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Articles containing the keyword 'Betula'.

Category: Research article

article id 9968, category Research article
Hubert Lachowicz, Anna Bieniasz, Rafał Wojtan. (2019). Variability in the basic density of silver birch wood in Poland. Silva Fennica vol. 53 no. 1 article id 9968. https://doi.org/10.14214/sf.9968
Highlights: Location, tree age and forest habitat type, and the interactions between those factors, have a statistically significant impact on the basic density of silver birch wood; The average basic density of silver birch wood increases with the age of the tree.

This work presents the findings of a study concerning variability in the basic density of silver birch (Betula pendula Roth) wood, depending on the geographical location of tree stands, the age and thickness of the trees, the forest habitat type, and interactions between some of these factors. The study was carried out on wood from trees aged approximately 30, 50 and 70 years in 12 forest districts located throughout Poland. In total 4777 wood samples, taken from 306 trees from 51 test plots, were measured. The location, the age of the trees, the thickness of the trees and the forest habitat type, as well as interactions between these factors, proved to have a significant influence on the basic density of silver birch wood. The highest mean values of the basic density of the birch wood were found in Sokołów forest district on the FBF habitat type (549 kg m–3) and in Giżycko forest district on the FMBF habitat type (548 kg m–3). For the entire set of examined material, the average values of the basic density of wood increase with tree age. For the examined material originating in FBF and FMBF habitats the average values of basic density showed no significant differences; however, in the cases of the forest districts of Giżycko, Łobez and Rudziniec, significant differences in the analysed property were observed.

  • Lachowicz, Department of Forest Utilization, Warsaw University of Life Sciences SGGW, Nowoursynowska 159 02-787 Warsaw, Poland ORCID ID:E-mail: hubert.lachowicz@wl.sggw.pl
  • Bieniasz, Department of Forest Utilization, Warsaw University of Life Sciences SGGW, Nowoursynowska 159 02-787 Warsaw, Poland ORCID ID:E-mail: anna.bieniasz@wl.sggw.pl (email)
  • Wojtan, Laboratory of Dendrometry and Forest Productivity, Warsaw University of Life Sciences SGGW, Nowoursynowska 159 02-787 Warsaw, Poland ORCID ID:E-mail: rwojtan@wl.sggw.pl
article id 10055, category Research article
Jaakko Repola, Hannu Hökkä, Hannu Salminen. (2018). Models for diameter and height growth of Scots pine, Norway spruce and pubescent birch in drained peatland sites in Finland. Silva Fennica vol. 52 no. 5 article id 10055. https://doi.org/10.14214/sf.10055
Highlights: Tree growth strongly correlated with site drainage status; Between-tree competition had a higher impact on tree diameter growth than on height growth; Growth predicted by the constructed models were calibrated using NFI11 data to ensure generally applicable growth predictions level in whole country.

The aim of this study was to develop individual-tree diameter and height growth models for Scots pine, Norway spruce, and pubescent birch growing in drained peatlands in Finland. Trees growing in peatland sites have growth patterns that deviate from that of trees growing in mineral soil sites. Five-year growth was explained by tree diameter, different tree and stand level competition measures, management operations and site characteristics. The drainage status of the site was influencing growth directly or in interaction with other variables. Site quality had a direct impact but was also commonly related to current site drainage status (need for ditch maintenance). Recent thinning increased growth of all species and former PK fertilization increased growth of pine and birch. Temperature sum was a significant predictor in all models and altitude for spruce and birch. The data were a subsample of the 7th National Forest Inventory (NFI) sample plots representing northern and southern Finland and followed by repeated measurements for 15–20 yrs. Growth levels predicted by the models were calibrated using NFI11 data to remove bias originating from the sample of the modelling data. The mixed linear models technique was used in model estimation. The models will be incorporated into the MOTTI stand simulator to replace the current peatlands growth models.

