Current issue: 58(5)

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Silva Fennica vol. 42 | 2008

Category : Research article

article id 467, category Research article

Annika Kangas, Ruut Haapakoski, Liisa Tyrväinen. (2008). Integrating place-specific social values into forest planning – Case of UPM-Kymmene forests in Hyrynsalmi, Finland. Silva Fennica vol. 42 no. 5 article id 467. https://doi.org/10.14214/sf.467

Keywords: collaborative planning; experienced values of forests; social value mapping; survey

Abstract | View details | Full text in PDF | Author Info

In participatory forest management planning, the perceived values of local inhabitants concerning the area under planning are collected. The results may, however, depend on the methods used. In this study, values of residents of Hyrynsalmi municipality concerning the nearby forests owned by UPM-Kymmene Ltd. were evaluated with a questionnaire consisting of general value questions and mapping of social values of forests. The data was collected from a public meeting and from a mailed survey from randomly sampled people and from members of municipal council. The aims of the study were to 1) test the social value mapping method in commercial forests in a rural-urban interface as well as to examine the benefits and drawbacks 2) in place-specific and non-specific data collection, and 3) in different data collection methods, from the viewpoint of forest management planning. We noted that while all respondents can claim to represent local values, different data collection methods produced statistically significantly different local values. This needs to be accounted for when planning a participatory process. In operational forest planning, place-specific information is more useful than questions concerning the general values, while the latter may help in defining forest policy goals. The social values mapping method is also relatively easy for the participants. However, in the studied case about one fifth of the area was delineated by the participants per each positive value. The answers were quite scattered, suggesting that most of the area had some social values for local people. This indicates that utilising a social values mapping method in planning needs further development in rural areas, where distinctive patches can not be easily detected.

Kangas, University of Helsinki, Department of Forest Management, P.O. Box 27, FI-00014 University of Helsinki E-mail: annika.kangas@helsinki.fi
Haapakoski, University of Helsinki, Department of Forest Management, P.O. Box 27, FI-00014 University of Helsinki E-mail: rh@nn.fi
Tyrväinen, Finnish Forest Research Institute, P.O. Box 16, FI-96301 Rovaniemi, Finland. E-mail: lt@nn.fi

article id 466, category Research article

Ilkka Korpela, Tuukka Tuomola, Timo Tokola, Bo Dahlin. (2008). Appraisal of seedling stand vegetation with airborne imagery and discrete-return LiDAR – an exploratory analysis. Silva Fennica vol. 42 no. 5 article id 466. https://doi.org/10.14214/sf.466

Keywords: silviculture; remote sensing; forest regeneration; classification; species

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The potential for combined use of airborne discrete-return LiDAR and digital imagery in the classification and measurement of common seedling stand vegetation was examined in southern Finland (61°50’N, 24°20’E). Classification was based on spectral and textural image features in addition to geometric and radiometric features of the LiDAR. The accuracy of leaf-on, LiDAR-based terrain elevation models was tested as well as the accuracy of LiDAR in the measurement of vegetation heights. LiDAR-based canopy height and the range-normalized intensity of the LiDAR were strong explanatory variables in vegetation classification. Interspecies variation was observed in the height measurement accuracy of LiDAR for different tree, shrub and low vegetation canopies. Elevation models derived with 1–15 pulses per m² showed an inherent noise of app. 15–25 cm, which restricts the use of LiDAR in regeneration assessment of very young stands. The spatial pattern of the competing vegetation was reproduced in classification-based raster surfaces, which could be useful in deriving meaningful treatment proposals.

Korpela, University of Helsinki, Dept of Forest Management, P.O. Box 27, FI-00014 University of Finland E-mail: ilkka.korpela@helsinki.fi
Tuomola, University of Helsinki, Dept of Forest Management, P.O. Box 27, FI-00014 University of Finland E-mail: tt@nn.fi
Tokola, University of Helsinki, Dept of Forest Management, P.O. Box 27, FI-00014 University of Finland E-mail: tt@nn.fi
Dahlin, University of Helsinki, Dept of Forest Management, P.O. Box 27, FI-00014 University of Finland E-mail: bd@nn.fi

article id 465, category Research article

Ken Olaf Storaunet, Jørund Rolstad, Målfrid Toeneiet, Erlend Rolstad. (2008). Effect of logging on the threatened epiphytic lichen Usnea longissima: a comparative and retrospective approach. Silva Fennica vol. 42 no. 5 article id 465. https://doi.org/10.14214/sf.465

Keywords: Picea abies; forest history; dendroecology; epiphytic lichens; historic logging; selective logging; stand reconstruction; Usnea longissima

Abstract | View details | Full text in PDF | Author Info

Storaunet, Norwegian Forest and Landscape Institute, P.O. Box 115, NO-1431 Ås, Norway E-mail: ken.storaunet@skogoglandskap.no
Rolstad, Norwegian Forest and Landscape Institute, P.O. Box 115, NO-1431 Ås, Norway E-mail: jr@nn.no
Toeneiet, Norwegian Forest and Landscape Institute, P.O. Box 115, NO-1431 Ås, Norway E-mail: mt@nn.no
Rolstad, Norwegian Forest and Landscape Institute, P.O. Box 115, NO-1431 Ås, Norway E-mail: er@nn.no

article id 227, category Research article

Ola Lindroos. (2008). The effects of increased mechanization on time consumption in small-scale firewood processing. Silva Fennica vol. 42 no. 5 article id 227. https://doi.org/10.14214/sf.227

Keywords: comparative time study; fuelwood; blade saw; wedge splitter; processor; senior worker; operator effects

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Firewood, which is mainly processed by the consumer, is still an important source of energy for heating houses in industrialised countries. Possibilities to compare the mechanization’s impact on efficiency of firewood processing are limited, due to variations between working conditions in previous studies. Therefore, the objective was to compare time consumption for two small-scale firewood processing systems with different levels of mechanisation under identical conditions. The systems were tested on two classes of wood: one with a homogeneous and medium-sized diameter of logs and one with a mixture of small and large-diameter-logs. Differences in time consumption were analysed for correlations with physical workloads, deviations to routine operations, operator influences and operator perceptions. Twelve operators (60–79 years old) were studied and they showed large variation in time consumption. However, the within-operator time consumption patterns were consistent. In other words, operators all responded similarly to the different combinations of systems and wood classes, but at different absolute levels. The time required to process a unit volume of wood was 25–33% lower when the more highly mechanised system was used, and the time required was 13–22% lower for the homogeneous wood class. Physical work load, deviations and perceptions of the work varied between operators, but were weakly correlated with time consumption. The results’ implications for analyses of investments in equipment for firewood-processing for self-sufficiency purposes are discussed.

Lindroos, Swedish University of Agricultural Sciences, Department of Forest Resource Management, SE-901 83 Umeå, Sweden E-mail: ola.lindroos@srh.slu.se

article id 226, category Research article

Anneli Viherä-Aarnio, Pirkko Velling. (2008). Seed transfers of silver birch (Betula pendula) from the Baltic to Finland – effect on growth and stem quality. Silva Fennica vol. 42 no. 5 article id 226. https://doi.org/10.14214/sf.226

Keywords: Betula pendula; yield; provenance; climatic adaptation; stem defect

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Silver birch (Betula pendula Roth) seed origins from the Baltic countries, Finland and Russia were compared for survival, growth and stem quality, and the effect of latitudinal seed transfer distance examined in two provenance trials. The trials were located on moist upland forest soils at Tuusula (60°21’N) in southern Finland and at Viitasaari (63°11’N) in central Finland. The material consisted of 21 stand and single tree origins ranging from latitudes 54° to 63°N. Survival, height, dbh, relative stem taper, stem volume/ha and the proportion of trees with a stem defect (vertical branch or forked stem), were assessed when the trees were 22 years old. Significant differences were detected among the origins regarding all the measured traits in both trials. Southern Finnish origins produced the highest volume per unit area in central Finland, whereas Estonian and north Latvian stand seed origins, as well as the southern Finnish plus tree origins, were the most productive ones in southern Finland. The more southern the origin, the higher was the proportion of trees with a stem defect in both trials. The latitudinal seed transfer distance had a significant but relatively small effect on survival, stem volume/ha and proportion of trees with a stem defect. The proportion of trees with a stem defect increased linearly in relation to the seed transfer distance from the south. The relationship of both survival and stem volume/ha to the seed transfer distance was curvilinear. Volume/ha was increased by transferring seed from ca. 2 degrees of latitude from the south. A longer transfer from the south, as well as transfer from the north, decreased the yield.

Viherä-Aarnio, Finnish Forest Research Institute, Vantaa Research Unit, P.O. Box 18, FI-01301 Vantaa, Finland E-mail: anneli.vihera-aarnio@metla.fi
Velling, Finnish Forest Research Institute, Vantaa Research Unit, P.O. Box 18, FI-01301 Vantaa, Finland E-mail: pv@nn.fi

article id 225, category Research article

Johan Bergh, Urban Nilsson, Harald Grip, Per-Ola Hedwall, Tomas Lundmark. (2008). Effects of frequency of fertilisation on production, foliar chemistry and nutrient leaching in young Norway spruce stands in Sweden. Silva Fennica vol. 42 no. 5 article id 225. https://doi.org/10.14214/sf.225

Keywords: boreal; sludge; wood-ash; N; P; K

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There is a great need to increase the production in Swedish forests to meet future demand from the forest industry and the bio-energy sector. One option to increase the production is to supply nutrients to young stands of Norway spruce. For the practical application it is important to develop and optimise fertilisation regimes in terms of production, economy and leaching of nutrients. The frequency of fertilisation is one important variable in the fertilisation regime, and this study aimed to study effects of different fertilisation frequencies on production and leaching of nitrogen. In 2001, five field experiments were established in southern, central and northern Sweden. Young stands of Norway spruce were fertilised every year, every second year and every third year. In addition, fertilisation with sludge pellets and wood-ash combined with nitrogen was investigated. The current annual increment after five years of treatment was significantly larger in fertilised than in unfertilised treatments. The difference in production between fertilisation every year and every second year was insignificant, while fertilisation every third year resulted in lower production. Sludge pellets and wood-ash fertilisation gave significantly lower production than fertilisation every second year even though approximately the same amount of nitrogen was applied. There was relatively little leaching of nitrate to ground water in all treatments; 0.6–1 kg N ha^–1 a^–1 from plots with fertilisation every year or every second year; and 2.7 kg N ha^–1 a^–1 from plots with fertilisation every third year. Most of the leaching was after the first fertilisation, in all treatments at all sites.

Bergh, Swedish University of Agricultural Sciences, Southern Swedish Forest Research Centre, P.O. Box 49, SE-230 53 Alnarp, Sweden E-mail: johan.bergh@ess.slu.se
Nilsson, Swedish University of Agricultural Sciences, Southern Swedish Forest Research Centre, P.O. Box 49, SE-230 53 Alnarp, Sweden E-mail: un@nn.se
Grip, Swedish University of Agricultural Sciences, Southern Swedish Forest Research Centre, P.O. Box 49, SE-230 53 Alnarp, Sweden E-mail: hg@nn.se
Hedwall, Swedish University of Agricultural Sciences, Southern Swedish Forest Research Centre, P.O. Box 49, SE-230 53 Alnarp, Sweden E-mail: poh@nn.se
Lundmark, Swedish University of Agricultural Sciences, Southern Swedish Forest Research Centre, P.O. Box 49, SE-230 53 Alnarp, Sweden E-mail: tl@nn.se

article id 224, category Research article

Xiangwen Xiao, Xiao Xu, Fan Yang. (2008). Adaptive responses to progressive drought stress in two Populus cathayana populations. Silva Fennica vol. 42 no. 5 article id 224. https://doi.org/10.14214/sf.224

Keywords: antioxidant enzymes; free proline; malondialdehyde; soluble sugars; drought tolerance; Populus cathayana

Abstract | View details | Full text in PDF | Author Info

The young, vegetatively propagated cuttings of Populus cathayana Rehder were exposed to a progressive drought stress for 12 weeks in a greenhouse to characterize the physiological and biochemical basis of drought adaptation in woody plants. Two contrasting populations were employed in our study, which were from the wet and dry climate regions in western China, respectively. The results showed that the adaptive responses of P. cathayana to drought were affected by drought intensity and poplar genotype (population). The progressive drought stress significantly inhibited plant growth, increased carotenoid contents and, at the same time, accumulated soluble sugars and free proline in the plants of both populations tested. On the other hand, the gradually increasing drought also induced antioxidative systems including the increase of the activities of superoxide dismutase (SOD) and guaiacol peroxidase (POD). Moreover, there were different responses to progressive drought stress between the two contrasting populations. Compared with the wet climate population, the dry climate population had lower shoot height and growth rate, higher free proline content, and more efficient photoprotective system (such as higher carotenoid content and Car/Chl) and antioxidant system (such as higher POD activity), as a result of drought stress. These results suggest that the dry climate population possesses better drought tolerance than the wet climate population. The differences in drought tolerance may be closely related with efficient photoprotective system, accumulation of the osmoprotectant proline as well as the increased capacity of the antioxidative system to scavenge reactive oxygen species, and the consequent suppressed level of lipid peroxidation under drought conditions.

Xiao, Chengdu Institute of Biology, Chinese Academy of Sciences, P.O. Box 416, Chengdu 610041, P. R. China; Graduate School of the Chinese Academy of Sciences, Beijing 100039, P. R. China E-mail: xiaoxw@cib.ac.cn
Xu, Chengdu Institute of Biology, Chinese Academy of Sciences, P.O. Box 416, Chengdu 610041, P. R. China; Graduate School of the Chinese Academy of Sciences, Beijing 100039, P. R. China E-mail: xx@nn.cn
Yang, Chengdu Institute of Biology, Chinese Academy of Sciences, P.O. Box 416, Chengdu 610041, P. R. China; Graduate School of the Chinese Academy of Sciences, Beijing 100039, P. R. China E-mail: fy@nn.cn

article id 239, category Research article

Matti Stendahl, Anders Roos. (2008). Antecedents and barriers to product innovation – a comparison between innovating and non-innovating strategic business units in the wood industry. Silva Fennica vol. 42 no. 4 article id 239. https://doi.org/10.14214/sf.239

Keywords: product development; obstacles for innovation; innovation strategy; organization

Abstract | View details | Full text in PDF | Author Info

Increased competitive pressure from low-cost economies and substituting materials has raised the need for new strategies focusing on product differentiation in the Nordic wood industry. With the aim to identify factors that can facilitate increased product innovation activity, this study compared organizational characteristics and perceived barriers to product development among innovating and non-innovating strategic business units (SBUs) in the Swedish and Finnish wood industry. Multivariate analysis of data from a cross-sectional sample of 110 SBUs suggested that organizational size and educational level among white-collar workers are significant antecedents of product innovation activity. Furthermore, the difficulty of giving practical priority to development work in the everyday stress was identified as the most important perceived barrier to product development among managers in both innovating and non-innovating SBUs. A low competence level among the personnel and a low need to innovate was perceived to be the second most important barriers to product development among managers in, respectively, innovating and non-innovating SBUs. Practitioners who wish to increase product innovation activity in the wood industry are advised to promote an increased educational level in wood industry companies. They are further encouraged to seek ways to reduce the perceived barriers to product innovation identified in this study.

Stendahl, Swedish University of Agricultural Sciences, Department of Forest Products, P.O. Box 7008, SE-750 07 Uppsala, Sweden E-mail: matti.stendahl@sprod.slu.se
Roos, Swedish University of Agricultural Sciences, Department of Forest Products, P.O. Box 7008, SE-750 07 Uppsala, Sweden E-mail: ar@nn.se

article id 238, category Research article

Mikko Kurttila, Pekka Leskinen, Jouni Pykäläinen, Tiina Ruuskanen. (2008). Forest owners' decision support in voluntary biodiversity-protection projects. Silva Fennica vol. 42 no. 4 article id 238. https://doi.org/10.14214/sf.238

Keywords: biodiversity protection; compensation fee; multi-criteria decision support; multi-objective forest planning

Abstract | View details | Full text in PDF | Author Info

New forest-biodiversity-protection instruments based on temporary protection periods and non-industrial private forest owners’ voluntary participation have been recently introduced and tested in pilot areas located in Southern Finland. Thanks to their several benefits, the use of voluntary instruments is becoming more common in many other countries as well. Voluntary protection here means that forest owners voluntarily set aside tracts of forest to be protected and define their compensation fees. Depending on the objectives of the forest owners, the compensation fee reflects the forest owners’ (positive) attitude towards biodiversity, scenic beauty, recreational values and/or the existence of long-term cutting possibilities. When a forest owner decides to offer part of his/her forest holding to be temporarily protected, the owner faces a new decision problem related to definition of the compensation fee, which should be based on diverse information concerning stand- and holding-level opportunity costs as well as on the biodiversity value of the stand. This article introduces three decision-support elements for assisting forest owners in defining their compensation fees. The first element relates to the assessment of the potential stand-level loss of timber harvesting income that the temporary protection of the stand may cause. The second element sets the holding-level opportunity cost of protection by utilizing the forest owners’ holding level goals, the holdings’ production possibilities and optimization methods. The third element describes the biodiversity value of the stand by means of a multi-criteria expert model. Case study material collected from the area of Central Karelia Herb-rich Forests Network pilot project is used to illustrate the characteristics of the decision-support elements and to point out some development needs for the future use of these elements.

Kurttila, University of Joensuu, Faculty of Forest Sciences, P.O. Box 111, FI-80101 Joensuu, Finland E-mail: mikko.kurttila@joensuu.fi
Leskinen, Finnish Environment Institute, Research Programme for Production and Consumption, P.O. Box 111, FI-80101 Joensuu, Finland E-mail: pl@nn.fi
Pykäläinen, Metsämonex Ltd., Joensuu, Finland E-mail: jp@nn.fi
Ruuskanen, University of Joensuu, Faculty of Forest Sciences, P.O. Box 111, FI-80101 Joensuu, Finland E-mail: tr@nn.fi

article id 237, category Research article

Jussi Peuhkurinen, Matti Maltamo, Jukka Malinen. (2008). Estimating species-specific diameter distributions and saw log recoveries of boreal forests from airborne laser scanning data and aerial photographs: a distribution-based approach. Silva Fennica vol. 42 no. 4 article id 237. https://doi.org/10.14214/sf.237

Keywords: diameter distribution; non-parametric estimation; pre-harvest measurement; stem data bank

Abstract | View details | Full text in PDF | Author Info

The low-density airborne laser scanning (ALS) data based estimation methods have been shown to produce accurate estimates of mean forest characteristics and diameter distributions, according to several studies. The used estimation methods have been based on the laser canopy height distribution approach, where various laser pulse height distribution -derived predictors are related to the stand characteristics of interest. This approach requires very delicate selection methods for selecting the suitable predictor variables. In this study, we introduce a new nearest neighbor search method that requires no complicated selection algorithm for choosing the predictor variables and can be utilized in multipurpose situations. The proposed search method is based on Minkowski distances between the distributions extracted from low density ALS data and aerial photographs. Apart from the introduction of a new search method, the aims of this study were: 1) to produce accurate species-specific diameter distributions and 2) to estimate factual saw log recovery, using the estimated height-diameter distributions and a stem data bank. The results indicate that the proposed method is suitable for producing species-specific diameter distributions and volumes at the stand level. However, it is proposed, that the utilization of more extensive and locally emphasized reference data and auxiliary variables could yield more accurate saw log recoveries.

Peuhkurinen, University of Joensuu, Faculty of Forest Sciences, P.O. Box 111, FI-80101 Joensuu, Finland E-mail: jp@nn.fi
Maltamo, University of Joensuu, Faculty of Forest Sciences, P.O. Box 111, FI-80101 Joensuu, Finland E-mail: mm@nn.fi
Malinen, Finnish Forest Research Institute, Joensuu Research Unit, P.O. Box 68, FI-80101 Joensuu, Finland E-mail: jm@nn.fi

article id 236, category Research article

Jaakko Repola. (2008). Biomass equations for birch in Finland. Silva Fennica vol. 42 no. 4 article id 236. https://doi.org/10.14214/sf.236

Keywords: birch; tree biomass; biomass functions; biomass of tree components

Abstract | View details | Full text in PDF | Author Info

Biomass equations were compiled for the above- and below-ground tree components of birch (Betula pendula Roth and Betula pubescens Ehrh.). The equations were based on 127 sample trees in 24 birch stands located on mineral soil sites. The study material consisted of 20 temporary plots and ten plots from four thinning experiments with different thinning intensities (unthinned, moderately and heavily thinned plots). The equations were estimated for the following individual tree components: stem wood, stem bark, living and dead branches, foliage, stump, and roots. In the data analysis, a multivariate procedure was applied in order to take into account the statistical dependency among the equations. Three multivariate variance component models were constructed for the above-ground biomass components, and one for the below-ground biomass components. The multivariate model (1) was mainly based on tree diameter and height, and in the multivariate models (2) and (3) additional commonly measured tree variables were used. The equations provided logical biomass predictions for a number of tree components, and were comparable with other functions used in Finland and Sweden. The applied statistical method generated equations that gave more reliable biomass estimates than the equations presented earlier. Furthermore, the structure of the multivariate models enables more flexible application of the equations, especially for research purposes.

Repola, Finnish Forest Research Institute, Rovaniemi Research Unit, P.O. Box 16, FI-96301 Rovaniemi, Finland E-mail: jaakko.repola@metla.fi

article id 235, category Research article

Ari Nikula, Ville Hallikainen, Risto Jalkanen, Mikko Hyppönen, Kari Mäkitalo. (2008). Modelling the factors predisposing Scots pine to moose damage in artificially regenerated sapling stands in Finnish Lapland. Silva Fennica vol. 42 no. 4 article id 235. https://doi.org/10.14214/sf.235

Keywords: Pinus sylvestris; boreal forest; forestry; Alces alces; damage; modelling

Abstract | View details | Full text in PDF | Author Info

Moose (Alces alces) damage in forest plantations have been at a high level in Finland in recent decades. Nowadays, moose is the most severe pest in Scots pine plantations also in Finnish Lapland. So far, despite the high level of damage and different bio-geographical conditions in Northern Finland, most of the moose-damage research has been carried out in Southern Finland. A number of research have also been performed to analyse factors affecting browsing but predictive models are rare. Data from 123 randomly selected and artificially regenerated pine plantations in Northern Finland were used in modelling the risk of moose browsing. The stands had been regenerated during 1984–1995. A total of 508 sample plots (range 2–8 plots per stand) were measured. Hierarchical logistic regression models with a random factor were constructed to predict the probability of leader-shoot browsing of pine on a plot. The number of planted pines and deciduous trees overtopping the pines were the most important predictors increasing the browsing probability. The results support earlier findings that deciduous trees overtopping or reaching the height of the pines should be cleaned from the immediate vicinity of the pines. Seedlings with a height ranging from 75 to 299 centimetres were more susceptible to browsing. Heavy soil scarification, such as ploughing or mounding, increased the browsing probability compared with lighter scarification methods. Soil type did not affect the browsing probability, but paludification decreased it. The within-stand variation in deciduous trees density and height should be taken into account in future moose browsing risk assessments. In Lapland, high moose damage risk areas are characterized by a low elevation and higher temperature sum.

Nikula, Finnish Forest Research Institute, Rovaniemi Research Unit, Eteläranta 55, FI-96300 Rovaniemi, Finland E-mail: ari.nikula@metla.fi
Hallikainen, Finnish Forest Research Institute, Rovaniemi Research Unit, Eteläranta 55, FI-96300 Rovaniemi, Finland E-mail: vh@nn.fi
Jalkanen, Finnish Forest Research Institute, Rovaniemi Research Unit, Eteläranta 55, FI-96300 Rovaniemi, Finland E-mail: rj@nn.fi
Hyppönen, Finnish Forest Research Institute, Rovaniemi Research Unit, Eteläranta 55, FI-96300 Rovaniemi, Finland E-mail: mh@nn.fi
Mäkitalo, Finnish Forest Research Institute, Rovaniemi Research Unit, Eteläranta 55, FI-96300 Rovaniemi, Finland E-mail: km@nn.fi

article id 234, category Research article

Enni Flykt, Sari Timonen, Taina Pennanen. (2008). Variation of ectomycorrhizal colonisation in Norway spruce seedlings in Finnish forest nurseries. Silva Fennica vol. 42 no. 4 article id 234. https://doi.org/10.14214/sf.234

Keywords: Picea abies; nursery; containerised seedlings; ectomycorrhiza; fungal diversity

Abstract | View details | Full text in PDF | Author Info

Ectomycorrhizal (ECM) colonisation patterns and seedling growth of containerised spruce seedlings were studied in five typical Finnish forest nurseries by morphotyping and molecular characterisation. ECM colonisation degree of 1-year-old spruce seedlings was below 20% in all studied Finnish forest nurseries. In 2-year-old spruce seedlings the ECM colonisation degree was ca. 50–60% in three of the nurseries, but negligible in others. The ECM fungal species richness varied from 0.1 to 3.8 types per seedling. Altogether seven ECM morphotypes were distinguished. The clearest factors associated with ECM colonisation patterns were nitrogen and phosphorus fertilisation. Particularly fertilisation in the early stage of seedling development appeared to diminish the degree of colonisation and species richness of ECM fungi. Root/shoot ratio was positively correlated with high colonisation degree and species richness of ECM fungi. Higher fertilisation inputs in these overall fertilisation levels did not increase the size of the seedlings. According to these results moderate fertilisation levels particularly in the beginning of seedling cultivation are critical for generating higher root/shoot ratios and sufficient ECM colonisation degree of the roots.

Flykt, University of Helsinki, Department of Applied Chemistry and Microbiology, P.O. Box 27, FI-00014 University of Helsinki, Finland E-mail: ef@nn.fi
Timonen, University of Helsinki, Department of Applied Chemistry and Microbiology, P.O. Box 27, FI-00014 University of Helsinki, Finland E-mail: st@nn.fi
Pennanen, Finnish Forest Research Institute, Vantaa Research Unit, P.O. Box 18, FI-01301 Vantaa, Finland E-mail: tp@nn.fi

article id 233, category Research article

Raija Laiho, Sakari Sarkkola, Seppo Kaunisto, Jukka Laine, Kari Minkkinen. (2008). Macroscale variation in peat element concentrations in drained boreal peatland forests. Silva Fennica vol. 42 no. 4 article id 233. https://doi.org/10.14214/sf.233

Keywords: drainage; peat soil; nutrient deficiencies; spatial variation; soil nutrients

Abstract | View details | Full text in PDF | Author Info

Information on the variation in soil element concentrations at different spatial scales is needed for, e.g., designing efficient sampling strategies, upscaling the processes related to carbon cycling, and planning land use and management. In spite of intensive land use, such information concerning peat soils is still scarce. We analyzed the variation in peat mineral element concentrations in boreal peatland forests drained 50–60 years earlier. We wanted to quantify the proportions of variation deriving from differences between regions and peatland basins and from within-peatland heterogeneity, and to model the variation using relatively easily measurable site and soil characteristics. We utilized 878 peat samples representing the 0–20 cm layer and collected from 289 sites in 79 peatland basins. The sites represented three different drained peatland forest site types. The two strongest gradients in the element composition captured by principal component analysis were correlated with both the North-South gradient and the site type variation, and the East-West gradient. In general, most of the variation in the element concentrations was contributed by differences among peatland basins, and variation within the floristically determined sites. Most of the element concentrations were best modeled when either the bulk density or the ash content of the peat, or both, were used in addition to site type and geographical location. The explanatory power remained modest for most element concentrations. As for the P concentrations in soil, however, our models provide means for estimating a large part of the variation among drained pine mire sites.

