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Silva Fennica vol. 44 no. 4 | 2010

Category: Research article

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 453, category Research article
Eduard Schiessl, Michael Grabner, Gerald Golesch, Thomas Geburek & Silvio Schueler. (2010). Sub-montane Norway spruce as alternative seed source for a changing climate? A genetic and growth analysis at the fringe of its natural range in Austria. Silva Fennica vol. 44 no. 4 article id 453. https://doi.org/10.14214/sf.453
Insights into the intraspecific variation in climate response of forest trees and the utilization of suitable seed sources are required to maintain forest ecoystems under expected climate change. Individuals of Norway spruce with an anomalous spherical-shaped crown were characterized by genetic (using a mtDNA marker) and dendroclimatic analysis. Such trees occur frequently at the fringe of the spruce distribution in east/south-east Austria. We employed pair-wise comparisons between trees with spherical and “regular” conical crowns on 47 sites. No evidence was found for a different phylogeographic history of spherical and conical spruces, but the high allelic diversity at the nad1 locus highlighted the importance of east/south-east Austria as refugium and migration corridor for Norway spruce. Analysis of mean annual increment revealed a larger amount of earlywood within the sapwood area and fewer negative pointer years for spherical spruces than for conical ones, pointing at a higher vitality and smaller interactions between climate and growth for spherical spruces. Although the results cannot explain the anomalous crown form, they suggest spherical trees to have a higher ability to cope the warm and dry climate of the region than “regular” conical spruces. We discuss the origin of spherical crowns in terms of population history and phenotypic plasticity and speculate on possible effects of crown architecture on canopy-atmosphere exchange.
  • Schiessl, Department of Genetics, Research and Training Centre for Forests, Natural Hazards and Landscape, Hauptstrasse 7, A-1140 Vienna, Austria ORCID ID:E-mail:
  • Grabner, Department of Material Sciences and Process Engineering, Institute of Wood Science and Technology, University of Natural Resources and Applied Life Sciences, Peter-Jordan-Strasse 82, A-1190 Vienna, Austria ORCID ID:E-mail:
  • Golesch, Department of Genetics, Research and Training Centre for Forests, Natural Hazards and Landscape, Hauptstrasse 7, A-1140 Vienna, Austria ORCID ID:E-mail:
  • Geburek, Department of Genetics, Research and Training Centre for Forests, Natural Hazards and Landscape, Hauptstrasse 7, A-1140 Vienna, Austria ORCID ID:E-mail:
  • Schueler, Department of Genetics, Research and Training Centre for Forests, Natural Hazards and Landscape, Hauptstrasse 7, A-1140 Vienna, Austria ORCID ID:E-mail: silvio.schueler@bfw.gv.at (email)
article id 135, category Research article
Ola Lindroos, Marina Henningsson, Dimitris Athanassiadis & Tomas Nordfjell. (2010). Forces required to vertically uproot tree stumps. Silva Fennica vol. 44 no. 4 article id 135. https://doi.org/10.14214/sf.135
Stumpwood attracts renewed interest due to increased use of forest biomass for bioenergy. In Nordic countries stumps are generally uprooted with crawler excavators, which have strong cranes (ca. 400 kNm gross lift torque), but are not designed for moving in forest terrain. Their use is based on practical experience with available and tested machine types rather than thorough examinations of requirements, partly due to limited knowledge of force requirements for uprooting of stumps. Therefore, in this work mean and maximum forces required to vertically uproot stumps of Norway spruce (Picea abies) and birch (Betula spp.) were quantified together with the effects of various soil types and uprooting methods. The used excavator’s crane-mounted uprooting device enabled comparisons between usage of solely crane force, and a method in which preparatory loosening forces were applied prior to crane force. Uprooting stumps in single pieces proved difficult; 61% split unintentionally. Force requirements were similar across tree species, increasing curve-linearly with stump diameter, and stumps uprooted in a single piece required more force than split stumps. Preparatory loosening reduced crane force requirements and, surprisingly, less force was required to uproot stumps from a mesic, till soil than from a moist, finer-textured soil. No stump required more than 60 kN crane force and functions for maximum force requirements indicate that powerful harvesters and forwarders (gross crane lifting capacity of 273 and 155 kNm, respectively) should be able to uproot all stumps with ≤ 61 cm and ≤ 32 cm diameter, respectively, in one piece. Larger stumps could be managed if it is acceptable that stumps are split before uprooting.
