Current issue: 53(2)

Under compilation: 53(3)

Impact factor 1.683
5-year impact factor 1.950
Silva Fennica 1926-1997
1990-1997
1980-1989
1970-1979
1960-1969
Acta Forestalia Fennica
1953-1968
1933-1952
1913-1932

Articles containing the keyword 'Populus'.

Category: Research article

article id 5656, category Research article
Lars-Göran Stener, Johan Westin. (2017). Early growth and phenology of hybrid aspen and poplar in clonal field tests in Scandinavia. Silva Fennica vol. 51 no. 3 article id 5656. https://doi.org/10.14214/sf.5656
Highlights: Growth and survival was in general higher for hybrid aspen than for poplar; The poor performance of poplar was likely due to poor climatic adaptation or to high soil acidity; The genetic results indicate good possibilities for effective clonal selection; The results support current recommendations for utilization of selected hybrid aspen and poplar regeneration material in Sweden.

Results on early survival, growth and shoot phenology of hybrid aspen (Populus tremula L. × P. tremuloides Michx.) and poplar clones (P. trichocarpa Torr. & A. Gray, P. balsamifera L., P. maximowiczii A. Henry and their hybrids) in 13 Scandinavian field trials are presented. The trials were established on forest land (7 sites) or former agricultural land (6 sites) within the latitude range of 56° to 65° N and were assessed 3–4 years after establishment. The main aim was to evaluate phenotypic and genetic differences related to early survival, growth and phenology for hybrid aspen and poplar for different site types and latitudes. Growth and survival was generally higher for hybrid aspen than poplar at all sites. The poor performance of poplar compared to hybrid aspen is likely due to climatic maladaptation or high soil acidity. The early growth performance of the species need to be confirmed at a higher age. The genetic variation and genetic control for growth, phenology and survival was in general intermediate to large indicating good possibilities for effective clonal selection. The genetic site x site correlations (rGE) for growth were for hybrid aspen mostly strong, indicating a weak genotype by environment interaction, while rGE were inconsistent for poplars.The result suggests that southern Sweden can be treated as a single test and utilization zone and in northern Sweden the region along the coast may be another zone. It is too early to make any corresponding conclusions for poplar. In addition, the result backs up the current recommendations for utilization of selected hybrid aspen and poplar regeneration material in Sweden.

  • Stener, The Forestry Research Institute of Sweden, Ekebo 2250, 268 90 Svalöv, Sweden ORCID ID:E-mail: lars-goran.stener@skogforsk.se (email)
  • Westin, The Forestry Research Institute of Sweden, Box 3, 918 21 Sävar, Sweden ORCID ID:E-mail: johan.westin@skogforsk.se
article id 1579, category Research article
Oktay Yildiz, Ernaz Altundağ, Bilal Çeti̇n, Ş Teoman Guner, Murat Sarginci, Bulent Toprak. (2017). Afforestation restoration of saline-sodic soil in the Central Anatolian Region of Turkey using gypsum and sulfur. Silva Fennica vol. 51 no. 1B article id 1579. https://doi.org/10.14214/sf.1579
Highlights: Significantly enhanced height and diameter growth of Elaeagnus angustifolia and height growth of Populus alba improved with soil chemical amendments in comparison to control; Infiltration rate on gypsum application sites was 55% higher than on sulfur application sites; Elaeagnus angustifolia survival rates with chemical treatments were 43% greater than controls; Tamarix smyrnensis had the highest mean survival rate of 80%, while Populus alba averaged 36%.

A significant amount of land area in the Central Anatolian Region of Turkey has saline-sodic soil properties. The aim of the current study was to use both soil amendment and tree to restore these degraded lands. The primary objective was to ameliorate soils by leaching excess sodium with gypsum and sulfur applications. Following soil treatments, salt cedar (Tamarix smyrnensis Bunge), Russian olive (Elaeagnus angustifolia L.) and silver poplar (Populus alba L.) seedlings were planted on experimental and control sites to evaluate the effects of the treatments on survival and growth of these species. In the fall of 2013, three-year-old seedlings were planted using 1.5 × 1.5 m spacing on each plot. Survival rates were determined and height and diameter were measured at the end of September 2015. Second year infiltration measurements indicated that both chemical treatments had significantly increased the infiltration capacity of the soil (P = 0.0003). Soil infiltration capacity on gypsum treated sites was about 55% higher than on sulfur sites. Following the second growing season, salt cedar had the highest survival rates of 80%. Silver poplar had 36% survival rates across the treatments. Russian olive had 50 cm height growth on both gypsum and sulfur application sites vs. only 25 cm on controls. Diameters of Russian olive on gypsum and sulfur sites were about 9.3 mm vs. 5 mm on the controls. Silver poplars on gypsum treated sites grew 42% taller than controls. Salt cedar had no significant growth responses among treatments. With appropriate soil amendments, especially gypsum, Russian olive gave the best overall two-year results.

  • Yildiz, Düzce University, Faculty of Forestry, 81620 Duzce, Turkey ORCID ID:E-mail: oktayyildiz@duzce.edu.tr (email)
  • Altundağ, Düzce University, Faculty of Arts and Sciences, 81620 Duzce, Turkey ORCID ID:E-mail: ernazaltundag@duzce.edu.tr
  • Çeti̇n, Düzce University, Faculty of Forestry, 81620 Duzce, Turkey ORCID ID:E-mail: bilalcetin@duzce.edu.tr
  • Guner, Eskişehir Soil and Ecological Research Institute, General Directorate of Forestry, 06560 Yenimahalle/Ankara, Turkey ORCID ID:E-mail: stguner@ogm.gov.tr
  • Sarginci, Düzce University, Faculty of Forestry, 81620 Duzce, Turkey ORCID ID:E-mail: muratsarginci@duzce.edu.tr
  • Toprak, Düzce University, Faculty of Forestry, 81620 Duzce, Turkey ORCID ID:E-mail: bulenttoprak@duzce.edu.tr
article id 1410, category Research article
Seppo Nevalainen, Juho Matala, Kari T. Korhonen, Antti Ihalainen, Ari Nikula. (2016). Moose damage in National Forest Inventories (1986–2008) in Finland. Silva Fennica vol. 50 no. 2 article id 1410. https://doi.org/10.14214/sf.1410
Highlights: Almost 100 000 stands were studied; The proportion of damage doubled during the study period; Tree species mixture had a clear effect on the damage frequency; The damage was more common in mineral soils than in peatlands, in artificially than in naturally regenerated stands and in stands that needed thinning or clearing or in which soil preparation was used.

The occurrence of moose damage was studied using data from three National Forest Inventories (NFIs) accomplished between 1986 and 2008 in Finland. The combined data included a total of 97 390 young stands. The proportion of moose damage increased from 3.6% to 8.6% between the 8th NFI (1986–1994) and the 10th NFI (2004–2008). The majority (75%) of the damage occurred in Scots pine-dominated stands. The proportion of damage was higher in aspen-dominated stands than in stands dominated by any other tree species. The tree species mixture also had a clear effect on the occurrence of damage. Pure Scots pine stands had less damage than mixed Scots pine stands, and moose damage decreased linearly with the increasing proportion of Scots pine. Stands on mineral soil had more frequent moose damage than stands on peatlands. The fertility class of the site had no straightforward effect on the damage frequency. Artificially regenerated stands had more damage than naturally regenerated stands. Accomplished soil preparation measures and the need for thinning or clearing operations increased moose damage. High proportions of moose damage in young stands were found around the country. In the 10th NFI, the largest concentration of damage was found in southwestern Finland. Our study shows the temporal and spatial changes in the occurrence of moose damage and pinpoints some important silvicultural factors affecting the relative risk of young stands over a large geographical area.

