Current issue: 58(5)

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Silva Fennica vol. 47 no. 3 | 2013

Category : Research article

article id 1009, category Research article

Inger Sundheim Fløistad, Aksel Granhus. (2013). Timing and duration of short-day treatment influence morphology and second bud flush in Picea abies seedlings. Silva Fennica vol. 47 no. 3 article id 1009. https://doi.org/10.14214/sf.1009

Keywords: Norway spruce; photoperiod; autumn bud break; root collar diameter; second bud break; sturdyness

Highlights: The duration of short-day treatment, calculated as number of days, influenced the root collar diameter growth more than the timing of the treatment; If short-day treatment starts early in summer, a longer duration of the treatment is recommended to avoid second bud flush.

Abstract | Full text in HTML | Full text in PDF | Author Info

A slower reaction of diameter growth cessation compared to that of height growth in response to short day (SD) treatment is well documented in Picea abies (L.) Karst. seedlings, suggesting that the height/diameter ratio of seedlings could be controlled through appropriate timing and/or duration of SD treatment is forest nurseries. Here, we applied specific combinations of timing (starting date 20 and 27 June, 4 or 11 July) and duration (7, 10, 14 or 17 days) of SD treatment to assess the possibility of obtaining more sturdy seedlings. We observed a rapid and uniform height growth cessation following SD treatment compared with the delayed cessation of diameter growth. Height growth responded significantly only to starting date of SD treatment, resulting in taller seedlings for later starting dates. Diameter growth responded to the duration of SD treatment, with significantly less diameter growth in seedlings exposed to 14 or 17 days of SD treatment than in seedlings exposed to 7 or 10 days of SD treatment. Also starting date influenced diameter growth, resulting in significantly more diameter growth with the earliest starting date compared with the two latest starting dates of the SD treatment. A second bud flush occurred only in seedlings exposed to SD treatment starting on 20 or 27 of June and only following 7-14 days of duration. This implies a need of longer duration if the SD treatment starts early. This will be at the expense of sustained diameter growth, thus compromising the objective of obtaining more sturdy seedlings.

Fløistad, Norwegian Institute for Agricultural and Environmental Research, Høgskolevn 7, N-1430 Ås, Norway & Norwegian Forest and Landscape Institute, P.O. Box 115, N-1431 Ås, Norway E-mail: isf@skogoglandskap.no
Granhus, Norwegian Forest and Landscape Institute, P.O. Box 115, N-1431 Ås, Norway E-mail: aksel.granhus@skogoglandskap.no

article id 1006, category Research article

Jörn Rathke, Maria A. Huka, Manfred Gronalt. (2013). The box assignment problem in log yards. Silva Fennica vol. 47 no. 3 article id 1006. https://doi.org/10.14214/sf.1006

Keywords: log yard planning; sawmill; linear optimization

Highlights: Logistic approach for the optimization of log yard in terms of arrangement of storage boxes and ejection boxes reduced transportation time by 16 percent compared with the original solution.

Abstract | Full text in HTML | Full text in PDF | Author Info

This paper presents an optimization approach to minimizing log yard round wood transportation time for a medium sized hardwood sawmill. The log yard, which has to ensure a smooth raw material supply to the entire production process, is the first processing step in a sawmill. The log yard also serves as an internal round wood sorting and storing capacity. Thus, an optimal assignment of ejection boxes, storage boxes and feeding carriages is required to minimize transportation time at a log yard. The main contribution of this paper is to present an integrated approach which simultaneously takes into account log transportation time, storage capacity and yard crane deployment. The approach is based on two steps: a) defining storage spaces per batch and calculating distances and b) determining optimum box assignments in the log yard in order to minimize overall transportation distance. The solution in step b) is compared with the results obtained by random box assignment as well as a spreadsheet based planning method. We have been able to show that our approach is much more flexible and results are more than 16 percent better than the corresponding real life solution.

