treatments within each experiment. Total amount of N added varied from 534 to 1908 kg ha–1 and that of P from 69 to 193 kg ha–1, repeated at every second N fertilisation. Liming was performed twice; in total, 6000 kg ha–1 of dolomite was applied. Nitrogen fertilisation increased the mass of the organic layer and the amount of carbon and consequently the amounts of most of the elements in the organic layer. In both the organic layer and the 0–10 cm layer of mineral soil, nitrogen fertilisation decreased the C/N ratio and tended to lower pH, although only slightly. Phosphorus fertilisation increased the amounts of P and Ca. Liming increased the total amounts of most elements in the organic layer, except for C and N. We were able to derive models to describe how changes in the chemical properties of the surface soil depended on doses of elements and on site and stand properties.
  • Saarsalmi, Finnish Forest Research Institute, P.O. Box 18, FI-01301 Vantaa, Finland ORCID ID:E-mail: anna.saarsalmi@metla.fi (email)
  • Tamminen, Finnish Forest Research Institute, P.O. Box 18, FI-01301 Vantaa, Finland ORCID ID:E-mail: pekka.tamminen@metla.fi
  • Kukkola, Finnish Forest Research Institute, P.O. Box 18, FI-01301 Vantaa, Finland ORCID ID:E-mail: mikko.kukkola@metla.fi
article id 980, category Research article
Atte Komonen, Panu Halme, Mari Jäntti, Tuuli Koskela, Janne S. Kotiaho & Tero Toivanen. (2014). Created substrates do not fully mimic natural substrates in restoration: the occurrence of polypores on spruce logs. Silva Fennica vol. 48 no. 1 article id 980. https://doi.org/10.14214/sf.980
Highlights: Polypore communities were more homogeneous among created than among natural logs; The old-growth forest indicator Phellinus ferrugineofuscus occurred frequently on natural logs, but occupied only a few created logs; Results show that created logs do not fully mimic natural logs.
Many protected areas have been under intensive forest management prior to protection and thus lack natural ecosystem structures and dynamics. Dead wood is a key structure in forests harboring hundreds of threatened species. We investigated the ecological success of dead wood creation as a boreal forest restoration measure. We analysed whether the polypore communities of chain-saw felled and girdled (subsequently fallen) Norway spruce (Picea abies (L.) H. Karst.) logs differ from naturally formed spruce logs of similar decay stage and size. The study was conducted in Leivonmäki National Park in central Finland 8 years after the restoration measures. The average number of polypore species was highest on the chain-saw felled logs and most of the common polypore species were most frequent on this substrate. However, among the natural logs, number of species increased more steeply with increasing number of logs, suggesting greater variation in community composition on this substrate. The old-growth forest indicator Phellinus ferrugineofuscus occurred frequently on natural logs, occupied a few girdled logs but was absent from chain-saw felled logs. Our results show that from the polypore perspective created logs do not fully mimic natural logs, suggesting that creating substrates for species may pose a challenge for restoration.
  • Komonen, Department of Biological and Environmental Science, P.O. Box 35, FI-40014, University of Jyväskylä, Finland ORCID ID:E-mail: atte.komonen@jyu.fi (email)
  • Halme, Department of Biological and Environmental Science, P.O. Box 35, FI-40014, University of Jyväskylä, Finland ORCID ID:E-mail: panu.halme@jyu.fi
  • Jäntti, Department of Biological and Environmental Science, P.O. Box 35, FI-40014, University of Jyväskylä, Finland ORCID ID:E-mail: mari.j.jantti@student.jyu.fi
  • Koskela, Department of Biological and Environmental Science, P.O. Box 35, FI-40014, University of Jyväskylä, Finland ORCID ID:E-mail: tuuli.e.koskela@student.jyu.fi
  • Kotiaho, Department of Biological and Environmental Science, P.O. Box 35, FI-40014, University of Jyväskylä, Finland ORCID ID:E-mail: janne.kotiaho@jyu.fi
  • Toivanen, Department of Biological and Environmental Science, P.O. Box 35, FI-40014, University of Jyväskylä, Finland; Current: Birdlife Finland, Annankatu 29 A 16, FI-00100 Helsinki, Finland ORCID ID:E-mail: tero.toivanen@birdlife.fi
article id 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 949, category Research article
Ken Olaf Storaunet, Jørund Rolstad & Erlend Rolstad. (2014). Effects of logging on the threatened epiphytic lichen Usnea longissima: an experimental approach. Silva Fennica vol. 48 no. 1 article id 949. https://doi.org/10.14214/sf.949
Highlights: A re-inventory of the threatened lichen Usnea longissima in ten Norway spruce forest stands where experimental selective loggings had been conducted 5 to 8 years before revealed that the number of lichen thalli had increased with 34%; The number of thalli increased more where the forest was open whether or not the low tree density was caused by the loggings.
Usnea longissima Ach. is a circumboreal epiphytic lichen draping tree canopies in moist coastal and mountainous forests. It is extinct from many European and North-American localities, presumably due to industrial forestry and air pollution, but still has a stronghold in parts of Scandinavia and U.S. and Canadian Pacific Northwest. In 2005/06 we used a comparative and retrospective approach to evaluate how present and historic tree and stand characteristics influenced the occurrence and abundance of the lichen (Storaunet et al. 2008). In 2012, we re-inventoried ten Norway spruce forest stands with 401 U. longissima-bearing trees and recorded changes in the number of U. longissima thalli. Seven of the stands had been experimentally, selectively logged 5–8 years before, where the lichen-bearing trees had been marked in the field and were avoided during the logging operation. Total number of lichen-bearing trees decreased slightly (2.9%), whereas the number of thalli had increased with 34%. Number of thalli increased more where the forest was open (low basal area, m2ha-1) whether or not the low tree density was caused by the logging events. At high tree densities the change in number of thalli was negligible. We suggest that selective logging, securing lichen-bearing trees, may be a viable management option to keep tree density from becoming too dense, thereby enhancing growth and establishment of U. longissima.
  • Storaunet, Norwegian Forest and Landscape Institute, P.O. Box 115, NO-1431 Ås, Norway ORCID ID:E-mail: stk@skogoglandskap.no (email)
  • Rolstad, Norwegian Forest and Landscape Institute, P.O. Box 115, NO-1431 Ås, Norway ORCID ID:E-mail: roj@skogoglandskap.no
  • Rolstad, Skogfaglig Rådgivning, Holmsida 126, NO-1488 Hakadal, Norway ORCID ID:E-mail: roe@skogoglandskap.no

Category: Review article

article id 1008, category Review article
Janusz Szmyt. (2014). Spatial statistics in ecological analysis: from indices to functions. Silva Fennica vol. 48 no. 1 article id 1008. https://doi.org/10.14214/sf.1008
Highlights: Spatial statistics provides a quantitative description of natural variables distributed in space and time; The objectives of spatial analysis are to detect spatial patterns and to confirm if a pattern found is significant; Spatially explicit indices and functions may be applied depending on the information collected from the field; Development of the specific software supports spatial analyses.
This paper presents a review of the most common methods in ecological studies aimed at spatial analysis of population structures (horizontal and vertical), based on point process statistics. Methods based on simple spatially explicit indices as well as more sophisticated methods relying on functions are described in a comprehensible manner. Simple indices revealing the information on spatial structure at the scale of the nearest neighbor can be easily implemented in practical forestry. On the other hand, spatial functions, based on much more detailed data, describe the spatial structure in terms of the spatial relationships between the natural processes and population structures and because of this complexity they are rarely used in forest practice. Including both methods in a single paper is also valuable from the potential reader’s point of view saving their time for searching and choosing the appropriate method to make their spatial analysis. This paper can also serve as an initial guide for young researchers or those who are going to start their studies on spatial aspects of bio-systems. Avoiding the statistical and mathematical details makes this paper understandable for readers who are not statisticians or mathematicians. Readers will find many references related to each method described here, allowing them to find solutions to different problems observed in practice. This paper ends with a list of the most common specific software packages available to support spatial analysis.
  • Szmyt, Department of Silviculture, Faculty of Forestry, Poznań University of Life Sciences, ul. Wojska Polskiego 69, 60-625 Poznań, Poland ORCID ID:E-mail: jszmyt@up.poznan.pl (email)

Category: Research note

article id 1053, category Research note
Aleksey Fedorkov. (2014). Vitality and height growth of two Larix species and provenances in a field trial located in north-west Russia. Silva Fennica vol. 48 no. 1 article id 1053. https://doi.org/10.14214/sf.1053
Highlights: Differences in tree vitality among provenances were insignificant (p > 0.05) at an early age; The provenance effect was significant (p < 0.05) for total height; These findings were in agreement with those of Lukkarinen et al. (2010) using the same material at the same age for field trial located in Punkaharju (Finland).
Vitality and height of Larix species and provenances originating from Russia were estimated in a 5-yr field trial performed in the Komi Republic (north-west Russia) using a fully randomized single-tree plot design with 7–8 blocks. Tree provenance had no significant (p > 0.05) effect on tree vitality, though for Larix sukazcewii originating from the European part of Russia, trees from the northern regions were more vital than those from southern regions. Provenance was a significant (p < 0.05) factor for height, where the average height of 136 cm varied considerably (168 cm for trees from Nizhnij Novgorod and 111 cm for trees from Ufa). There were no significant correlations when vitality and height were compared to geographic and climatic variables for the locations.
  • Fedorkov, Institute of Biology, Komi Science Center, Russian Academy of Sciences, Syktyvkar, 167982, Kommunisticheskaya st., 28, Russia ORCID ID:E-mail: fedorkov@ib.komisc.ru (email)

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