  • Nevalainen, Natural Resources Institute Finland (Luke), Management and Production of Renewable Resources, P.O. Box 68, FI-80101 Joensuu, Finland ORCID ID:E-mail: seppo.nevalainen@luke.fi (email)
  • Matala, Natural Resources Institute Finland (Luke), Management and Production of Renewable Resources, P.O. Box 68, FI-80101 Joensuu, Finland ORCID ID:E-mail: juho.matala@luke.fi
  • Korhonen, Natural Resources Institute Finland (Luke), Economics and society, P.O. Box 68, FI-80101 Joensuu, Finland ORCID ID:E-mail: kari.t.korhonen@luke.fi
  • Ihalainen, Natural Resources Institute Finland (Luke), Economics and society, P.O. Box 18, FI-01301 Vantaa, Finland ORCID ID:E-mail: antti.ihalainen@luke.fi
  • Nikula, Natural Resources Institute Finland (Luke), Economics and society, P.O. Box 16, FI-96301 Rovaniemi, Finland ORCID ID:E-mail: ari.nikula@luke.fi
article id 1135, category Research article
Matts Lindbladh, Per-Ola Hedwall, Ida Wallin, Annika M. Felton, Henrik Böhlenius, Adam Felton. (2014). Short-rotation bioenergy stands as an alternative to spruce plantations: implications for bird biodiversity. Silva Fennica vol. 48 no. 5 article id 1135. https://doi.org/10.14214/sf.1135
Highlights: There is a gap in knowledge regarding the biodiversity implications of replacing production forests with bioenergy stands; We compared the avian biodiversity of early rotation hybrid aspen stands and spruce plantations, the latter being the dominant production forest type in southern Sweden; Our results indicate that young hybrid aspen stands can support relatively diverse and distinctive bird communities.
Global efforts to decrease dependence on fossil fuels have increased interest in bioenergy production. One source of bioenergy is fast growing deciduous tree species, such as hybrid aspen (Populus × wettsteinii Hämet-Ahti). The majority of research on hybrid aspen which assesses biodiversity implications, has however primarily focused on agricultural lands as the reference condition. This has resulted in a substantial gap in our knowledge regarding the biodiversity implications of replacing production forest types with hybrid aspen, a form of reforestation taking place in northern Europe. In this study we address this knowledge gap by comparing the avian biodiversity of young hybrid aspen and spruce (Picea abies L.) plantations of similar age, the latter being the most prevalent forestry alternative in in southern Sweden. We found that hybrid aspen stands had higher bird species richness and abundance as well as a distinct community composition compared to the spruce stands. We suggest that the most likely driver was the greater structural and tree species complexity in the aspen stands, provided for by the fenced exclusion of ungulates from the regenerating hybrid aspen stands. Our results indicate that at least during early stages of regeneration, and in comparison to the dominating production forest type in the region, hybrid aspen stands can support relatively high levels of bird diversity, and a bird species composition more closely associated with broadleaf habitat types requiring restoration in this region.
  • Lindbladh, Southern Swedish Forest Research Centre, SLU – Swedish University of Agricultural Sciences, P.O. Box 49, SE-230 53 Alnarp, Sweden ORCID ID:E-mail: matts.lindbladh@slu.se (email)
  • Hedwall, Southern Swedish Forest Research Centre, SLU – Swedish University of Agricultural Sciences, P.O. Box 49, SE-230 53 Alnarp, Sweden ORCID ID:E-mail: per-ola.hedwall@slu.se
  • Wallin, Southern Swedish Forest Research Centre, SLU – Swedish University of Agricultural Sciences, P.O. Box 49, SE-230 53 Alnarp, Sweden ORCID ID:E-mail: ida.wallin@slu.se
  • Felton, Southern Swedish Forest Research Centre, SLU – Swedish University of Agricultural Sciences, P.O. Box 49, SE-230 53 Alnarp, Sweden ORCID ID:E-mail: annika.felton@slu.se
  • Böhlenius, Southern Swedish Forest Research Centre, SLU – Swedish University of Agricultural Sciences, P.O. Box 49, SE-230 53 Alnarp, Sweden ORCID ID:E-mail: henrik.bohlenius@slu.se
  • Felton, Southern Swedish Forest Research Centre, SLU – Swedish University of Agricultural Sciences, P.O. Box 49, SE-230 53 Alnarp, Sweden ORCID ID:E-mail: adam.felton@slu.se
article id 1107, category Research article
Arvo Tullus, Arne Sellin, Priit Kupper, Reimo Lutter, Linnar Pärn, Anna K. Jasinska, Meeli Alber, Maarja Kukk, Tea Tullus, Hardi Tullus, Krista Lõhmus, Anu Sõber. (2014). Increasing air humidity – a climate trend predicted for northern latitudes – alters the chemical composition of stemwood in silver birch and hybrid aspen. Silva Fennica vol. 48 no. 4 article id 1107. https://doi.org/10.14214/sf.1107
Highlights: Hybrid aspen and silver birch trees grew more slowly under increased air humidity conditions and had higher concentrations of N and P and a lower K to N ratio in stemwood; Minor species-specific changes were detected in stemwood concentrations of cellulose and hemicellulose; Density, calorific value and concentrations of lignin and ash in stemwood were not affected by elevated humidity.
We studied the physicochemical properties of stemwood in saplings of silver birch (Betula pendula Roth) and hybrid aspen (Populus tremula L. × P. tremuloides Michx.), grown for four years under artificially elevated relative air humidity (on average by 7%) in field conditions, using the Free Air Humidity Manipulation (FAHM) research facility in Estonia. Altogether 91 sample trees from three experimental plots with manipulated air humidity and from three control plots were cut in the dormant season and sampled for the analysis of cellulose, hemicellulose, acid detergent lignin, macronutrients (N, P, K), ash content, density, and calorific value of wood. The analysed trees grew significantly more slowly under elevated humidity conditions, with a more pronounced effect on aspens. Significantly higher concentrations of N and P were observed in the stemwood of both aspens and birches grown under elevated humidity. This could be the result of a change in the content of living parenchyma cells and/or enhanced retranslocation of nutrients into wood parenchyma. Additionally, humidification resulted in a significantly higher concentration of cellulose and a lower concentration of hemicellulose in aspen stemwood, and in significantly lower concentrations of cellulose and K in birch stemwood. Elevated humidity did not affect lignin concentration, ash content, basic density and calorific value of stemwood. Results from the FAHM experiment suggest that the increasing air humidity accompanying global warming at northern latitudes will affect the growth and functioning of deciduous trees and forests, with obvious consequences also for forest management and industry.
  • Tullus, Department of Botany, Institute of Ecology and Earth Sciences, Faculty of Science and Technology, University of Tartu, Lai 40, Tartu 51005, Estonia ORCID ID:E-mail: arvo.tullus@ut.ee (email)
  • Sellin, Department of Botany, Institute of Ecology and Earth Sciences, Faculty of Science and Technology, University of Tartu, Lai 40, Tartu 51005, Estonia ORCID ID:E-mail: arne.sellin@ut.ee
  • Kupper, Department of Botany, Institute of Ecology and Earth Sciences, Faculty of Science and Technology, University of Tartu, Lai 40, Tartu 51005, Estonia ORCID ID:E-mail: priit.kupper@ut.ee
  • Lutter, Institute of Forestry and Rural Engineering, Estonian University of Life Sciences, Kreutzwaldi 5, Tartu 51014, Estonia ORCID ID:E-mail: reimo.lutter@emu.ee
  • Pärn, Institute of Forestry and Rural Engineering, Estonian University of Life Sciences, Kreutzwaldi 5, Tartu 51014, Estonia ORCID ID:E-mail: linnar.parn@emu.ee
  • Jasinska, Department of Botany, Institute of Ecology and Earth Sciences, Faculty of Science and Technology, University of Tartu, Lai 40, Tartu 51005, Estonia & Institute of Dendrology, Polish Academy of Sciences, Parkowa 5, 62-035 Kórnik, Poland ORCID ID:E-mail: jasiak9@wp.pl
  • Alber, Department of Botany, Institute of Ecology and Earth Sciences, Faculty of Science and Technology, University of Tartu, Lai 40, Tartu 51005, Estonia ORCID ID:E-mail: meeli.alber@ut.ee
  • Kukk, Department of Botany, Institute of Ecology and Earth Sciences, Faculty of Science and Technology, University of Tartu, Lai 40, Tartu 51005, Estonia ORCID ID:E-mail: maarja.kukk@ut.ee
  • Tullus, Institute of Forestry and Rural Engineering, Estonian University of Life Sciences, Kreutzwaldi 5, Tartu 51014, Estonia ORCID ID:E-mail: tea.tullus@emu.ee
  • Tullus, Institute of Forestry and Rural Engineering, Estonian University of Life Sciences, Kreutzwaldi 5, Tartu 51014, Estonia ORCID ID:E-mail: hardi.tullus@emu.ee
  • Lõhmus, Department of Botany, Institute of Ecology and Earth Sciences, Faculty of Science and Technology, University of Tartu, Lai 40, Tartu 51005, Estonia ORCID ID:E-mail: krista.lohmus@ut.ee
  • Sõber, Department of Botany, Institute of Ecology and Earth Sciences, Faculty of Science and Technology, University of Tartu, Lai 40, Tartu 51005, Estonia ORCID ID:E-mail: anu.sober@ut.ee
article id 1019, category Research article
Michael Henke, Stephan Huckemann, Winfried Kurth, Branislav Sloboda. (2014). Reconstructing leaf growth based on non-destructive digitizing and low-parametric shape evolution for plant modelling over a growth cycle. Silva Fennica vol. 48 no. 2 article id 1019. https://doi.org/10.14214/sf.1019
Highlights: A complete pipeline for plant organ modelling (at the example of poplar leaves) is presented, from non-destructive data acquisition, over automated data extraction, to growth and shape modelling; Leaf contour models are compared; Resulting “organ” modules are ready for use in FSPMs.
A simple and efficient photometric methodology is presented, covering all steps from field data acquisition to binarization and allowing for leaf contour modelling. This method comprises the modelling of area and size (correlated and modelled with a Chapman-Richards growth function, using final length as one parameter), and four shape descriptors, from which the entire contour can be reconstructed rather well using a specific spline methodology. As an improvement of this contour modelling method, a set of parameterized polynomials was used. To model the temporal kinetics of the shape, geodesics in shape spaces were employed. Finally it is shown how this methodology is integrated into the 3D modelling platform GroIMP.
  • Henke, Department Ecoinformatics, Biometrics & Forest Growth, University of Göttingen, 37077 Göttingen, Germany ORCID ID:E-mail: mhenke@uni-goettingen.de (email)
  • Huckemann, Institute of Mathematical Stochastics, University of Göttingen, 37077 Göttingen, Germany ORCID ID:E-mail: huckeman@math.uni-goettingen.de
  • Kurth, Department Ecoinformatics, Biometrics & Forest Growth, University of Göttingen, 37077 Göttingen, Germany ORCID ID:E-mail: wk@informatik.uni-goettingen.de
  • Sloboda, Department Ecoinformatics, Biometrics & Forest Growth, University of Göttingen, 37077 Göttingen, Germany ORCID ID:E-mail: bslobod@web.de
article id 1077, category Research article
Göran Bergqvist, Roger Bergström, Märtha Wallgren. (2014). Recent browsing damage by moose on Scots pine, birch and aspen in young commercial forests – effects of forage availability, moose population density and site productivity. Silva Fennica vol. 48 no. 1 article id 1077. https://doi.org/10.14214/sf.1077
Highlights: Moose damage was most common on aspen and least common on Scots pine; Damage to Scots pine increased when the amount of pine browse decreased, moose index and site index increased and when birch was overtopping pine; Damage to birch increased when moose index increased and damage to aspen increased when the amount of pine and birch browse decreased.
Moose browsing damage from the winter preceding the study (recent damage) on Scots pine, birch and aspen was examined in relation to forage availability, an index of moose population density and site productivity in young forests in the hemiboreal zone. Recent damage was observed for 4.1 ± 0.54% (mean ± SE; Scots pine), 16.8 ± 1.89% (birch) and 67.6 ± 13.76% (aspen) of the trees. A multiple regression with five independent variables explained 19% (Scots pine) 14% (birch) and 33% (aspen) of the variation in recent damage. Cover of Scots pine browse was the most important variable for predicting damage to Scots pine and accounted for 44% of the explained variation. When birch was overtopping pine there was a significant increase in damage to pine. Moose index was the only significant variable to explain recent damage to birch, and accounted for 64% of the explained variation. For aspen, damage was negatively correlated to coverage of Scots pine and birch browse, each variable accounting for 38% of the explained variation. For Scots pine, increasing the number of pines ha–1 and performing pre-commercial thinning in such a way that pines are not overtopped may be efficient ways of reducing damage proportions, whereas birch needs to be protected from moose (by a reduction of the moose population or otherwise) in order to escape damage. Increased amounts of Scots pine browse and birch browse may also reduce damage levels to aspen, according to this study.
  • Bergqvist, Swedish Association for Hunting and Wildlife Management, Öster Malma, SE-611 91 Nyköping, Sweden ORCID ID:E-mail: goran.bergqvist@jagareforbundet.se (email)
  • Bergström, Forestry Research Institute of Sweden, Uppsala Science Park, SE-751 83 Uppsala, Sweden; (present) Gropgränd 2 A, SE-753 10 Uppsala, Sweden ORCID ID:E-mail: larsrogerbergstrom@yahoo.com
  • Wallgren, Forestry Research Institute of Sweden, Uppsala Science Park, SE-751 83 Uppsala, Sweden ORCID ID:E-mail: martha.wallgren@skogforsk.se
article id 962, category Research article
Paul A. Klockow, Anthony W. D'Amato, John B. Bradford, Shawn Fraver. (2014). Nutrient concentrations in coarse and fine woody debris of Populus tremuloides Michx.-dominated forests, northern Minnesota, USA. Silva Fennica vol. 48 no. 1 article id 962. https://doi.org/10.14214/sf.962
Highlights: We examine effects of size, species, and decay on woody debris nutrient concentrations; Results indicate wide variation in nutrient concentrations across the factors examined; Fine woody debris nutrient concentrations were greater than in coarse woody debris; Coarse woody debris nutrient concentrations generally increased as decay progressed; Results suggest high fine woody debris stocks can represent an important nutrient source.
Contemporary forest harvesting practices, specifically harvesting woody biomass as a source of bioenergy feedstock, may remove more woody debris from a site than conventional harvesting. Woody debris, particularly smaller diameter woody debris, plays a key role in maintaining ecosystem nutrient stores following disturbance. Understanding nutrient concentrations within woody debris is necessary for assessing the long-term nutrient balance consequences of altered woody debris retention, particularly in forests slated for use as bioenergy feedstocks. Nutrient concentrations in downed woody debris of various sizes, decay classes, and species were characterized within one such forest type, Populus tremuloides Michx.-dominated forests of northern Minnesota, USA. Nutrient concentrations differed significantly between size and decay classes and generally increased as decay progressed. Fine woody debris (≤ 7.5 cm diameter) had higher nutrient concentrations than coarse woody debris (> 7.5 cm diameter) for all nutrients examined except Na and Mn, and nutrient concentrations varied among species. Concentrations of N, Mn, Al, Fe, and Zn in coarse woody debris increased between one and three orders of magnitude, while K decreased by an order of magnitude with progressing decay. The variations in nutrient concentrations observed here underscore the complexity of woody debris nutrient stores in forested ecosystems and suggest that retaining fine woody debris at harvest may provide a potentially important source of nutrients following intensive removals of bioenergy feedstocks.
  • Klockow, Department of Forest Resources, University of Minnesota, St. Paul, MN 55108, USA ORCID ID:E-mail: klock039@umn.edu (email)
  • D'Amato, Department of Forest Resources, University of Minnesota, St. Paul, MN 55108, USA ORCID ID:E-mail: damato@umn.edu
  • Bradford, US Geological Survey, Southwest Biological Science Center, Flagstaff, AZ 86001, USA ORCID ID:E-mail: jbradford@usgs.gov
  • Fraver, School of Forest Resources, University of Maine, Orono, ME 04469, USA ORCID ID:E-mail: shawn.fraver@maine.edu
article id 1043, category Research article
Jorge Martín-García, Luc Barbaro, Julio Javier Diez, Hervé Jactel. (2013). Contribution of poplar plantations to bird conservation in riparian landscapes. Silva Fennica vol. 47 no. 4 article id 1043. https://doi.org/10.14214/sf.1043
Highlights: Poplar plantations should not be used as surrogate habitat for native riparian forests with the aim of preserving bird species diversity; Native riparian forests should be preserved or restored as far as possible; Bird communities occurring in poplar plantations can still accommodate rich communities of forest bird species, providing that suitable management is applied at local and landscape levels.
In Mediterranean areas, riparian zones are particularly important for maintaining biodiversity. Nevertheless, the native vegetation in these zones has been modified or lost at an alarming rate during the last decades. The main objective of this study was to investigate the influence of poplar plantations on bird diversity in riparian zones, in order to estimate the ecological implications of a substantial expansion of poplar plantations. Breeding birds were sampled by the point-count method in twenty-four poplar plantations of I-214 clone, according to a factorial design combining stand age and understory management. Furthermore, the three native riparian forests remaining in the study area were also surveyed. Explanatory variables included (1) dendrometric, (2) understory and (3) landscape variables within six different radii of circular buffers. The species richness and abundance index were higher in riparian forests than in poplar plantations. Landscape variables (percentage of poplar plantations in the surrounding landscape) strongly influenced bird diversity in poplar plantations. Furthermore, at the local scale, understory cover was also a key factor in shaping bird assemblages. This suggests that poplar plantations should not be used as surrogates for native forests. Nevertheless, poplar plantations can still accommodate rich communities of forest bird species, providing that suitable management is applied at local and landscape levels.
  • Martín-García, Sustainable Forest Management Research Institute, University of Valladolid – INIA, Avenida Madrid, 57, 34004 Palencia, Spain ORCID ID:E-mail: jorgemg@pvs.uva.es (email)
  • Barbaro, NRA, UMR 1202 BIOGECO, 69 Route d’Arcachon, F-33612 Cestas cedex, France ORCID ID:E-mail: luc@pierroton.inra.fr
  • Diez, Sustainable Forest Management Research Institute, University of Valladolid – INIA, Avenida Madrid, 57, 34004 Palencia, Spain ORCID ID:E-mail: jdcasero@pvs.uva.es
  • Jactel, NRA, UMR 1202 BIOGECO, 69 Route d’Arcachon, F-33612 Cestas cedex, France; Université de Bordeaux, UMR 1202, Bordeaux, F-33000 France ORCID ID:E-mail: herve.jactel@pierroton.inra.fr
article id 932, category Research article
Jun Wang, Le Shi, Shaoyu Song, Ju Tian, Xiangyang Kang. (2013). Tetraploid production through zygotic chromosome doubling in Populus. Silva Fennica vol. 47 no. 2 article id 932. https://doi.org/10.14214/sf.932
The most direct approach in breeding triploid Populus is crossing allotetraploids with diploids. However, the lack of allotetraploid Populus restricts application of this approach. In this investigation, zygotic chromosome doubling was induced with colchicine and high temperatures to produce ((Populus pseudo-simonii × P. nigra ‘Zheyin3#’) × (P. × beijingensis)) allotetraploids. We screened 6 and 25 tetraploid individual offspring from the colchicine and high-temperature treatments respectively, indicating that both colchicine and high temperature are effective for tetraploid production by zygotic chromosome doubling of Populus. Developmental characteristics of seed hairs in the ovaries were temporally associated with zygotic development, which was used to successfully guide the colchicine and high-temperature treatments. During certain stages of hair development, the efficiency of tetraploid production was significantly high. However, efficiency of production was not significantly influenced by other factors, i.e. colchicine concentration, temperature or duration of high-temperature treatment. Size and frequency of leaf stomata between tetraploid and diploid plants were significantly different, suggesting that this character can be altered via genomic increase in material. The allotetraploids produced in this investigation, having different genotypes, provide important parental germplasms for further triploid breeding.