Rathke, University of Natural Resources and Life Sciences, Institute of Production and Logistics, Feistmantelstraße 4, 1180 Vienna, Austria E-mail: joern.rathke@boku.ac.at
Huka, University of Natural Resources and Life Sciences, Institute of Production and Logistics, Feistmantelstraße 4, 1180 Vienna, Austria E-mail: maria.huka@boku.ac.at
Gronalt, University of Natural Resources and Life Sciences, Institute of Production and Logistics, Feistmantelstraße 4, 1180 Vienna, Austria E-mail: manfred.gronalt@boku.ac.at

article id 1005, category Research article

Marjut Turtiainen, Jari Miina, Kauko Salo, Juha-Pekka Hotanen. (2013). Empirical prediction models for the coverage and yields of cowberry in Finland. Silva Fennica vol. 47 no. 3 article id 1005. https://doi.org/10.14214/sf.1005

Keywords: generalized linear mixed model; abundance; berry yield; Vaccinium vitis-idaea L.

Highlights: The site fertility significantly affected the abundance of cowberry on mineral soils, spruce mires and pine mires; The stand basal area and dominant tree species were among the most important forest structural predictors in the model for the coverage; In the cowberry yield model developed for mineral soil sites, the stand basal area and coverage of cowberry plants were statistically significant predictors.

Abstract | Full text in HTML | Full text in PDF | Author Info

Empirical models for the coverage and berry yield of cowberry (Vaccinium vitis-idaea L.) were developed using generalized linear mixed models (GLMMs). The percentage coverage of cowberry was predicted as a function of site and stand characteristics using data from the Finnish National Forest Inventory (NFI) in 1995. The average annual yield, including the between-year variation in the yield, was predicted as a function of percentage coverage and stand characteristics using permanent experimental plots (MASI) established in different areas of Finland and measured in 2001-2012. The model for cowberry yields (Model 2) was developed for mineral soil forests. The model for the coverage (Model 1) was constructed so that it considers both mineral soil sites and also many other sites where cowberry occurs in the field layer. According to Model 1, the site fertility significantly affected the abundance of cowberry on mineral soils, spruce mires and pine mires. The stand basal area and dominant tree species were among the most important forest structural predictors in Model 1. The site fertility was not a significant predictor in the cowberry yield model. Instead, the stand basal area and coverage of cowberry plants were found to be statistically significant predictors in Model 2. The estimated models were used to predict the cowberry coverage, average annual yield and its 95 % confidence interval along with stand development. The models of this study can be used for multi-objective forest planning purposes.

Turtiainen, University of Eastern Finland, School of Forest Sciences, P.O. Box 111, FI-80101 Joensuu, Finland E-mail: marjut.turtiainen@uef.fi
Miina, Finnish Forest Research Institute, Joensuu Unit, P.O. Box 68, FI-80101 Joensuu, Finland E-mail: jari.miina@metla.fi
Salo, Finnish Forest Research Institute, Joensuu Unit, P.O. Box 68, FI-80101 Joensuu, Finland E-mail: kauko.salo@metla.fi
Hotanen, Finnish Forest Research Institute, Joensuu Unit, P.O. Box 68, FI-80101 Joensuu, Finland E-mail: juha-pekka.hotanen@metla.fi

article id 1000, category Research article

Sören Wulff, Cornelia Roberge, Anna Hedström Ringvall, Sören Holm, Göran Ståhl. (2013). On the possibility to monitor and assess forest damage within large scale monitoring programmes – a simulation study. Silva Fennica vol. 47 no. 3 article id 1000. https://doi.org/10.14214/sf.1000

Keywords: forest health; forest inventory; environmental monitoring and assessment; forest condition

Abstract | Full text in HTML | Full text in PDF | Author Info

There is a growing demand for information on forest health due to fears that climate change may cause new kinds of damage that have not previously been encountered. In many cases, forest damage monitoring is conducted exclusively within sparse large-scale grids of sample plots and it is doubtful whether these are capable of providing relevant information to support mitigation programmes or other actions required to reduce economic losses due to damage outbreaks. In this study, we used simulated sampling to assess the precision of estimators related to forest state and changes in the damage sustained by trees within an area corresponding to the Swedish region Götaland, assuming a sampling design corresponding to that used in the Swedish National Forest Inventory (NFI) under different damage scenarios. Large and uniformly distributed damage outbreaks were well captured by an NFI-type inventory, but scattered damage outbreaks produced estimates with poor precision. As a consequence, we propose that there might be a need to revise current forest damage monitoring programmes to make them more useful for monitoring the kinds of damage that are likely to arise as a consequence of climate change.

Wulff, Swedish University of Agricultural Sciences, Department of Forest Resource Management, Skogsmarksgränd, SE-901 83 Umeå, Sweden E-mail: soren.wulff@slu.se
Roberge, Swedish University of Agricultural Sciences, Department of Forest Resource Management, Skogsmarksgränd, SE-901 83 Umeå, Sweden E-mail: cornelia.roberge@slu.se
Ringvall, Swedish University of Agricultural Sciences, Department of Forest Resource Management, Skogsmarksgränd, SE-901 83 Umeå, Sweden E-mail: anna.ringvall@slu.se
Holm, Swedish University of Agricultural Sciences, Department of Forest Resource Management, Skogsmarksgränd, SE-901 83 Umeå, Sweden E-mail: soren.holm@slu.se
Ståhl, Swedish University of Agricultural Sciences, Department of Forest Resource Management, Skogsmarksgränd, SE-901 83 Umeå, Sweden E-mail: goran.stahl@slu.se

article id 993, category Research article

Jori Uusitalo, Jari Ala-Ilomäki. (2013). The significance of above-ground biomass, moisture content and mechanical properties of peat layer on the bearing capacity of ditched pine bogs. Silva Fennica vol. 47 no. 3 article id 993. https://doi.org/10.14214/sf.993

Keywords: logging; peatland; tree harvesting; trafficability

Abstract | Full text in HTML | Full text in PDF | Author Info

Intensive utilisation of peatland forests calls for logging activities to be increasingly carried out in conditions other than those in harsh winter. The low bearing capacity of peatlands forms a severe obstacle for the prevailing harvesting machinery. The aim of this study was to clarify and quantify the significance of above-ground biomass, brash mat, moisture content and mechanical properties of peat layer on the bearing capacity of pine bogs. In-situ driving tests were conducted in Western Finland on a pine bog covering a large variation of growing stock. Portable tools were tested for measuring strength properties of the top layer of peat. According to the results, shear modulus of top layer of peat, volume of trees and the existence of cutting debris are the most important factors affecting bearing capacity. Spiked shear vane was shown to be a promising tool in predicting the strength properties of peat soil.

Uusitalo, Finnish Forest Research Institute, Parkano Unit, Kaironiementie 15, FI-39700 Parkano, Finland E-mail: jori.uusitalo@metla.fi
Ala-Ilomäki, Finnish Forest Research Institute, Vantaa Unit, P.O. Box 18, FI-01301 Vantaa, Finland E-mail: jari.ala-ilomaki@metla.fi

article id 973, category Research article

Sergio Rossi, Hubert Morin, François Gionest, Danielle Laprise. (2013). Spatially explicit structure of natural stands dominated by black spruce. Silva Fennica vol. 47 no. 3 article id 973. https://doi.org/10.14214/sf.973

Keywords: boreal forest; Picea mariana; mortality; recruitment; stand dynamics

Abstract | Full text in HTML | Full text in PDF | Author Info

Black spruce [Picea mariana (Mill.) BSP] regeneration emerges in clusters near the pre-existing boles within a few years after the passage of fire. This paper tested the hypothesis that black spruce forests still maintain the spatial structure deriving from postfire stand initiation. Trees and saplings were monitored during 2000-2007 and the horizontal and vertical structure of the stands were investigated on four permanent plots in the boreal forest of Quebec, Canada. Plots showed 1300-2150 trees ha^-1, and were composed of trees with homogeneous sizes and a very small proportion of saplings. These characteristics identify single cohorts generated by complete, or almost-complete, stand replacement by fire. Ripley’s L(r) functions showed that the spatial pattern of trees and saplings ranged from random to aggregated, thus demonstrating that the clustering distribution of the individuals in black spruce forests can be maintained even after 80-120 years from stand initiation. These findings could results from incomplete self-thinning or from an environment with heterogeneous distribution of resources. The practices of ecosystem management recently developed in Eastern Canada should take into account both the horizontal and vertical structure to better modulate the competition among individuals during partial harvesting.

Rossi, Département des Sciences Fondamentales, Université du Québec à Chicoutimi, 555 boulevard de l’Université, Chicoutimi (QC), G7H2B1, Canada E-mail: sergio.rossi@uqac.ca
Morin, Département des Sciences Fondamentales, Université du Québec à Chicoutimi, 555 boulevard de l’Université, Chicoutimi (QC), G7H2B1, Canada E-mail: hubert_morin@uqac.ca
Gionest, Département des Sciences Fondamentales, Université du Québec à Chicoutimi, 555 boulevard de l’Université, Chicoutimi (QC), G7H2B1, Canada E-mail: francois_gionest@uqac.ca
Laprise, Département des Sciences Fondamentales, Université du Québec à Chicoutimi, 555 boulevard de l’Université, Chicoutimi (QC), G7H2B1, Canada E-mail: danielle_laprise@uqac.ca

article id 972, category Research article

Outi H. Manninen, Rainer Peltola. (2013). Effects of picking methods on the berry production of bilberry (Vaccinium myrtillus), lingonberry (V. vitis-idaea) and crowberry (Empetrum nigrum ssp. hermaphroditum) in Northern Finland. Silva Fennica vol. 47 no. 3 article id 972. https://doi.org/10.14214/sf.972

Keywords: berry yields; commercial picking; wild forest berries

Highlights: Berry production of bilberry, lingonberry and crowberry was studied after picking the berries by plastic hand rake, long-handed metal rake, and powerful picking by long-handed metal rake; Berry production was not affected by the damage caused by any of the picking method; Current commercial picking methods do not endanger the berry production of the berry species at least in short-term.

Abstract | Full text in HTML | Full text in PDF | Author Info

The effect of commercial wild berry picking on berry yields is under a strong public debate in Finland. Especially high concern has been arisen over damages caused by metal rakes used in commercial picking to subsequent berry production. We studied the berry production of bilberry (Vaccinium myrtillus L.), lingonberry (V. vitis-idaea L.) and crowberry (E. nigrum ssp. hermaphroditum (Hagerup) Böcher) after picking the berries by 1) plastic hand rake, 2) long-handed metal rake and 3) powerful picking by long-handed metal rake, in northern Finland during 2010–2012. In the powerful long-handed metal rake treatment the aboveground vegetation was raked twice to the moss layer after berry picking. Biomass, which was removed from the vegetation by rakes was collected and used as a measure of the damage. We assumed that picking by plastic hand rake would result in lowest, long-handed metal rake intermediate and powerful picking by long-handed metal rake highest biomass loss from vegetation. The amount of biomass loss should in turn be reversely reflected into berry production. However, only the powerful picking by long-handed metal rake removed higher amount of biomass than other picking methods in bilberry and lingonberry. In crowberry, the amount of biomass removed by rakes increased from treatment to treatment. Contrary to our assumption, berry production of bilberry, lingonberry and crowberry was not affected by the damage caused by any of the picking method. We conclude that long-handed metal rake used in commercial picking is comparable to hand rake in terms of berry production.

Manninen, Agrifood Research Finland MTT, Eteläranta 55, FI-96300 Rovaniemi, Finland E-mail: outi.h.manninen@mtt.fi
Peltola, Agrifood Research Finland MTT, Eteläranta 55, FI-96300 Rovaniemi, Finland E-mail: rainer.peltola@mtt.fi

article id 970, category Research article

Zhen-Yu Du, Qing-Hua Wang, Shang-Jun Xing, Fang-Chun Liu, Bing-Yao Ma, Hai-Lin Ma, De-Xi Liu. (2013). Fine root distribution, characteristics and rhizosphere soil properties in a mixed stand of Robinia pseudoacacia and Fraxinus velutina in a saline soil. Silva Fennica vol. 47 no. 3 article id 970. https://doi.org/10.14214/sf.970

Keywords: mixed forest; fine root; black locust; velvet ash; rhizhosphere soil

Abstract | Full text in HTML | Full text in PDF | Author Info

The spatial distribution and characteristics of fine roots (< 2 mm in diameter), and rhizosphere soil properties were studied in a mixed planted forest of black locust (Robinia pseudoacacia L.) and velvet ash (Fraxinus velutina Torr.) 27 years after planting in a coastal saline soil of the Yellow River delta, China. The results of fine root analysis showed that the fine roots of both black locust and velvet ash were mainly distributed in the soil layer at 0–20 cm depth and 50–150 cm from trees. The fine root distribution of both species suggests a strategy of avoiding salinity rather than salt –tolerance. The horizontal spread distance of fine roots of velvet ash was evidently longer than that of black locust. The fine root biomass, specific root length, specific root area, specific root volume and root activity were significantly higher for velvet ash in comparison with black locust. The results of soil analysis showed that rhizosphere soil pH of black locust and velvet ash were significantly lower compared with non-rhizosphere soil. The available N content in rhizosphere soil of black locust was higher than that of velvet ash. However, the contents of soluble salt, organic matter, available P and available K in rhizosphere soil of velvet ash were higher than those of black locust. The above results indicated that the differences between black locust and velvet ash in fine root distribution, characteristics and rhizosphere soil properties were the major reasons for that velvet ash showed stronger acclimation responses than black locust to the coastal saline soil.

Du, Shandong Academy of Forestry, 42 Wenhua East Road, Jinan 250014, P. R. China E-mail: zydu@qq.com
Wang, Shandong Academy of Forestry, Jinan, P. R. China E-mail: wqh0228@163.com
Xing, Shandong Academy of Forestry, Jinan, P. R. China E-mail: xingsj-126@126.com
Liu, Shandong Academy of Forestry, Jinan, P. R. China E-mail: fchliu@126.com
Ma, Shandong Academy of Forestry, Jinan, P. R. China E-mail: mby777@163.com
Ma, Shandong Academy of Forestry, Jinan, P. R. China E-mail: mahlin@163.com
Liu, Shandong Academy of Forestry, Jinan, P. R. China E-mail: llyldx@163.com

article id 964, category Research article

Liisa Huttunen, Matthew P. Ayres, Pekka Niemelä, Susanne Heiska, Riitta Tegelberg, Matti Rousi, Seppo Kellomäki. (2013). Interactive effects of defoliation and climate change on compensatory growth of silver birch seedlings. Silva Fennica vol. 47 no. 3 article id 964. https://doi.org/10.14214/sf.964

Keywords: root; shoot ratio; biomass; Betula pendula; elevated CO2; elevated temperature; folivory

Highlights: The main components affecting growth compensation in silver birch seedlings are the timing and severity of foliage damage; The ability to compensate growth is also dependent upon the limits of temperature and nutrient availability; The responses of birches imply that folivory does not necessarily lead to reduced net productivity under changing climate