  • Repola, Natural Resources Institute Finland (Luke), Natural resources, Eteläranta 55, FI-96300 Rovaniemi, Finland ORCID ID:E-mail: jaakko.repola@luke.fi (email)
  • Hökkä, Natural Resources Institute Finland (Luke), Natural resources, Paavo Havaksen tie 3, FI-90014 University OF Oulu, Finland ORCID ID:E-mail: hannu.hokka@luke.fi
  • Salminen, Natural Resources Institute Finland (Luke), Natural resources, Eteläranta 55, FI-96300 Rovaniemi, Finland ORCID ID:E-mail: hannu.salminen@luke.fi
article id 10013, category Research article
Hardo Becker, Jürgen Aosaar, Mats Varik, Gunnar Morozov, Kristiina Aun, Ülo Mander, Kaido Soosaar, Veiko Uri. (2018). Annual net nitrogen mineralization and litter flux in well-drained downy birch, Norway spruce and Scots pine forest ecosystems. Silva Fennica vol. 52 no. 4 article id 10013. https://doi.org/10.14214/sf.10013
Highlights: The net nitrogen mineralization (NNM) flux in drained peat soils depends largely on the C/N ratio and tree species; The soil NNM process is affected by trees through organic litter input into soil; Pine stand in low-fertility drained transitional bog is dominated by net ammonification; Birch and spruce stands on the fertile drained peat soil with higher pH and N content are dominated by net nitrification.

The main aim of the current study was to estimate the annual net nitrogen mineralization (NNM) flux in stands of different tree species growing on drained peatlands, as well as to clarify the effect of tree species, soil properties and litter on annual NNM dynamics. Three study sites were set up in May 2014: a downy birch (Betula pubescens Ehrh.) stand and a Norway spruce (Picea abies (L.) Karst.) stand in Oxalis full-drained swamp (ODS) and a Scots pine (Pinus sylvestris L.) stand in Myrtillus full-drained swamp (MDS). The NNM flux was estimated using the in situ method with incubated polyethylene bags. The highest value of NNM was found in stands that were growing on fertile ODS: 127.5 kg N ha–1 yr–1 and 87.7 kg N ha–1 yr–1, in the downy birch stand and in the Norway spruce stand, respectively. A significantly lower annual NNM flux (11.8 kg N ha–1 yr–1) occurred in the Scots pine stand growing in MDS. Nitrification was highest at fertile ODS sites and ammonification was the highest at the low fertility MDS site. For all study sites, positive correlation was found between soil temperature and NNM intensity. The difference in annual NNM between the downy birch stand and the Norway spruce stand growing on similar drained fertile peatlands was due to litter quality. The annual N input into the soil through leaf litter was the highest at the downy birch site where also the C/N ratio of litter was the lowest. The second highest N input into the soil was found in the spruce stand and the lowest in the pine stand.

  • Becker, Chair of Silviculture and Forest Ecology, Institute of Forestry and Rural Engineering, Estonian University of Life Sciences, Friedrich Reinhold Kreutzwaldi 1, 51014 Tartu, Estonia ORCID ID:E-mail: hardo.becker@emu.ee (email)
  • Aosaar, Chair of Silviculture and Forest Ecology, Institute of Forestry and Rural Engineering, Estonian University of Life Sciences, Friedrich Reinhold Kreutzwaldi 1, 51014 Tartu, Estonia ORCID ID:E-mail: jyrgen.aosaar@emu.ee
  • Varik, Chair of Silviculture and Forest Ecology, Institute of Forestry and Rural Engineering, Estonian University of Life Sciences, Friedrich Reinhold Kreutzwaldi 1, 51014 Tartu, Estonia ORCID ID:E-mail: mats.varik@emu.ee
  • Morozov, Chair of Silviculture and Forest Ecology, Institute of Forestry and Rural Engineering, Estonian University of Life Sciences, Friedrich Reinhold Kreutzwaldi 1, 51014 Tartu, Estonia ORCID ID:E-mail: gunnar.morozov@emu.ee
  • Aun, Chair of Silviculture and Forest Ecology, Institute of Forestry and Rural Engineering, Estonian University of Life Sciences, Friedrich Reinhold Kreutzwaldi 1, 51014 Tartu, Estonia ORCID ID:E-mail: kristiina.aun@emu.ee
  • Mander, Department of Geography, Institute of Ecology & Earth Sciences, University of Tartu, Ülikooli 18, 50090 Tartu, Estonia ORCID ID:E-mail: ulo.mander@ut.ee
  • Soosaar, Department of Geography, Institute of Ecology & Earth Sciences, University of Tartu, Ülikooli 18, 50090 Tartu, Estonia ORCID ID:E-mail: kaido.soosaar@ut.ee
  • Uri, Chair of Silviculture and Forest Ecology, Institute of Forestry and Rural Engineering, Estonian University of Life Sciences, Friedrich Reinhold Kreutzwaldi 1, 51014 Tartu, Estonia ORCID ID:E-mail: veiko.uri@emu.ee
article id 9996, category Research article
Mulualem Tigabu, Mostafa Farhadi, Lars-Göran Stener, Per C. Odén. (2018). Visible + Near Infrared Spectroscopy as taxonomic tool for identifying birch species. Silva Fennica vol. 52 no. 4 article id 9996. https://doi.org/10.14214/sf.9996
Highlights: Multivariate modelling of visible + near infrared (NIR) reflectance spectra of single seeds distinguished Betula pubescens and B. pendula with 100% and 99% accuracy, respectively; The results demonstrate the feasibility of NIR spectroscopy as taxonomic tool for classification of species that have morphological resemblance.

The genus Betula L. is composed of several species, which are difficult to distinguish in the field on the basis of morphological traits. The aim of this study was to evaluate the taxonomic importance of using visible + near infrared (Vis + NIR) spectra of single seeds for differentiating Betula pendula Roth and Betula pubescens Ehrh. Seeds from several families (controlled crossings of known parent trees) of each species were used and Vis + NIR reflectance spectra were obtained from single seeds. Multivariate discriminant models were developed by Orthogonal Projections to Latent Structures – Discriminant Analysis (OPLS-DA). The OPLS-DA model fitted on Vis + NIR spectra recognized B. pubescens with 100% classification accuracy while the prediction accuracy of class membership for B. pendula was 99%. However, the discriminant models fitted on NIR spectra alone resulted in 100% classification accuracies for both species. Absorption bands accounted for distinguishing between birch species were attributed to differences in color and chemical composition, presumably polysaccharides, proteins and fatty acids, of the seeds. In conclusion, the results demonstrate the feasibility of NIR spectroscopy as taxonomic tool for classification of species that have morphological resemblance.

  • Tigabu, Swedish University of Agricultural Sciences, Southern Swedish Forest Research Centre, Box 49, SE-230 52 Alnarp, Sweden ORCID ID:E-mail: mulualem.tigabu@slu.se (email)
  • Farhadi, Swedish University of Agricultural Sciences, Southern Swedish Forest Research Centre, Box 49, SE-230 52 Alnarp, Sweden ORCID ID:E-mail: mostafa.farhadi@gmail.com
  • Stener, The Forestry Research Institute of Sweden, Ekebo 2250, SE-268 90 Svalöv, Sweden ORCID ID:E-mail: lars-goran.stener@skogforsk.se
  • Odén, Swedish University of Agricultural Sciences, Southern Swedish Forest Research Centre, Box 49, SE-230 52 Alnarp, Sweden ORCID ID:E-mail: per.christer.oden@slu.se
article id 7731, category Research article
Anneli Viherä-Aarnio, Pirkko Velling. (2017). Growth, wood density and bark thickness of silver birch originating from the Baltic countries and Finland in two Finnish provenance trials. Silva Fennica vol. 51 no. 4 article id 7731. https://doi.org/10.14214/sf.7731
Highlights: Baltic origins of silver birch had significantly thicker bark than the Finnish ones; In terms of wood density, no consistent difference was detected between the Baltic and Finnish origins; Incidence of darkened core wood increased with increasing seed origin latitude; Frost cracks were most common in south Latvian origins grown in central Finland.

Silver birch (Betula pendula Roth) seed origins from the Baltic countries and from Finland were compared in terms of growth, wood density, bark thickness and the incidence of darkened core wood, frost cracks and decay, and the effect of seed origin latitude was examined in two Finnish provenance trials. The material consisted of 21 stand and single tree origins ranging from latitudes 54° to 63°N from the Baltic countries and Finland. The trials, measured at the age of 22 years, were located at Tuusula (60°21´N), southern Finland and at Viitasaari (63°11´N), central Finland. The Baltic origins were superior to the Finnish ones in the southern trial regarding height, whereas in central Finland the Finnish origins grew better. There was no consistent difference between the Baltic and the Finnish group of origins in wood density. Bark thickness decreased with increasing seed origin latitude. The Baltic origins had significantly thicker bark than the Finnish origins. A moderate positive correlation was detected between the seed origin latitude and the incidence of darkened core wood in the southern trial, where the darkened core wood was more common in the Finnish origins than in the Baltic ones. The highest proportion of trees with frost cracks was detected in the south-western Latvian origins growing in central Finland. Seed transfers from the Baltic would have an increasing effect on the bark thickness of birch logs, but no or only minor effects on wood density. Based on our results, there is no reason to recommend the use of non-native Baltic seed origins in Finland instead of the native locally adapted seed sources.

  • Viherä-Aarnio, Natural Resources Institute Finland (Luke), Green technology, P.O. Box 2, FI-00791 Helsinki, Finland ORCID ID:E-mail: anneli.vihera-aarnio@luke.fi (email)
  • Velling, ORCID ID:E-mail: pike.velling@phnet.fi
article id 2017, category Research article
Pentti Niemistö, Soili Kojola, Anssi Ahtikoski, Raija Laiho. (2017). From useless thickets to valuable resource? – Financial performance of downy birch management on drained peatlands. Silva Fennica vol. 51 no. 3 article id 2017. https://doi.org/10.14214/sf.2017
Highlights: The most profitable management regimes for pulpwood and energy wood production in dense downy birch stands on drained peatlands include no thinnings, but final cutting at the stand age of 40–45 years as whole-tree harvesting, or as integrated harvesting of pulpwood and delimbed energy wood stems about 10 years later depending on applicable harvesting method; A competitive management regime is early precommercial thinning at 4 m dominant height to a density of 2500 stems per hectare and production of pulpwood with a rotation of 55–65 years. Equal profitability is achieved with or without traditional first thinning, which can thus be included for other reasons, for example to improve regeneration of spruce.

Downy birch (Betula pubescens Ehrh.) stands on drained peatlands are often considered useless because they typically do not yield good-quality sawn timber. However, covering an area of ca. 0.5 million hectares and with total yields of up to 250 m3 ha–1, downy birch stands on peatlands in Finland have a potential for pulpwood and/or energy wood production. We examined the financial performance of alternative management regimes (with or without thinnings, different thinning intensities, several rotation lengths) combined with alternative harvesting methods (pulpwood, energy wood, or integrated, energy wood being delimbed stems or whole trees). We used data from 19 experimental stands, monitored for 20–30 years. For harvesting removals we considered both actual thinning removals and final-cutting removals with alternative timings that were based on the monitoring data. We assessed the profitability as a combination of the net present value of the birch generation and the bare land value of future generations of Norway spruce (Picea abies (L.) Karst.). The most profitable management was growing without thinnings until whole-tree final cutting at the stand age of 40–45 years with an advanced multi-tree harvesting method. In contrast, the standard method in whole-tree final cutting resulted in the lowest profitability, and an integrated method with the energy wood as delimbed stems was the best of the standard methods. Thinnings were unprofitable especially when aiming to produce energy wood, whereas aiming for pulpwood, light precommercial thinning was competitive. Commercial thinning at the traditional “pulpwood stage” had little effect on profitability. The best stand age for final cutting was 40–65 years – earlier for very dense stands and whole-tree energy wood harvesting with advanced method, later for precommercially thinned stands and pulpwood harvesting.

  • Niemistö, Natural Resources Institute Finland (Luke), Management and Production of Renewable Resources, Kampusranta 9 C, 60320 Seinäjoki, Finland ORCID ID:E-mail: pentti.niemisto@luke.fi (email)
  • Kojola, Natural Resources Institute Finland (Luke), Management and Production of Renewable Resources, Latokartanonkaari 9, 00790 Helsinki, Finland ORCID ID:E-mail: soili.kojola@luke.fi
  • Ahtikoski, Natural Resources Institute Finland (Luke), Management and Production of Renewable Resources, Paavo Havaksentie 3, 90014 University of Oulu, Finland ORCID ID:E-mail: anssi.ahtikoski@luke.fi
  • Laiho, Natural Resources Institute Finland (Luke), Management and Production of Renewable Resources, Latokartanonkaari 9, 00790 Helsinki, Finland ORCID ID:E-mail: raija.laiho@luke.fi
article id 1461, category Research article
Ludmila Novitskaya, Nadezhda Nikolaeva, Natalia Galibina, Tatiana Tarelkina, Ludmila Semenova. (2016). The greatest density of parenchyma inclusions in Karelian birch wood occurs at confluences of phloem flows. Silva Fennica vol. 50 no. 3 article id 1461. https://doi.org/10.14214/sf.1461
Highlights: Dark-colored inclusions creating the figured pattern in Karelian birch wood consist of storage parenchyma cells; Their greatest density is formed above branch attachments and below forks; In these zones, the sucrose content is elevated since photoassimilate flows of the trunk and branches merge into one pathway; A high level of sucrose enhances the differentiation of parenchyma cells.

The specific pattern of the wood of Karelian birch (Betula pendula Roth var. carelica (Merckl.) Hämet-Ahti), is created mainly by dark-coloured inclusions of parenchyma tissue. Our study revealed that the greatest density of parenchyma inclusions in Karelian birch wood is observed above branch attachments to the trunk and below forks. In the place of branch attachment, phloem flows of photoassimilates (sucrose) from the branch and along the trunk merge into one pathway, causing a rise in sucrose content in tissues there. In the area below the fork, sucrose flows from two (or more) trunk axes are combined. Many studies have demonstrated that elevated sucrose level is associated with the differentiation of parenchyma. We believe that where large phloem fluxes merge a high level of sucrose promotes mass differentiation of parenchyma cells instead of fibers and vessels. As a result, the density of the figured pattern in the wood increases. The obtained data have a practical value and can be used in developing recommendations for Karelian birch cultivation.

  • Novitskaya, Forest Research Institute, Karelian Research Center, Russian Academy of Sciences, Pushkinskaya str. 11, 185910, Petrozavodsk, Russia ORCID ID:E-mail: ludnovits@rambler.ru (email)
  • Nikolaeva, Forest Research Institute, Karelian Research Center, Russian Academy of Sciences, Pushkinskaya str. 11, 185910, Petrozavodsk, Russia ORCID ID:E-mail: kar-birch@mail.ru
  • Galibina, Forest Research Institute, Karelian Research Center, Russian Academy of Sciences, Pushkinskaya str. 11, 185910, Petrozavodsk, Russia ORCID ID:E-mail: galibina@krc.karelia.ru
  • Tarelkina, Forest Research Institute, Karelian Research Center, Russian Academy of Sciences, Pushkinskaya str. 11, 185910, Petrozavodsk, Russia ORCID ID:E-mail: karelina.t.v@gmail.com
  • Semenova, Forest Research Institute, Karelian Research Center, Russian Academy of Sciences, Pushkinskaya str. 11, 185910, Petrozavodsk, Russia ORCID ID:E-mail: mi7enova@gmail.com
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 1279, category Research article
Andreas Kreutz, Tuomas Aakala, Russell Grenfell, Timo Kuuluvainen. (2015). Spatial tree community structure in three stands across a forest succession gradient in northern boreal Fennoscandia. Silva Fennica vol. 49 no. 2 article id 1279. https://doi.org/10.14214/sf.1279
Highlights: We studied the tree community spatial structure in three 1.2-ha plots representing naturally developed northern boreal forests of varying ages; Spatial structure showed little differences between the mid-successional, late-successional and old-growth stands; The occurrence of Picea abies relative to Betula spp. indicated a mosaic-like spatial assembly; Mosaics are likely maintained by species-specific replacement, not reciprocal replacement as thought earlier.
Development of species composition during succession is well studied in natural boreal forests, but empirical assessments of how within-stand spatial structure develops in late-successional stages are few. Here, we quantified spatial patterns in three unmanaged stands consisting of Picea abies (L.) Karst. and Betula pubescens Ehrh. and Betula pendula Roth (hereafter Betula spp.) in northern boreal Fennoscandia. We conducted a comprehensive analysis of small-scale spatial point patterns in three fully mapped 1.2-ha sample plots, representing different forest developmental stages: mid-successional, late-successional and old-growth forest. We used several variants of Ripley’s K-function to analyze the spatial point patterns along the successional gradient. Univariate analyses showed that mature trees of both species were either randomly distributed or clumped. P. abies saplings were clumped, and Betula spp. saplings occurred in a random or clumped manner. In the bivariate analyses, saplings were more likely to be found in the surroundings of mature trees of the same species, but occurred independent of the individuals of other tree species. Mature trees showed interspecific repulsion. Only modest differences occurred in the univariate patterns between the three successional stages, but in the bivariate analyses the most evident patterns, i.e. intraspecific attraction and interspecific repulsion, were stronger in the older successional stages. Overall, the studied stands appear structured as species-specific mosaics. These mosaics, along with mixed species composition, seem to be maintained by species self-replacement, which contrasts with findings from earlier studies.
  • Kreutz, Department of Forest Sciences, University of Helsinki, P.O. Box 27, FI-00014 University of Helsinki, