Current issue: 53(3)

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Silva Fennica 1926-1997
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Acta Forestalia Fennica
1953-1968
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Articles containing the keyword 'crown'.

Category: Research article

article id 10179, category Research article
Lauri Korhonen, Jaakko Repola, Tomi Karjalainen, Petteri Packalen, Matti Maltamo. (2019). Transferability and calibration of airborne laser scanning based mixed-effects models to estimate the attributes of sawlog-sized Scots pines. Silva Fennica vol. 53 no. 3 article id 10179. https://doi.org/10.14214/sf.10179
Highlights: Attributes of individual sawlog-sized pines estimated by transferring ALS-based models between sites; Mixed effects models were more accurate than k-NN imputation tested earlier; Calibration with a small number of field measured trees improved the accuracy.

Airborne laser scanning (ALS) data is nowadays often available for forest inventory purposes, but adequate field data for constructing new forest attribute models for each area may be lacking. Thus there is a need to study the transferability of existing ALS-based models among different inventory areas. The objective of our study was to apply ALS-based mixed models to estimate the diameter, height and crown base height of individual sawlog sized Scots pines (Pinus sylvestris L.) at three different inventory sites in eastern Finland. Different ALS sensors and acquisition parameters were used at each site. Multivariate mixed-effects models were fitted at one site and the models were validated at two independent test sites. Validation was carried out by applying the fixed parts of the mixed models as such, and by calibrating them using 1–3 sample trees per plot. The results showed that the relative RMSEs of the predictions were 1.2–6.5 percent points larger at the test sites compared to the training site. Systematic errors of 2.4–6.2 percent points also emerged at the test sites. However, both the RMSEs and the systematic errors decreased with calibration. The results showed that mixed-effects models of individual tree attributes can be successfully transferred and calibrated to other ALS inventory areas in a level of accuracy that appears suitable for practical applications.

  • Korhonen, University of Eastern Finland, School of Forest Sciences, P.O. Box 111, FI-80101 Joensuu, Finland ORCID ID: http://orcid.org/0000-0002-9352-0114 E-mail: lauri.korhonen@uef.fi (email)
  • Repola, Natural Resources Institute of Finland (Luke), Natural resources, Eteläranta 55, FI-96300 Rovaniemi, Finland ORCID ID:E-mail: jaakko.repola@luke.fi
  • Karjalainen, University of Eastern Finland, School of Forest Sciences, P.O. Box 111, FI-80101 Joensuu, Finland ORCID ID:E-mail: tomikar@uef.fi
  • Packalen, University of Eastern Finland, School of Forest Sciences, P.O. Box 111, FI-80101 Joensuu, Finland ORCID ID:E-mail: petteri.packalen@uef.fi
  • Maltamo, University of Eastern Finland, School of Forest Sciences, P.O. Box 111, FI-80101 Joensuu, Finland ORCID ID:E-mail: matti.maltamo@uef.fi
article id 10006, category Research article
Matti Maltamo, Tomi Karjalainen, Jaakko Repola, Jari Vauhkonen. (2018). Incorporating tree- and stand-level information on crown base height into multivariate forest management inventories based on airborne laser scanning. Silva Fennica vol. 52 no. 3 article id 10006. https://doi.org/10.14214/sf.10006
Highlights: The most accurate tree-level alternative is to include crown base height (CBH) to nearest neighbour imputation; Also mixed-effects models can be applied to predict CBH using tree attributes and airborne laser scanning (ALS) metrics; CBH prediction can be included with an accuracy of 1–1.5 m to forest management inventory applications.

This study examines the alternatives to include crown base height (CBH) predictions in operational forest inventories based on airborne laser scanning (ALS) data. We studied 265 field sample plots in a strongly pine-dominated area in northeastern Finland. The CBH prediction alternatives used area-based metrics of sparse ALS data to produce this attribute by means of: 1) Tree-level imputation based on the k-nearest neighbor (k-nn) method and full field-measured tree lists including CBH observations as reference data; 2) Tree-level mixed-effects model (LME) prediction based on tree diameter (DBH) and height and ALS metrics as predictors of the models; 3) Plot-level prediction based on analyzing the computational geometry and topology of the ALS point clouds; and 4) Plot-level regression analysis using average CBH observations of the plots for model fitting. The results showed that all of the methods predicted CBH with an accuracy of 1–1.5 m. The plot-level regression model was the most accurate alternative, although alternatives producing tree-level information may be more interesting for inventories aiming at forest management planning. For this purpose, k-nn approach is promising and it only requires that field measurements of CBH is added to the tree lists used as reference data. Alternatively, the LME-approach produced good results especially in the case of dominant trees.

  • Maltamo, University of Eastern Finland, School of Forest Sciences, P.O. Box 111, FI-80101 Joensuu, Finland ORCID ID:E-mail: matti.maltamo@uef.fi (email)
  • Karjalainen, University of Eastern Finland, School of Forest Sciences, P.O. Box 111, FI-80101 Joensuu, Finland ORCID ID:E-mail: tomimkarjalainen@gmail.com
  • Repola, Natural Resources Institute of Finland (Luke), Natural resources, Eteläranta 55, FI-96300 Rovaniemi, Finland ORCID ID:E-mail: jaakko.repola@luke.fi
  • Vauhkonen, Natural Resources Institute of Finland (Luke), Bioeconomy and environment, Yliopistokatu 6, 80100 Joensuu, Finland ORCID ID:E-mail: jari.vauhkonen@luke.fi
article id 7748, category Research article
Dominik Bayer, Hans Pretzsch. (2017). Reactions to gap emergence: Norway spruce increases growth while European beech features horizontal space occupation – evidence by repeated 3D TLS measurements. Silva Fennica vol. 51 no. 5 article id 7748. https://doi.org/10.14214/sf.7748
Highlights: Analysis of the closure dynamics of a Norway spruce, a European beech and a mixed forest gap by repeated TLS measurements; Norway spruce allocated additional resources predominantly into DBH growth and displayed stronger resilience against mechanical crown damage; European beech allocated resources towards space occupation and displayed higher crown plasticity; Species mixture had no significant effect.

The reach of different tree species’ crowns and the velocity of gap closure during the occupation of canopy gaps resulting from mortality and thinning during stand development determine species-specific competition and productivity within forest stands. However, classical dendrometric methods are rather inaccurate or even incapable of time- and cost-effectively measuring 3D tree structure, crown dynamics and space occupation non-destructively. Therefore, we applied terrestrial laser scanning (TLS) in order to measure the structural dynamics at tree and stand level from gap cutting in 2006 until 2012 in pure and mixed stands of Norway spruce (Picea abies [L.] Karst.) and European beech (Fagus sylvatica L.). In conclusion, our results suggest that Norway spruce invests newly available above-ground resources primarily into DBH as well as biomass growth and indicate a stronger resilience against loss of crown mass induced by mechanical damage. European beech showed a vastly different reaction, investing gains from additional above-ground resources primarily into faster occupation of canopy space. Whether our sample trees were located in pure or mixed groups around the gaps had no significant impact on their behavior during the years after gap cutting.

  • Bayer, Address Technical University of Munich (TUM), Chair for Forest Growth and Yield Science, Hans-Carl-von-Carlowitz-Platz 2, 85354, Freising, Germany ORCID ID: http://orcid.org/0000-0002-2084-3019 E-mail: dominik.bayer@lrz.tu-muenchen.de (email)
  • Pretzsch, Address Technical University of Munich (TUM), Chair for Forest Growth and Yield Science, Hans-Carl-von-Carlowitz-Platz 2, 85354, Freising, Germany ORCID ID:E-mail: hans.pretzsch@lrz.tu-muenchen.de
article id 7748, category Research article
Dominik Bayer, Hans Pretzsch. (2017). Reactions to gap emergence: Norway spruce increases growth while European beech features horizontal space occupation – evidence by repeated 3D TLS measurements. Silva Fennica vol. 51 no. 5 article id 7748. https://doi.org/10.14214/sf.7748
Highlights: Analysis of the closure dynamics of a Norway spruce, a European beech and a mixed forest gap by repeated TLS measurements; Norway spruce allocated additional resources predominantly into DBH growth and displayed stronger resilience against mechanical crown damage; European beech allocated resources towards space occupation and displayed higher crown plasticity; Species mixture had no significant effect.

The reach of different tree species’ crowns and the velocity of gap closure during the occupation of canopy gaps resulting from mortality and thinning during stand development determine species-specific competition and productivity within forest stands. However, classical dendrometric methods are rather inaccurate or even incapable of time- and cost-effectively measuring 3D tree structure, crown dynamics and space occupation non-destructively. Therefore, we applied terrestrial laser scanning (TLS) in order to measure the structural dynamics at tree and stand level from gap cutting in 2006 until 2012 in pure and mixed stands of Norway spruce (Picea abies [L.] Karst.) and European beech (Fagus sylvatica L.). In conclusion, our results suggest that Norway spruce invests newly available above-ground resources primarily into DBH as well as biomass growth and indicate a stronger resilience against loss of crown mass induced by mechanical damage. European beech showed a vastly different reaction, investing gains from additional above-ground resources primarily into faster occupation of canopy space. Whether our sample trees were located in pure or mixed groups around the gaps had no significant impact on their behavior during the years after gap cutting.

  • Bayer, Address Technical University of Munich (TUM), Chair for Forest Growth and Yield Science, Hans-Carl-von-Carlowitz-Platz 2, 85354, Freising, Germany ORCID ID: http://orcid.org/0000-0002-2084-3019 E-mail: dominik.bayer@lrz.tu-muenchen.de (email)
  • Pretzsch, Address Technical University of Munich (TUM), Chair for Forest Growth and Yield Science, Hans-Carl-von-Carlowitz-Platz 2, 85354, Freising, Germany ORCID ID:E-mail: hans.pretzsch@lrz.tu-muenchen.de
article id 1781, category Research article
Petr Čermák, Michal Rybníček, Tomáš Žid, Kjell Andreassen, Isabella Børja, Tomáš Kolář. (2017). Impact of climate change on growth dynamics of Norway spruce in south-eastern Norway. Silva Fennica vol. 51 no. 2 article id 1781. https://doi.org/10.14214/sf.1781
Highlights: Correlations between tree-ring width and climate parameters showed temporal instability in their relationship during the period 1915–2012; A statistically significant positive correlation of April–May precipitation on tree-ring growth was identified since the mid-1970s; The concomitant temperature increase may have contributed to the changes of growth dynamics.

The ongoing climate change may have a distinct effect on Norway spruce growth, one of the most important tree species in European forest management. Therefore, the understanding and assessment of climate-growth relationship can help to reveal relevant patterns in temporal variability that may result in lower tree vitality and decline. The main objective of our study was to evaluate the long-term climate-growth variability of Norway spruce in south-eastern Norway, at the northern edge of the temperate zone. We sampled in total 270 dominant and co-dominant trees from 18 plots in south-eastern Norway. We analysed stem cores and evaluated crown condition parameters to assess the retrospective tree growth and vitality. Despite considerable differences in the crown parameters, high similarity among tree-ring width (TRW) series allowed compiling the regional tree-ring width chronology. Correlations between TRW and climate parameters showed temporal instability in their relationship during the period 1915–2012. While we did not detect any significant relationships between TRW and climate parameters in the first half of the study period (1915–1963), a significant correlation between TRW and spring precipitation was observed for the period 1964–2012. This shift appeared concurrent with temperatures reaching above-average values compared to the average of the climate normal period 1961–1990.

  • Čermák, Faculty of Forestry and Wood Technology, Mendel University in Brno, Zemědělská 3, 613 00 Brno, Czech Republic ORCID ID:E-mail: cermacek@mendelu.cz (email)
  • Rybníček, Faculty of Forestry and Wood Technology, Mendel University in Brno, Zemědělská 3, 613 00 Brno, Czech Republic; Global Change Research Institute, The Czech Academy of Sciences, Bělidla 986/4a, 603 00 Brno, Czech Republic ORCID ID:E-mail: michalryb@post.cz
  • Žid, Faculty of Forestry and Wood Technology, Mendel University in Brno, Zemědělská 3, 613 00 Brno, Czech Republic ORCID ID:E-mail: tom.z@centrum.cz
  • Andreassen, Norwegian Institute of Bioeconomy Research (NIBIO), P.O. Box 115, NO-1431 Ås, Norway ORCID ID:E-mail: Kjell.Andressen@nibio.no
  • Børja, Norwegian Institute of Bioeconomy Research (NIBIO), P.O. Box 115, NO-1431 Ås, Norway ORCID ID:E-mail: Isabella.Borja@nibio.no
  • Kolář, Faculty of Forestry and Wood Technology, Mendel University in Brno, Zemědělská 3, 613 00 Brno, Czech Republic; Global Change Research Institute, The Czech Academy of Sciences, Bělidla 986/4a, 603 00 Brno, Czech Republic ORCID ID:E-mail: koldatom@gmail.com
article id 1310, category Research article
Deliang Lu, Jiaojun Zhu, Yirong Sun, Lile Hu, Guangqi Zhang. (2015). Gap closure process by lateral extension growth of canopy trees and its effect on woody species regeneration in a temperate secondary forest, Northeast China. Silva Fennica vol. 49 no. 5 article id 1310. https://doi.org/10.14214/sf.1310
Highlights: Gap closure process by lateral extension growth can be described by quadratic functions; Large gaps (514–621 m2) had higher closure rates but lower closure percentages compared with middle (174–321 m2) and small gaps (68–125 m2); Gaps promoted woody species regeneration in early stage; Large and middle gaps would provide opportunities for filling regeneration, but regeneration in small gaps may eventually fail.

Gap formation and its effects on regeneration have been reported as being important in forest development, but seldom studies concentrated on the gap closure process by lateral extension growth of canopy trees surrounding gaps. We monitored the closure process of 12 artificial gaps for 7 years with three size classes: small (from 68 m2 to 125 m2), middle (from 174 m2 to 321 m2), and large (from 514 m2 to 621 m2); and investigated the regeneration twice in a temperate secondary forest, Northeast China. The closure process can be described through quadratic functions, which showed the closure rates slowed down with gap ages. Large gaps had a higher closure rate (39 m2 a–1) than middle gaps (25 m2 a–1) and small gaps (11 m2 a–1). According to the quadratic equations, the lateral growth could last 11, 13 and 16 years for small, middle and large gaps with a remaining size of 12, 69 and 223 m2, respectively. As expected, regeneration exhibited the highest seedling density and volume in large gaps. There was no significant difference in regeneration density between middle gaps, small gaps and forest understory in the final investigation; but the volume of regenerated woody species increased significantly from small gaps to large gaps compared with forest understory. These results may provide references on the choice of appropriate gap sizes to promote the regeneration in temperate secondary forests.

  • Lu, State Key Laboratory of Forest and Soil Ecology, Qingyuan Forest CERN, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016, China;  University of Chinese Academy of Sciences, Beijing 100049, China ORCID ID:E-mail: delianglu14@hotmail.com
  • Zhu, State Key Laboratory of Forest and Soil Ecology, Qingyuan Forest CERN, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016, China ORCID ID:E-mail: jiaojunzhu@iae.ac.cn (email)
  • Sun, State Key Laboratory of Forest and Soil Ecology, Qingyuan Forest CERN, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016, China ORCID ID:E-mail: yirongsun@iae.ac.cn
  • Hu,  Chinese Research Academy of Environmental Sciences, Beijing 100012, China ORCID ID:E-mail: lilehu@gmail.com
  • Zhang, State Key Laboratory of Forest and Soil Ecology, Qingyuan Forest CERN, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016, China;  University of Chinese Academy of Sciences, Beijing 100049, China ORCID ID:E-mail: zgq04713@163.com
article id 1243, category Research article
Curt Almqvist, Gunnar Jansson. (2015). Effects of pruning and stand density on cone and pollen production in an experimental Pinus sylvestris seed orchard. Silva Fennica vol. 49 no. 4 article id 1243. https://doi.org/10.14214/sf.1243
Highlights: Pollen production of Pinus sylvestris began at the same age for all studied stand density and pruning height combinations but increased more rapidly at higher densities; Treatments with dense spacing increased seed production earlier; Many combinations of stand density and target height gave comparable levels of seed production, yielding a wide range of viable management options.

Seed orchards are the link between tree breeding and reforestation. This paper presents data on cone, seed and pollen production and seed quality gathered over 21 years in a Pinus sylvestris (L.) experimental seed orchard containing plots with 14 different combinations of stand density and targeted pruning height. The treatments’ stand densities ranged from 267 to 4000 stems ha-1, and the target graft heights ranged from 2 to 6 meters. Pollen production began at the same orchard age for all studied combinations of stand density and target height but the level of pollen production per hectare increased more rapidly in treatments with higher stand densities. In treatments with dense spacing, cone and seed production initially increased more rapidly than in treatments with wider spacing, thereby providing an earlier return on investment and a shorter seed production lag time. However, the levels of cone and seed production in such treatments over the entire study period were not appreciably different to those achieved in treatments with wider spacing and higher target height. The treatments did not differ substantially with respect to seed quality. These results show that comparable levels of seed production can be obtained with different combinations of stand density and target height, giving seed orchard owners and managers a wide range of viable management options.