Laiho, University of Helsinki, Department of Forest Ecology, FI-00014 University of Helsinki, Finland E-mail: raija.laiho@helsinki.fi
Sarkkola, Finnish Forest Research Institute, Vantaa Research Unit, P.O. Box 18, FI-01301 Vantaa, Finland E-mail: ss@nn.fi
Kaunisto, Finnish Forest Research Institute, Parkano Research Unit, Kaironiementie 54, FI-39700 Parkano, Finland E-mail: sk@nn.fi
Laine, Finnish Forest Research Institute, Parkano Research Unit, Kaironiementie 54, FI-39700 Parkano, Finland E-mail: jl@nn.fi
Minkkinen, University of Helsinki, Department of Forest Ecology, FI-00014 University of Helsinki, Finland E-mail: km@nn.fi

article id 232, category Research article

Thomas Wutzler. (2008). Effect of the aggregation of multi-cohort mixed stands on modeling forest ecosystem carbon stocks. Silva Fennica vol. 42 no. 4 article id 232. https://doi.org/10.14214/sf.232

Keywords: stand structure; thinning; inventory; scale; model; stratification; bias; inventorystand structure

Abstract | View details | Full text in PDF | Author Info

Studies of the carbon sink of forest ecosystems often stratify the studied stands by the dominating species and thereby abstract from differences in the mixed-species, multi-cohort structure of many forests. This case study infers whether the aggregation of forestry data introduces a bias in the estimates of carbon stocks and their changes at the scale of individual stands and the scale of a forest district. The empirical TreeGrOSS-C model was applied to 1616 plots of a forest district in Central Germany to simulate carbon dynamics in biomass, woody debris, and soil. In a first approach each stand was explicitly simulated with all cohorts. In three other approaches the forest inventory data were aggregated in several ways, including a stratification of the stands to 110 classes according to the dominating species, age class, and site conditions. A small but significant bias was confirmed. At stand scale the initial ecosystem carbon stocks by the aggregated approach differed from that of the detailed approach by 2.3%, but at the district scale only by 0.05%. The differences in age between interspersed and dominant cohorts as well as differences in litter production were important for the differences in initial carbon stocks. The amounts of wood extracted by thinning operations were important for the differences in the projection of the carbon stocks over 100 years. Because of the smallness of bias, this case study collects evidence that the approaches, that represent stands or stratums by a single cohort, are valid at the scale of a forest district or larger.

Wutzler, Max Planck Institute for Biogeochemistry, Hans Knöll Str. 10, DE-07745, Jena, Germany E-mail: thomas.wutzler@bgc-jena.mpg.de

article id 231, category Research article

Hilppa Gregow, Ulla Puranen, Ari Venäläinen, Heli Peltola, Seppo Kellomäki, David Schultz. (2008). Temporal and spatial occurrence of strong winds and large snow load amounts in Finland during 1961-2000. Silva Fennica vol. 42 no. 4 article id 231. https://doi.org/10.14214/sf.231

Keywords: soil frost; coniferous forest; wind climate; precipitation; snow

Abstract | View details | Full text in PDF | Author Info

Information on the temporal and spatial occurrence of strong winds and snow loads on trees is important for the risk management of wind- and snow-induced damage. Meteorological measurements made at 19 locations across Finland during 1961–2000 are used to understand the temporal and spatial occurrence of strong winds and large snow loads. A Kriging interpolation method was used to produce a spatial analysis of wind-speed events above 11 m s–1, 14 m s–1, and greater or equal to 17 m s–1 and snowfall accumulation above 20 kg m–2 and 30 kg m–2. According to the analysis, wind speeds exceeded 14 m s–1 at least 155 times and reached 17 m s–1 only 5 times at inland locations during the 40 years. Large snowfall accumulations were more frequent in the higher-elevation inland areas than along the coast. The snow load on trees exceeded 20 kg m–2 about 65 times a year when averaged over all 40 years, but was as high as 150 times a year during the mild 1990s. The maximum number of heavy snow-load events occurred in 1994 in northern Finland, consistent with a forest inventory by the Finnish Forest Research Institute in 1992–1994. The findings of this study imply that the risk of wind-induced damage is highest in the late autumn when trees do not have the additional support of frozen soil. In contrast, the risk of snow-induced damage is highest at higher-elevations inland, especially in northern Finland.

* Erratum (23 Oct 2012): The authors have requested inclusion of an additional author. Author information should thus be as follows: Hilppa Gregow, Ulla Puranen, Ari Venäläinen, Heli Peltola, Seppo Kellomäki & David Schultz

Gregow, Finnish Meteorological Institute, P.O. Box 503, FI-00101 Helsinki, Finland E-mail: hilppa.gregow@fmi.fi
Puranen, Finnish Meteorological Institute, P.O. Box 503, FI-00101 Helsinki, Finland E-mail: up@nn.fi
Venäläinen, Finnish Meteorological Institute, P.O. Box 503, FI-00101 Helsinki, Finland E-mail: av@nn.fi
Peltola, University of Joensuu, Faculty of Forest Sciences, P.O. Box 111, FI-80101 Joensuu, Finland E-mail: heli.peltola@uef.fi
Kellomäki, University of Joensuu, Faculty of Forest Sciences, P.O. Box 111, FI-80101 Joensuu, Finland E-mail: seppo.kellomaki@uef.fi
Schultz, Finnish Meteorological Institute, P.O. Box 503, FI-00101 Helsinki, Finland E-mail: ds@nn.fi

article id 230, category Research article

Risto Jalkanen, Sheila Hicks, Tarmo Aalto, Hannu Salminen. (2008). Past pollen production reconstructed from needle production in Pinus sylvestris at the northern timberline: a tool for evaluating palaeoclimate reconstructions. Silva Fennica vol. 42 no. 4 article id 230. https://doi.org/10.14214/sf.230

Keywords: Scots pine; age-depth chronology; annual resolution; needle trace method; NTM; pollen accumulation rate; temperature reconstruction; tree line

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Annual needle production (PROD) of Scots pine (Pinus sylvestris L.) and pine pollen accumulation rates (PAR) are compared along a 5-site transect from the Arctic Circle to the northern timberline. PROD is calculated using the Needle Trace Method (NTM). PAR is monitored by two series of pollen traps, located in the centres of mires and within forests, respectively. There is a strong year-to-year agreement in PAR and PROD between the sites for the common 19-year period for which both proxies are available. Mean July temperature of the previous year (T_JUL–1) correlates statistically significantly with PROD at all five sites and with PAR in the four northernmost sites. There is also a significant relationship between T_JUN–1 and PROD at all sites, and T_JUN and PAR at the two northernmost sites. PROD and PAR correlate most strongly in the three near tree line sites, where PROD explains up to 51% of the variation in PAR. On the basis of the calibration between PROD, PAR and T_JUL–1, PROD and T_JUL–1 are used to reconstruct past PAR. That such a reconstruction is realistic is supported by its agreement with the pollen record for 1982–2000 and with records of male flowering for the period 1956–1973. The use of PROD in reconstructing past PAR can help in interpreting the fossil pollen signal in terms of climate rather than vegetation change and in evaluating the high-resolution dating of peat profiles and calculations of the rate of peat accumulation.

Jalkanen, Finnish Forest Research Institute, Rovaniemi Research Unit, P.O. Box 16, FI-96301 Rovaniemi, Finland E-mail: risto.jalkanen@metla.fi
Hicks, Institute of Geosciences, P.O. Box 3000, FI-90014 University of Oulu, Finland E-mail: sh@nn.fi
Aalto, Finnish Forest Research Institute, Rovaniemi Research Unit, P.O. Box 16, FI-96301 Rovaniemi, Finland E-mail: ta@nn.fi
Salminen, Finnish Forest Research Institute, Rovaniemi Research Unit, P.O. Box 16, FI-96301 Rovaniemi, Finland E-mail: hs@nn.fi

article id 229, category Research article

Carmen Martín, Teresa Parra, Margarita Clemente-Muñoz, Esteban Hernández-Bermejo. (2008). Genetic diversity and structure of the endangered Betula pendula subsp. fontqueri populations in the south of Spain. Silva Fennica vol. 42 no. 4 article id 229. https://doi.org/10.14214/sf.229

Keywords: Betula pendula; B. pendula subsp. fontqueri; genetic diversity; population; RAPD

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Betula pendula subsp. fontqueri, present in the south of Spain, has been considered in danger of extinction and, for this reason, some regional governments in Spain have included their populations in conservation programmes. In order to establish the genetic structure of the Betula pendula subsp. fontqueri populations, a random amplified polymorphic DNA (RAPD) analysis was carried out. Two B. pubescens populations were included in the study as taxonomic controls. B. pendula subsp. fontqueri populations were clearly differentiated through UPGMA, and showed significant pairwise genetic distance (Φ_ST) values between all pairs of populations obtained by AMOVA. Genetic diversity found between populations was not correlated to geographical distances. The significant differences among populations must be due to progressive isolation of Betula populations along their paleogeographical history, and more recently to the drastic fragmentation and reduction of some of these populations. The results obtained in this work show clear genetic differences which could be considered in the management of conservation strategies for Betula pendula subsp. fontqueri in its Iberian meridional distribution.

Martín, Departamento de Biología Vegetal, Escuela Técnica Superior de Ingenieros Agrónomos de Madrid, Universidad Politécnica de Madrid, Ciudad Universitaria s/n, 28040-Madrid, Spain E-mail: mariacarmen.martin@upm.es
Parra, Departamento de Ciencias y Recursos Agrícolas y Forestales, Universidad de Córdoba, Avda. Linneo s/n, 14004-Córdoba, Spain E-mail: tp@nn.es
Clemente-Muñoz, Departamento de Ciencias y Recursos Agrícolas y Forestales, Universidad de Córdoba, Avda. Linneo s/n, 14004-Córdoba, Spain E-mail: mcm@nn.es
Hernández-Bermejo, Departamento de Ciencias y Recursos Agrícolas y Forestales, Universidad de Córdoba, Avda. Linneo s/n, 14004-Córdoba, Spain E-mail: ehb@nn.es

article id 248, category Research article

Tuula Jyske, Harri Mäkinen, Pekka Saranpää. (2008). Wood density within Norway spruce stems. Silva Fennica vol. 42 no. 3 article id 248. https://doi.org/10.14214/sf.248

Keywords: Picea abies; wood density; inter-ring variation; intra-ring variation; maturation

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We studied the variation in average wood density of annual rings, earlywood density, and latewood density in addition to ring width and latewood percentage within Norway spruce (Picea abies (L.) Karst.) stems from the pith to the bark, and from the stem base towards the stem apex. Moreover, the variation in wood density within annual rings was studied at the different heights and radial positions in the stem. The material consisted of 85 trees from central and south-eastern Finland. Variation between the annual rings accounted for 11–27% of the total variation in wood density. Only small differences (3–6%) in wood density were found between different heights in the stem. The largest (49–80%) variation in wood density was found within the annual rings. The difference in wood density between earlywood and latewood was smaller in the rings near the pith than in the outer rings. The increasing wood density from the pith outwards was related to increasing latewood density and latewood percentage, whereas the earlywood density increased only slightly from the pith outwards. In a given cambial age (i.e., given rings from the pith), the average wood density of annual rings increased with increasing stem height. In contrast, in the rings formed in the same calendar years (i.e., given rings from the bark), the average wood density of annual rings decreased with increasing stem height. The results of this study verify our knowledge of wood density variation and can further contribute to creating models to predict wood density.

Jyske, The Finnish Forest Research Institute, Vantaa Research Unit, P.O. Box 18, FI-01301 Vantaa, Finland E-mail: tuula.jyske@metla.fi
Mäkinen, The Finnish Forest Research Institute, Vantaa Research Unit, P.O. Box 18, FI-01301 Vantaa, Finland E-mail: hm@nn.fi
Saranpää, The Finnish Forest Research Institute, Vantaa Research Unit, P.O. Box 18, FI-01301 Vantaa, Finland E-mail: ps@nn.fi

article id 247, category Research article

Ane Zubizarreta Gerendiain, Heli Peltola, Pertti Pulkkinen, Veli-Pekka Ikonen, Raimo Jaatinen. (2008). Differences in growth and wood properties between narrow and normal crowned types of Norway spruce grown at narrow spacing in Southern Finland. Silva Fennica vol. 42 no. 3 article id 247. https://doi.org/10.14214/sf.247

Keywords: fibre length; stem volume; height; diameter; wood density; earlywood; latewood

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In recent years there has been increased interest in the so called narrow crowned Norway spruce (Picea abies f. pendula), which is a rare mutant of Norway spruce (Picea abies (L.) Karsten), as a suitable wood raw material source for pulp and paper production. This is because it is less sensitive to competition than the normal crowned Norway spruce, and thus, could be more productive especially at dense spacing. In the above context, we investigated how the growth and yield (such as height, diameter, stem volume and ring width) in addition to wood density traits and fibre properties (such as wood density, fibre length and width, cell wall thickness and fibre coarseness) were affected in trees from 9 full-sib families representing narrow crowned Norway spruce grown at narrow spacing of 1 m 1 m in Southern Finland. For comparison, we used normal crowned Norway spruce trees from 6 breeding regions. We found that, compared to growth and yield traits, wood density traits and fibre properties showed, on average, lower phenotypic variations. In addition, these variations were smaller for narrow crowned families than for normal crowned genetic entries. Narrow crowned families also showed, on average, higher growth and yield and fibre length, but lower wood density. Moreover, the phenotypic correlations between growth, yield, wood density traits and fibre properties, ranged, on average, from moderate (narrow crowned) to high (normal crowned). As a whole, the growth and wood properties of narrow crowned families were found to be less sensitive to tree competition than the normal crowned genetic entries used as a comparison.

Zubizarreta Gerendiain, University of Joensuu, Faculty of Forest Sciences, Joensuu, Finland E-mail: ane.zubizarreta@joensuu.fi
Peltola, University of Joensuu, Faculty of Forest Sciences, Joensuu, Finland E-mail: hp@nn.fi
Pulkkinen, Finnish Forest Research Institute, Haapastensyrjä Breeding Station, Läyliäinen, Finland E-mail: pp@nn.fi
Ikonen, University of Joensuu, Faculty of Forest Sciences, Joensuu, Finland E-mail: vpi@nn.fi
Jaatinen, Finnish Forest Research Institute, Haapastensyrjä Breeding Station, Läyliäinen, Finland E-mail: rj@nn.fi

article id 246, category Research article

Maria Jonsson. (2008). Live-storage of Picea abies for two summers after storm felling in Sweden. Silva Fennica vol. 42 no. 3 article id 246. https://doi.org/10.14214/sf.246

Keywords: Norway spruce; blue stain; MC; storage decay; windthrown

Abstract | View details | Full text in PDF | Author Info

After recent severe storm fellings in Sweden, as harvest, transport, and storage capacities were insufficient, interest in live-storage (leaving windthrown trees in the stand) increased. This study follows windthrown Norway spruce (Picea abies (L.) Karst.) trees during 20 months, i.e. two summers, of live-storage in southern Sweden. Moisture content, blue stain, and storage decay were compared in trees from a site with all trees windthrown and a site with scattered windthrows. After the first summer of live-storage, the quality losses were small. After 20 months, the trees had dried significantly and had numerous infestations of blue stain and storage decay. Trees from the site with scattered windthrows were of better quality compared to trees from the site with all trees windthrown. Live-storage is a suitable method for one year of storage, but the second year losses in wood quality are considerable.

Jonsson, Swedish University of Agricultural Sciences, Dept. of Forest Products, Uppsala, Sweden E-mail: maria.jonsson@sprod.slu.se

article id 245, category Research article

Saija Huuskonen, Jari Hynynen, Risto Ojansuu. (2008). Stand characteristics and external quality of young Scots pine stands in Finland. Silva Fennica vol. 42 no. 3 article id 245. https://doi.org/10.14214/sf.245

Keywords: Scots pine; growth and yield; precommercial thinning; external stem quality; young stand management

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The effects of silvicultural practices (regeneration method and young stand management) on the stand characteristics of young Scots pine (Pinus sylvestris (L.)) stands were studied. Stand density, mean diameter, crown ratio and external quality of young Scots pine stands were analysed on the basis of extensive inventory data. The study material consisted of 181 stands containing inventory growth plots, representing the most common site types for Scots pine and covering all the important wood production areas in Finland. Intensive management practices, i.e. artificial regeneration and precommercial thinning, clearly enhanced mean diameter development of the stand. The overall stand density of the crop trees was relatively low in the material (1925 trees ha–1). In more than one third of the stands, the stem number of crop trees was below 1500 trees ha–1. Stand density was not affected by forest management, but it was slightly higher in Southern than in Northern Finland. The geographical location, in terms of annual effective temperature sum, affected the average slenderness and crown ratio. At a given mean stand diameter, the dominant height of the stand was lower, and the mean crown ratio was higher, in Northern than in Southern Finland. The average external quality of the Scots pine trees was relatively low. The proportion of trees without any observed defects was 54%. The most common external defects were curved stems (23%) and branchiness (9%). Branchiness was more frequent among the largest trees, while curved stems were more common in smaller trees. Defects were the most frequent in planted stands, and in stands growing on fresh sites. The defects were more frequent in Northern Finland than in Southern Finland. The relatively low stand density and poor external quality of the young stands emphasize the importance of stem quality as a tree selection criterion in commercial thinnings of Scots pine stands, if the goal is to produce high quality timber.

Huuskonen, University of Helsinki, Department of Forest Ecology, Helsinki, Finland E-mail: saija.huuskonen@helsinki.fi
Hynynen, Finnish Forest Research Institute, Vantaa Research Unit, Vantaa, Finland E-mail: jh@nn.fi
Ojansuu, Finnish Forest Research Institute, Vantaa Research Unit, Vantaa, Finland E-mail: ro@nn.fi

article id 244, category Research article

Georg E. Kindermann, Ian McCallum, Steffen Fritz, Michael Obersteiner. (2008). A global forest growing stock, biomass and carbon map based on FAO statistics. Silva Fennica vol. 42 no. 3 article id 244. https://doi.org/10.14214/sf.244

Keywords: biomass map; downscaling; regression analysis

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Currently, information on forest biomass is available from a mixture of sources, including in-situ measurements, national forest inventories, administrative-level statistics, model outputs and regional satellite products. These data tend to be regional or national, based on different methodologies and not easily accessible. One of the few maps available is the Global Forest Resources Assessment (FRA) produced by the Food and Agriculture Organization of the United Nations (FAO 2005) which contains aggregated country-level information about the growing stock, biomass and carbon stock in forests for 229 countries and territories. This paper presents a technique to downscale the aggregated results of the FRA2005 from the country level to a half degree global spatial dataset containing forest growing stock; above/below-ground biomass, dead wood and total forest biomass; and above-ground, below-ground, dead wood, litter and soil carbon. In all cases, the number of countries providing data is incomplete. For those countries with missing data, values were estimated using regression equations based on a downscaling model. The downscaling method is derived using a relationship between net primary productivity (NPP) and biomass and the relationship between human impact and biomass assuming a decrease in biomass with an increased level of human activity. The results, presented here, represent one of the first attempts to produce a consistent global spatial database at half degree resolution containing forest growing stock, biomass and carbon stock values. All results from the methodology described in this paper are available online at www.iiasa.ac.at/Research/FOR/.

Kindermann, International Institute for Applied Systems Analysis, Laxenburg, Austria E-mail: kinder@iiasa.ac.at
McCallum, International Institute for Applied Systems Analysis, Laxenburg, Austria E-mail: im@nn.at
Fritz, International Institute for Applied Systems Analysis, Laxenburg, Austria E-mail: sf@nn.at
Obersteiner, International Institute for Applied Systems Analysis, Laxenburg, Austria E-mail: mo@nn.at

article id 243, category Research article

Rupert Seidl, Werner Rammer, Petra Lasch, Franz-Werner Badeck, Manfred J. Lexer. (2008). Does conversion of even-aged, secondary coniferous forests affect carbon sequestration? A simulation study under changing environmental conditions. Silva Fennica vol. 42 no. 3 article id 243. https://doi.org/10.14214/sf.243

Keywords: forest management; Norway spruce; climate change mitigation; PICUS; 4C; model comparison

Abstract | View details | Full text in PDF | Author Info

To circumvent problems associated with even-aged, pure coniferous stands propagated outside their natural range alternative management strategies and conversion programs are currently discussed in Central Europe. However, a mainstreaming of such adapted silvicultural systems with climate change mitigation objectives is missing to date. In this study the objective was to assess in situ C storage under conditions of climate change in a secondary Norway spruce (Picea abies (L.) Karst.) forest management unit in Austria. Four management strategies (Norway spruce age class forestry, transition to continuous cover forestry with Norway spruce, conversion to mixed conifer/broadleaved stands, no management) were investigated under current climate and two transient climate change scenarios in a simulation study. By comparing the results of two independent forest ecosystem models (PICUS v1.41, 4C) applied under identical forcings and boundary conditions we aimed at addressing uncertainties in model-based projections. A transition to continuous cover forestry increased C storage in all climate scenarios (+45.4 tC·ha^–1 to +74.0 tC·ha^–1 over the 100 year analysis period) compared to the approximately balanced C budget under the age class system. For the mixed conifer/broadleaved management variant predictions of the two models diverged significantly (+29.4 tC·ha^–1 and –10.6 tC·ha^–1 in PICUS and 4C respectively, current climate). With regard to climate change impacts both models agreed on distinct effects on productivity but lower sensitivity of C stocks due to compensation from respiration and adaptive harvest levels. In conclusion, considering the potential effects of silvicultural decisions on C stocks climate change mitigation should be addressed explicitly in programs advocating targeted change in management paradigms.

Seidl, Institute of Silviculture, BOKU, Vienna, Austria E-mail: rupert.seidl@boku.ac.at
Rammer, Institute of Silviculture, BOKU, Vienna, Austria E-mail: wr@nn.at
Lasch, Potsdam Institute for Climate Impact Research e.V., Potsdam, Germany E-mail: pl@nn.de
Badeck, Potsdam Institute for Climate Impact Research e.V., Potsdam, Germany E-mail: fwb@nn.de
Lexer, Institute of Silviculture, BOKU, Vienna, Austria E-mail: mjl@nn.at

article id 242, category Research article

Jyrki Hytönen, Paula Jylhä. (2008). Fifteen-year response of weed control intensity and seedling type on Norway spruce survival and growth on arable land. Silva Fennica vol. 42 no. 3 article id 242. https://doi.org/10.14214/sf.242

Keywords: Norway spruce; afforestation; frost damage; seedling size; seedling type; vegetation control

Abstract | View details | Full text in PDF | Author Info

The effects of seedling type (2-year-old container seedlings vs. 4-year-old bare-rooted seedlings) and post-planting vegetation control intensity on the growth and survival of Norway spruce (Picea abies (L.) Karst.) seedlings were compared based on 15-year data from a field experiment established on arable land. Vegetation control treatments with terbuthylazine and glyphosate were carried out 1–3 times on successive years, either as overall or spot applications. The highest stand volumes were obtained with the combination of large bare-rooted seedlings and effective vegetation control. Volume of bare-rooted seedlings was greater than that of container seedlings in all treatments (e.g. on the control plots 9.5 m³/ha vs. 4.1 m³/ha). The best results were obtained with the most intensive weed control treatments (spot treatment repeated twice and overall application repeated three times). These treatments increased both bare-rooted and containerised seedlings’ survival by 33–40% units and their height, breast height diameter, and volume by 45–49%, 17–47%, and 249–279%, respectively. In terms of survival, the container seedlings, in due part to their smaller size, benefited from vegetation control more than the bare-rooted seedlings. Successive early summer frosts damaged the seedlings and significantly retarded their growth. The frequency of frost damage was not affected by vegetation control nor was it attributed to seedling type.

Hytönen, Finnish Forest Research Institute, Kannus Research Unit, P.O. Box 44, FI-69101, Kannus, Finland E-mail: jyrki.hytonen@metla.fi
Jylhä, Finnish Forest Research Institute, Kannus Research Unit, P.O. Box 44, FI-69101, Kannus, Finland E-mail: pj@nn.fi

article id 241, category Research article

Hailemariam Temesgen, Tara M. Barrett, Greg Latta. (2008). Estimating cavity tree abundance using Nearest Neighbor Imputation methods for western Oregon and Washington forests. Silva Fennica vol. 42 no. 3 article id 241. https://doi.org/10.14214/sf.241

Keywords: stand structure; nearest neighbor imputation; snag size; snag frequency; forest landscape modeling

Abstract | View details | Full text in PDF | Author Info

Cavity trees contribute to diverse forest structure and wildlife habitat. For a given stand, the size and density of cavity trees indicate its diversity, complexity, and suitability for wildlife habitat. Size and density of cavity trees vary with stand age, density, and structure. Using Forest Inventory and Analysis (FIA) data collected in western Oregon and western Washington, we applied correlation analysis and graphical approaches to examine relationships between cavity tree abundance and stand characteristics. Cavity tree abundance was negatively correlated with site index and percent composition of conifers, but positively correlated with stand density, quadratic mean diameter, and percent composition of hardwoods. Using FIA data, we examined the performance of Most Similar Neighbor (MSN), k nearest neighbor, and weighted MSN imputation with three variable transformations (regular, square root, and logarithmic) and Classification and Regression Tree with MSN imputation to estimate cavity tree abundance from stand attributes. There was a large reduction in mean root mean square error from 20% to 50% reference sets, but very little reduction in using the 80% reference sets, corresponding to the decreases in mean distances. The MSN imputation using square root transformation provided better estimates of cavity tree abundance for western Oregon and western Washington forests. We found that cavity trees were only 0.25 percent of live trees and 13.8 percent of dead trees in the forests of western Oregon and western Washington, thus rarer and more difficult to predict than many other forest attributes. Potential applications of MSN imputation include selecting and modeling wildlife habitat to support forest planning efforts, regional inventories, and evaluation of different management scenarios.

Temesgen, Department of Forest Resources, Oregon State University, Corvallis, OR, USA E-mail: hailemariam.temesgen@oregonstate.edu
Barrett, Pacific Northwest Research Station, Anchorage, AK, USA E-mail: tmb@nn.us
Latta, Department of Forest Resources, Oregon State University, Corvallis, OR, USA E-mail: gl@nn.us

article id 240, category Research article

Monika Dering, Andrzej Lewandowski, Krzysztof Ufnalski, Aleksandra Kedzierska. (2008). How far to the east was the migration of white oaks from the Iberian refugium? Silva Fennica vol. 42 no. 3 article id 240. https://doi.org/10.14214/sf.240

Keywords: refugia; oaks; postglacial recolonization; Quercus robur; Quercus petrea

Abstract | View details | Full text in PDF | Author Info

The goal of this study was to investigate the postglacial recolonization pathways of the white oaks Quercus robur and Quercus petrea in Poland, and especially to evaluate the impact of Iberian refugium in this part of Europe. Chloroplast DNA polymorphism of 310 individuals older than 200 years was analyzed. Six haplotypes in total were found to differentiate three maternal lineages: the Balkan (haplotypes 4, 5, and 7), the Apennine (haplotypes 1 and 2), and the Iberian (haplotype 12). The most abundant were members of the Balkan (71.5% of all samples) and the Apennine lineage (23.1%), and only 5.4% of individuals were of Iberian origin. The geographic distribution of the three lineages is clearly structured. The northernmost territories of Poland are occupied by Apennine (haplotype 1) and Iberian (haplotype 12) lineages, whereas samples in central and southern Poland represents the Balkan lineage. The population structure might be the result of competitive colonization among lineages after migration from different refugia. It is likely that colonization of northernmost parts of Poland by the Balkan lineage was halted or at least hampered due to the arrival of the Apennine populations. The most significant result of this study concerns the presence and status of the Iberian lineage in Poland, which is most likely of natural origin.

Dering, Polish Academy of Sciences, Institute of Dendrology, Parkowa 5, Kornik, Poland E-mail: usnea@o2.pl
Lewandowski, Polish Academy of Sciences, Institute of Dendrology, Parkowa 5, Kornik, Poland E-mail: al@nn.pl
Ufnalski, Polish Academy of Sciences, Institute of Dendrology, Parkowa 5, Kornik, Poland E-mail: ku@nn.pl
Kedzierska, Polish Academy of Sciences, Institute of Dendrology, Parkowa 5, Kornik, Poland E-mail: ak@nn.pl

article id 468, category Research article

Antti Lännenpää, Tuomas Aakala, Heikki Kauhanen, Timo Kuuluvainen. (2008). Tree mortality agents in pristine Norway spruce forests in northern Fennoscandia. Silva Fennica vol. 42 no. 2 article id 468. https://doi.org/10.14214/sf.468

Keywords: Picea abies; northern Fennoscandia; Coniophora; mortality agent; pristine forest

Abstract | View details | Full text in PDF | Author Info

We examined tree mortality agents in pristine old Norway spruce (Picea abies (L.) Karst.) forests in northern Finland and northwestern Russia. The data was collected on nine 40 m 400 m transects. The primary mortality agents of recently dead trees were recorded and their frequencies were calculated. The pattern of tree growth prior to death was studied based on increment core samples and compared with the growth of healthy dominant trees. Of all recently dead trees, 72% could be associated with a primary mortality agent. In both study areas the most common primary mortality agent was a Coniophora (Mérat) DC. -genus fungi, which was found on average in 33% of trees sampled. The fungi Phellinus chrysoloma (Fr.) Don and Onnia leporina (Fr.) H. Jahn as mortality agents were more common in the Finnish area compared to the Russian area. Analysis on the growth patterns indicated weak differences between different pathogens’ influence on prior-to-death growth of trees, so that fungi rotting the whole tree decreased tree growth more rapidly than fungi rotting only the heart wood. The results demonstrated that in old Norway spruce forests of northern Fennoscandia the most common primary tree mortality agents were wood rotting fungi, which weaken the mechanical stability of tree stems until they fall due to snow or wind, which should be considered only as secondary mortality agents. It is evident that tree death in pristine forest typically results from a long-lasting process involving both biotic and abiotic factors.

Lännenpää, Department of Forest Ecology, University of Helsinki, Finland E-mail: al@nn.fi
Aakala, Department of Forest Ecology, University of Helsinki, Finland E-mail: tuomas.aakala@helsinki.fi
Kauhanen, Kolari Research Unit, Finnish Forest Research Institute, Finland E-mail: hk@nn.fi
Kuuluvainen, Department of Forest Ecology, University of Helsinki, Finland E-mail: tk@nn.fi

article id 259, category Research article

Jani Laturi, Jarmo Mikkola, Jussi Uusivuori. (2008). Carbon reservoirs in wood products-in-use in Finland: current sinks and scenarios until 2050. Silva Fennica vol. 42 no. 2 article id 259. https://doi.org/10.14214/sf.259

Keywords: climate change; wood products; carbon pool; present value; decay function

Abstract | View details | Full text in PDF | Author Info

This study addresses the question of how much carbon will be sequestered in wood products during the coming decades in Finland. Using sawnwood and other wood material consumption data since the 1950s and inventory data of carbon reservoirs of wood products in the Finnish construction and civil engineering sector, we first derive estimates for the carbon reservoirs in wood products-in-use in that sector. We then extend the estimate to include all wood products-in-use. We find that the carbon pool of wood products in the Finnish construction and civil engineering sector grew by about 12% since an inventory for 2000, and that the overall estimate for carbon reservoirs of Finnish wood products in 2004 was 26.6 million tons of carbon. In building the scenarios until 2050, econometric time series models accounting for the relationship between wood material consumption and the development of GDP were used. The results indicate that the range of carbon reservoirs of wood products in Finland will be 39.6–64.2 million tons of carbon in the year 2050. The impacts of different forms of the decay function on the time-path of a carbon sink and its value in wood products were also studied. When a logistic decay pattern is used, the discounted value of the predicted carbon sink of wood products in Finland is between EUR850 and EUR1380 million – at the price level of EUR15/CO₂ ton – as opposed to 440–900 million euros, if a geometric decay pattern is used.

Laturi, Finnish Forest Research Institute, Vantaa Research Unit, P.O. Box 18, FI-01301 Vantaa, Finland E-mail: jani.laturi@metla.fi
Mikkola, Finnish Forest Research Institute, Vantaa Research Unit, P.O. Box 18, FI-01301 Vantaa, Finland E-mail: jm@nn.fi
Uusivuori, Finnish Forest Research Institute, Vantaa Research Unit, P.O. Box 18, FI-01301 Vantaa, Finland E-mail: ju@nn.fi

article id 258, category Research article

Ursula Schatz, Henrik Heräjärvi, Kari Kannisto, Matti Rantatalo. (2008). Influence of saw and secateur pruning on stem discolouration, wound cicatrisation and diameter growth of Betula pendula. Silva Fennica vol. 42 no. 2 article id 258. https://doi.org/10.14214/sf.258

Keywords: Betula pendula; colour defects; pruning saw; secateur; technical quality

Abstract | View details | Full text in PDF | Author Info

The aim of this case study was to compare the impacts of saw and secateur pruning on silver birch (Betula pendula Roth). Data were collected from two saw pruned stands in 2005, and one secateur pruned stand in 2003. All the stands were located in southern Finland. The sample stems were felled, and their butt logs were sawn into flitches, whose knot features and colour defects were measured. In addition, discs were sawn from each stem in order to study the annual ring widths. In this material, pruning with secateurs appeared to cause less colour defects than pruning with a saw. Irrespective of the pruning method used, the colour defects in the stem wood were at their largest in cases where the basal knob or the stem bark appeared to be damaged by pruning. Colour defects spread mainly towards the pith, only in a few cases towards the stem surface. The cicatrisation time of the knots as well as the length of the bark stick remaining inside the stem did not show significant differences between the two pruning methods. Pruning of the lowest living branches appears to have no effect on the diameter growth of silver birch trees.

Schatz, Peltotievantie 27, FI-99440 Leppäjärvi, Finland E-mail: us@nn.fin
Heräjärvi, Finnish Forest Research Institute, Joensuu Research Unit, P.O. Box 111, FI-80101 Joensuu, Finland E-mail: henrik.herajarvi@metla.fi
Kannisto, Finnish Forest Research Institute, Parkano Research Unit, Kaironiementie 54, FI-39700 Parkano, Finland E-mail: kk@nn.fi
Rantatalo, Peltotievantie 27, FI-99440 Leppäjärvi, Finland E-mail: mr@nn.fi

article id 257, category Research article

Nadir Ayrilmis. (2008). Effect of compression wood on dimensional stability of medium density fiberboard. Silva Fennica vol. 42 no. 2 article id 257. https://doi.org/10.14214/sf.257

Keywords: compression wood; linear expansion; linear contraction; thickness swelling; thickness shrinkage; medium density fiberboard; dimensional stability

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This study evaluated the effect of compression wood on dimensional stability of medium density fiberboards (MDF) manufactured from fiber furnishes of pine (Pinus nigra Arnold var. pallasiana) containing compression wood. Two panel types were manufactured from two different compression wood (CW) portion / normal wood (NW) portions in the furnish, 75/25 and 10/90, respectively. Linear and thickness variations of the panels exposed to various relative humidites at 20 °C, linear expansion/contraction and thickness swelling/shrinkage, were measured according to the procedures defined by DIN EN 318 (2005) standard test method. Panels made from fiber furnish containing 75% the CW had higher linear expansion and linear contraction values with an average value of 0.286% and 0.247% than those of panels made from fiber furnish containing 10% the CW with an average value of 0.184% and 0.152%, respectively. As for thickness swelling and thickness shrinkage properties, panels made from fiber furnish containing 75% the CW had the thickness swelling and thickness shrinkage values with an average of 5.042% and 4.402% while panels made from fiber furnish containing 10% the CW had the values with 3.621% and 2.861%, respectively. Consequently, based on the findings obtained from this study, expansion and swelling properties of the MDF panels were negatively affected by compression wood increase.

Ayrilmis, University of Istanbul, Faculty of Forestry, Department of Wood Mechanics and Technology, Bahcekoy, TR-34473 Istanbul, Turkey E-mail: nadiray@istanbul.edu.tr

article id 256, category Research article

Juha Laitila. (2008). Harvesting technology and the cost of fuel chips from early thinnings. Silva Fennica vol. 42 no. 2 article id 256. https://doi.org/10.14214/sf.256

Keywords: productivity; harvesting; logging; energy wood; early thinnings; costs

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This study compared and analyzed the procurement cost of whole tree chips when using supply chains based on comminution at the roadside landing or at the terminal. It also identified the bottlenecks of the most common logging systems used in Finland. The study was done by using existing and published productivity parameters and models. The procurement cost calculations were made for a stand where the forwarding distance was 200 metres, removal of whole trees was 60 m per hectare and the area of the stand was 2.0 hectares. The average size of the removed whole trees was 30 litres. The direct transport distance from the stand to the terminal or to the end use facility was 40 km while the secondary distance from the terminal to the end use facility was 10 km. A stumpage price for the harvested raw material was not included in this study. According to the study the cost of whole trees chips were 31.9–41.6 euros/m at the plant, or 14.9–19.4 euros/MWh when the moisture content of chips was estimated to be 40%. The two-machine system was found to be the most cost competitive logging system in pre-commercial thinnings thanks to both efficient cutting and, especially, forwarding work. In the manual worker based logging, the costs of felling bunching were the same as the mechanised system, whereas in forwarding the costs were almost double. Using the harwarder system the logging costs were found to be the highest, but in the larger tree volumes and removals the costs were almost equal to the manual worker based logging. The supply chain based on chipping at the roadside landing was more cost efficient compared to the chipping at the terminal system. The lower comminution cost at the terminal was not enough to cover the higher transportation cost of unprocessed material to the terminal, handling cost of chips at the terminal or the delivery cost to the end use facility.

Laitila, Finnish Forest Research Institute, Joensuu Research Unit, Joensuu, Finland E-mail: juha.laitila@metla.fi

article id 255, category Research article

Claude Vidal, Adrian Lanz, Erkki Tomppo, Klemens Schadauer, Thomas Gschwantner, Lucio di Cosmo, Nicolas Robert. (2008). Establishing forest inventory reference definitions for forest and growing stock: a study towards common reporting. Silva Fennica vol. 42 no. 2 article id 255. https://doi.org/10.14214/sf.255

Keywords: national forest inventories; reference definitions; growing stock; harmonisation; analytical decomposition

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International agreements such as the Kyoto protocol and Convention on Biological Diversity (1992), as well as, criteria and indicator processes require reports on the status of nations’ forests. Any comparison of the current status and trends of forest resources among nations presumes that the nations’ applied definitions and concepts produce comparable estimates of the status of forests. In spite of this, the FAO has already collected global information for 60 years and made noticeable efforts in creating common definitions, but forest related data are still collected using diverse definitions, even regarding basic concepts such as forest and forest area. A simple consequence is that the cross-countries estimates are not comparable. The reasons behind the differences in the definitions are diverse histories, and sometimes different use of forests. In an ideal case, national forest inventories should fulfil both national and international needs. In addition to the FAO’s Forest Resources Assessment process, other efforts are made to assess the status of forests in European countries, e.g. European Forest Information and Communication System (EFICS). EFICS produced reports about forest inventories but does not suggest any common definition or method to convert estimates from one definition to another one. This article presents principles and methods to create commonly acceptable and adoptable definitions for forest inventories. The principles and methods are demonstrated using two examples: the reference definitions of forest and growing stock. The article is based on the work of COST Action E43 (http://www.metla.fi/eu/cost/e43/).

Vidal, Inventaire Forestier National, Château des Barres, Nogent-sur-Vernisson, France E-mail: claude.vidal@ifn.fr
Lanz, WSL/FNP, Abteilung Landschaftsinventuren, Birmensdorf, Switzerland E-mail: al@nn.ch
Tomppo, Finnish Forest Research Institute, Vantaa Research Unit, Vantaa, Finland E-mail: et@nn.fi
Schadauer, Bundesamt und Forschungszentrum für Wald, Wien, Austria E-mail: ks@nn.at
Gschwantner, Bundesamt und Forschungszentrum für Wald, Wien, Austria E-mail: tg@nn.at
di Cosmo, ISAFA, Villazzano, Italy E-mail: ldc@nn.it
Robert, Inventaire Forestier National, Ch‰teau des Barres, Nogent-sur-Vernisson, France E-mail: nr@nn.fr

article id 254, category Research article

Johanna Joensuu, Kari Heliövaara, Eino Savolainen. (2008). Risk of bark beetle (Coleoptera, Scolytidae) damage in a spruce forest restoration area in central Finland. Silva Fennica vol. 42 no. 2 article id 254. https://doi.org/10.14214/sf.254

Keywords: biodiversity; dead wood; damage; forest pests; forest restoration

Abstract | View details | Full text in PDF | Author Info

A beetle inventory using window traps was performed to examine the effect of forest restoration by artificial addition of dead wood on the abundance of beetles and to evaluate the risk of bark beetle damage in a forest restoration area. The number of beetle families was slightly increased, but no consistent differences were found in the abundance of families containing saproxylic Coleoptera between the restoration and control plots. The abundance and species number of bark beetles and longhorn beetles were significantly higher on the restoration plots. Ips typographus and Pityogenes chalcographus increased only slightly in abundance. In the regression models produced, the abundance of bark beetles was best explained by the volume of recently dead wood. However, the bark beetle species whose abundance increased most were secondary and the material also suggests an increase in the abundance of bark beetles’ natural enemies. The risk of bark beetle damage in the area is thus considered insignificant.

Joensuu, Dept. of Forest Ecology, University of Helsinki, Finland E-mail: johanna.joensuu@metsanhoitajat.fi
Heliövaara, Dept. of Forest Ecology, University of Helsinki, Finland E-mail: kh@nn.fi
Savolainen, Kuopio Natural History Museum, Kuopio, Finland E-mail: es@nn.fi

article id 253, category Research article

Riitta Väänänen, Mika Nieminen, Martti Vuollekoski, Hannu Nousiainen, Tapani Sallantaus, Eeva-Stiina Tuittila, Hannu Ilvesniemi. (2008). Retention of phosphorus in peatland buffer zones at six forested catchments in southern Finland. Silva Fennica vol. 42 no. 2 article id 253. https://doi.org/10.14214/sf.253

Keywords: peatland; buffer zone area; phosphorus; retention

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Our current knowledge of the P retention efficiency of peatland buffer zone areas used to reduce sediment and nutrient leaching from forestry areas is insufficient. Especially the role of P sorption by soil in buffer zones needs closer examination as there is considerable variation in the efficiency of P retention. Six sites in southern Finland were chosen for the study. The buffer zone areas varied between 0.1–4.9% of the catchment area. A total of 10 kg of solute PO₄–P was added to the inflow of the buffer zone areas and the concentrations of PO₄–P in inflow and outflow were measured for 2–4 years. P retention characteristics of the surface peat were determined with sorption-desorption isotherms before and after PO₄–P addition and the effective buffer zone area over which the added P was spread was determined from soil water samples. P retention in the two largest buffer zone areas was complete (100% retention), and the third largest buffer retained 94%. Retention in the three smallest buffer zones was 24%, 95% and 95% of the added P. As a result of P addition reduction in peat P retention capacity was detected in three out of four cases. The effective buffer zone area varied from 67% to 100% of the total buffer zone area. Factors contributing to efficient P retention were large buffer size and low hydrological load whereas high hydrological load combined with the formation of preferential flow paths, especially during early spring or late autumn was disadvantageous. High P retention capacity in peat contributed to the sustainability of P retention. The study showed that even relatively small buffer zone areas are able to efficiently reduce P load.

Väänänen, Department of Forest Ecology, University of Helsinki, P.O. Box 27, FI-00014 University of Helsinki, Finland E-mail: riitta.vaananen@helsinki.fi
Nieminen, Finnish Forest Research Institute, Vantaa Research Unit, Finland E-mail: mn@nn.fi
Vuollekoski, Finnish Forest Research Institute, Vantaa Research Unit, Finland E-mail: mv@nn.fi
Nousiainen, Finnish Forest Research Institute, Vantaa Research Unit, Finland E-mail: hn@nn.fi
Sallantaus, Finnish Environment Institute, Nature Division, Helsinki, Finland E-mail: ts@nn.fi
Tuittila, Department of Forest Ecology, University of Helsinki, Finland E-mail: est@nn.fi
Ilvesniemi, Finnish Forest Research Institute, Vantaa Research Unit, Finland E-mail: hi@nn.fi

article id 252, category Research article

Tuomo Kalliokoski, Pekka Nygren, Risto Sievänen. (2008). Coarse root architecture of three boreal tree species growing in mixed stands. Silva Fennica vol. 42 no. 2 article id 252. https://doi.org/10.14214/sf.252

Keywords: Pinus sylvestris; Betula pendula; Picea abies; site type; branching pattern; influence area; developmental stage

Abstract | View details | Full text in PDF | Author Info

Root system architecture determines many of the vital functions of a tree, e.g. stability of anchorage and resource uptake. The shoot:root ratio is determined through the allocation of resources. Studies on below-ground architectural elements in boreal mixed forests are relatively scarce despite the fact that knowledge on below-ground interactions and allocation changes in relation to stand developmental stage and soil fertility is needed both in ecological and silvicultural research. In this study, sixty tree root systems of three different tree species, Betula pendula, Picea abies and Pinus sylvestris, were excavated in five mixed forest stands in order to quantify differences between the species and sites in terms of rooting behaviour. Root architecture differed greatly between the species, implying different solutions for the functions of root systems. Half of the P. sylvestris had developed a taproot as a response to anchorage needs, while P. abies correspondingly had pronounced secondary growth of proximal roots. Betula pendula had the most extensive root system, illustrating the greater demand of deciduous trees for water. Betula pendula was also the most sensitive to soil fertility: it favoured exploration on the poorest site, as illustrated by the high total root length, whereas on the most fertile site its strategy was to efficiently exploit soil resources through increased branching intensity. The results obtained in this study provide basic knowledge on the architectural characteristics of boreal tree root systems for use by forestry professionals and modellers.

Kalliokoski, The Finnish Forest Research Institute, Vantaa Research Unit, P.O. Box 18, FI-01301 Vantaa, Finland E-mail: tuomo.kalliokoski@metla.fi
Nygren, Department of Forest Ecology, P.O. Box 27, FI-00014 University of Helsinki, Finland E-mail: pn@nn.fi
Sievänen, The Finnish Forest Research Institute, Vantaa Research Unit, P.O. Box 18, FI-01301 Vantaa, Finland E-mail: rs@nn.fi

article id 251, category Research article

Lina R. Steinke, Andrea C. Premoli, Cintia P. Souto, Mikael Hedrén. (2008). Adaptive and neutral variation of the resprouter Nothofagus antarctica growing in distinct habitats in north-western Patagonia. Silva Fennica vol. 42 no. 2 article id 251. https://doi.org/10.14214/sf.251

Keywords: isozymes; morphological variation; leaf traits; South America; temperate forest

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N. antarctica occurs in the widest range of habitat types among all South American Notho–fagus. The aim of this study is to investigate adaptive responses by variation in morphological (tree form and leaf characters), and environmental traits (soils) of the polymorphic N. ant–arctica. Also we analyze the effect of genetic drift and limited gene flow in such predominantly apomict by means of neutral variation (isozymes). We studied four potentially different morphological variants each associated with a separate habitat 1) an arboreal variant growing in optimal environments; 2) a sparsely branched variant of temporarily flooded basins or flats; 3) a dwarf variant growing at high elevation, and 4) a shrub-like variant inhabiting matorral environments. The study was restricted latitudinally to Nahuel Huapi National Park, Argentina. For each habitat type we investigated two sites. Nothofagus antarctica shows locally occurring phenotypes. The forest and the high elevation variants were morphologically distinct from the matorral and the basin types. The latter were undistinguishable except for more profuse branching in the matorral type as a result of sprouting due to recent fires. Isozyme evidence indicates a great deal of within-population genetic diversity which is maintained by outcrossing and significant among-site divergence (F_ST = 18%) that reflects limited gene flow.The apparent high phenotypic and genetic variability in N. antarctica is due to both plasticity and genotypic effects as a result of stable population structure and long periods of isolation which may be reinforced by selection at diverse biotopes.

Steinke, Plant Ecology and Systematics, Lund University, Ecology Department, 223 62 Lund, Sweden E-mail: lks@nn.se
Premoli, Universidad Nacional del Comahue, Laboratorio Ecotono – CRUB, Quintral 1250, 8400 Bariloche, Argentina E-mail: apremoli@crub.uncoma.edu.ar
Souto, Universidad Nacional del Comahue, Laboratorio Ecotono – CRUB, Quintral 1250, 8400 Bariloche, Argentina E-mail: cps@nn.ar
Hedrén, Plant Ecology and Systematics, Lund University, Ecology Department, 223 62 Lund, Sweden E-mail: mh@nn.se

article id 250, category Research article

Saara Lilja-Rothsten, Michelle de Chantal, Chris Peterson, Timo Kuuluvainen, Ilkka Vanha-Majamaa, Pasi Puttonen. (2008). Microsites before and after restoration in managed Picea abies stands in southern Finland: effects of fire and partial cutting with dead wood creation. Silva Fennica vol. 42 no. 2 article id 250. https://doi.org/10.14214/sf.250

Keywords: biodiversity; boreal forest; regeneration; coarse woody debris; disturbance dynamics; CWD; managed forest

Abstract | View details | Full text in PDF | Author Info

Different types of microsites, e.g. CWD (coarse woody debris), mounds, and uprooting pits, are important for tree regeneration and biodiversity. However, microsite diversity is greatly reduced in managed stands. We studied how restoration treatments changed microsite distribution in mature managed Picea abies stands. Four cutting treatments were used: uncut, low-CWD (5 m³ ha^–1 of down retention trees, DRT, and 50 m³ ha^–1 of standing retention trees), intermediate-CWD (as previous but leaving 30 m³ ha^–1 of DRT), and high-CWD (as previous but with 60 m³ ha^–1 of DRT). Timber harvested from stands ranged from 108–168 m³ ha^–1. Half of the stands were burned, and half remained unburned. Sampling was stratified into upland and paludified biotopes within each stand. The pre-treatment microsite distributions were dominated by level ground in both biotopes; mounds and microsites on or next to CWD or a stump were slightly more abundant in the paludified than in the upland biotopes. Microsites were more diverse after cutting, with and without fire. The cutting treatment increased the relative abundances of microsites on or next to CWD. Fire consumed small diameter dead wood and flattened mounds. Microsites were more diverse in paludified than in upland biotopes. The results demonstrate that microsite diversity can rapidly be restored to structurally impoverished managed Picea stands despite a large portion of wood volume being harvested.

Lilja-Rothsten, University of Helsinki, Dept. of Forest Ecology, Finland E-mail: saara.lilja@helsinki.fi
Chantal, University of Helsinki, Dept. of Forest Ecology, Finland E-mail: mdc@nn.fi
Peterson, Dept. of Plant Biology, University of Georgia, Athens, GA, USA E-mail: cp@nn.us
Kuuluvainen, University of Helsinki, Dept. of Forest Ecology, Finland E-mail: tk@nn.fi
Vanha-Majamaa, The Finnish Forest Research Institute, Vantaa Unit, Finland E-mail: ivm@nn.fi
Puttonen, The Finnish Forest Research Institute, Vantaa Unit, Finland E-mail: pp@nn.fi

article id 267, category Research article

Manfred Gronalt, Peter Rauch. (2008). Vendor managed inventory in wood processing industries – a case study. Silva Fennica vol. 42 no. 1 article id 267. https://doi.org/10.14214/sf.267

Keywords: building materials; service level; solid structure timber; SST; wood construction

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Solid structure timber (SST) is an important building material in the wood construction business, in which its production volume is largely related to that respective business. Due to the large variability in the demand and seasonal factors, SST producers’ inventories are likely to be simultaneously overstocked for one type of timber and out of stock of another. An inventory policy that ensures a high service level and relatively low stocks is required. In the present paper, we propose the vendor managed inventory (VMI) approach for controlling the stock of deals that are produced at a sawmill and delivered as raw material for SST-production. We evaluate two VMI implementations against the actual inventory management for three different market scenarios. Furthermore, we layout the necessities for reconfiguring the business processes, and subsequently set up an organisational framework within VMI, which is indeed applicable in this segment of the woodworking industry. In our application background, VMI as an inventory control system is able to reduce the overall raw material stock by more than 37% by simultaneously increasing the SST service level.

Gronalt, BOKU – University of Natural Resources and Applied Life Sciences, Feistmantelstr. 4, 1180 Vienna, Austria E-mail: mg@nn.at
Rauch, BOKU – University of Natural Resources and Applied Life Sciences, Feistmantelstr. 4, 1180 Vienna, Austria E-mail: peter.rauch@boku.ac.at

article id 266, category Research article

Mikko Havimo, Juha Rikala, Jari Sirviö, Marketta Sipi. (2008). Distributions of tracheid cross-sectional dimensions in different parts of Norway spruce stems. Silva Fennica vol. 42 no. 1 article id 266. https://doi.org/10.14214/sf.266

Keywords: Norway spruce; cell wall thickness; earlywood; latewood; tracheid dimension; tangential width; radial width

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Distributions of three cross-sectional dimensions: radial and tangential tracheid width, and cell wall thickness in different timber assortments of Norway spruce were investigated. Wood samples from a mature stand were measured with SilviScan. In the analysis, virtual trees were constructed from measurement data, and divided into three assortments: whole stem, top pulpwood and sawmill chips. Average values and distributions of the properties were calculated for all assortments, and distributions divided into earlywood and latewood across the whole tree assortment. There was considerable variation within latewood in all three cross-sectional dimensions, but variation in earlywood was slight in radial width and cell wall thickness. In earlywood, tangential tracheid width showed considerable internal variation, and the difference between earlywood and latewood in tangential width was small. Within-assortment variation of all three properties was larger than between assortments. We may conclude that only a moderate difference in pulp properties can be achieved by sorting raw material into sawmill chips and top pulpwood. Pulp fractionation into earlywood and latewood seems to be a more efficient method, since it gives classes with small within-class variation and distinct average properties. However, it should be kept in mind that the results are valid only in mature stands, where growth rate variation and juvenile wood content are small.

Havimo, University of Helsinki, Department of Forest Resource Management, P.O. Box 27, FI-00014 University of Helsinki, Finland E-mail: mikko.havimo@helsinki.fi
Rikala, University of Helsinki, Department of Forest Resource Management, P.O. Box 27, FI-00014 University of Helsinki, Finland E-mail: jr@nn.fi
Sirviö, KCL, P.O. Box 70, FI-02151 Espoo, Finland E-mail: js@nn.fi
Sipi, University of Helsinki, Department of Forest Resource Management, P.O. Box 27, FI-00014 University of Helsinki, Finland E-mail: ms@nn.fi

article id 265, category Research article

Emil Cienciala, Erkki Tomppo, Arnor Snorrason, Mark Broadmeadow, Antoine Colin, Karsten Dunger, Zuzana Exnerova, Bruno Lasserre, Hans Petersson, Tibor Priwitzer, Gerardo Sanchez, Göran Ståhl. (2008). Preparing emission reporting from forests: use of National Forest Inventories in European countries. Silva Fennica vol. 42 no. 1 article id 265. https://doi.org/10.14214/sf.265

Keywords: forest carbon pools; greenhouse gas inventory; Kyoto Protocol; UNFCCC

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We examine the current status of greenhouse gas inventories of the sector Land Use, Land-Use Change and Forestry (LULUCF), in European countries, with specific focus on the utilization of National Forest Inventory (NFI) programs. LULUCF inventory is an integral part of the reporting obligations under the United Nations Framework Convention on Climate Change (UNFCCC) and its Kyoto Protocol. The analysis is based on two questionnaires prepared by the COST Action E43 “Harmonisation of National Forest Inventories in Europe”, which were answered by greenhouse gas reporting experts in European countries. The following major conclusions can be drawn from the analysis: 1) definitions used to obtain carbon pool change estimates vary widely among countries and are not directly comparable 2) NFIs play a key role for LULUCF greenhouse gas estimation and reporting under UNFCCC, and provide the fundamental data needed for the estimation of carbon stock changes covering not only living biomass, but increasingly also deadwood, litter and soil compartments. The study highlights the effects of adopting different definitions for two major reporting processes, namely UNFCCC and FAO, and exemplifies the effect of different tree diameter thresholds on carbon stock change estimates for Finland. The results demonstrate that more effort is needed to harmonize forest inventory estimates for the purpose of making the estimates of forest carbon pool changes comparable. This effort should lead to a better utilization of the data from the European NFI programs and improve the European greenhouse gas reporting.

Cienciala, Institute of Forest Ecosystem Research (IFER), Areal 1. Jilovske a.s. 1544, 254 01 Jilove u Prahy, Czech Republic E-mail: emil.cienciala@ifer.cz
Tomppo, Metla, Finnish Forest Research Institute, Finland E-mail: et@nn.fi
Snorrason, Icelandic Forest Research, Iceland E-mail: as@nn.is
Broadmeadow, Forestry Commission, Forest Research Alice Holt Logdge, United Kingdom E-mail: mb@nn.uk
Colin, French National Forest Inventory, France E-mail: ac@nn.fr
Dunger, Federal Research Centre for Forestry and Forest Products, Institute of Forest Ecology and Forest Assessment, Germany E-mail: kd@nn.de
Exnerova, Institute of Forest Ecosystem Research, Czech Republic E-mail: ze@nn.cz
Lasserre, Department of Environment and Territory Sciences and Technologies, University of Molise, Italy E-mail: bl@nn.it
Petersson, Swedish University of Agricultural Sciences, Department of Forest Resource Management, Sweden E-mail: hp@nn.se
Priwitzer, National Forest Centre, Forest Research Institute. Slovak Republic E-mail: tb@nn.sk
Sanchez, Forest Health Unit, General Directorate for Biodiversity, Environmental Ministry, Spain E-mail: gs@nn.es
Ståhl, Swedish University of Agricultural Sciences, Department of Forest Resource Management, Sweden E-mail: gs@nn.se

article id 264, category Research article

Yrjö Nuutinen, Kari Väätäinen, Jaakko Heinonen, Antti Asikainen, Dominik Röser. (2008). The accuracy of manually recorded time study data for harvester operation shown via simulator screen. Silva Fennica vol. 42 no. 1 article id 264. https://doi.org/10.14214/sf.264

Keywords: accuracy of timing; mixed effects models; time studies

Abstract | View details | Full text in PDF | Author Info

The aim of the study was to investigate the effect of work experience on the accuracy and variation of observers recording the operation time of a harvester. A simulated thinning operation using a harvester, shown as video via a television screen in laboratory conditions, was observed by 20 inexperienced students and 10 experienced work study researchers. All the observers timed the different work elements of the harvester work with special fieldwork timers. The duration of different work elements measured by the human observers were compared to the corresponding recordings by the harvester’s automated data collector. Although the inexperienced students made more measurement mistakes than the experienced researchers, the differences in measurement error averages were not statistically significant between the groups. However, the variances of tree specific errors were significantly higher in the measurements done by the students. As inexperienced recorders, the students were not able to properly record short work elements, which lasted a maximum of 4 seconds. Due to systematic measurement errors, there was a large variation in the timing structures of the work elements among all observers. Observers’ skills and experience seems to affect measurement accuracy and thus the derived results, especially in intensive time studies. Therefore, the recorder should receive detailed training and practical experience in timing of different work elements of forest operations. In the future, with the use of automated data collectors time studies with large, detailed and accurate data will be implemented. However, due to the varying timing conditions in the forest, manual data collection is still required because of its greater flexibility.

Nuutinen, Finnish Forest Research Institute, Joensuu Research Unit, P.O. Box 68, FI-80101 Joensuu, Finland E-mail: yrjo.nuutinen@metla.fi
Väätäinen, Finnish Forest Research Institute, Joensuu Research Unit, P.O. Box 68, FI-80101 Joensuu, Finland E-mail: kv@nn.fi
Heinonen, Finnish Forest Research Institute, Joensuu Research Unit, P.O. Box 68, FI-80101 Joensuu, Finland E-mail: jh@nn.fi
Asikainen, Finnish Forest Research Institute, Joensuu Research Unit, P.O. Box 68, FI-80101 Joensuu, Finland E-mail: aa@nn.fi
Röser, Finnish Forest Research Institute, Joensuu Research Unit, P.O. Box 68, FI-80101 Joensuu, Finland E-mail: dr@nn.fi

article id 263, category Research article

Aksel Granhus, Dag Fjeld. (2008). Time consumption of planting after partial harvests. Silva Fennica vol. 42 no. 1 article id 263. https://doi.org/10.14214/sf.263

Keywords: planting; work study; mechanical site preparation; partial cutting; scarification

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Partial harvesting combined with underplanting may be a means to reduce the risk of regeneration failure when e.g. unfavourable microclimatic conditions or severe damage by bark-feeding insects may be expected after clear-cutting, and to maintain or establish certain stand structures or tree species mixture. In this study, we performed time studies of manual planting with and without prior site preparation (patch scarification, inverting) in partially harvested stands of Norway spruce (Picea abies (L.) Karst.). The harvest treatments included basal area removals of approx. 35, 45, and 55%, and a patch clear-cut treatment that was assumed to provide the same conditions for planting as conventional clear-cutting. Site preparation had a much larger influence on time consumption plant^–1 (main time) than the harvest treatment. The lowest time consumption was found with inverting and the highest without site preparation. The time spent on walking between planting spots increased with decreasing harvest intensity, reflecting a lower density of planted seedlings in the partially harvested stands. A corresponding increase in main time per plant only occurred after site preparation, since the time spent on clearing the planting spot (removal of logging residue and humus) on untreated plots was higher at the higher harvest strengths. The variation in time consumption attributed to the six replicate stands was large and mainly due to the difference among stands planted by different workers.

Granhus, Norwegian University of Life Sciences, Dept. of Ecology and Natural Resource Management (INA), P.O.Box 5003, NO-1432 Ås, Norway E-mail: aksel.granhus@umb.no
Fjeld, Swedish University of Agricultural Sciences, Dept. of Forest Resource Management, SE-901 83 Umeå, Sweden E-mail: df@nn.se

article id 262, category Research article

Julian C. Fox, Huiquan Bi, Peter K. Ades. (2008). Modelling spatial dependence in an irregular natural forest. Silva Fennica vol. 42 no. 1 article id 262. https://doi.org/10.14214/sf.262

Keywords: correlogram; Eucalypt; growth modelling; moving average autoregression; Moran’s I; spatial autocorrelation

Abstract | View details | Full text in PDF | Author Info

The spatial dependence present in a natural stand of Eucalyptus pilularis (Smith) dominated mixed species forest was characterised and modelled. Two wildfires imposed a significant spatial dependence on the post disturbance stand. It was hypothesised that spatial variation in the intensity of the wildfires generated the observed structures. The influence of patch formation, micro-site variability and competitive influences were also noted in the residuals of a distance-dependent individual-tree growth model. A methodology capable of modelling these complicated patterns of observed dependence was sought, and candidates included the spatial interaction, direct specification and Papadakis methods. The spatial interaction method with a moving average autoregression was identified as the most appropriate method for explicitly modelling spatial dependence. Both the direct specification and Papadakis methods failed to capture the influence of competition. This study highlights the possibility that stand disturbances such as natural and artificial fires, insect and fungal attacks, and wind and snow damage are capable of imposing powerful spatial dependencies on the post disturbance stand. These dependencies need to be considered if individual tree growth models are to provide valid predictions in disturbed stands.

Fox, School of Forest and Ecosystem Science, University of Melbourne, Burnley Campus, 500 Yarra Blvd, Richmond, Victoria 3121 Australia E-mail: jcfox@unimelb.edu.au
Bi, Forest Resources Research, New South Wales Department of Primary Industries, PO Box 100, Beecroft, NSW 2119 Australia E-mail: hb@nn.au
Ades, School of Forest and Ecosystem Science, University of Melbourne, Burnley Campus, 500 Yarra Blvd, Richmond, Victoria 3121 Australia E-mail: pka@nn.au

article id 261, category Research article

Miina Rautiainen, Matti Mõttus, Pauline Stenberg, Sanna Ervasti. (2008). Crown envelope shape measurements and models. Silva Fennica vol. 42 no. 1 article id 261. https://doi.org/10.14214/sf.261

Keywords: Norway spruce; Scots pine; crown profile; reflectance model; remote sensing

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This paper addresses tree crown envelope shape modeling from the perspective of optical passive remote sensing. The aims are 1) to review the specific requirements of crown shape models and ground measurement techniques in optical remote sensing, and 2) to present preliminary results from empirical, parametric crown shape and volume modeling of Scots pine and Norway spruce applicable in Finland. Results indicated that the basic dimensions (maximum radius, its height and crown length) of tree crowns were better predicted for pines, but the profile shape of the upper part of the crowns varied more than in spruce. Pine crowns were also slightly less concave than spruce crowns. No regularities were observed concerning the lower part of the crowns. The asymmetry of crowns increased as a function of tree age for both species, spruce crowns being more asymmetric than pine crowns. A comparison of measured crown volume with several simple geometrical crown shape envelopes showed that using a cone as a crown shape model for Scots pine and Norway spruce underestimates crown volume most severely. Other crown envelope shape models (e.g. ellipsoids) rendered crown volumes closer to the measured volume and did not differ considerably from each other.