  • Lindroos, Department of Forest Resource Management, Swedish University of Agricultural Sciences, SE-901 83 Umeå, Sweden ORCID ID:E-mail: ola.lindroos@srh.slu.se (email)
  • Henningsson, Komatsu Forest AB, Box 7124, SE-907 04 Umeå, Sweden ORCID ID:E-mail:
  • Athanassiadis, Department of Forest Resource Management, Swedish University of Agricultural Sciences, SE-901 83 Umeå, Sweden ORCID ID:E-mail:
  • Nordfjell, Department of Forest Resource Management, Swedish University of Agricultural Sciences, SE-901 83 Umeå, Sweden 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 133, category Research article
Fumiaki Kitahara, Nobuya Mizoue & Shigejiro Yoshida. (2010). Effects of training for inexperienced surveyors on data quality of tree diameter and height measurements. Silva Fennica vol. 44 no. 4 article id 133. https://doi.org/10.14214/sf.133
Due to the large number of sample plots and variables to be measured, inexperienced surveyors are expected to take field measurements in National Forest Inventories (NFIs). However, very little information exists on the data quality that can be expected from inexperienced surveyors given different levels of training. We evaluated the quality of data produced by inexperienced undergraduate students when measuring the most fundamental variables: tree diameter using a diameter tape and height using an ultrasonic Vertex III hypsometer. We found that a single training session on how to use the instruments and how to reduce measurement errors was insufficient for inexperienced surveyors to achieve measurement quality objectives (MQOs). Providing a single feedback of control team measurements significantly improved data quality, except in the measurements of tree height of broad-leaved trees, but additional feedback did not contribute to further improvement. We propose that field training courses for inexperienced surveyors incorporate a one-day exercise with feedback instruction.
  • Kitahara, Graduate School of Bioresource and Bioenvironmental Science, Kyushu University, 6-10-1 Hakozaki, Higashiku, Fukuoka 812-8581, Japan ORCID ID:E-mail: bunsho@ffpri.affrc.go.jp (email)
  • Mizoue, Faculty of Agriculture, Kyushu University, Fukuoka, Japan ORCID ID:E-mail:
  • Yoshida, Faculty of Agriculture, Kyushu University, Fukuoka, Japan ORCID ID:E-mail:
article id 132, category Research article
Mats Berlin, Lars Lönnstedt, Gunnar Jansson, Öje Danell & Tore Ericsson. (2010). Developing a Scots pine breeding objective: a case study involving a Swedish sawmill. Silva Fennica vol. 44 no. 4 article id 132. https://doi.org/10.14214/sf.132
The aim of this study was to develop a Scots pine (Pinus sylvestris L.) breeding objective for a vertically integrated sawmill in northern Sweden. The production system was defined as comprising the sawmill and the forests supplying it. Volume per hectare, wood density, survival and straightness were used as objective traits and the related selection criteria were measurements, collected at young tree age, of height, diameter, pilodyn penetration, vitality and straightness. A bio-economic model was used to calculate economic weights for the objective traits identified. We also investigated the efficiency of different selection indices based on these economic weights, in combination with available data on genetic parameters. Furthermore, we studied the effect of different discount rates on the calculated economic weights. The results showed that, compared to the full index (which included all selection criteria), omitting either vitality or straightness had a negligible effect, reducing predicted profit gain per hectare by less than one per cent. Height or diameter each had a greater effect, with a loss of predicted profit gain per hectare of up to 6%. Excluding pilodyn penetration from the selection index caused the largest reduction in predicted profit gain per hectare, amounting to over 10%. However, when both height and diameter were removed the predicted profit gain per hectare dropped to one-third of that based on the full index. Finally, ranking and genetic selection for the developed breeding objective was insensitive to changes in the discount rate.
  • Berlin, Skogforsk, Uppsala Science Park, SE-751 83 Uppsala, Sweden ORCID ID:E-mail: mats.berlin@skogsforsk.se (email)
  • Lönnstedt, Skogforsk, Uppsala Science Park, SE-751 83 Uppsala, Sweden ORCID ID:E-mail:
  • Jansson, Skogforsk, Uppsala Science Park, SE-751 83 Uppsala, Sweden ORCID ID:E-mail:
  • Danell, Skogforsk, Uppsala Science Park, SE-751 83 Uppsala, Sweden ORCID ID:E-mail:
  • Ericsson, Skogforsk, Uppsala Science Park, SE-751 83 Uppsala, Sweden ORCID ID:E-mail:
article id 131, category Research article
Timo Pukkala, Tatu Hokkanen & Teijo Nikkanen. (2010). Prediction models for the annual seed crop of Norway spruce and Scots pine in Finland. Silva Fennica vol. 44 no. 4 article id 131. https://doi.org/10.14214/sf.131
Many studies indicate that the flowering abundance of boreal trees strongly correlates with the weather conditions of the previous summer. This study developed prediction models for the seed crops of Norway spruce and Scots pine using weather variables one and two years prior to flowering year as predictors. Weather data, systematically recorded at many weather stations, were obtained from the Finnish Meteorological Institute. Seed crop monitoring data came from 22 spruce stands and 44 pine stands. In every stand, seed crop has been monitored for many years, the longest continuous period being 45 years. Monthly mean temperatures, monthly rainfalls, and periodical temperature sums were used as predictors in the seed crop models. Generally, both tree species flowered abundantly one year after a warm summer and two years after a cool summer. While the models only explained about 45% of the variation in the annual seed crop, they accurately predicted good and bad seed years: when the models predicted good seed crops the likelihood to have at least a medium seed crop was very high and when the models predicted small seed crops, the likelihood to obtain medium or good seed crop was very low. Therefore, the models reliably predict if a particular year will be a good seed year or a poor seed year. These predictions can be used in forestry practice for proper timing of natural regeneration activities, and when activities in seed orchards are planned.