  • Almqvist, Skogforsk (The Forestry Research Institute of Sweden), Uppsala Science Park, SE-751 83 Uppsala, Sweden ORCID ID:E-mail: curt.almqvist@skogforsk.se (email)
  • Jansson, Skogforsk (The Forestry Research Institute of Sweden), Uppsala Science Park, SE-751 83 Uppsala, Sweden ORCID ID:E-mail: gunnar.jansson@skogforsk.se
article id 1002, category Research article
Pentti Niemistö. (2013). Effect of growing density on biomass and stem volume growth of downy birch stands on peatland in Western and Northern Finland. Silva Fennica vol. 47 no. 4 article id 1002. https://doi.org/10.14214/sf.1002
Highlights: The thinning response in young downy birch stands was low and the mortality of merchantable stems was tolerable even in dense unthinned thickets during the rotation of 50 years; The production of above-ground woody biomass and stem volume or even the production of pulpwood increased with stand density, with these values being greatest for unthinned or very lightly thinned plots.
The objective of the study was to ascertain the relationship of thinning intensity of downy birch (Betula pubescens Ehrh.) stands with height, crown, and diameter development as well as pulpwood, stem volume, and biomass increment using long-term (20−30 years) field experiments. Diameter growth of birches increased with thinning intensity during the first 15 years from thinning in all development phases, though after that it did so only for the youngest stands. The thinning response was low. Thinning intensity had no influence on increase in height. In terms of stem volume with bark, the mortality in unthinned stands during the study period was 30–45 m3 ha-1. The mean stem number in unthinned birch thickets fell from 25 000 ha-1 at a dominant height of 7 m to 3000 ha-1 at 18 m. The stem volume increment over the first 15 years was highest (5–6 m3 ha-1 a-1) on the very lightly thinned or unthinned plots, but later there was no significant difference between initial thinning intensities. The maximum above-ground leafless biomass (over 100 Mg ha-1) was achieved on very lightly thinned plots. Also, the total production (including thinning removal) of biomass or stem volume or even the production of pulpwood increased with stand density, with these values being greatest for very lightly thinned or unthinned plots. During 50-year rotation, the highest leafless above-ground biomass production was 2.5 Mg ha-1 a-1 as a mean value from the experiments. The highest mean annual production of pulpwood (d > 6.5 cm) was 3.2 m3 ha-1 a-1, and, in practice, no saw timber or veneer timber was produced, because of the small size and low quality of the stems. A thinning in downy birch stands increased slightly the size of stems to be removed in future cuttings, but with exception for very light thinning it decreased the production of biomass and merchantable wood.
  • Niemistö, Finnish Forest Research Institute, Parkano Unit, FI-39700 Parkano, Finland ORCID ID:E-mail: pentti.niemisto@metla.fi (email)
article id 41, category Research article
Ying Hou, Jintao Qu, Zukui Luo, Chao Zhang, Kaiyun Wang. (2011). Morphological mechanism of growth response in treeline species Minjiang fir to elevated CO2 and temperature. Silva Fennica vol. 45 no. 2 article id 41. https://doi.org/10.14214/sf.41
To test whether and how morphological traits are linked with growth responses of plants to temperature and CO2 is important for understanding the mechanism underlying how plant growth will respond to global warming. In this study, using closed-top chambers to mimic future elevated CO2 and temperature, the growth response, morphological traits of Minjiang fir (Abies faxoniana Rehd.et Wils.) and the relationship of the two were investigated after two years of exposure to the single and combined elevation of CO2 and temperature. The results showed that biomass of Minjiang fir was 21%, 31%, and 35% greater than the control in elevated CO2, elevated temperature and the combination of elevated CO2 and temperature treatments, respectively. Elevated CO2 and temperature significantly affected the morphology of Minjiang fir, and a few morphological traits were highly correlated with growth responses. Larger branch angles at the upper layer, crown volume, and relative crown length contributed to positive growth responses to elevated CO2, while decreased specific leaf area (SLA) constricted any further growth response. Leaf morphological traits were more closely correlated with the response ratio than crown did in the elevated temperature, while in the combination of elevated CO2 and temperature, crown was more correlated with the response ratio than the leaf morphological traits. Thus, our results indicate that morphological traits may contribute differently to growth responses under different experimental conditions.
  • Hou, Department of Life Sciences, Shangqiu Normal University, Shangqiu, China ORCID ID:E-mail:
  • Qu, Department of Life Sciences, Shangqiu Normal University, Shangqiu, China ORCID ID:E-mail:
  • Luo, School of Environment and Life Sciences, Kaili University, Kaili, China ORCID ID:E-mail:
  • Zhang, Shanghai Key Laboratory of Urbanization and Ecological Restoration, East China Normal University, Shanghai, China, and University of Eastern Finland, School of Forest Sciences, Joensuu, Finland ORCID ID:E-mail:
  • Wang, Shanghai Key Laboratory of Urbanization and Ecological Restoration, East China Normal University, Shanghai, China, and University of Eastern Finland, School of Forest Sciences, Joensuu, Finland ORCID ID:E-mail: kywang@re.ecnu.edu.cn (email)
article id 453, category Research article
Eduard Schiessl, Michael Grabner, Gerald Golesch, Thomas Geburek, Silvio Schueler. (2010). Sub-montane Norway spruce as alternative seed source for a changing climate? A genetic and growth analysis at the fringe of its natural range in Austria. Silva Fennica vol. 44 no. 4 article id 453. https://doi.org/10.14214/sf.453
Insights into the intraspecific variation in climate response of forest trees and the utilization of suitable seed sources are required to maintain forest ecoystems under expected climate change. Individuals of Norway spruce with an anomalous spherical-shaped crown were characterized by genetic (using a mtDNA marker) and dendroclimatic analysis. Such trees occur frequently at the fringe of the spruce distribution in east/south-east Austria. We employed pair-wise comparisons between trees with spherical and “regular” conical crowns on 47 sites. No evidence was found for a different phylogeographic history of spherical and conical spruces, but the high allelic diversity at the nad1 locus highlighted the importance of east/south-east Austria as refugium and migration corridor for Norway spruce. Analysis of mean annual increment revealed a larger amount of earlywood within the sapwood area and fewer negative pointer years for spherical spruces than for conical ones, pointing at a higher vitality and smaller interactions between climate and growth for spherical spruces. Although the results cannot explain the anomalous crown form, they suggest spherical trees to have a higher ability to cope the warm and dry climate of the region than “regular” conical spruces. We discuss the origin of spherical crowns in terms of population history and phenotypic plasticity and speculate on possible effects of crown architecture on canopy-atmosphere exchange.
  • Schiessl, Department of Genetics, Research and Training Centre for Forests, Natural Hazards and Landscape, Hauptstrasse 7, A-1140 Vienna, Austria ORCID ID:E-mail:
  • Grabner, Department of Material Sciences and Process Engineering, Institute of Wood Science and Technology, University of Natural Resources and Applied Life Sciences, Peter-Jordan-Strasse 82, A-1190 Vienna, Austria ORCID ID:E-mail:
  • Golesch, Department of Genetics, Research and Training Centre for Forests, Natural Hazards and Landscape, Hauptstrasse 7, A-1140 Vienna, Austria ORCID ID:E-mail:
  • Geburek, Department of Genetics, Research and Training Centre for Forests, Natural Hazards and Landscape, Hauptstrasse 7, A-1140 Vienna, Austria ORCID ID:E-mail:
  • Schueler, Department of Genetics, Research and Training Centre for Forests, Natural Hazards and Landscape, Hauptstrasse 7, A-1140 Vienna, Austria ORCID ID:E-mail: silvio.schueler@bfw.gv.at (email)
article id 156, category Research article
Ilkka Korpela, Hans Ole Ørka, Matti Maltamo, Timo Tokola, Juha Hyyppä. (2010). Tree species classification using airborne LiDAR – effects of stand and tree parameters, downsizing of training set, intensity normalization, and sensor type. Silva Fennica vol. 44 no. 2 article id 156. https://doi.org/10.14214/sf.156
Tree species identification constitutes a bottleneck in remote sensing-based forest inventory. In passive images the differentiating features overlap and bidirectional reflectance hampers analysis. Airborne LiDAR provides radiometric and geometric information. We examined the single-trees-level response of two LiDAR sensors in over 13 000 forest trees in southern Finland. We focused on the commercially important species. Our aims were to 1) explore the relevant LiDAR features and study their dependencies on stand and tree variables, 2) examine two sensors and their fusion, 3) quantify the gain from intensity normalizations, 4) examine the importance of the size of the training set, and 5) determine the effects of stand age and site fertility. A set of 570 semiurban broad-leaved trees and exotic conifers was analyzed to 6) examine the LiDAR signal in the economically less important species. An accuracy of 88 90% was achieved in the classification of Scots pine, Norway spruce, and birch, using intensity variables. Spruce and birch showed the highest levels of confusion. Downsizing the training set from 30% to 2.5% of all trees had only a marginal effect on the performance of classifiers. The intensity features were dependent on the absolute and relative sizes of trees, especially for birch. The results suggest that leaf size, orientation, and foliage density affect the intensity, which is thus not affected by reflectance only. Some of the ecologically important species in Finland may be separable, since they gave rise to high intensity values. Comparison of the sensors implies that performance of the intensity data for species classification varies between sensors for reasons that remained uncertain. Both range and gain receiver normalization improved species classification. Weighting of the intensity values improved the fusion of two LiDAR datasets.
  • Korpela, University of Helsinki, Department of Forest Sciences, P.O. Box 27, FI-00014 University of Helsinki, Finland ORCID ID:E-mail: ilkka.korpela@helsinki.fi (email)
  • Ørka, Norwegian University of Life Sciences, Department of Ecology and Natural Resource Management, P.O.Box 5003, NO-1432 Ås, Norway ORCID ID:E-mail:
  • Maltamo, University of Eastern Finland, School of Forest Science, P.O. Box 111, FI-80101 Joensuu, Finland ORCID ID:E-mail:
  • Tokola, University of Eastern Finland, School of Forest Science, P.O. Box 111, FI-80101 Joensuu, Finland ORCID ID:E-mail:
  • Hyyppä, Finnish Geodetic Institute, Department of Photogrammetry and Remote Sensing, P.O.Box 15, FI-02431 Masala, Finland ORCID ID:E-mail:
article id 203, category Research article
Matti Maltamo, Jussi Peuhkurinen, Jukka Malinen, Jari Vauhkonen, Petteri Packalén, Timo Tokola. (2009). Predicting tree attributes and quality characteristics of Scots pine using airborne laser scanning data. Silva Fennica vol. 43 no. 3 article id 203. https://doi.org/10.14214/sf.203
The development of airborne laser scanning (ALS) during last ten years has provided new possibilities for accurate description of the living tree stock. The forest inventory applications of ALS data include both tree and area-based plot level approaches. The main goal of such applications has usually been to estimate accurate information on timber quantities. Prediction of timber quality has not been focused to the same extent. Thus, in this study we consider here the prediction of both basic tree attributes (tree diameter, height and volume) and characteristics describing tree quality more closely (crown height, height of the lowest dead branch and sawlog proportion of tree volume) by means of high resolution ALS data. The tree species considered is Scots pine (Pinus sylvestris), and the field data originate from 14 sample plots located in the Koli National Park in North Karelia, eastern Finland. The material comprises 133 trees, and size and quality variables of these trees were modeled using a large number of potential independent variables calculated from the ALS data. These variables included both individual tree recognition and area-based characteristics. Models for the dependent tree characteristics to be considered were then constructed using either the non-parametric k-MSN method or a parametric set of models constructed simultaneously by the Seemingly Unrelated Regression (SUR) approach. The results indicate that the k-MSN method can provide more accurate tree-level estimates than SUR models. The k-MSN estimates were in fact highly accurate in general, the RMSE being less than 10% except in the case of tree volume and height of the lowest dead branch.
  • Maltamo, University of Joensuu, Faculty of Forest Sciences, FI-80101 Joensuu, Finland ORCID ID:E-mail: matti.maltamo@joensuu.fi (email)
  • Peuhkurinen, University of Joensuu, Faculty of Forest Sciences, FI-80101 Joensuu, Finland ORCID ID:E-mail:
  • Malinen, Finnish Forest Research Institute, Joensuu Research Unit, FI-80101 Joensuu, Finland ORCID ID:E-mail:
  • Vauhkonen, University of Joensuu, Faculty of Forest Sciences, FI-80101 Joensuu, Finland ORCID ID:E-mail:
  • Packalén, University of Joensuu, Faculty of Forest Sciences, FI-80101 Joensuu, Finland ORCID ID:E-mail:
  • Tokola, University of Joensuu, Faculty of Forest Sciences, FI-80101 Joensuu, Finland ORCID ID:E-mail:
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
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 ORCID ID:E-mail: miina.rautiainen@helsinki.fi (email)
  • Mõttus, Tartu Observatory, 61602 Tõravere, Estonia ORCID ID:E-mail:
  • Stenberg, Department of Forest Resource Management, P.O. Box 27, FI-00014 University of Helsinki, Finland ORCID ID:E-mail:
  • Ervasti, City of Vantaa, Land Use and Environment / Green Area Unit, Kielotie 13, FI-01300 Vantaa, Finland ORCID ID:E-mail:
article id 352, category Research article
Juha-Pekka Hotanen, Matti Maltamo, Antti Reinikainen. (2006). Canopy stratification in peatland forests in Finland. Silva Fennica vol. 40 no. 1 article id 352. https://doi.org/10.14214/sf.352
Abundance and species number of the tree and shrub vegetation in different canopy layers were analysed according to site quality class and drainage succession phase on permanent sample plots on spruce mires (n = 268) and pine mires (n = 628) in the Finnish National Forest Inventory in 1995. The abundances based on the crown coverage were compared with the abundances based on the parallel basal area of the tree stand. The canopy coverages and species number for peatland forests were also compared with those for mineral soil forests on the permanent sample plots (n = 1725) in 1995. In general, effective temperature sum correlated positively, although not very strongly, with the coverages and species number in most of the canopy layers, as well as with the mean range of the diameter distribution. The effects of both site quality class and drainage phase were stronger on pine mires than on spruce mires, most probably due to the longer fertility gradient and large potential free growing space in the former group. On pine mires, drainage increased the abundances and species number in the different canopy layers, as well as the structural inequality of the tree stands. On spruce mires, the increase was principally allocated to the abundances of the dominant and intermediate tree layers. The correlations between the total crown coverage of the tree layers and stand basal area were r = 0.45 for spruce mires and r = 0.70 for pine mires. Compared to mineral soil forests, in addition to having a higher abundance of Betula pubescens, the dominant layer was not as pronounced in peatland forests. On spruce mires, the coverage of the shrub layer on mesotrophic and meso-oligotrophic sites was higher than that in mineral soil forests. The average species number in different canopy layers did not differ significantly between spruce mires and mineral soil forests in corresponding site quality classes. On pine mires, the species number was generally lower (except for the mesotrophic sites) than that in corresponding mineral soil forests.
  • Hotanen, Finnish Forest Research Institute, Joensuu Research Unit, P.O. Box 68, FI-80101 Joensuu, Finland ORCID ID:E-mail: juha-pekka.hotanen@metla.fi (email)
  • Maltamo, University of Joensuu, Faculty of Forestry, P.O. Box 111, FI-80101 Joensuu, Finland ORCID ID:E-mail:
  • Reinikainen, Finnish Forest Research Institute, Vantaa Research Unit, P.O. Box 18, FI-01301 Vantaa, Finland ORCID ID:E-mail:
article id 386, category Research article
Jouni Kalliovirta, Timo Tokola. (2005). Functions for estimating stem diameter and tree age using tree height, crown width and existing stand database information. Silva Fennica vol. 39 no. 2 article id 386. https://doi.org/10.14214/sf.386
The aim was to investigate the relations between diameter at breast height and maximum crown diameter, tree height and other possible independent variables available in stand databases. Altogether 76 models for estimating stem diameter at breast height and 60 models for tree age were formulated using height and maximum crown diameter as independent variables. These types of models can be utilized in modern remote sensing applications where tree crown dimensions and tree height are measured automatically. Data from Finnish national forest inventory sample plots located throughout the country were used to develop the models, and a separate test site was used to evaluate them. The RMSEs of the diameter models for the entire country varied between 7.3% and 14.9% from the mean diameter depending on the combination of independent variables and species. The RMSEs of the age models for entire country ranged from 9.2% to 12.8% from the mean age. The regional models were formulated from a data set in which the country was divided into four geographical areas. These regional models reduced local error and gave better results than the general models. The standard deviation of the dbh estimate for the separate test site was almost 5 cm when maximum crown width alone was the independent variable. The deviation was smallest for birch. When tree height was the only independent variable, the standard deviation was about 3 cm, and when both height and maximum crown width were included it was under 3 cm. In the latter case, the deviation was equally small (11%) for birch and Norway spruce and greatest (13%) for Scots pine.
  • Kalliovirta, University of Helsinki, Department of Forest Resource Management, P.O. Box 27, FI-00014 University of Helsinki, Finland ORCID ID:E-mail:
  • Tokola, University of Helsinki, Department of Forest Resource Management, P.O. Box 27, FI-00014 University of Helsinki, Finland ORCID ID:E-mail: timo.tokola@helsinki.fi
article id 520, category Research article
Rüdiger Grote. (2002). Foliage and branch biomass estimation of coniferous and deciduous tree species. Silva Fennica vol. 36 no. 4 article id 520. https://doi.org/10.14214/sf.520
Under changing environmental conditions, biomass development on the tree and the stand level may differ from today, regardless if the induced change is due to a shift in the general climate properties or to forest management. Under these conditions, tree biomass can not be derived from tables based on former investigations but has to be defined from particular biomass investigations, which generally calculate tree and stand biomass from sample branches using allometric relationships. Therefore, sample measurements on harvested trees are needed. In this paper, foliage and branch biomass estimation for 6 Norway spruces (Picea abies) and 6 beeches (Fagus sylvatica) harvested in a 56-year-old mixed stand in southern Germany is presented. Different allometric models are investigated to derive branch biomass from branch dimension for both species. The equations that are based on branch length, foliated branch fraction, and branch diameter are used for tree and stand level estimates. However, the variation within the 6 trees of each species was too large for a reliable calculation of stand biomass, especially in case of beech branch wood. Furthermore, the necessity of allometric relations and their applicability in individual-tree models is discussed, and the importance of suitable branch- and tree selection is underlined.
  • Grote, TU München, Chair of Forest Yield Science, Am Hochanger 13, D-85354 Freising, Germany ORCID ID:E-mail: ruediger.grote@lrz.tu-muenchen.de (email)
article id 654, category Research article
Margus Pensa, Risto Jalkanen. (1999). Needle chronologies on Pinus sylvestris in northern Estonia and southern Finland. Silva Fennica vol. 33 no. 3 article id 654. https://doi.org/10.14214/sf.654
A needle trace method was used to reveal the chronology of needle retention on Scots pine (Pinus sylvestris L.) in southern Finland (two stands) and northern Estonia (two stands). The average annual summer needle retention along the main stem varied from 2.2 to 3.1 in Estonian stands and between 3.4 and 4.2 in Finnish stands during the period 1966–1990. The 23-year-mean needle age was 3.0 and 2.1 years in Finland and Estonia, respectively. In all stands, the mean needle age decreased sharply in 1980s.
  • Pensa, Institute of Ecology, Department of Northeast Estonia, Pargi 15, EE-41537 Jõhvi, Estonia ORCID ID:E-mail: margus@ecoviro.johvi.ee (email)
  • Jalkanen, Finnish Forest Research Institute, Rovaniemi Research Station, P.O. Box 16, FIN-96301 Rovaniemi, Finland ORCID ID:E-mail:
article id 670, category Research article
Jouni Vettenranta. (1999). Distance-dependent models for predicting the development of mixed coniferous forests in Finland. Silva Fennica vol. 33 no. 1 article id 670. https://doi.org/10.14214/sf.670
Distance-dependent growth models and crown models, based on extensive material, were built for Scots pine and Norway spruce growing in a mixed forest. The crown ratio was also used as a predictor in a diameter growth model to better describe the thinning reaction. The effect of crown ratio on the growth dynamics was studied in simulation examples. Monte Carlo simulation was used to correct the bias caused by nonlinear transformations of predictors and response. After thinnings the crown ratio as a predictor was found to be a clear growth-retarding factor. The growth retarding effect was stronger among pines with thinnings from below, whereas the estimated yield of spruces over rotation was slightly greater when the crown ratio was included than without it. With each type of thinning the effect of crown ratio on pine growth was almost the same, but the growth of spruces was clearly delayed when the stand was thinned from above. Simulation examples also showed that it is profitable to raise the proportion of spruces during rotation, since spruces maintain the growth more vigorous at older ages. The total yield during 90 years rotation was about 20% higher if the stand was transformed into a pure spruce stand instead of pine.
  • Vettenranta, Kivirinnanpolku 4, FIN-40950 Muurame, Finland ORCID ID:E-mail: vettenr@cc.joensuu.fi (email)

Category: Research note

article id 1518, category Research note
Francesco Chianucci. (2016). A note on estimating canopy cover from digital cover and hemispherical photography. Silva Fennica vol. 50 no. 1 article id 1518. https://doi.org/10.14214/sf.1518
Highlights: Comparison of fisheye (DHP) and cover (DCP) photography for estimating canopy cover; Digital photographic estimates validated against artificial images with known cover; Accuracy of cover estimates from DHP is influenced by mean gap size and actual cover; Accuracy of cover estimates from DCP is not influenced by mean gap size and actual cover.

Fast and accurate estimates of canopy cover are central for a wide range of forestry studies. As direct measurements are impractical, indirect optical methods have often been used in forestry to estimate canopy cover. In this paper the accuracy of canopy cover estimates from two widely used canopy photographic methods, hemispherical photography (DHP) and cover photography (DCP) was evaluated. Canopy cover was approximated in DHP as the complement of gap fraction data at narrow viewing zenith angle range (0°–15°), which was comparable with that of DCP. The methodology was tested using artificial images with known canopy cover; this allowed exploring the influence of actual canopy cover and mean gap size on canopy cover estimation from photography. DCP provided robust estimates of canopy cover, whose accuracy was not influenced by variation in actual canopy cover and mean gap size, based on comparison with artificial images; by contrast, the accuracy of cover estimates from DHP was influenced by both actual canopy cover and mean gap size, because of the lower ability of DHP to detect small gaps within crown. The results were replicated in both DHP and DCP images collected in real forest canopies. Finally, the influence of canopy cover on foliage clumping index and leaf area index was evaluated using a theoretical gap fraction model. The main findings indicate that DCP can overcome the limits of indirect techniques for obtaining unbiased and precise estimates of canopy cover, which are comparable to those obtainable from direct, more labour-intensive techniques, being therefore highly suitable for routine monitoring and inventory purposes.

  • Chianucci, Consiglio per la Ricerca in Agricoltura e l’Analisi dell’Economia Agraria – Forestry Research Centre, viale Santa Margherita 80, 52100 Arezzo, Italy ORCID ID: http://orcid.org/0000-0002-5688-2060 E-mail: fchianucci@gmail.com (email)

Category: Article

article id 7402, category Article
Gustaf Sirén. (1950). Alikasvoskuusten biologiaa. Acta Forestalia Fennica vol. 58 no. 2 article id 7402. https://doi.org/10.14214/aff.7402
English title: On the biology of undergrown Norway spruce.

Norway spruce (Picea abies (L.) Karst.) invading sites is common in Finland. The species tends to establish itself as undergrowth, and takes over when it gets space to grow. To determine whether the undergrowth is suitable as the new generation requires knowledge on the biology of spruce undergrowth. One of the issues is determining the age of the stunted trees. In this investigation, 100 undergrown spruce trees, their crown and their root systems were studied. A method was developed to determine the age of the trees.

The root system of all trees in Vaccinium sites and of stunted trees in Myrtillius sites were superficial. The root systems of older spruces were purely of adventitious origin. The longer the period of stunting growth, the younger is the root system. In addition to acropetal and general adventitious ramification there is often adventitious branching of the roots of pathological causes. Mortality among the long roots is frequent.

A stunted tree has not the same ability as a viable tree to make use of already existing branches for building assimilating surface. When comparing trees with equally large assimilating surface, a stunted tree had greater sum of roots compared to a viable tree. The root system of a stunted undergrown spruce was very superficial compared with the other trees.

The PDF includes a summary in English.

  • Sirén, ORCID ID:E-mail:
article id 7354, category Article
P. S. Tikka. (1940). Puiden vikanaisuuksien merkitys ja huomioon ottaminen Perä-Pohjolan mäntymetsien hoidossa. Acta Forestalia Fennica vol. 50 no. 1 article id 7354. https://doi.org/10.14214/aff.7354
English title: The effect of injuries in trees on forest management of Scots pine stands in Northern Finland.

The aim of the study was to find out what are the causes of damage in Scots pine (Pinus sylvestris L.) stands and the frequency of different kinds of injuries, which are then discussed in relation to the silvicultural state and management of the stands in comparison to ideal forests. Sample plots were studied in over 80-year old Scots pine dominated stands in mineral soil sites of different forest types in Northern Finland in the area of Perä-Pohjola. 10–40 trees were chosen as sample trees in each sample plot. The sample trees were felled, and the diameter, height of crown and injuries outside and inside of the stem were recorded.

Length of knot-free part of the stem was higher in the dominant trees and in older age classes of the trees. The form of the stem becomes broader and rounder with the age. The crowns are, however, longer in Northern Finland compared to Southern Finland. In management of Scots pine stands, all trees diseased by Scots pine blister rust (Cronartium flaccidum) should be removed. The disease is common in Northern Finland, and the number of diseased trees increases as the stands get older. Decay was more common in trees that had fire wounds. In general, injuries decreased the length and diameter growth of the trees. From the dominant trees should only injured and diseased trees removed in the thinnigs. Codominant trees can be left to grow when spare trees are needed to replace missing dominant trees. Detailed instruction of selection of the removed trees are given for each age class.

The PDF includes a summary in German.

  • Tikka, ORCID ID:E-mail:
article id 7286, category Article
Matti Jalava. (1934). Havaintoja puun aseman vaikutuksesta puun ominaisuuksiin. Acta Forestalia Fennica vol. 40 no. 9 article id 7286. https://doi.org/10.14214/aff.7286
English title: Influence of the position of a tree in the stand upon the properties of the wood.

The growth of a tree is influenced by inherited properties and external circumstances, including climate, soil, the position of the tree in the stand, and the position of the wood in the stem. The tree species have optimum climate and optimum conditions. The aim of this study was to determine if the summerwood content of the wood of Scots pine (Pinus sylvestris L.) is dependent on the rate of growth of the tree. Comparing the position of the sample trees in the stand, it seems that the position of the tree and the size of its crown influences strongly the quality of the wood. In a dense stand the summerwood content was higher in the trees that had small crowns. Thinning of the stand decreased the difference in summerwood content of the trees.

The PDF includes a summary in English.

  • Jalava, ORCID ID:E-mail:
article id 7251, category Article
Lauri Ilvessalo. (1929). Puuluokitus ja harvennusasteikko. Acta Forestalia Fennica vol. 34 no. 38 article id 7251. https://doi.org/10.14214/aff.7251
English title: Utilization of tree classification in thinnings.
English keywords: crown class; thinning method

Doctor Lauri Ilvessalo modified tree classification developed by professor Gunnar Schotte to develop a tree classification and thinning system that suited Finnish conditions. His system was first applied when the Finnish Forest Research Institute began thinning experiments in a large scale in 1924. The system distinguishes four crown storeys: the predominating crown storey, dominated crown storey, emergent trees and undergrowth. Into the predominating storeys belong dominant trees and co-dominant trees, and into the dominated storeys the intermediate and ground trees. The trees in all the storeys can be divided in to normal trees with well-formed crown and stem, trees with defectively developed crown, trees with defective stem, and injured and diseased trees. The article describes different thinning methods (cleaning thinning, selective thinning from below, selective thinning from above, increment felling, freeing felling) using the tree-classification.

The volume 34 of Acta Forestalia Fennica is a jubileum publication of professor Aimo Kaarlo Cajander. The PDF includes a summary in English.

  • Ilvessalo, ORCID ID:E-mail:
article id 5632, category Article
Annikki Mäkelä, Veli-Pekka Ikonen, Petteri Vanninen. (1997). An application of process-based modelling to the development of branchiness in Scots pine. Silva Fennica vol. 31 no. 3 article id 5632. https://doi.org/10.14214/sf.a8534

A process-oriented tree and stand growth model is extended to be applicable to the analysis of timber quality, and how it is influenced by silvicultural treatments. The tree-level model is based on the carbon balance and it incorporates the dynamics of five biomass variables as well as tree height, crown base, and breast height diameter. Allocation of carbon is based on the conservation of structural relationships, in particular, the pipe model. The pipe-model relationships are extended to the whorl level, but in order to avoid a 3-dimensional model of entire crown structure, the branch module is largely stochastic and aggregated. In model construction, a top-down hierarchy is used where at each step down, the upper level sets constraints for the lower level. Some advantages of this approach are model consistency and efficiency of calculations, but probably at the cost of reduced flexibility. The detailed structure related with the branching module is preliminary and will be improved when more data becomes available. Model parameters are identified for Scots pine (Pinus sylvestris L.) in Southern Finland, and example simulations are carried out to compare the development of quality characteristics in different stocking densities.

  • Mäkelä, ORCID ID:E-mail:
  • Ikonen, ORCID ID:E-mail:
  • Vanninen, ORCID ID:E-mail:
article id 5624, category Article
Hervé Sinoquet, Christophe Godin, Pierre Rivet. (1997). Assessment of the three-dimensional architecture of walnut trees using digitising. Silva Fennica vol. 31 no. 3 article id 5624. https://doi.org/10.14214/sf.a8525

A method for the measurement of the three-dimensional (3D) architecture of trees was applied to describe two 20-year-old walnut trees, one of them is a timber tree while the other is a fruit tree. The method works at the shoot level and simultaneously describes the plant topology, the plant geometry and the shoot morphology. The method uses a 3D digitiser (3SPACE® FASTRAK®, Polhemus Inc.) associated with software DiplAmi designed for digitiser control and data acquisition management. Plant images may be reconstructed from the data set by using the ray tracing software POV-Ray. Visual comparison between photographs of the walnut trees and images synthesised from digitising was satisfactory. Distribution of basal shoot diameter, as well as leaf area and fruit distributions for both the timber and the fruit tree were non-uniformly distributed in the crown volume. Gradients were likely to be related to the light distribution within the tree. This is in agreement with previous experimental results on several tree species, and also with the predictions of tree architecture models based on light-vegetation interactions.