  • Wang, National Engineering Laboratory for Tree Breeding; Key Laboratory of Genetics and Breeding in Forest Trees and Ornamental Plants, Ministry of Education; College of Biological Sciences and Technology, Beijing Forestry University, Beijing 100083, P.R. China ORCID ID:E-mail: wangjun@bjfu.edu.cn (email)
  • Shi, National Engineering Laboratory for Tree Breeding; Key Laboratory of Genetics and Breeding in Forest Trees and Ornamental Plants, Ministry of Education; College of Biological Sciences and Technology, Beijing Forestry University, Beijing 100083, P.R. China ORCID ID:E-mail: 7320932@qq.com
  • Song, National Engineering Laboratory for Tree Breeding; Key Laboratory of Genetics and Breeding in Forest Trees and Ornamental Plants, Ministry of Education; College of Biological Sciences and Technology, Beijing Forestry University, Beijing 100083, P.R. China ORCID ID:E-mail: angela-song@foxmail.com
  • Tian, National Engineering Laboratory for Tree Breeding; Key Laboratory of Genetics and Breeding in Forest Trees and Ornamental Plants, Ministry of Education; College of Biological Sciences and Technology, Beijing Forestry University, Beijing 100083, P.R. China ORCID ID:E-mail: 1215813245@qq.com
  • Kang, National Engineering Laboratory for Tree Breeding; Key Laboratory of Genetics and Breeding in Forest Trees and Ornamental Plants, Ministry of Education; College of Biological Sciences and Technology, Beijing Forestry University, Beijing 100083, P.R. China ORCID ID:E-mail: kangxy@bjfu.edu.cn
article id 62, category Research article
Nadia Goué, Nathalie Noël-Boizot, Michel Vallance, Elisabeth Magel, Philippe Label. (2012). Microdissection to isolate vascular cambium cells in poplar. Silva Fennica vol. 46 no. 1 article id 62. https://doi.org/10.14214/sf.62
Vascular cambium is the lateral meristem producing xylem cells inwards and phloem cells outwards in plant stem. Thus, in trees, the quality and quantity of wood is a result of highly regulated developmental process depending initially on the vascular cambium cell production. The availability of accurate transcriptomics technologies based on high coverage sequencing raises the level of expectations on tissue sampling to a very high degree. What is the benefit of top-level transcriptomics in wood formation studies if we are using these technologies on raw tissues, mixing cells at the organ level or even higher scale? The presented work describes a nine-step procedure, from standing tree to isolated ray and fusiform cells from cryolyophilized tangential sections of the poplar cambial zone. The aim of this paper is to present a step by step procedure including advices on how to select the optimal tree, how to fell the tree while securing its physiological parameters, how to cryolyophilize and microdissect under binocular, presenting the time schedule of the whole process and RNA analysis.
  • Goué, UMR5546 CNRS-Université Paul Sabatier, Castanet Tolosan, France; (INRA-UAGPF, 2163 Avenue de la Pomme de Pin, 45075 Orléans cedex 2, France) ORCID ID:E-mail: goue@lrsv.ups-tlse.fr (email)
  • Noël-Boizot, INRA-UAGPF, 2163 Avenue de la Pomme de Pin, 45075 Orléans cedex 2, France ORCID ID:E-mail:
  • Vallance, INRA-UAGPF, 2163 Avenue de la Pomme de Pin, 45075 Orléans cedex 2, France ORCID ID:E-mail:
  • Magel, Universität Hamburg, Zentrum Holzwirtschaft, Deutschland ORCID ID:E-mail:
  • Label, INRA-UAGPF, 2163 Avenue de la Pomme de Pin, 45075 Orléans cedex 2, France ORCID ID:E-mail:
article id 450, category Research article
Miaoer Lu, Pekka Nygren, Jari Perttunen, Stephen G. Pallardy, David R. Larsen. (2011). Application of the functional-structural tree model LIGNUM to growth simulation of short-rotation eastern cottonwood. Silva Fennica vol. 45 no. 3 article id 450. https://doi.org/10.14214/sf.450
The functional-structural tree growth model LIGNUM was developed as a general research tool that can be applied to several tree species. The growth simulation of short-rotation eastern cottonwood (Populus deltoides Bartr. ex Marsh.) inherits the basic LIGNUM modeling concepts including modular tree structure, L-system-based description of structural development, and carbon budget. New developments of LIGNUM model in this study were the incorporation of a biochemically-derived photosynthesis submodel; nested time steps for simulating physiological processes, structural development, and annual biomass production; incorporation of field-measured weather data for modeling the response of physiological processes to environmental variation; and application of a Monte-Carlo voxel space submodel for simulating the stochasticity of tree growth and improving computational efficiency. A specific parameter system was applied for modeling P. deltoides growth in the central Missouri, USA, environment. This adaptation of LIGNUM was applied on modeling growth of P. deltoides in a short-rotation agroforestry practice. The simulated height and biomass growth were close to field observations. Visualization of simulation results closely resembled the trees growing in an open site. The simulated response of tree growth to variations in photon flux input was reasonable. The LIGNUM model may be used as a complement to field studies on P. deltoides in short-rotation forestry and agroforestry.
  • Lu, Deparment of Forestry, University of Missouri, Columbia, MO, USA ORCID ID:E-mail:
  • Nygren, The Finnish Society of Forest Science, P.O. 18, FI-01301 Vantaa, Finland ORCID ID:E-mail: pekka.nygren@metla.fi (email)
  • Perttunen, Finnish Forest Research Institute, Vantaa, Finland ORCID ID:E-mail:
  • Pallardy, Deparment of Forestry, University of Missouri, Columbia, MO, USA ORCID ID:E-mail:
  • Larsen, Deparment of Forestry, University of Missouri, Columbia, MO, USA ORCID ID:E-mail:
article id 28, category Research article
Lu-Min Vaario, Kim Yrjälä, Matti Rousi, Timo Sipilä, Pertti Pulkkinen. (2011). Leaf number indicates salt tolerance of young seedling families of European aspen (Populus tremula L.) growing in different soils. Silva Fennica vol. 45 no. 1 article id 28. https://doi.org/10.14214/sf.28
Soil salinity limits plant productivity and quality. We evaluated the response of 12 aspen (Populus tremula) families to salt stress in two different soils irrigated for 4-weeks with 0, 80 or 160 mM saline solution. Easily measurable characteristics such as shoot height, leaf number, dry mass as well as the distribution of sodium (Na+) ions were measured in 5-month-old aspen seedlings raised in controlled greenhouse conditions on two different soils. Growth among families varied significantly, and the interaction between family and soil type was significant. From 2–5 months, leaf number correlated with that of the first month and salinity tolerance. Sodium ions varied significantly within plants and among families; seedlings that accumulated higher Na+ concentrations in root had more leaves and lower Na+ in shoot. These results suggest that leaf number indicates salt tolerance in young seedlings. Seedling performance was also affected by soil type, especially the root/shoot ratio, suggesting an interaction between salt tolerance and growth medium. This study has identified significant intra-specific variation in salt tolerance of aspen in 160 mM saline and highlighted the potential to select and develop a method for efficient pre-screening of trees to be used in the reclamation of salt-affected land.
  • Vaario, Finnish Forest Research Institute, Vantaa Research Unit, P. O. Box 18, FI-01301 Vantaa, Finland ORCID ID:E-mail: lu-min.vaario@metla.fi (email)
  • Yrjälä, MEM group, Department of Biosciences, P.O. Box 56, FI-00014 University of Helsinki, Finland ORCID ID:E-mail:
  • Rousi, Finnish Forest Research Institute, Vantaa Research Unit, P. O. Box 18, FI-01301 Vantaa, Finland ORCID ID:E-mail: matti.rousi@metla.fi
  • Sipilä, Department of Agricultural Sciences, P.O. Box 56, FI-00014 University of Helsinki, Finland ORCID ID:E-mail:
  • Pulkkinen, Pulkkinen, Finnish Forest Research Institute, Haapastensyrjä Research Unit, Haapastensyrjäntie 34, FI-12600 Läyliäinen, Finland ORCID ID:E-mail: pertti.pulkkinen@metla.fi
article id 160, category Research article
Fan Yang, Ling-Feng Miao. (2010). Adaptive responses to progressive drought stress in two poplar species originating from different altitudes. Silva Fennica vol. 44 no. 1 article id 160. https://doi.org/10.14214/sf.160
Cuttings of Populus kangdingensis C. Wang et Tung and Populus cathayana Rehder, originating from high and low altitudes in the eastern Himalaya, respectively, were examined during one growing season in a greenhouse to determine the effects of progressive drought stress. The results manifested that the adaptive responses to progressive drought stress were different in these two species from different altitudes. Significant changes in stem height, leaf development, relative water content (RWC), malondialdehyde (MDA) and hydrogen peroxide (H2O2) appeared earlier in P. cathayana than in P. kangdingensis, whereas changes in soluble protein, soluble sugar, free proline and antioxidant enzymes appeared earlier in P. kangdingensis. In addition, changes in these parameters became more and more significant when the drought stress progressed, especially under severe drought stress in P. cathayana. Plant growth showed significant positive correlations with soluble proteins and sugars, free proline and antioxidants and a significant negative correlation with RWC under water stressed treatment in two poplar species. Compared with P. cathayana, P. kangdingensis was able to maintain a superior height growth and leaf development under drought stress. Also, P. kangdingensis possessed greater increments in soluble protein, soluble sugar, free proline and antioxidant enzymes, but lower increments in MDA and H2O2 than did P. cathayana when the cuttings were exposed to progressive drought stress. Our results suggest that P. kangdingensis originating from the high altitude has a better drought tolerance than does P. cathayana originating from the low altitude. Furthermore, this study manifested that acclimation to drought stress are related the rapidity, severity, duration of the drought event and the altitude of two poplar species.
