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Silva Fennica vol. 47 no. 4 | 2013

Category: Research article

article id 1057, category Research article
Jouni Siipilehto & Lauri Mehtätalo. (2013). Parameter recovery vs. parameter prediction for the Weibull distribution validated for Scots pine stands in Finland. Silva Fennica vol. 47 no. 4 article id 1057. https://doi.org/10.14214/sf.1057
Highlights: A parameter recovery method (PRM) was developed for forest stand inventories and compared with previously developed parameter prediction methods (PPM) in Finland; PRM for the 2-parameter Weibull function provided compatibility for the main stand characteristics: stem number, basal area and one of the four optional mean characteristics; PRM provided comparable and at its best, superior accuracy in volume characteristics compared with PPM.
The moment-based parameter recovery method (PRM) has not been applied in Finland since the 1930s, even after a continuation of forest stand structure modelling in the 1980s. This paper presents a general overview of PRM and some useful applications. Applied PRM provided compatibility for the included stand characteristics of stem number (N) and basal area (G) with either mean (D), basal area-weighted mean (DG), median (DM) or basal area-median (DGM) diameter at breast height (dbh). A two-parameter Weibull function was used to describe the dbh-frequency distribution of Scots pine stands in Finland. In the validation, PRM was compared with existing parameter prediction models (PPMs). In addition, existing models for stand characteristics were used for the prediction of unknown characteristics. Validation consisted of examining the performance of the predicted distributions with respect to variation in stand density and accuracy of the localised distributions, as well as accuracy in terms of bias and the RMSE in stand characteristics in the independent test data set. The validation data consisted of 467 randomly selected stands from the National Forest Inventory based plots. PRM demonstrated excellent accuracy if G and N were both known. At its best, PRM provided accuracy that was superior to any existing model in Finland – especially in young stands (mean height < 9 m), where the RMSE in total and pulp wood volumes, 3.6 and 5.7%, respectively, was reduced by one-half of the values obtained using the best performing existing PPM (8.7–11.3%). The unweighted Weibull distribution solved by PRM was found to be competitive with weighted existing PPMs for advanced stands. Therefore, using PRM, the need for a basal area weighted distribution proved unnecessary, contrary to common belief. Models for G and N were shown to be unreliable and need to be improved to obtain more reliable distributions using PRM.
  • Siipilehto, Finnish Forest Research Institute, Vantaa Research Unit, P.O. Box 18, FI-01301 Vantaa, Finland ORCID ID:E-mail: jouni.siipilehto@metla.fi (email)
  • Mehtätalo, University of Eastern Finland, School of Computing, P.O. Box 111, FI-80101 Joensuu, Finland ORCID ID:E-mail: lauri.mehtatalo@uef.fi
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 1046, category Research article
Eva-Maria Nordström, Hampus Holmström & Karin Öhman. (2013). Evaluating continuous cover forestry based on the forest owner’s objectives by combining scenario analysis and multiple criteria decision analysis. Silva Fennica vol. 47 no. 4 article id 1046. https://doi.org/10.14214/sf.1046
Highlights: Scenario analysis and multiple criteria decision analysis were combined to evaluate alternative forest management strategies for Linköping municipality, Sweden; Continuous cover forestry (CCF) promoted ecological and social objectives better than even-aged forestry but was worse for economic objectives; Ecological and social objectives were important to the municipality and thus, in summary, CCF seemed to be a suitable strategy.
Forests are increasingly managed both to provide a sustainable yield of timber and for supplying a range of ecosystem services in line with the concept of sustainable forest management. Several incommensurable interests must then be considered, and it is necessary to strike a balance between different objectives. In evaluation of trade-offs to be made, both objective factors and subjective values need to be taken into account. In recent years, continuous cover forestry (CCF) has been put forward as an alternative to even-aged forestry. The aim of this study was to use scenario analysis in combination with multi criteria decision analysis (MCDA) to evaluate whether CCF is a suitable strategy based on the decision makers’ objectives and preferences for sustainable forest management in a specific landscape. This approach was applied to a planning case on the forest estate of the Linköping municipality in southwestern Sweden. The scenario analyses provided insights into relevant quantitative factors, while the MCDA evaluation helped in clarifying the objectives of the forest management and in assessing the relative importance of various objectives. The scenario analyses showed that in this case CCF is a good management strategy in ecological and social terms but yields worse economic outcomes than conventional even-aged forestry. In the Linköping case, there was a relatively strong emphasis on ecological and social aspects and thus, in summary, CCF seemed to be the most suitable option.