  • Pukkala, University of Eastern Finland, School of Forest Sciences, P.O. Box 111, FI-80101 Joensuu, Finland ORCID ID:E-mail: timo.pukkala@uef.fi (email)
  • Hokkanen, Finnish Forest Research Institute, P.O. Box 18, FI-01301 Vantaa, Finland ORCID ID:E-mail:
  • Nikkanen, Finnish Forest Research Institute, Finlandiantie 18, FI-58450 Punkaharju, Finland ORCID ID:E-mail:
article id 130, category Research article
Yongqing Yang, Yinan Yao & Xuejiang Zhang. (2010). Comparison of growth and physiological responses to severe drought between two altitudinal Hippophae rhamnoides populations. Silva Fennica vol. 44 no. 4 article id 130. https://doi.org/10.14214/sf.130
Growth and physiological differences in response to drought were compared between two sea buckthorn (Hippophae rhamnoides L.) populations inhabited in the southeast of the Qinghai-Tibetan Plateau of China. The experimental design included two water regimes (100% and 25% of field capacity) and two populations from the low and high altitude zone. Our experiments were conducted in a naturally lit greenhouse under semi-controlled environmental conditions for a whole growing season in a dry valley (1800 m above the sea level). We found that drought tolerance is highly related to the plant antioxidant capacity and water use efficiency as well as leaf nutrient status in H. rhamnoides. The highland population (HP) experienced a greater inhibition in plant growth and leaf enlargement, lower leaf nitrogen and phosphorus content, lower root nodule biomass and root mass/foliage area ratio, and higher leaf water content loss paralleling with higher enhancement of abscisic acid level in response to drought, as compared with lowland population (LP). Additionally, reduction of leaf lignin content in HP further reduced its drought tolerance. On the contrary, LP showed effective adaptation strategies such as improvement of water economy and maintaining high ascorbic acid content. Therefore, we conclude that LP was more tolerant to drought than HP, and could be selected for reforestation in the dry valleys of upper Minjiang River regions in China.
  • Yang, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi, 830011, China & College of Life Sciences, Chongqing Normal University, Chongqing, 400047, China ORCID ID:E-mail:
  • Yao, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi, 830011, China ORCID ID:E-mail: yaoya@ms.xjb.ac.cn (email)
  • Zhang, Institute for Plant Protection and Soil sciences, Hubei Academy of Agricultural Sciences, Wuhan, 430064, China ORCID ID:E-mail:
article id 129, category Research article
Mikko Moilanen, Markku Saarinen & Klaus Silfverberg. (2010). Foliar nitrogen, phosphorus and potassium concentrations of Scots pine in drained mires in Finland. Silva Fennica vol. 44 no. 4 article id 129. https://doi.org/10.14214/sf.129
An imbalanced nutrient status in Scots pine stands on drained mires is primarily a consequence of excess nitrogen (N) in relation to mineral nutrients such as phosphorus (P) and potassium (K). In this study, the variation of foliar N, P, and K concentrations relative to some site and environmental characteristics was examined. Foliar nutrient concentrations were determined on needle samples collected from mires representing different drainage ages, site types, geographical locations and annual weather conditions. In the overall data (n = 971 samples in 333 stands) the foliar N concentration varied between 6.7 and 24.2 mg g-1, the P concentration between 0.83 and 2.32 mg g-1, and the K concentration between 2.22 and 6.23 mg g-1. The original (pre-drainage) mire site type proved to be an important factor in explaining the nutrient status of the trees: on originally forested sites, the nutrient balance (N versus K; N versus P) was mostly adequate, whereas on sparsely forested and treeless sites, K deficiency was common. N deficiency was the most common in forested ‘nitrogen-poor’ sites, while P and K deficiencies were more common in originally treeless or sparsely forested ‘nitrogen rich’ sites, where the nutrient imbalance was also the greatest. Over the whole data, 29% of the cases were diagnosed to be N-deficient, 51% P-deficient, and 25% K-deficient. The foliar N concentration increased with increasing temperature sum. The foliar K concentration decreased with increasing depth of the peat layer. On former treeless or sparsely forested sites, foliar K decreased slightly with increasing drainage age. In contrast, on thin-peated sites the foliar P concentration increased with increasing drainage age. The climate conditions (location), the original site type of the mire and peat thickness should be taken into account when planning silvicultural measures on mires drained for forestry.