Rautiainen, Tartu Observatory, 61602 Tõravere, Estonia, and Department of Forest Resource Management, P.O. Box 27, FI-00014 University of Helsinki, Finland E-mail: miina.rautiainen@helsinki.fi
Mõttus, Tartu Observatory, 61602 Tõravere, Estonia E-mail: mm@nn.ee
Stenberg, Department of Forest Resource Management, P.O. Box 27, FI-00014 University of Helsinki, Finland E-mail: ps@nn.fi
Ervasti, City of Vantaa, Land Use and Environment / Green Area Unit, Kielotie 13, FI-01300 Vantaa, Finland E-mail: se@nn.fi

article id 260, category Research article

Panagiotis Michopoulos, George Baloutsos, Anastassios Economou. (2008). Nitrogen cycling in a mature mountainous beech forest. Silva Fennica vol. 42 no. 1 article id 260. https://doi.org/10.14214/sf.260

Keywords: bulk deposition; Fagus sylvatica; litterfall; stemflow; stream water; throughfall

Abstract | View details | Full text in PDF | Author Info

The nitrogen cycle in a mature, mountainous European beech (Fagus sylvatica) forest in Greece was examined for two hydrological years, 2001–2002 and 2002–2003. Bulk deposition was 1383 mm in 2001–2002 and 2392 mm in 2002–2003. Winter temperatures were mild in the first year and low in the second year. Despite these climatological differences, the inorganic N inputs to the forest floor, by means of throughfall and stemflow, were quite similar for the two years, i.e. 12.4 and 14.6 kg ha^–1 yr^–1. Litterfall production was significantly (p < 0.05) higher in the second year but the N amounts in litterfall did not differ. The ratio of N/P in foliar tissue did not change significantly in 2003 compared with ratio values in the last years. The N amounts used for the annual stem and branch increments are rather high preventing, in this way, some nitrogen from being recycled in the near future. The total soil N content to a depth of 80 cm amounted to more than 5000 kg ha^–1, and the C/N ratio in the Oh horizon was approximately 15 but the beech forest did not appear susceptible to N leaching. The concentrations of ammonium and nitrate N in stream water did not reach high values reported in the literature, and did not differ significantly in the two hydrological years. The fluxes of inorganic N in throughfall plus stemflow were higher than those in stream water indicating N retention in soil. Another reason for N retention in the ecosystem is probably the large difference between N requirements and uptake indicating N deficiency. Despite the maturity of the beech trees, the low C/N ratio in the Oh horizon and the relatively high N content in soil, the forest can be considered to be neither saturated nor having reached a N saturation transition stage.

Michopoulos, Forest Research Institute of Athens, Terma Alkmanos, Athens 115 28, Greece E-mail: mipa@fria.gr
Baloutsos, Forest Research Institute of Athens, Terma Alkmanos, Athens 115 28, Greece E-mail: gb@nn.gr
Economou, Forest Research Institute of Athens, Terma Alkmanos, Athens 115 28, Greece E-mail: ae@nn.gr

Category : Review article

article id 249, category Review article

Rimvydas Vasaitis, Jan Stenlid, Iben M. Thomsen, Pia Barklund, Anders Dahlberg. (2008). Stump removal to control root rot in forest stands. A literature study. Silva Fennica vol. 42 no. 3 article id 249. https://doi.org/10.14214/sf.249

Keywords: biofuel; stand growth; Armillaria; forest disturbance; Heterobasidion; Phellinus weirii

Abstract | View details | Full text in PDF | Author Info

Tree stumps are expected to be increasingly used for energy production in Fennoscandia, thus environmental consequences of stump removal from forest land must be assessed. Aim of this work was to compile available data on the efficacy of stump removal in eradication of root rot fungi (Heterobasidion, Armillaria, and Phellinus), and to review its potential impacts on establishment and productivity of next forest generation. Site disturbance and some technical and economical aspects are discussed, and needs for future research outlined in northern European context. The review demonstrates that stump removal from clear-felled forest areas in most cases results in, a) reduction of root rot in the next forest generation, b) improved seedling establishment, and c) increased tree growth and stand productivity. Observed disturbances caused to a site by stumping operations are normally acceptable. The available data strongly suggests that possibly many (if achievable, all) rot-containing stumps must be removed during harvesting of stumps. Provided equal availability, the priority should be given for stump removal from root rot-infested forest areas, instead of healthy ones. As most studies were done in North America and Britain, several questions must be yet answered under Fennoscandian conditions: a) if and to which extent the conventional stump removal for biofuel on clear-felled sites could reduce the occurrence of Heterobasidion and Armillaria in the next forest generation, b) what impact is it likely to have on survival of replanted tree seedlings, and c) what consequences will there be for growth and productivity of next forest generation.

Vasaitis, Department of Forest Mycology & Pathology, Swedish University of Agricultural Sciences, P.O. Box 7026, SE-75007 Uppsala, Sweden E-mail: rimvys.vasaitis@mykopat.slu.se
Stenlid, Department of Forest Mycology & Pathology, Swedish University of Agricultural Sciences, P.O. Box 7026, SE-75007 Uppsala, Sweden E-mail: js@nn.se
Thomsen, Forest & Landscape, University of Copenhagen, Hoersholm Kongevej 11, DK-2970 Hoersholm, Denmark E-mail: imt@nn.dk
Barklund, Department of Forest Mycology & Pathology, Swedish University of Agricultural Sciences, P.O. Box 7026, SE-75007 Uppsala, Sweden E-mail: pb@nn.se
Dahlberg, Swedish Species Information Centre, Swedish University of Agricultural Sciences, P.O. Box 7007, SE-75007 Uppsala, Sweden E-mail: ad@nn.se

Category : Research note

article id 228, category Research note

Aku Riihelä, Terhikki Manninen. (2008). Measuring the vertical albedo profile of a subarctic boreal forest canopy. Silva Fennica vol. 42 no. 5 article id 228. https://doi.org/10.14214/sf.228

Keywords: boreal forest; albedo; validation; canopy transmission

Abstract | View details | Full text in PDF | Author Info

The validation of airborne and satellite-derived albedo measurements suffers from the fact that the surface albedo of forest is difficult to measure in-situ over large areas. The goal of this study is to examine whether or not the estimation of the surface albedo of a forest stand from ground level measurements is possible. In addition, knowledge about the vertical behavior of albedo, and therefore transmitted solar radiation, is important in the modeling of interactions of sunlight with the forest canopy. Such modeling is useful for forest growth estimations among other things. To achieve these goals, an albedometer set-up capable of vertical albedo profiling has been used to obtain data from a boreal forest stand in Northern Finland during periods in summer 2006 and winter 2007. The results show a strong relationship between the data and fitted power-law regression curves. Power-law regression fits best likely because of the radiation transmission characteristics of boreal forest.

Riihelä, Finnish Meteorological Institute, P.O. Box 503, FI-00200 Helsinki, Finland E-mail: aku.riihela@fmi.fi
Manninen, Finnish Meteorological Institute, P.O. Box 503, FI-00200 Helsinki, Finland E-mail: tm@nn.fi

article id 269, category Research note

Christian Kiffner, Elisabeth Rössiger, Oliver Trisl, Rainer Schulz, Ferdinand Rühe. (2008). Probability of recent bark stripping damage by red deer (Cervus elaphus) on Norway spruce (Picea abies) in a low mountain range in Germany – a preliminary analysis. Silva Fennica vol. 42 no. 1 article id 269. https://doi.org/10.14214/sf.269

Keywords: forest management; logistic regression; wildlife management

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Red deer (Cervus elaphus) can cause considerable damage to forest stands by bark stripping. Here, we examined the probability of bark stripping of susceptible Norway spruce (Picea abies) during winter in relation to local environmental characteristics in the western Harz Mountains, Lower Saxony, Germany. We present the results of a multiple logistic regression model for recent bark stripping damage by red deer which we developed from two systematic cluster sampling inventories after two winter periods along with associated meteorological data and records of bagged deer. Our model suggests that the risk of bark stripping increased significantly (P 0.05) with rising slope angle, cumulating snow depth and increasing index values of red deer population density. Spruces growing in closed forest stands were debarked at a higher probability than spruces located close to forest edges. Further on, spruce stands on eastern slopes had a lower probability of bark damage than spruce stands on northern slopes. Other tested variables (altitude, length of daily solar irradiation, duration of snow cover, age of spruce stand within the age range of 16–50 years) had no significant effect on the probability of new bark stripping. We conclude that red deer in the western Harz Mountains seem to use bark as food resource at preferred locations and in times of low food availability. To improve fit and predictive power of bark stripping models we recommend including stand characteristics. We propose to reduce the population size of red deer in order to diminish bark stripping damages to an economically acceptable level.

Kiffner, University Göttingen, Büsgen-Institute, Department of Forest Zoology and Forest Protection incl. Wildlife Biology and Game Management, Büsgenweg 3, 37077 Göttingen, Germany E-mail: ckiffne@gwdg.de
Rössiger, University Göttingen, Büsgen-Institute, Department of Forest Zoology and Forest Protection incl. Wildlife Biology and Game Management, Büsgenweg 3, 37077 Göttingen, Germany E-mail: er@nn.de
Trisl, Planungsbüro Trisl, In der Schleene 7, 36037 Waake, Germany E-mail: ot@nn.de
Schulz, University Göttingen, Büsgen-Institute, Department of Ecological Informatics, Biometry and Forest Growth, Büsgenweg 4, 37077 Göttingen, Germany E-mail: rs@nn.de
Rühe, University Göttingen, Büsgen-Institute, Department of Forest Zoology and Forest Protection incl. Wildlife Biology and Game Management, Büsgenweg 3, 37077 Göttingen, Germany E-mail: fr@nn.de

article id 268, category Research note

Adam Boratynski, Katarzyna Marcysiak, Amelia Lewandowska, Anna Jasinska, Grzegorz Iszkulo, Jaroslaw Burczyk. (2008). Differences in leaf morphology between Quercus petraea and Q. robur adult and young individuals. Silva Fennica vol. 42 no. 1 article id 268. https://doi.org/10.14214/sf.268

Keywords: morphological diversity; plant variation; biometry; Quercus; leaf polymorphism

Abstract | View details | Full text in PDF | Author Info

The characters of Quercus robur and Q. petraea leaves are of main taxonomic value and the adult trees of both species can be distinguished on them. However, young individuals, mostly seedlings but also saplings, are told to be undistinguishable or only partly distinguishable on the leaf morphology. The aim of the study was to verify this hypothesis on the basis of biometrical analyses of leaf characteristics of adults trees and saplings in two mixed oak woods, one located close to the north-eastern limit, the other about 400 km inside of the Q. petraea range in Poland. The analysis of discriminations and minimum spanning tree on the squares of Mahalanobis distances were analysed to find differences between Q. robur, Q. petraea and intermediate adults and saplings. The differences between saplings of Q. robur and Q. petraea were found lower than between adult trees. Nevertheless, the biometrical analysis confirmed determination of saplings in the field.

Boratynski, Polish Academy of Sciences, Institute of Dendrology, 5 Parkowa str., 62-035 Kórnik, Poland E-mail: borata@man.poznan.pl
Marcysiak, Kazimierz Wielki University, Institute of Biology and Environment Protection, 12 Ossolinskich str., 85-064 Bydgoszcz, Poland E-mail: km@nn.pl
Lewandowska, Kazimierz Wielki University, Institute of Biology and Environment Protection, 12 Ossolinskich str., 85-064 Bydgoszcz, Poland E-mail: al@nn.pl
Jasinska, Polish Academy of Sciences, Institute of Dendrology, 5 Parkowa str., 62-035 Kórnik, Poland E-mail: aj@nn.pl
Iszkulo, Polish Academy of Sciences, Institute of Dendrology, 5 Parkowa str., 62-035 Kórnik, Poland E-mail: gi@nn.pl
Burczyk, Kazimierz Wielki University, Institute of Biology and Environment Protection, 12 Ossolinskich str., 85-064 Bydgoszcz, Poland E-mail: jb@nn.pl

Category : Discussion article

article id 270, category Discussion article

Seppo Rouvinen, Jari Kouki. (2008). The natural northern European boreal forests: unifying the concepts, terminologies, and their application. Silva Fennica vol. 42 no. 1 article id 270. https://doi.org/10.14214/sf.270

Keywords: human influence; biodiversity; natural ecosystems; natural forests; protection; terminology

Abstract | View details | Full text in PDF | Author Info

Recent emphasis on conserving the biodiversity has stressed the value of natural ecosystems in saving the species from extinction. In the Fennoscandian region the conifer-dominated boreal forests form the largest single ecosystem. The forests have been under varying intensity of human influence for decades or centuries. Recent attempts have tried to seek the last remaining natural forests to be included in the protection programmes. However, due to long and widespread human influence, finding and defining the natural forests has proven to be extremely difficult, not only because they are so rare but also because the concept of natural forest is vague. These difficulties are partly seen through the diverse terminology used. We first review the varying terminology as seen in recent studies. Secondly, we propose the basis for defining the natural forest and show some intriguing and challenging difficulties are involved in the concept. These difficulties are at least partly related to inherent strong and long-term dynamic component in boreal forest ecosystems that is manifested over several temporal and spatial scales. Finally, we outline a more general terminology with associated indicators and measurements that might be used in the classification and terminology. Conceptual clarification is necessary, for example, to compile ecologically justified and representative global, national and regional forest statistics. Many currently applied definitions of “forest” and “natural” that are applied in the context of forest statistics overlook ecologically important components of natural forests, and thus provide quite misleading or inadequate data of existing diversity patterns in these ecosystems.

Rouvinen, University of Joensuu, Faculty of Forest Sciences, P.O. Box 111, FI-80101 Joensuu, Finland E-mail: sr@nn.fi
Kouki, University of Joensuu, Faculty of Forest Sciences, P.O. Box 111, FI-80101 Joensuu, Finland E-mail: jari.kouki@joensuu.fi

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