  • Nordström, Swedish University of Agricultural Sciences, Department of Forest Resource Management, Skogsmarksgränd, SE-901 83 Umeå, Sweden ORCID ID:E-mail: eva-maria.nordstrom@slu.se (email)
  • Holmström, Swedish University of Agricultural Sciences, Department of Forest Resource Management, Skogsmarksgränd, SE-901 83 Umeå, Sweden ORCID ID:E-mail: hampus.holmstrom@slu.se
  • Öhman, Swedish University of Agricultural Sciences, Department of Forest Resource Management, Skogsmarksgränd, SE-901 83 Umeå, Sweden ORCID ID:E-mail: karin.ohman@slu.se
article id 1043, category Research article
Jorge Martín-García, Luc Barbaro, Julio Javier Diez & Hervé Jactel. (2013). Contribution of poplar plantations to bird conservation in riparian landscapes. Silva Fennica vol. 47 no. 4 article id 1043. https://doi.org/10.14214/sf.1043
Highlights: Poplar plantations should not be used as surrogate habitat for native riparian forests with the aim of preserving bird species diversity; Native riparian forests should be preserved or restored as far as possible; Bird communities occurring in poplar plantations can still accommodate rich communities of forest bird species, providing that suitable management is applied at local and landscape levels.
In Mediterranean areas, riparian zones are particularly important for maintaining biodiversity. Nevertheless, the native vegetation in these zones has been modified or lost at an alarming rate during the last decades. The main objective of this study was to investigate the influence of poplar plantations on bird diversity in riparian zones, in order to estimate the ecological implications of a substantial expansion of poplar plantations. Breeding birds were sampled by the point-count method in twenty-four poplar plantations of I-214 clone, according to a factorial design combining stand age and understory management. Furthermore, the three native riparian forests remaining in the study area were also surveyed. Explanatory variables included (1) dendrometric, (2) understory and (3) landscape variables within six different radii of circular buffers. The species richness and abundance index were higher in riparian forests than in poplar plantations. Landscape variables (percentage of poplar plantations in the surrounding landscape) strongly influenced bird diversity in poplar plantations. Furthermore, at the local scale, understory cover was also a key factor in shaping bird assemblages. This suggests that poplar plantations should not be used as surrogates for native forests. Nevertheless, poplar plantations can still accommodate rich communities of forest bird species, providing that suitable management is applied at local and landscape levels.
  • Martín-García, Sustainable Forest Management Research Institute, University of Valladolid – INIA, Avenida Madrid, 57, 34004 Palencia, Spain ORCID ID:E-mail: jorgemg@pvs.uva.es (email)
  • Barbaro, NRA, UMR 1202 BIOGECO, 69 Route d’Arcachon, F-33612 Cestas cedex, France ORCID ID:E-mail: luc@pierroton.inra.fr
  • Diez, Sustainable Forest Management Research Institute, University of Valladolid – INIA, Avenida Madrid, 57, 34004 Palencia, Spain ORCID ID:E-mail: jdcasero@pvs.uva.es
  • Jactel, NRA, UMR 1202 BIOGECO, 69 Route d’Arcachon, F-33612 Cestas cedex, France; Université de Bordeaux, UMR 1202, Bordeaux, F-33000 France ORCID ID:E-mail: herve.jactel@pierroton.inra.fr
article id 1030, category Research article
Jussi Manner, Tomas Nordfjell & Ola Lindroos. (2013). Effects of the number of assortments and log concentration on time consumption for forwarding. Silva Fennica vol. 47 no. 4 article id 1030. https://doi.org/10.14214/sf.1030
Highlights: We analysed the effects of total and forwarded log concentrations (m3 (100 m)–1) and the number of loaded assortments on forwarding; The combination of the number of loaded assortments and their abundance (i.e. forwarded log concentration) affected time consumption most; This knowledge enables improved efficiency by optimizing number and assortment proportions in the various loads required to forward a stand.
Forwarding has been carried out for 50 years, but much is still unknown about this work. Its complexity comes from both stand features and essential decision-making. Forwarding time consumption is influenced by e.g. log concentrations and number of assortments. Traditionally, focus has been on the total log concentration (TLC), referring to all logs at the harvesting site. However, we focused on forwarded log concentration (FLC), the load-specific log concentration which depends on the assortment distribution at harvesting site and the load-specific number of assortments. To evaluate the effects of TLC, number of assortments in a load and FLC on the loading and unloading times, a standardized field experiment was carried out. Pile and load sizes were constant, while TLC and FLC were manipulated by varying the pile distribution on the test path. For all work elements, the time consumption per m3 was significantly affected by the number of assortments that were loaded, but only the “driving while loading” work element was also significantly influenced by TLC. However, when untangling the intercorrelation between tested factors, it was found that the time consumption for driving while loading significantly decreased as a function of FLC and was unaffected by the number of assortments in a load. That FLC influences the forwarding time consumption highlights the need to study the effects of combining various assortment proportions in a load. Such knowledge will enable analysis of the most efficient number and assortment proportions to combine in the various loads required to forward a given stand.
  • Manner, Swedish University of Agricultural Sciences, Department of Forest Biomaterial and Technology, SE-901 83 Umeå, Sweden ORCID ID:E-mail: jussi.manner@slu.se (email)
  • Nordfjell, Swedish University of Agricultural Sciences, Department of Forest Biomaterial and Technology, SE-901 83 Umeå, Sweden ORCID ID:E-mail: tomas.nordfjell@slu.se
  • Lindroos, Swedish University of Agricultural Sciences, Department of Forest Biomaterial and Technology, SE-901 83 Umeå, Sweden ORCID ID:E-mail: ola.lindroos@slu.se
article id 1022, category Research article
Eero Muinonen, Perttu Anttila, Jaakko Heinonen & Jukka Mustonen. (2013). Estimating the bioenergy potential of forest chips from final fellings in Central Finland based on biomass maps and spatially explicit constraints. Silva Fennica vol. 47 no. 4 article id 1022. https://doi.org/10.14214/sf.1022
The technical potential of forest chips from final fellings in Central Finland was estimated using a method based on biomass maps derived from a multi-source forest inventory technique. Image segmentation techniques were applied to a satellite image mosaic to detect stand boundaries. The technical potential of forest chips was computed based on primary forestry residues, i.e. logging residues and stumps from final fellings. Harvesting level definitions for final fellings were established using realized statistics for roundwood at the municipality level as well as larger area statistics. The sensitivity of the potential to ecological and technical constraints in the model was also examined. The technical recovery rate of stump harvesting according to biomass harvesting guidelines was evaluated separately. The critical prerequisites for using the advanced, spatially explicit approach to analysing forest energy potentials may lie in the existence of spatially explicit forest inventory data and the biometric models for tree biomass assortments. The method applied was capable of taking into account the constraints that rely upon map data, such the actual forwarding distance or steepness of the slope in the terrain. The calculation results can be used for strategic decision making in the field of forest bioenergy production.
  • Muinonen, Finnish Forest Research Institute, Joensuu Unit, P.O. Box 68, FI-80101 Joensuu, Finland ORCID ID:E-mail: eero.muinonen@metla.fi (email)
  • Anttila, Finnish Forest Research Institute, Joensuu Unit, P.O. Box 68, FI-80101 Joensuu, Finland ORCID ID:E-mail: perttu.anttila@metla.fi
  • Heinonen, Finnish Forest Research Institute, Joensuu Unit, P.O. Box 68, FI-80101 Joensuu, Finland ORCID ID:E-mail: jaakko.heinonen@metla.fi
  • Mustonen, Stora Enso, Talvikkitie 40 C, FI-01300 Vantaa, Finland ORCID ID:E-mail: jukka.mustonen@storaenso.com
article id 1016, category Research article
Karin Johansson, Eva Ring & Lars Högbom. (2013). Effects of pre-harvest fertilization and subsequent soil scarification on the growth of planted Pinus sylvestris seedlings and ground vegetation after clear-felling. Silva Fennica vol. 47 no. 4 article id 1016. https://doi.org/10.14214/sf.1016
Highlights: Pre-harvest N fertilization had no significant effect on seedling growth and ground vegetation biomass; Scarification improved seedling survival and growth and reduced the amount of ground vegetation; Without scarification, pre-harvest fertilization increased the amount of damaged seedlings.