  • Moilanen, Finnish Forest Research Institute, Muhos and Parkano Research Units, Finland ORCID ID:E-mail: mikko.moilanen@metla.fi (email)
  • Saarinen, Finnish Forest Research Institute, Muhos and Parkano Research Units, Finland ORCID ID:E-mail:
  • Silfverberg, Finnish Forest Research Institute, Muhos and Parkano Research Units, Finland ORCID ID:E-mail:
article id 128, category Research article
Shelley L. Hunt, Andrew M. Gordon & Dave M. Morris. (2010). Carbon stocks in managed conifer forests in northern Ontario, Canada. Silva Fennica vol. 44 no. 4 article id 128. https://doi.org/10.14214/sf.128
Carbon pools and net primary productivity (aboveground) were measured in managed stands of jack pine (Pinus banksiana Lamb.) and black spruce (Picea mariana [Mill.] B.S.P.), ranging in age from 10 to 53 years, in the Lake Nipigon area of northern Ontario. Organic carbon in the forest floor and surface mineral soil (top 15 cm) ranged from 13 to 46 Mg C ha-1 and 10 to 29 Mg C ha-1, respectively. Carbon in aboveground tree biomass ranged from 11 to 74 Mg C ha-1 in crop trees, and 0 to 11 Mg C ha-1 in non-crop trees. Coarse woody debris (downed woody debris and snags) contained between 1 and 17 Mg C ha-1. Understory vegetation rarely represented more than 1% of total ecosystem carbon accumulation, but was responsible for a larger proportion of aboveground net primary productivity (ANPP). Rates of ANPP (expressed as carbon) ranged from 0.8 to 3.5 Mg C ha-1 y-1. Carbon stocks in managed stands were compared with published values from similarly aged fire-origin stands in the North American boreal region. Carbon stocks in our study stands generally exceeded those in unmanaged fire-origin stands of the same age, due to larger tree and forest floor carbon pools.
  • Hunt, University of Guelph, School of Environmental Sciences, 50 Stone Road East, Guelph, Ontario, Canada N1G 2W1 ORCID ID:E-mail: shunt@uoguelph.ca (email)
  • Gordon, University of Guelph, School of Environmental Sciences, 50 Stone Road East, Guelph, Ontario, Canada N1G 2W1 ORCID ID:E-mail:
  • Morris, Ontario Ministry of Natural Resources, Centre for Northern Forest Ecosystem Research, 955 Oliver Rd., Thunder Bay, Ontario, Canada P7B 5E1 ORCID ID:E-mail:

Category: Research note

article id 136, category Research note
Tomasz D. Mazgajski, Michal Zmihorski & Katarzyna Abramowicz. (2010). Forest habitat loss and fragmentation in Central Poland during the last 100 years. Silva Fennica vol. 44 no. 4 article id 136. https://doi.org/10.14214/sf.136
The process of habitat fragmentation consists of two components – habitat loss and fragmentation per se. Both are thought to be among the most important threats to biodiversity. However, the biological consequences of this process such as species occurrence, abundance, or genetic structure of population are driven by current, as well as previous, landscape configurations. Therefore, historical analyses of habitat distribution are of great importance in explaining the current species distribution. In our analysis, we describe the forest fragmentation process for an area of 178 km2 in the northern part of Mazowsze region of central Poland. Topographical maps from the years 1890, 1957 and 1989 were used. Over the 100-year period, forest coverage in this area changed from 17% to 5.6%, the number of patches increased from 19 to 42, while the area of the forest interior decreased from 1933 ha to 371 ha. The two components of fragmentation were clearly separated in time. Habitat loss occurred mainly during the first period (1890–1957) and fragmentation per se in the second (1957–1989). Moreover, we recorded that only 47.7% of all the currently (in 1989) afforested areas constitute sites where forests previously occurred (in 1890 and 1957). For forest dwelling organisms characterized by low dispersal abilities, the effective forest coverage seems to be a half of the real forest area in the studied landscape. New afforestations should be planned especially to increase those patches which contain ancient forest, where various plants and animals sensitive to fragmentation may have survived.
  • Mazgajski, Polish Academy of Sciences, Museum & Institute of Zoology, Wilcza 64, PL 00-679 Warsaw, Poland ORCID ID:E-mail: mazgaj@miiz.waw.pl (email)
  • Zmihorski, Polish Academy of Sciences, Museum & Institute of Zoology, Wilcza 64, PL 00-679 Warsaw, Poland ORCID ID:E-mail:
  • Abramowicz, Department of Ecology, University of Warsaw, Banacha 2, PL 02-097 Warsaw, Poland ORCID ID:E-mail:

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