  • Yang, Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan, Hubei 430074, P. R. China (yangfan@wbgcas.cn) & Chengdu Institute of Biology, Chinese Academy of Sciences, P.O. Box 416, Chengdu, Sichuan 610041, P. R. China ORCID ID:E-mail: fanyangmlf6303@163.com (email)
  • Miao, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, Hubei 430071, P. R. China ORCID ID:E-mail:
article id 189, category Research article
Lars Rytter, Gunnar Jansson. (2009). Influence of pruning on wood characters in hybrid aspen. Silva Fennica vol. 43 no. 4 article id 189. https://doi.org/10.14214/sf.189
Fast-growing hybrid aspens (Populus tremula L. x P. tremuloides Michx.) are currently of great interest in Sweden since they can produce biomass at high rates and, at the same time, can be used to produce higher value wood products. This study focuses on the effects of pruning hybrid aspen to improve its wood quality. About 50% of the trees in the experimental stand were pruned by removing twigs, at heights up to 4 m, when they were 7–8 years old. Ten years later, 20 pruned and 20 unpruned trees, representing four clones, were randomly selected. Ten knots or twig/stem junctions, respectively, per tree were exposed for inspection using a chain saw and examined. The results revealed that pruned trees cicatrised the knots within about three years and thereafter produced substantial amounts of faultless wood. In contrast, unpruned trees (which had retained almost 80% of their twigs, often as dry twigs with bark pockets) had produced small uneven amounts of quality wood. Removal of twigs with acute angles and/or large diameters resulted in greater colour defects and rot in annual rings outside the pruning position, but the time of cicatrisation was not significantly affected. The results show that pruning can be used to enhance the wood quality of hybrid aspen over a short time period, and that pruning should be performed early during the rotation period when branches are small, in order to minimize discolouration and rot in the new annual rings.
  • Rytter, The Forestry Research Institute of Sweden (Skogforsk), Ekebo 2250, SE-26890 Svalöv ORCID ID:E-mail: lars.rytter@skogforsk.se (email)
  • Jansson, The Forestry Research Institute of Sweden (Skogforsk), Uppsala Science Park, SE-751 83 Uppsala ORCID ID:E-mail:
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
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 ORCID ID:E-mail: xiaoxw@cib.ac.cn (email)
  • 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 ORCID ID:E-mail:
  • 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 ORCID ID:E-mail:
article id 342, category Research article
Jaana Luoranen, Juha Lappi, Gang Zhang, Heikki Smolander. (2006). Field performance of hybrid aspen clones planted in summer. Silva Fennica vol. 40 no. 2 article id 342. https://doi.org/10.14214/sf.342
We investigated the possibility to plant clonal hybrid aspen (Populus tremula x tremuloides) during the summer of propagation when the plants are 20–25 cm tall and only a few months old. In four experiments carried out in years 1998–2001, survival of summer-planted hybrid aspens was at least as high as that of hybrid aspen planted in autumn and spring. In all experiments, compared to planting in September or the following May, height growth was greater with planting in July and early August. Root egress of hybrid aspens planted in July and August was also greater than that of aspens planted in autumn or the following spring. Summer planting was thus possible both with plants produced by micropropagation and with those produced from root cuttings.
  • Luoranen, Finnish Forest Research Institute, Suonenjoki Research Unit, Juntintie 154, FI-77600 Suonenjoki, Finland ORCID ID:E-mail: jaana.luoranen@metla.fi (email)
  • Lappi, Finnish Forest Research Institute, Suonenjoki Research Unit, Juntintie 154, FI-77600 Suonenjoki, Finland ORCID ID:E-mail:
  • Zhang, College of Horticulture, Agricultural University of Hebei, Baoding, Hebei, China ORCID ID:E-mail:
  • Smolander, Finnish Forest Research Institute, Suonenjoki Research Unit, Juntintie 154, FI-77600 Suonenjoki, Finland ORCID ID:E-mail:
article id 393, category Research article
Seppo Rouvinen, Anne Rautiainen, Jari Kouki. (2005). A relation between historical forest use and current dead woody material in a boreal protected old-growth forest in Finland. Silva Fennica vol. 39 no. 1 article id 393. https://doi.org/10.14214/sf.393
Assessing the human impact on the naturalness and vegetation characteristics of protected areas is one of the key issues when designing forest conservation networks in Fennoscandia. We studied the small-scale, detailed relationship between forest utilization history and the current availability of dead woody material in a protected old-growth forest area in North Karelia, eastern Finland. From the study area of 32.4 ha, all the stumps (diameter ≥ 5 cm and height < 1.3 m, classified as natural, man-made and of undetermined origin) were measured using 25 x 25 m sub-plots. Standing and fallen dead trees (dbh ≥ 5 cm) were measured on 50 x 50 m plots in an area of 7.8 ha. The average number of stumps was 130 per ha, and over half of the stumps were classified as man-made. However, the historical documents since the 1910s showed no logging in the area: some of the largest man-made stumps probably originated from an earlier time, but most of those stumps were made considerably later. The variation in the total number of stumps (per ha) was great (range 0–560/ha, 0–16 m2/ha), with no clear clustering in space. However, clustering of man-made stumps was detected. The average volume of pooled standing and fallen trees was 84 m3/ha, with a range of 37–146 m3/ha. The other noticeable man-made disturbance besides logging was notching of aspens, which has a scatteredly significant influence on the amount of dead trees. In conclusion, the protected old-growth forest was not as a whole in a natural state but showed different degrees of human impact from virtually untouched patches to quite heavily managed patches. The results suggest that the number of man-made stumps may be a relatively quick and easy method of assessing the naturalness of woody biomass structure in the Fennoscandian boreal forests.
  • Rouvinen, University of Joensuu, Faculty of Forestry, P.O. Box 111, FI-80101 Joensuu, Finland ORCID ID:E-mail: seppo.rouvinen@joensuu.fi (email)
  • Rautiainen, University of Joensuu, Faculty of Forestry, P.O. Box 111, FI-80101 Joensuu, Finland ORCID ID:E-mail:
  • Kouki, University of Joensuu, Faculty of Forestry, P.O. Box 111, FI-80101 Joensuu, Finland ORCID ID:E-mail:
article id 577, category Research article
Jouni Siipilehto. (2001). Effect of weed control with fibre mulches and herbicides on the initial development of spruce, birch and aspen seedlings on abandoned farmland. Silva Fennica vol. 35 no. 4 article id 577. https://doi.org/10.14214/sf.577
Post-planting weed control methods on abandoned farmland were studied in three field trials in southern Finland using a completely randomized design with four treatments and 30 to 40 replications. Mulches of 60 x 60 cm [sheet mulch – strips of plane waste and plastic fibre, newspaper – waste paper slurry, wood chips, pure wood fibre slurry], herbicides [i.e. glyphosate or terbuthylazine alone or mixed and dichlobenile applied to 1 m2 spots] and hoeing treatments were compared to an untreated control plot. The study material consisted of two-year-old containerized aspen (Populus tremula L.), silver birch (Betula pendula (L.) Roth) and Norway spruce (Picea abies (L.) Karst.) seedlings planted in spring 1996. The ground vegetation was dominated by Elymys repens, Deschampsia cespitosa, Cirsium arvense and Epilobium angustifolium. Monitoring of the trials over a 3-year period showed a moderate effect of weed control, which varied according to the method used and by the crop species. Significant growth responses were found with herbicide in spruce, wood chips in spruce and birch and with sheet mulch in aspen seedlings. Sheet mulch also encouraged vole nesting thus increasing damages. Generally, slurry mulches proved to be insufficiently durable. Mulching had a clear insulating effect, which may increase the risk of winter drought.
  • Siipilehto, Finnish Forest Research Institute, Vantaa Research Centre, P.O. Box 18, FIN-01301 Vantaa, Finland ORCID ID:E-mail: jouni.siipilehto@metla.fi (email)
article id 647, category Research article
Tapio Linkosalo. (1999). Regularities and patterns in the spring phenology of some boreal trees. Silva Fennica vol. 33 no. 4 article id 647. https://doi.org/10.14214/sf.647
Phenological time series of flowering and bud burst of Populus tremula (L.) and Betula sp., and the flowering of Pinus sylvestris (L.), Alnus glutinosa (L.) and Alnus incana (L.) were constructed from data collected in Finland during the period 1896–1955. The resulting combined time series were examined with two aims in mind: first, to determine the phenological regularities between different species and, second, to detect patterns of spring advancement over a geographically large area. The results indicate that the geographical pattern of spring advancement is rather uniform from year to year, and between different species. Furthermore, the mechanisms regulating the timing of phenological events in different species seem to function in a similar way, suggesting an unanimous optimal response to climatic conditions.
  • Linkosalo, University of Helsinki, Department of Forest Ecology, Unioninkatu 40 B, P.O. Box 24, FIN-00014 University of Helsinki, Finland ORCID ID:E-mail: tapio.linkosalo@helsinki.fi (email)

Category: Review article

article id 688, category Review article
John A. Stanturf, Callie J. Schweitzer, Emile S. Gardiner. (1998). Afforestation of marginal agricultural land in the Lower Mississippi River Alluvial Valley, U.S.A. Silva Fennica vol. 32 no. 3 article id 688. https://doi.org/10.14214/sf.688
Afforestation of marginal agricultural land in the Lower Mississippi Alluvial Valley (LMAV) relies on native species, planted mostly in single-species plantations. Hard mast species such as oak and pecan are favored for their value to wildlife, especially on public land. Successful afforestation requires an understanding of site variation within floodplains and matching species preferences and tolerances to site characteristics, in particular to inundation regimes. Soil physical conditions, root aeration, nutrient availability, and moisture availability during the growing season also must be considered in matching species to site. Afforestation methods include planting seedlings or cuttings, and direct-seeding. Both methods can be done by hand or by machine. If good quality seedlings are planted properly and well cared for before planting, the chances for successful establishment are high but complete failures do occur. Mortality and poor growth are caused by many factors: extended post-planting drought or flooding; poor planting or seeding practices; poor quality seed or seedlings; animal depredation; or herbicide drift from aerial application to nearby cropland. More species can be planted, even on continuously flooded sites. Direct-seeding, while limited to heavy-seeded species (oaks and hickories), costs less than 50% of planting seedlings. Growth varies considerably by soil type; most bottomland hardwoods grow best on silt loam and less well on clay soils. Up to 200 000 ha of land in the LMAV subject to spring and early summer backwater flooding could be afforested over the next decade.
  • Stanturf, USDA Forest Service, Southern Research Station, P.O. Box 227, Stoneville, MS 38776, USA ORCID ID:E-mail: jstantur/srs_stoneville@fs.fed.us (email)
  • Schweitzer, USDA Forest Service, Southern Research Station, P.O. Box 227, Stoneville, MS 38776, USA ORCID ID:E-mail:
  • Gardiner, USDA Forest Service, Southern Research Station, P.O. Box 227, Stoneville, MS 38776, USA ORCID ID:E-mail:

Category: Research note

article id 7798, category Research note
Jānis Liepiņš, Jānis Ivanovs, Andis Lazdiņš, Jurģis Jansons, Kaspars Liepiņš. (2017). Mapping of basic density within European aspen stems in Latvia. Silva Fennica vol. 51 no. 5 article id 7798. https://doi.org/10.14214/sf.7798
Highlights: Stem bark is significantly denser than wood and does not follow the same variation patterns along the stem; The main trend in radial variation of wood density was the increase from pith to bark; There is a weak relationship between mean basic density and commonly measured stand and tree parameters.

The objective of this study was to investigate basic density and its within-stem variation by studying 84 European aspen stems from 28 forest stands in Latvia. The studied forest stands covered all age classes from young stands to matured forests in representative growth conditions of European aspen. The densities of 2722 wood and 1022 bark specimens were measured from the sampled trees. Only the knot-free wood specimens without obvious wood defects were chosen for analyses. A map of basic density summarizing its radial and axial variations was constructed to show species-specific, within-stem variability and the relationships between density and tree and stand variables were examined. Stem wood and bark of the European aspen show different patterns of basic density variation along the tree stem. Wood density increases from pith to bark up to certain dimensions and shows a slight decrease afterwards. The weighted basic density of bark (446 ± 39.6 kg m–3) was higher than stem wood density (393 ± 30.4 kg m–3). Our results suggest that wood and bark density measurements obtained at breast height can be used for reliable estimation of the densities of whole-tree stem components, while tree parameters such as diameter at breast height (DBH), tree height and social status or stand parameters, including number of trees, basal area and age, are weak predictors in this context.

  • Liepiņš, Latvian State Forest Research Institute “Silava”, 111 Rigas Str., LV 2169, Salaspils, Latvia ORCID ID:E-mail: janis.liepins@silava.lv (email)
  • Ivanovs, Latvian State Forest Research Institute “Silava”, 111 Rigas Str., LV 2169, Salaspils, Latvia ORCID ID:E-mail: janis.ivanovs@silava.lv
  • Lazdiņš, Latvian State Forest Research Institute “Silava”, 111 Rigas Str., LV 2169, Salaspils, Latvia ORCID ID:E-mail: andis.lazdins@silava.lv
  • Jansons, Latvian State Forest Research Institute “Silava”, 111 Rigas Str., LV 2169, Salaspils, Latvia ORCID ID:E-mail: jurgis.jansons@silava.lv
  • Liepiņš, Latvian State Forest Research Institute “Silava”, 111 Rigas Str., LV 2169, Salaspils, Latvia ORCID ID:E-mail: kaspars.liepins@silava.lv
article id 1126, category Research note
Rebecka Mc Carthy, Per Magnus Ekö, Lars Rytter. (2014). Reliability of stump sprouting as a regeneration method for poplars: clonal behavior in survival, sprout straightness and growth. Silva Fennica vol. 48 no. 3 article id 1126. https://doi.org/10.14214/sf.1126
Highlights: Clonal differences were found in stump sprout survival; Clonal differences occurred in sprout straightness; It is uncertain if the ability to produce a high number of stump sprouts is beneficial.
The interest in poplars (Populus spp.) has increased globally as a result of the current incentive to expand the use of biomass for energy. So far, knowledge about poplar stump sprouting is generally poor. The objective of this study was to investigate poplar stump sprouting as regeneration method in harvested plantations. A 19-year-old poplar clonal test, including 23 different clones, on former arable land was harvested in the winter. After one year, stumps were assessed for sprout survival, sprout straightness, number of sprouts, sprout height and basal diameter. Differences between clones were found for survival and sprout straightness. Clonal differences were also found in mean size of sprouts (basal diameter and height). However, no differences were found between clones when comparing size of the tallest sprout or number of sprouts produced on stumps. This study indicates that stump sprouts from various poplar clones differ in survival, sprout straightness and mean growth, which should be taken into account when planning for the next tree generation. The study needs to be complemented with other studies to better assess sprouting characteristics for different clones.
  • Mc Carthy, Forestry Research Institute of Sweden, Skogforsk, Ekebo 2250, SE-268 90 Svalöv, Sweden & Southern Swedish Forest Research Centre, Swedish University of Agricultural Sciences, P.O. Box 49, SE-230 53 Alnarp, Sweden ORCID ID:E-mail: rebecka.mccarthy@skogforsk.se (email)
  • Ekö, Southern Swedish Forest Research Centre, Swedish University of Agricultural Sciences, P.O. Box 49, SE-230 53 Alnarp, Sweden ORCID ID:E-mail: Per.Magnus.Eko@slu.se
  • Rytter, Forestry Research Institute of Sweden, Skogforsk, Ekebo 2250, SE-268 90 Svalöv, Sweden ORCID ID:E-mail: lars.rytter@skogforsk.se

Category: Article

article id 7118, category Article
Paavo J. Ollinmaa. (1959). Reaktiopuututkimuksia. Acta Forestalia Fennica vol. 72 no. 1 article id 7118. https://doi.org/10.14214/aff.7118
English title: Study on reaction wood.

Compression wood of the tree species studied in this investigation, Scots pine (Pinus sylvestris L.), Norway spruce (Picea abies (L.) Karst.) and common juniper (Juniperus communis L.), was found to be characterized in its cross section by the thick walls and rounded shape of its tracheids and the profuse occurence of spaces. Tension wood of aspen (Populus tremula L.) and alder (Alnus incana (L.) Moench) was found in microscopic examination to be characterized by the gelatinous appearance of the wood fibres, by its small cell cavities and by the thickness and buckling of the inner layer of the cecondary wall. Tracheids of the compression wood were found to have shorter length than normal on an average, while the tension wood fibres were found to be longer.

The microchemical studies suggest a higher than normal lignin content in compression wood and lower than normal lignin content in tension wood, as compared to normal wood. The reverse would be true for the cellulose contents. Volume weight of absolute dry reaction wood was distinctly higher than that of normal wood. The longitudinal shrinkage of reaction wood, particularly of compression wood, is several times that of normal wood. Transversal shrinkage of compression wood is much less than normal wood. Swelling tests revealed pushing effect of compression wood on elongation and pulling effect on tension wood on constraction. Volume shrinkage of compression wood is less than that of normal wood, in contrast to tension wood. The strength of compression wood in absolutely dry condition was nearly same as that of normal wood.

The PDF includes a summary in English.

  • Ollinmaa, ORCID ID:E-mail:
article id 5568, category Article
Tord Johansson. (1996). Site index curves for European aspen (Populus tremula L.) growing on forest land of different soils in Sweden. Silva Fennica vol. 30 no. 4 article id 5568. https://doi.org/10.14214/sf.a8503

Growth data were collected from 40 European aspen (Populus tremula L.) stands growing on eight localities in Sweden. The stands ranged in latitude from 56 to 66°N. The mean age of the stands was 32 years (range, 12–63), the mean stand density 1978 stems ha-1 (range, 300–6,000), and the mean diameter at breast height (on bark) 17 cm (range, 8–34).

Site index curves were constructed for total age. Curves for H40 (dominant height at 40 years total age) were made for total Sweden. Curves fitted for H40 total age have another shape than curves presented by other Nordic studies. The curves from the present study have slower growth for young aspens than curves from Norwegian and Finnish conditions. For 50–70-year-old aspen stands, curves from the present study indicate taller heights than from Nordic studies.

Classified soil types from the stands were grouped into three groups: sandy till (17), light clay (15) and medium clay till (4). As there was only one stand growing in the fine sand group and one stand in the heavy clay till group and two stands in the silty till group, these stands were not presented with growth curves. There were no statistically significant differences in site index between the three soil type groups. Some recommendations for management of aspen stand are given. Damages caused by moose, fungi and other injuries are discussed as a problem for height yield production and a good timber quality.

  • Johansson, ORCID ID:E-mail:
article id 5255, category Article
Matti Kärkkäinen, Jukka Pietilä, Raili Vihola. (1985). Suomalaisten puulajien iskutaivutuslujuus tuoreena. Silva Fennica vol. 19 no. 4 article id 5255. https://doi.org/10.14214/sf.a15434
English title: Impact bending strength of Finnish tree species in green condition.

There are great impact forces in mechanized harvesting and wood yard in the mills which can cause breaks in timber. The impact strength of timber in green condition was tested in temperatures of +18°C and -18°C using sawn pieces (20 x 20 x 300 mm) of Scots pine (Pinus sylvestris L.), Norway spruce (Picea abies (L.) H. Karst.), birch (Betula pendula Roth and B. pubescens Ehrh.), grey alder (Alnus incana L.) and aspen (Populus tremula L.). In addition, unbarked naturally round sticks (length 300 mm, diameter 15 and 35 mm) of the same species were tested.

The impact strength of round sticks was 1.5–4.4 times as great as that of sawn pieces. The reasons are possibly the avoidance of cell breaks at the surface as well as growth stresses. The frozen samples were clearly weaker than the unfrozen ones. As a rule, the impact bending strength increased with increased density of the species. However, the correlation varied greatly between species. If density was kept constant, an increase in the growth ring width decreased the impact strength. The reason may lie in the fracture mechanism.

The PDF includes a summary in English.

  • Kärkkäinen, ORCID ID:E-mail:
  • Pietilä, ORCID ID:E-mail:
  • Vihola, ORCID ID:E-mail:
article id 5174, category Article
Tiina Heinonen. (1983). Haavikon lannoituskoe. Silva Fennica vol. 17 no. 1 article id 5174. https://doi.org/10.14214/sf.a15089
English title: A fertilization experiment in a Populus tremula stand.
Original keywords: haapa; lannoitus; typpi; pohjapinta-ala

The growth response of aspen (Populus tremula L.) to fertilization was studied in an experiment laid out in a naturally regenerated 35-year old stand on a previously burned-over land. The site was rather fertile. One-tree plot method was used. Applications of nitrogen (150 kg/ha as ammonium nitrate with lime), phosphorus (35 kg/ha as superphosphate), and potassium (66 kg/ha as potassium chloride) separately and in all possible combinations were used; the test included 11 replications. The growth reaction was measured as basal area growth excluding bark during 5 years. The factorial effects were computed using Yates method.

Potassium did not have any effect on basal growth of the trees. The response to phosphorus was also rather small. On the other hand, nitrogen appeared to have increased the basal area growth. The growth increase obtained with nitrogen alone was greater than when it was applied together with phosphorus and/or potassium.

The PDF includes a summary in English.

  • Heinonen, ORCID ID:E-mail:
article id 5118, category Article
Matti Nuorteva, Jyrki Patomäki, Lennart Saari. (1981). Large poplar longhorn, Saperda carcharias (L.), as food for white-backed woodpecker, Dendrocopos leucotos (Bechst.). Silva Fennica vol. 15 no. 2 article id 5118. https://doi.org/10.14214/sf.a15059

In a locality in Southern Finland where the white-backed woodpecker, Dendrocopos leucotos (Bechst.), was previously breeding was found many conical borings excavated during the winter in young aspens (Populus tremula L.) on average 8.1 cm in diameter. Full-grown larvae of Saperda carcharias (L.) (Coleoptera, Cerambycidae) hibernated in pupal chambers constructed about 0.5 m above ground level. Below this chamber the larva has usually prepared an exit hole. After the larva has blocked itself in the pupating chamber it is easy to prey for the woodpecker during the whole winter.

There were usually 1–5 conical borings in the same trunk. The number of these borings did not correspond with the amounts of larvae eaten, since the woodpecker often made these borings in places from which it could not obtain a prey. The woodpeckers stopped excavating in those cases when the larvae in the galleries were dead. The exit holes and the conical borings occluded within a few years. The galleries within the tree will not heal and several years later a new larva may utilize them. In the wintering habitats of the white-backed woodpecker the availability of food could be improved by increasing the amount of S. sarcharias larvae. This is easily done by encouraging young aspens.

The PDF includes a summary in Finnish.

  • Nuorteva, ORCID ID:E-mail:
  • Patomäki, ORCID ID:E-mail:
  • Saari, ORCID ID:E-mail:
article id 5114, category Article
Matti Kärkkäinen. (1981). Haapa- ja poppelilajien (Populus) käyttö. Silva Fennica vol. 15 no. 2 article id 5114. https://doi.org/10.14214/sf.a15055
English title: Utilization of aspen and poplars (genus Populus).
Original keywords: haapa; poppelit; viljely; puulajit; käyttö

The aim of this study was to establish from the literature the purposes and for which aspen (Populus tremula L.) and related poplar species are used and can be used.  According to the literature, numerous Populus species can be utilized in the industry with success instead of light softwood species in addition to them. The main emphasis is in the growing of large-sized timber, and there is no clear trend to changing to the short-rotation forestry of poplar. However, the utilization of the good sprouting properties of Populus species will probably increase as this regeneration method is cheap.

The PDF includes a summary in English.

  • Kärkkäinen, ORCID ID:E-mail:
article id 5090, category Article
Matti Kärkkäinen, Raili Voipio. (1980). Suomalainen haapa- ja poppelilajeja (Populus) koskeva kirjallisuus 1759...1979. Silva Fennica vol. 14 no. 4 article id 5090. https://doi.org/10.14214/sf.a15031
English title: Finnish literature on aspen and poplar species (genus Populus), 1759–1979.

The first Finnish paper on aspen (Populus tremula L.) was published in 1759 in Åbo (Turku). After this dissertation, numerous scientific and other articles and reports have been published. In this bibliography about 340 papers are listed. Most of the papers deal only with aspen or other species of the genus Populus. Besides these even those articles have been included which deal with other problems but contain some information on the features of poplars.

The titles are listed without any translation or classification. If an article has a summary, it is shown in the title.

The PDF includes a summary in English.

  • Kärkkäinen, ORCID ID:E-mail:
  • Voipio, ORCID ID:E-mail:
article id 5086, category Article
Jussi Meriluoto. (1980). MCPA- ja 2,4,5-T-herbisidien käyttökelpoisuus taimiston hoidossa. Silva Fennica vol. 14 no. 4 article id 5086. https://doi.org/10.14214/sf.a15027
English title: Applicability of MCPA- and 2,4,5-T-herbicides in sapling stand management.

The applicability of MCPA- and 2,4,5-T-herbicides for use in the management of sapling stands and the possibilities of carrying out foliar spraying at an earlier date than at precent with smaller doses of the active ingredient were examined in this study. The results were obtained from foliage spraying experiments carried out in Central Finland in summer 1976. MCPA and 2,4,5-T were as effective as each other against deciduous tree species. However, MCPA was slightly more effective against aspen (Populus tremula L.) than 2,4,5-T. The spraying date had no effect on the mortality rate of aspen or birch (Betula pendula Roth and B. pubescens Ehrh.) There were only very slight differences between the results for different dosage levels. The damage caused to Scots pine (Pinus sylvestris L.) was very slight. The temperature conditions prevailing during spraying affected spraying effectiveness in such way that the mortality rate decreased during cold period.

The PDF includes a summary in English.

  • Meriluoto, ORCID ID:E-mail:
article id 5004, category Article
Matti Kärkkäinen. (1978). Haapatukkien lahoisuus. Silva Fennica vol. 12 no. 3 article id 5004. https://doi.org/10.14214/sf.a14858
English title: Occurrence of decay in aspen logs.
Original keywords: haapa; tukki; laho; tyvitukit
English keywords: aspen; Populus tremula; logs; decay; butt logs

At three Finnish match factories 1,629 aspen logs were measured (see Kärkkäinen and Salmi 1978). When the estimation was based on the condition of the butt cross section of a log, less than half of the logs were sound without any discoloration or decay. Based on the condition of the top cross-section, the corresponding figure was a little higher than 50%. The logs with decay were bigger than those without it. There were relatively more butt logs among the logs with decay than among the totally sound logs.

The PDF includes a summary in Finnish.

  • Kärkkäinen, ORCID ID:E-mail:
article id 4922, category Article
Matti Kärkkäinen. (1975). Koivu- ja haapatukkien poikkipinta-alan mittaaminen. Silva Fennica vol. 9 no. 3 article id 4922. https://doi.org/10.14214/sf.a14764
English title: Measurement of the cross-sectional area of birch and aspen logs.

The aim of the study was to determine the extent to which the cross section of birch (Betula sp.) and aspen (Populus tremula L.) logs differ from a circle and to test some simple methods for measuring the cross-sectional area which can be used, for instance, for determining the volume of the logs. The material consisted of 420 debarked birch disks and 240 aspen disks which were representative of the logs arriving at two factories.

The convex deficit values for the material were very small, the cross-sectional area error being in general less than 1%. On the other hand, the other parameters deviated from the circular form to quite a large degree. It was also evident that the radii measured from the piths to the surface of the wood varied considerably more in the same disk, as regards length, than the diameters measured in different directions.

It was evident that the shape of the average cross-sectional area was not in general elliptical. It thus appears that any method for measuring the cross-sectional area which is based on elliptical formula is not suitable. The method which gave the best result was that in which the cross-sectional area was taken as the average of the area of the circle calculated from the smallest diameter and that calculated from the diameter passing at right angles to it. This method also appeared to be the best for disks which deviated to quite a large degree from the circular form. The suitability of this method is increased by the fact that the relative error is only slightly dependent on the size of the disk.

The PDF includes a summary in English.

  • Kärkkäinen, ORCID ID:E-mail:
article id 4901, category Article
Veli Pohjonen. (1974). Istutustiheyden vaikutus eräiden lyhytkiertoviljelyn puulajien ensimmäisen vuoden satoon ja pituuskasvuun. Silva Fennica vol. 8 no. 2 article id 4901. https://doi.org/10.14214/sf.a14745
English title: Effect of spacing on the first-year yield and height increment of some species undergoing short rotation culture.

The effect of spacing on the first-year yield and height increment of Alnus incana (L.) Moench, Populus tremula L. x Populus tremuloides Michx. (Populus x wettsteinii), Salix ’Aquatica Gigantea’, and Salix phylicifolia L. was studied at the Arctic Circle Agricultural Experimental Station in Northern Finland. S. ’Aquatica Gigantea’ gave yields which were twice as high as those of the other species in the study. The highest yields were of the order of 60 tons per hectare (fresh yield including foliage). The annual height growth in S. ’Aquatica Gigantea’ was about 100 cm, in the others about 30–50 cm. S. ’Aquatica Gigantea’ had a maximal height growth when the distance between the seedlings was 25 cm.

The PDF includes a summary in English.

  • Pohjonen, ORCID ID:E-mail:
article id 4901, category Article
Veli Pohjonen. (1974). Istutustiheyden vaikutus eräiden lyhytkiertoviljelyn puulajien ensimmäisen vuoden satoon ja pituuskasvuun. Silva Fennica vol. 8 no. 2 article id 4901. https://doi.org/10.14214/sf.a14745
English title: Effect of spacing on the first-year yield and height increment of some species undergoing short rotation culture.

The effect of spacing on the first-year yield and height increment of Alnus incana (L.) Moench, Populus tremula L. x Populus tremuloides Michx. (Populus x wettsteinii), Salix ’Aquatica Gigantea’, and Salix phylicifolia L. was studied at the Arctic Circle Agricultural Experimental Station in Northern Finland. S. ’Aquatica Gigantea’ gave yields which were twice as high as those of the other species in the study. The highest yields were of the order of 60 tons per hectare (fresh yield including foliage). The annual height growth in S. ’Aquatica Gigantea’ was about 100 cm, in the others about 30–50 cm. S. ’Aquatica Gigantea’ had a maximal height growth when the distance between the seedlings was 25 cm.

The PDF includes a summary in English.

  • Pohjonen, ORCID ID:E-mail:
article id 4871, category Article
Kari Löyttyniemi. (1972). Hybridihaavikoiden hyönteistuhoista. Silva Fennica vol. 6 no. 3 article id 4871. https://doi.org/10.14214/sf.a14678
English title: Insect damages in hybrid aspen stands.
Original keywords: hybridihaapa; hyönteistuhot

Hybrid aspen (Populus tremula L. x Populus tremuloides Michx.) has been grown in Finland for about 20 years, and the area of the stands is currently about 400 ha. Growing is planned to be greatly expanded to grow raw material for match industry. The aim of this investigation was to study susceptibility of hybrid aspen to insect damages. Insect damages in hybrid aspen, growing in Southern Finland, were examined in 15 stands in 1972. Saperda species were observed to be the most numerous and harmful insect species. Saperda carcharias L. occurred in 26% and Saperda populnea L. in 36% off trees inspected. Mass occurrence of Chionaspis salicis L. was observed in some sample areas.

  • Löyttyniemi, ORCID ID:E-mail:
article id 4871, category Article
Kari Löyttyniemi. (1972). Hybridihaavikoiden hyönteistuhoista. Silva Fennica vol. 6 no. 3 article id 4871. https://doi.org/10.14214/sf.a14678
English title: Insect damages in hybrid aspen stands.
Original keywords: hybridihaapa; hyönteistuhot

Hybrid aspen (Populus tremula L. x Populus tremuloides Michx.) has been grown in Finland for about 20 years, and the area of the stands is currently about 400 ha. Growing is planned to be greatly expanded to grow raw material for match industry. The aim of this investigation was to study susceptibility of hybrid aspen to insect damages. Insect damages in hybrid aspen, growing in Southern Finland, were examined in 15 stands in 1972. Saperda species were observed to be the most numerous and harmful insect species. Saperda carcharias L. occurred in 26% and Saperda populnea L. in 36% off trees inspected. Mass occurrence of Chionaspis salicis L. was observed in some sample areas.

  • Löyttyniemi, ORCID ID:E-mail:
article id 4858, category Article
Tauno Kallio. (1972). Erään 10-vuotiaan hybridihaapametsikön lahovikaisuus. Silva Fennica vol. 6 no. 1 article id 4858. https://doi.org/10.14214/sf.a14661
English title: Decay in a ten-year old stand of hybrid aspen.
Original keywords: hybridihaapa; sienitaudit; laho; bakteerit

A ten-year old stand of hybrid aspen (Populus tremula x Populus tremuloides), growing in Southern Finland on about 1.5 ha of Oxalis-Myrtillus type (OMT) soil and affected by crown blight, was examined in 1971. The study revealed that almost all trees, both those removed by thinning and the remaining growing stock, were decayed. A number of bacteria, Fungi imperfecti species and ascomycetous fungi were isolated from the discoloured heartwood of the affected trees. No fungus of the Bacidiomycetes was found in the discoloured wood material.

The PDF includes a summary in English.

  • Kallio, ORCID ID:E-mail:
article id 4576, category Article
Bo-Eric Blumenthal. (1942). Studier angående aspens förekomst och egenskaper i Finland. Silva Fennica no. 56 article id 4576. https://doi.org/10.14214/sf.a9080
English title: Distribution and properties of aspen in Finland.

Aspen (Populus tremula L.) is a common tree in Finland, and has been used, for instance, in matchstick industry. However, there has been little studies on its distribution and properties. In this study, 142 sample trees in different forest site types in Valtimo and Onkamo in Eastern Finland were measured in detail in 1935.

According to the results, during the first 10 years aspens height growth is fastest of the Finnish tree species surpassing, for instance, Scots pine (Pinus sylvestris L.) and birch (Betula sp.) . The diameter growth is similar to Scots pine up to the age of 50 years, after which the growth of aspen exceeds Scots pine. Branchless portion of the stem compared to the height of the tree increases until it reaches about 50% of the height of the tree. In poorer sites aspen is prone to decay.

Aspen regenerates easily both by root shoots and seeds. If root shoots are left to grow, the mother tree should be free of decay. In general, seedlings are of better quality. Good quality aspen stands require thinning and a rich forest type. If an old aspen stand has decay, the trees should be ring-barked and the site regenerated with a new tree species.

The article includes an abstract in German.

  • Blumenthal, ORCID ID:E-mail:

Register
Click this link to register for Silva Fennica submission and tracking system.
Log in
If you are a registered user, log in to save your selected articles for later access.
Contents alert
Sign up to receive alerts of new content
Your selected articles

Committee on Publication Ethics A Trusted Community-Governed Archive