Fertilization and scarification are both performed to increase tree production at different stages of forest rotation periods. In this study, the effects of previous nitrogen fertilizations and scarification after clear felling on planted Pinus sylvestris L. seedlings and ground vegetation were investigated. Two fertilization experiments established around 1980 were harvested in 2006, after which the plots were scarified by disc trenching and re-planted. The plots had been repeatedly fertilized over a 20-year period before harvesting, with total N doses of 0, 450, 900 or 1800 kg N ha-1. After five growing seasons, the growth, survival and nutrient contents of the seedlings were measured, and ground vegetation was collected to estimate its biomass and nutrient content. Pre-harvest fertilization alone had only minor effects on the results, but scarification increased both the survival and growth of the planted seedlings. However, without scarification, seedling mortality increased with increasing fertilization intensity. The ground vegetation biomass was higher in plots without scarification, but the total biomass of seedlings and ground vegetation was similar in all treatments. Scarification thus favored seedling growth at the expense of ground vegetation. Only a few effects on nutrient content were found, but there were no signs of nutrient imbalance in any of the treatments. At higher levels of fertilization, the K:N ratio in the seedlings decreased while the K content in the ground vegetation increased. Overall, scarification had a greater impact than pre-harvest fertilization on the planted seedlings and the ground vegetation.
  • Johansson, Skogforsk, The Forestry Research Institute of Sweden, Ekebo 2250, SE-268 90 Svalöv, Sweden & Southern Swedish Forest Research Centre, SLU, Box 49, SE-230 53 Alnarp, Sweden ORCID ID:E-mail: karin.johansson@skogforsk.se (email)
  • Ring,  Skogforsk, The Forestry Research Institute of Sweden, Uppsala Science Park, SE-751 83 Uppsala, Sweden ORCID ID:E-mail: eva.ring@skogforsk.se
  • Högbom,  Skogforsk, The Forestry Research Institute of Sweden, Uppsala Science Park, SE-751 83 Uppsala, Sweden ORCID ID:E-mail: lars.hogbom@skogforsk.se
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

Category: Research note

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 1024, category Research note
Petter Nilsen & Line Tau Strand. (2013). Carbon stores and fluxes in even- and uneven-aged Norway spruce stands. Silva Fennica vol. 47 no. 4 article id 1024. https://doi.org/10.14214/sf.1024
Highlights: Long term (81 years) C sequestration is slightly higher in an even-aged compared to an uneven-aged spruce stand; The even-aged stand has at 81 years age a slightly lower soil C content than the uneven-aged stand; Present C fluxes indicate that the difference in long term C sequestration will increase in favour the even-aged stand if final felling is postponed.
This investigation compares present C stores, fluxes and historic tree C sequestration in an uneven-aged and an even-aged Norway spruce stand under similar high productive soil conditions in south-eastern Norway. A selection cutting system has been performed in the uneven-aged forest stand for 81 years and the even-aged stand was established after clear-cutting 81 years ago. Timber productivity has been measured in the uneven stand for 81 years and in the even-aged stand for 52 years. C storage was determined based on tree measurements, tree biomass functions, soil samples and C analyses from trees and soil. Litter fall was sampled during one year and CO2 efflux from the soil was measured during one growing season. The present tree C storage (including roots) was 210 Mg C ha-1 in the even-aged stand and 76 Mg C ha-1 in the uneven-aged stand, while the corresponding figures for C in the soil was 178 and 199 Mg C ha-1. The long term timber production in the uneven-aged stand was measured to be 95% of the even-aged stand and the difference in net C sequestration was 37 Mg ha-1 in an 81 year period in favour the even-aged stand. The highest present CO2 efflux from soil was measured in the even-aged stand. The total net C sequestered in trees during 81 years minus the present soil C-stock accounts to 16 Mg ha-1 in favour the even-aged system
  • Nilsen, The Research Council of Norway, P.O. Box 2700, St. Hanshaugen, N-0131 Oslo, Norway ORCID ID:E-mail: pn@rcn.no (email)
  • Strand, Department of Plant and Environmental Sciences, Norwegian University of Life Sciences, P.O. Box 5003, N-1432 Ås, Norway ORCID ID:E-mail: line.strand@umb.no

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