  • Sinoquet, ORCID ID:E-mail:
  • Godin, ORCID ID:E-mail:
  • Rivet, ORCID ID:E-mail:
article id 5527, category Article
Leena Finér. (1994). Variation in needle nutrient concentrations in the crown of Scots pine on peatland. Silva Fennica vol. 28 no. 1 article id 5527. https://doi.org/10.14214/sf.a9161

Variation in needle nutrient concentrations with age and vertical location in the crown was studied in three Scots pine (Pinus sylvestris L.) stands growing on peat soils in Eastern Finland. The concentrations of N, P, Fe and Zn decreased down the crown and those of Ca and Mn increased. Potassium and magnesium concentration patterns differed between sites.

Potassium and Mg concentrations were highest in the current needles at all heights in the crown, iron and manganese concentrations were highest in the oldest needles. The concentrations of N, P and Zn did not vary with needle age.

  • Finér, ORCID ID:E-mail:
article id 5513, category Article
Tapani Pöykkö, Pirkko Velling. (1993). Inheritance of the narrow-crowned Scots pine E 1101, "Kanerva pine". Silva Fennica vol. 27 no. 3 article id 5513. https://doi.org/10.14214/sf.a15674

There is some evidence to support the hypothesis that crown form of Scots pine (Pinus sylvestris L.) can be inherited either mono- or polygenically. In Finland, a narrow, horizontal whorl-layer structure is striking in about one half of the offspring of a genotype E 1101, ”Kanerva pine”. The offspring are characterized by a narrow crown, short and thin branches at an angle of 90° to the stem, minimal tapering and by numerous long, lateral shoots, long needles and the common occurrence of three-needled fascicles among the dwarf shoots. These features are connected to a high growth rate, a high harvest index and to tortuosity of the stem. It is suggested that this complex of characters is determined by a single dominant gene.

In this study, several offspring of the E 1101 were classified into three form types in seven sets of progeny test data, including progenies of various ages having E 1101 as either maternal or paternal parent as well as open pollinated progenies of second-generation offspring. A segregation close to 1:1 was found both in the first and in the second-generation progenies when wilds and intermediates were combined and compared with Kanervas. The result indicates that the three types of Kanerva form can be due to a single dominant allele (K). Kanervas are heterozygous (Kk) for the allele and wilds are recessive homozygotes (kk) resulting 1:1 segregation in their progenies. However, there were also remarkable deviations from the expected distribution. The differences as well as the inheritance pattern are discussed.

The PDF includes an abstract in Finnish.

  • Pöykkö, ORCID ID:E-mail:
  • Velling, ORCID ID:E-mail:
article id 5507, category Article
John L. Innes. (1993). Methods to estimate forest health. Silva Fennica vol. 27 no. 2 article id 5507. https://doi.org/10.14214/sf.a15668

A range of different indices are available for assessing the health of trees in forests. An even larger range can be used for the assessment of the health of forest ecosystems. Most studies made in connection with ”forest decline” and the impact of air pollution and other environmental stresses on forests have concentrated on the assessment of crown transparency and crown discoloration in individual trees. These are non-specific indicators which are now known to be sometimes of relatively little value when determining the health of a forest ecosystem. Numerous problems exist with both, and the standardisation of assessments between and even within countries has not been achieved. Consequently, studies claiming to compare ”defoliation” between different countries cannot be substantiated. The emphasis on crown transparency and crown discoloration has resulted in the neglect of a number of other indices that could be of considerable value. These include a variety of visual measures of crown condition and also several non-visual bioindicators. Some of these techniques are objective, reducing the present reliance on observed standardization. A large number of potential techniques are currently at the research stage and have yet to be adequately tested in field trials. This represent an area where a substantial amount of further research is required.

  • Innes, ORCID ID:E-mail:
article id 5459, category Article
Pertti Pulkkinen. (1991). Crown form and harvest increment in pendulous Norway spruce. Silva Fennica vol. 25 no. 4 article id 5459. https://doi.org/10.14214/sf.a15617

Crown characteristics and the distribution of three years’ (1986–88) biomass production of 20 pendulous Norway spruce (Picea abies f. pendula (Lawson) Sylvén) trees with heritable narrow crown and 15 normal-growned spruces (Picea abies (L.) H. Karst.) were studied in a 19-year-old mixed stand.

The form of the crown is conical in normal-crowned trees, columnar and narrow in pendulous trees. The partitioning of aboveground biomass to stems during the studied 3-year period was significantly higher in pendulous (0.281) than in normal-crowned trees (0.255) and also the ratio between growth of stemwood and growth of needle biomass during three years was higher in pendulous trees (0.67 g g-1) than in normal-crowned trees (0.52 g g-1). The needle biomass was distributed higher in the crown in pendula than in normal-crowned trees and they had a higher needle biomass/branchwood biomass ratio than normal trees. The difference in harvest increment between the two crown types are mostly due to the significantly lower branchwood biomass values in pendulous than in normal-crowned trees. The higher needle ’efficiency’ in pendulous trees is probably connected with high partitioning of needle biomass to the upper part of the crown in pendulous trees.

The PDF includes an abstract in Finnish.

  • Pulkkinen, ORCID ID:E-mail:
article id 5458, category Article
Jaroslaw Burczyk, Grzegorz Kosiński, Andrzej Lewandowski. (1991).  . Silva Fennica vol. 25 no. 4 article id 5458. https://doi.org/10.14214/sf.a15616
English title: Mating pattern and empty seed formation in relation to crown level of Larix decidua (Mill.) clones.

The mating system was analysed in the upper and lower crown of two groups of European larch (Larix decidua Mill.) clones divided according to the percentage of full seeds in the upper and lower crown parts. The overall multilocus estimate of outcrossing rate (t) was calculated to be 0.929. The differences of outcrossing rates between crown levels and clonal groups respectively were not statistically significant. The t estimates were greater for the upper crown level and for clones with higher percentage of full seeds in the upper crown level. However, among all observations there was no correlation between outcrossing rates and percentages of full seeds for particular crown levels and groups of clones. Observed similarity of outcrossing among grafts of the same clones may indicate genetic control of self-fertilization rate in individual European larch. 

The PDF includes an abstract in Finnish.

  • Burczyk, ORCID ID:E-mail:
  • Kosiński, ORCID ID:E-mail:
  • Lewandowski, ORCID ID:E-mail:
article id 5347, category Article
Timo Kuuluvainen, Markku Kanninen, Juha-Pekka Salmi. (1988). Tree architecture in young Scots pine: properties, spatial distribution and relationships of components of tree architecture. Silva Fennica vol. 22 no. 2 article id 5347. https://doi.org/10.14214/sf.a15504

The architecture of Scots pine (Pinus sylvestris L.) was studied in an eight-year-old progeny test. The measurements included characteristics of crown structure, spatial distribution of shoots and yield components. The spatial distribution of shoots showed striking between-tree differences, and two extreme distribution patterns were detected. One represented a non-layered structure with a vertically relative even shoot distribution, and the other a layered structure with a vertically highly uneven shoot distribution.

Close correlations existed between several components of tree architecture and it is suggested that changes in the phenotypic architecture in Scots pine follow an epigenetic pattern, which enables the prediction of adaptational changes in structural components. The structural characteristics related to high above-ground biomass were a long crown, high total shoot length, high number of branches per whorl and big shoots of low needle density occupying a big share of the crown volume.

The PDF includes a summary in Finnish.

  • Kuuluvainen, ORCID ID:E-mail:
  • Kanninen, ORCID ID:E-mail:
  • Salmi, ORCID ID:E-mail:
article id 5316, category Article
Timo Pukkala, Timo Kuuluvainen. (1987). Effect of canopy structure on the diurnal interception of direct solar radiation and photosynthesis in a tree stand. Silva Fennica vol. 21 no. 3 article id 5316. https://doi.org/10.14214/sf.a15473

The utilization of direct radiation was studied in five model stands of Poisson-type tree distribution and cone-shaped crowns. The radiation extinction depended on the self-shading of the crown and the shading caused by other trees. The results indicate that at low sun elevation a stand populated by very narrow-crowned trees is most effective in light interception and photosynthesis. At high sun elevation a broad-crowned canopy is best illuminated and most favourable for photosynthesis. A stand with a two-storey canopy is effective in all latitudes when the crowns are moderately narrow. In two-storey canopies the foliage of the lower storey can be better illuminated than in the lower parts of the upper storey, because of the smaller self-shading in the small crowns of the lower storey. A canopy where the crown volume is concentrated on few big crowns is less effective than a canopy consisting of many small crowns.

The PDF includes an abstract in Finnish.

  • Pukkala, ORCID ID:E-mail:
  • Kuuluvainen, ORCID ID:E-mail:
article id 5189, category Article
Anneli Viherä, Seppo Kellomäki. (1983). Havaintoja nuorten mäntyjen latvusten hienorakenteesta ja kasvusta. Silva Fennica vol. 17 no. 3 article id 5189. https://doi.org/10.14214/sf.a15172
English title: Observations on structure and growth of crowns of young Scots pines.

A study based on four young Scots pines (Pinus sylvestris L.) showed that the number of needle-covered shoots per crown volume unit was independent on tree position representing a constant value of 600–700 shoots/m3. This was true, even though the total shoot number decreased with deteriorating tree position. In tree crown there were fourth-order shoots in good light conditions but only first- and second-order-shoots, when light conditions were poor. The length of shoots decreased in accordance with increasing order of the shoot.

The share of the needle biomass and growth increased, when the shoot order increased. Similarly, the share of needles increased with deteriorating tree position. This was especially true in the upper crown. On the other hand, the share of the crown from the total biomass and growth increased with improving tree position. The percentage of crown system of a dominant tree in a sparse stand was 64% of that of biomass and 83% of that of growth. The corresponding values for a suppressed tree in a dense stand were 36% and 35%. The growth of wood, bark and needles in crown systems was linearly correlated with prevailing light conditions around the branch. It is evident that the tree position and light condition within the stand control the wood, bark and needle growth in the crown system and their interrelationships.

The PDF includes a summary in English.

  • Viherä, ORCID ID:E-mail:
  • Kellomäki, ORCID ID:E-mail:
article id 5189, category Article
Anneli Viherä, Seppo Kellomäki. (1983). Havaintoja nuorten mäntyjen latvusten hienorakenteesta ja kasvusta. Silva Fennica vol. 17 no. 3 article id 5189. https://doi.org/10.14214/sf.a15172
English title: Observations on structure and growth of crowns of young Scots pines.

A study based on four young Scots pines (Pinus sylvestris L.) showed that the number of needle-covered shoots per crown volume unit was independent on tree position representing a constant value of 600–700 shoots/m3. This was true, even though the total shoot number decreased with deteriorating tree position. In tree crown there were fourth-order shoots in good light conditions but only first- and second-order-shoots, when light conditions were poor. The length of shoots decreased in accordance with increasing order of the shoot.

The share of the needle biomass and growth increased, when the shoot order increased. Similarly, the share of needles increased with deteriorating tree position. This was especially true in the upper crown. On the other hand, the share of the crown from the total biomass and growth increased with improving tree position. The percentage of crown system of a dominant tree in a sparse stand was 64% of that of biomass and 83% of that of growth. The corresponding values for a suppressed tree in a dense stand were 36% and 35%. The growth of wood, bark and needles in crown systems was linearly correlated with prevailing light conditions around the branch. It is evident that the tree position and light condition within the stand control the wood, bark and needle growth in the crown system and their interrelationships.

The PDF includes a summary in English.

  • Viherä, ORCID ID:E-mail:
  • Kellomäki, ORCID ID:E-mail:
article id 5171, category Article
Seppo Kellomäki, Pauline Oker-Blom. (1983). Canopy structure and light climate in a young Scots pine stand. Silva Fennica vol. 17 no. 1 article id 5171. https://doi.org/10.14214/sf.a15086

The needle area distribution and crown structure of a young planted Scots pine (Pinus sylvestris L.) stand are described. The crown structure and crown shape showed apparent regularity in crown structure regardless of stand dynamics. Similarly, the shoot structure and individual needle area showed regularity in the number of needles per branch and shoot length unit, and consequent phytoarea density inside the needle cylinder. Also, the shoot area and needle area distributions were found to show a regular distribution of needle biomass throughout the crown, also inside the crown, in the dominant trees. In the suppressed trees the needle biomass was located in the upper crown and on the surface area of the crown. Estimates of the canopy needle area and distributions are given. The results were applied in calculations of the within-stand light regime. The results correlated well with the empirical results.

The PDF includes a summary in Finnish.

  • Kellomäki, ORCID ID:E-mail:
  • Oker-Blom, ORCID ID:E-mail:
article id 7048, category Article
O. J. Lakari. (1920). Tutkimuksia männyn muodosta. Acta Forestalia Fennica vol. 16 no. 6 article id 7048. https://doi.org/10.14214/aff.7048
English title: Studies on the stem and crown form of Scots pine.
English keywords: stem form; canopy layer; crown class

Crown class is useful tool both in forest management and forest mensuration. The study presents a detailed crown classification for Scots pine (Pinus sylvestris L.). It was used to classify the sample trees prior detailed measurements of the crown and stem form. The stem form of a tree was dependent on which canopy layer it belonged. This relation was detected on both Vaccinium and Calluna site type forests. In addition, the stem tapers faster in poorer forest site types compared to better sites. The shorter the self-pruned part of the stem is, the faster the stem tapers. According to the study, the stems of stunted trees taper faster than trees of other crown classes. Also the age group affects stem form.

The PDF includes a summary in German.

  • Lakari, ORCID ID:E-mail:
article id 5125, category Article
Ilppo Greis, Seppo Kellomäki. (1981). Crown structure and stem growth of Norway spruce undergrowth under varying shading. Silva Fennica vol. 15 no. 3 article id 5125. https://doi.org/10.14214/sf.a15066

The crown structure and stem growth of Norway spruce (Picea abies (L.) H. Karst.) undergrowth was studied in relation to the prevailing light conditions and potential photosynthesis. Shading decreased the stem height growth more than the length increment of laterals, producing a plate-shaped crown in deep shade. Needles responded to shading by adopting a horizontal inclination in deep shade. The needles were wide and thin respectively in shade. In the open the needle cross-section was almost square. Stem radial growth and height growth were both affected by shading exhibiting a linear response to the prevailing light conditions and the potential photosynthesis. Light conditions under dominating trees were closely correlated with the basal area of the dominating trees.

The PDF includes a summary in Finnish.

  • Greis, ORCID ID:E-mail:
  • Kellomäki, ORCID ID:E-mail:
article id 5125, category Article
Ilppo Greis, Seppo Kellomäki. (1981). Crown structure and stem growth of Norway spruce undergrowth under varying shading. Silva Fennica vol. 15 no. 3 article id 5125. https://doi.org/10.14214/sf.a15066

The crown structure and stem growth of Norway spruce (Picea abies (L.) H. Karst.) undergrowth was studied in relation to the prevailing light conditions and potential photosynthesis. Shading decreased the stem height growth more than the length increment of laterals, producing a plate-shaped crown in deep shade. Needles responded to shading by adopting a horizontal inclination in deep shade. The needles were wide and thin respectively in shade. In the open the needle cross-section was almost square. Stem radial growth and height growth were both affected by shading exhibiting a linear response to the prevailing light conditions and the potential photosynthesis. Light conditions under dominating trees were closely correlated with the basal area of the dominating trees.

The PDF includes a summary in Finnish.

  • Greis, ORCID ID:E-mail:
  • Kellomäki, ORCID ID:E-mail:
article id 5116, category Article
Seppo Kellomäki, Pauline Oker-Blom. (1981). Specific needle area of Scots pine and its dependence on light conditions inside the canopy. Silva Fennica vol. 15 no. 2 article id 5116. https://doi.org/10.14214/sf.a15057

The specific needle area of young Scots pine (Pinus sylvestris L.) showed a substantial within-tree and between-tree variation which was associated with the position of the tree and the position of the whorl as indicated by the prevailing crown and branch illumination. In suppressed trees the values of the specific needle area were three to four times those in dominating trees. A similar morphogenesis was discernible in comparison of the lower and the upper part of the crown. The mean specific needle area value for the whole stand was 184 cm2/g.

The PDF includes a summary in Finnish.

  • Kellomäki, ORCID ID:E-mail:
  • Oker-Blom, ORCID ID:E-mail:
article id 5116, category Article
Seppo Kellomäki, Pauline Oker-Blom. (1981). Specific needle area of Scots pine and its dependence on light conditions inside the canopy. Silva Fennica vol. 15 no. 2 article id 5116. https://doi.org/10.14214/sf.a15057

The specific needle area of young Scots pine (Pinus sylvestris L.) showed a substantial within-tree and between-tree variation which was associated with the position of the tree and the position of the whorl as indicated by the prevailing crown and branch illumination. In suppressed trees the values of the specific needle area were three to four times those in dominating trees. A similar morphogenesis was discernible in comparison of the lower and the upper part of the crown. The mean specific needle area value for the whole stand was 184 cm2/g.

The PDF includes a summary in Finnish.

  • Kellomäki, ORCID ID:E-mail:
  • Oker-Blom, ORCID ID:E-mail:
article id 5092, category Article
Seppo Kellomäki, Markku Kanninen. (1980). Eco-physiological studies on young Scots pine stands. IV. Silva Fennica vol. 14 no. 4 article id 5092. https://doi.org/10.14214/sf.a15033

Crown and stem growth of young Scots pines (Pinus sylvestris L.) were studied in relation to photosynthate supply and light condition in a stand. The magnitude of needle and bud formation, and radial and height growth were to a great extent dependent on the photosynthate supply. However, in shaded conditions the growth of each characteristics was greater than expected on the basis of photosynthate supply. In the stem system this was especially apparent for height growth. Consequently, height growth was favoured at the expense of radial growth in shaded conditions. It also appeared that the basic density of wood was negatively related to both tree position and photosynthate supply.

The PDF includes a summary in Finnish.

  • Kellomäki, ORCID ID:E-mail:
  • Kanninen, ORCID ID:E-mail:
article id 5079, category Article
Seppo Kellomäki, Pertti Hari, Pirkko Ilonen, Markku Kanninen. (1980). Eco-physiological studies on young Scots pine stands. II. Silva Fennica vol. 14 no. 3 article id 5079. https://doi.org/10.14214/sf.a15020

The technique of double normalizing, i.e. normalizing the relative needle biomass and the length of the living crown system, is applied to the modelling of the distribution of needle biomass in the canopy of young Scots pine (Pinus sylvestris L.) stands. The study based on the parameters of β-function shows that at the individual-tree level, the variance in needle distribution was not closely associated with any tree characteristics. A shift in the point of maximum needle biomass upwards unsuppressed trees was, however, evident. This was associated with an increase in the height of the trees. At the stand level, the stand mean height and stand density had an equal and a rather high potential for explaining the variance in the needle distribution. The normalized crowns are utilized in models for determining light extinction in the crown. A special technique for determining the amount of photosynthates available for growth in a particular tree is presented.

The PDF includes a summary in Finnish.

  • Kellomäki, ORCID ID:E-mail:
  • Hari, ORCID ID:E-mail:
  • Ilonen, ORCID ID:E-mail:
  • Kanninen, ORCID ID:E-mail:
article id 7519, category Article
Jori Uusitalo. (1997). Pre-harvest measurement of pine stands for sawing production planning. Acta Forestalia Fennica no. 259 article id 7519. https://doi.org/10.14214/aff.7519

To enhance the utilization of the wood, the sawmills are forced to place more emphasis on planning to master the whole production chain from the forest to the end product. One significant obstacle to integrating the forest-sawmill-market production chain is the lack of appropriate information about forest stands. Since the wood procurement point of view in forest planning systems has been almost totally disregarded there has been a great need to develop an easy and efficient pre-harvest measurement method, allowing separate measurement of stands prior to harvesting. The main purpose of this study was to develop a measurement method for Scots pine (Pinus sylvestris L.) stands which forest managers could use in describing the properties of the standing trees for sawing production planning.

Study materials were collected from ten Scots pine stands located in North Häme and South Pohjanmaa, in Southern Finland. The data comprise test sawing data on 314 pine stems, diameter at breast height (dbh) and height measures of all trees and measures of the quality parameters of pine sawlog stems in all ten study stands as well as the locations of all trees in six stands. The study was divided into four sub-studies which deal with pine quality prediction, construction of diameter and dead branch height distributions, sampling designs and applying height and crown height models. The final proposal for the pre-harvest measurement method is a synthesis of the individual sub-studies.

Quality analysis resulted in choosing dbh, distance from stump height to the first dead branch, crown height and tree height as the most appropriate quality characteristics of Scots pine. Dbh and dead branch height are measured from each pine sample tree while height and crown height are derived from dbh measures by aid of mixed height and crown height models. Pine and spruce diameter distribution as well as dead branch height distribution are most effectively predicted by the kernel function. Roughly 25 sample trees seem to be appropriate in pure pine stands. In mixed stands the number of sample trees needs to be increased in proportion to the intensity of pines in order to attain the same level of accuracy.

  • Uusitalo, ORCID ID:E-mail:
article id 7685, category Article
Risto Ojansuu. (1993). Prediction of Scots pine increment using a multivariate variance component model. Acta Forestalia Fennica no. 239 article id 7685. https://doi.org/10.14214/aff.7685

Diameter and volume increment as well as change in stem form of Scots pine (Pinus sylvestris L.) were analysed to predict tree increment variables. A stem curve set model is presented, based on prediction of the diameters at fixed angles in a polar coordinate system. This model consists of three elementary stem curves: 1) with bark, 2) without bark, and 3) without bark five years earlier. The differences between the elementary stem curves are the bark curve and the increment curve. The error variances at fixed angles and covariances between the fixed angles are divided into between-stand and within-stand components. Using principal components, the between-stand and within-stand covariance matrices are condensed separately for stem curve with bark, bark curve and increment curve. The two first principal components of the bark curve describe the vertical change in Scots pine bark type and the first principal component of the increment curve describes the increment rate. The elementary stem curves, bark curve and increment curve as well as corresponding stem volumes, bark volume and volume increment can be predicted for all trees in the stand with free choice of sample tree measurements. When only a few sample trees are measured, the stem curve set model gives significantly more accurate predictions of bark volume and volume increment for tally trees than does the volume method, which is based on the differences between two independent predictions of volume. The volume increment of tally trees can be predicted as reliably with as without measurement of sample tree height increment.

The PDF includes a summary in English.

  • Ojansuu, ORCID ID:E-mail:
article id 4600, category Article
Aarne Nyyssönen. (1950). Vertailevia havaintoja hoidettujen ja luonnontilaisten männiköiden rakenteesta ja kehityksestä. Silva Fennica no. 68 article id 4600. https://doi.org/10.14214/sf.a9091
English title: Comparative study on structure and development of managed and natural Scots pine stands.

The Forest Research Institute of Finland has established permanent sample plots to survey the effect of thinnings on the stands. This study compares the development of tended and natural Scots pine (Pinus sylvestris L.) stands growing on three different forest types: Oxalis-Myrtillus, Vaccinium and Calluna site type. The effect of heavy thinning from below (Oxalis-Myrtillus and Vaccinium site types) and increment felling (Calluna site type) was assessed by dividing the trees of the stands in tree classification classes according to their crown storey and defects.

The results show that thinning from below and increment thinning increase the proportion of trees in the 1st crown storey, which is already large in the natural stands. Also the diameter distribution is more even and the mean diameter higher after the thinnings.

In Scots pine stands in natural state, volume increment per stem is highest in the 1st crown storey and diminishes strongly towards the lower crown storeys. Thinnings increased the increment. The study indicates that many of the objectives of the intermediate cuttings, including promoting the growth of the best trees and improving the quality of the stand, have in general been achieved. Consequently, the thinnings give means to achieve the most valuable yield in the stand.

The article includes a summary in English.

  • Nyyssönen, ORCID ID:E-mail:
article id 4546, category Article
Peitsa Mikola. (1938). Kuusen latvus- ja runkomuodosta Maanselän lumituhoalueella. Silva Fennica no. 47 article id 4546. https://doi.org/10.14214/sf.a9071
English title: Crown and stem form of Norway spruce in the snow damage areas of Maanselkä in Northern Finland.

Finnish tree species have adapted differently to heavy snow loads that occur especially in fell areas in Kuusamo and Salla as well as Maanselkä area in Sotkamo and Rautavaara in Northern Finland. Norway spruce (Picea abies Karst. L) is adapted better than Scots pine (Pinus sylvestris L.). The aim of this study was to investigate how crown and stem form of Norway spruce in the snow damage area of Maanselkä area differ from other areas in the same region.  

Relatively broad crown at the base of the stem, quickly tapering crown and narrow and even upper crown were typical for trees growing in the snow damaged areas. The higher the altitude is, the stronger tapering the crown is. The tapering begins usually in a height of 4-5 meters. Even the stem diameter begins to taper strongly at this height. In the areas where heavy snow does not cause snow damage, top of crown is broader. Also, in the snow damage areas the damaged trees seem to have broader crown shape than the trees with little damages.  

Height of the trees decreases in the snow damage areas compared to forests in lower altitudes, which can be caused both by wind and snow load. 

The article includes a German summary. 

  • Mikola, ORCID ID:E-mail:
article id 4546, category Article
Peitsa Mikola. (1938). Kuusen latvus- ja runkomuodosta Maanselän lumituhoalueella. Silva Fennica no. 47 article id 4546. https://doi.org/10.14214/sf.a9071
English title: Crown and stem form of Norway spruce in the snow damage areas of Maanselkä in Northern Finland.

Finnish tree species have adapted differently to heavy snow loads that occur especially in fell areas in Kuusamo and Salla as well as Maanselkä area in Sotkamo and Rautavaara in Northern Finland. Norway spruce (Picea abies Karst. L) is adapted better than Scots pine (Pinus sylvestris L.). The aim of this study was to investigate how crown and stem form of Norway spruce in the snow damage area of Maanselkä area differ from other areas in the same region.  

Relatively broad crown at the base of the stem, quickly tapering crown and narrow and even upper crown were typical for trees growing in the snow damaged areas. The higher the altitude is, the stronger tapering the crown is. The tapering begins usually in a height of 4-5 meters. Even the stem diameter begins to taper strongly at this height. In the areas where heavy snow does not cause snow damage, top of crown is broader. Also, in the snow damage areas the damaged trees seem to have broader crown shape than the trees with little damages.  

Height of the trees decreases in the snow damage areas compared to forests in lower altitudes, which can be caused both by wind and snow load. 

The article includes a German summary. 

  • Mikola, ORCID ID:E-mail:
article id 4546, category Article
Peitsa Mikola. (1938). Kuusen latvus- ja runkomuodosta Maanselän lumituhoalueella. Silva Fennica no. 47 article id 4546. https://doi.org/10.14214/sf.a9071
English title: Crown and stem form of Norway spruce in the snow damage areas of Maanselkä in Northern Finland.

Finnish tree species have adapted differently to heavy snow loads that occur especially in fell areas in Kuusamo and Salla as well as Maanselkä area in Sotkamo and Rautavaara in Northern Finland. Norway spruce (Picea abies Karst. L) is adapted better than Scots pine (Pinus sylvestris L.). The aim of this study was to investigate how crown and stem form of Norway spruce in the snow damage area of Maanselkä area differ from other areas in the same region.  

Relatively broad crown at the base of the stem, quickly tapering crown and narrow and even upper crown were typical for trees growing in the snow damaged areas. The higher the altitude is, the stronger tapering the crown is. The tapering begins usually in a height of 4-5 meters. Even the stem diameter begins to taper strongly at this height. In the areas where heavy snow does not cause snow damage, top of crown is broader. Also, in the snow damage areas the damaged trees seem to have broader crown shape than the trees with little damages.  

Height of the trees decreases in the snow damage areas compared to forests in lower altitudes, which can be caused both by wind and snow load. 

The article includes a German summary. 

  • Mikola, ORCID ID:E-mail:

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