Abstract | Full text in HTML | Full text in PDF | Author Info

Atmospheric warming increases the abundance of insect herbivores and intensifies the risk of defoliation, especially in high latitude forests. At the same time, the effects of increasing temperature and CO₂ on plant responses to foliage damage are poorly understood. We examined if previous-year defoliation, varying between 0 and 75% of total leaf area, and different combinations of elevated temperature, CO₂ and nutrient availability alter the growth of two-year old silver birch (Betula pendula Roth) seedlings. We measured the greatest height growth in seedlings that were fertilized and defoliated twice at the level of 50% of total leaf area, and subjected to elevated temperature with ambient CO₂. The lowest growth was recorded in unfertilized seedlings that were defoliated twice at the level of 25% of total leaf area, and grew under ambient temperature with ambient CO₂. The total biomass increased in all seedlings that were fertilized or grew under elevated temperature. The root: shoot ratios were low in defoliated seedlings, or seedlings subjected to fertilization or temperature elevation. Our conclusion is that ability of birches to compensate height growth is highly dependent upon the magnitude and frequency of defoliation on the limits of temperature and nutrient availability. These responses imply that folivory does not necessarily lead to reduced net productivity of trees under changing climate.

Huttunen, Section of Ecology, Department of Biology, University of Turku, FI-20014 Turku, Finland E-mail: liisa.huttunen@utu.fi
Ayres, Biological Sciences, Dartmouth College, Hanover, NH 03755, USA E-mail: matt.ayres@dartmouth.edu
Niemelä, Section of Biodiversity and Environmental Science, Department of Biology, University of Turku, FI-20014 Turku, Finland E-mail: pekka.niemela@utu.fi
Heiska, The Finnish Forest Research Institute, Punkaharju Unit, Finlandiantie 18, FI-58450 Punkaharju, Finland E-mail: susanne.heiska@metla.fi
Tegelberg, Digitarium - Digitization Centre of the Finnish Museum of Natural History and the University of Eastern Finland, Joensuu Science Park, P.O. Box 111, FI-80101 Joensuu, Finland E-mail: riitta.tegelberg@helsinki.fi
Rousi, The Finnish Forest Research Institute, Vantaa Unit, P.O. Box 18, FI-01301 Vantaa, Finland E-mail: matti.rousi@metla.fi
Kellomäki, Faculty of Science and Forestry, School of Forest Sciences, University of Eastern Finland, P.O. Box 111, FI-80101 Joensuu, Finland E-mail: seppo.kellomaki@uef.fi

Category : Research note

article id 1017, category Research note

Jeanette Edlund, Urban Bergsten, Hans Arvidsson. (2013). A forest machine bogie with a bearing capacity dependent contact area: acceleration and angular orientation when passing obstacles and drawbar pull force and free rolling resistance on firm ground. Silva Fennica vol. 47 no. 3 article id 1017. https://doi.org/10.14214/sf.1017

Keywords: ground damages; soft ground; traction force

Highlights: The Long Tracked Bogie principle (LTB) has low contact area on firm ground with low load, it increases when higher traction force is needed and on softer soil; Free rolling resistance on firm ground was 60% of the value for a conventional bogie; LTB appears to pass wider ditches/cavities, more smoothly with lower pitch angle, than a conventional bogie.

Abstract | Full text in HTML | Full text in PDF | Author Info

The Long Tracked Bogie with contact area dependent on bearing capacity was compared to a conventional bogie. Two unloaded Vimek 608 forwarders with different bogies and with the traction from the front wheel removed were compared. Two high obstacles, 0.1 and 0.2 m high, respectively and 0.15 m in width, and two deep obstacles/ditches with a depth of 0.2 m and a width 1 and 1.5 m were used for tests. Towing tests on flat ground were done by connecting the machines to each other with a load cell in between. There were no or small differences in acceleration when passing obstacles between the two types of bogie. LTB passed wider ditches/cavities with lower pitch angles (one bogie/side passing) and 0.2 m obstacles with higher roll angles than a conventional bogie. On firm ground, free rolling resistance of the LTB was about 60% of the resistance of the conventional bogie. The drawbar pull force for the LTB was indicated to be a few percentage units higher than for the conventional bogie when it was driving with a towed machine acting as a braking force. The LTB principle might yield opportunities to improve the way we construct bogies for forest machines. Even if the contact area is low on firm ground when the machine is running with low load, it increases when higher traction force is needed and on softer soil. Further field tests are needed to evaluate the LTB when used on soft ground and with higher load as well.

Edlund, Sveaskog AB, SE-941 86 Piteå, Sweden E-mail: jeanette.edlund@sveaskog.se
Bergsten, Swedish University of Agricultural Sciences, Department of Silviculture, SE-901 83 Umeå, Sweden E-mail: urban.bergsten@slu.se
Arvidsson, SMP Umeå, SE-904 03 Umeå, Sweden E-mail: hans.arvidsson@smp.sp.se

article id 974, category Research note

Kristina Ahnlund Ulvcrona, Lars Karlsson, Ingegerd Backlund, Urban Bergsten. (2013). Comparison of silvicultural regimes of lodgepole pine (Pinus contorta) in Sweden 5 years after precommercial thinning. Silva Fennica vol. 47 no. 3 article id 974. https://doi.org/10.14214/sf.974

Keywords: direct seeding; forest production; corridor thinning; biomass harvest; PCT

Highlights: Management regimes can serve different purposes such as biomass production, pulp and timber production or a combination of those; 30 tons biomass or 38–45 m³ stem volume ha^–1 could be derived by schematic corridor thinning (70%) at year 20; Producing large amounts of biomass early in the rotation period does not exclude a conversion into pulp and timber production.

Abstract | Full text in HTML | Full text in PDF | Author Info

Early effects (stem volume, mean diameter at breast height weighted against basal area (Dgv) (Dgv), biomass and damage frequency) of different silvicultural regimes 18-19 years after direct seeding of lodgepole pine in northern Sweden were analysed. A Conventional regime, (i) precommercial thinning (PCT) to 2200 stems ha^-1, was compared to: (ii) High biomass production (15 300 stems ha^-1, no PCT) with and without corridor thinning at year 20, (iii) production of Large dimension trees (PCT to 1700 stems ha^-1), (iv), Combined high biomass production and production of conventional round wood (PCT to 4500 stems ha^-1). PCT was done 15 yrs after direct seeding for all PCT treatments. Local biomass functions showed that the regimes aiming at High biomass production displayed ca 144-157% more biomass and 134-143% more stem volume than the Conventional and Large dimension regimes (ca 21 tons and 31 m³ ha^-1). Dgv for the 1000 (9.2 cm) and 2000 (8.3 cm) largest trees ha^-1 appeared unaffected by regime. By schematic corridor thinning (70% of the total area) at year 20 in the High biomass regime, 27-32 tons of biomass ha^-1 and 38-45 m³ ha^-1 could be derived while still having a Dgv of the 1000 largest trees ha^-1 of about 8 cm. Therefore, this study indicates that it is possible to produce and harvest large amounts of biomass and stem volume early in the rotation period without excluding later pulp and timber production. This initial regime comparison should be continued over time.

Ahnlund Ulvcrona, SLU, Forest Biomaterials and Technology, Skogsmarksgränd, SE-901 83 Umeå, Sweden E-mail: kristina.ulvcrona@slu.se
Karlsson, SLU, Forest Biomaterials and Technology, Skogsmarksgränd, SE-901 83 Umeå, Sweden E-mail: lars.karlsson@slu.se
Backlund, SLU, Forest Biomaterials and Technology, Skogsmarksgränd, SE-901 83 Umeå, Sweden E-mail: ingegerd.backlund@slu.se
Bergsten, SLU, Forest Biomaterials and Technology, Skogsmarksgränd, SE-901 83 Umeå, Sweden E-mail: urban.bergsten@slu.se

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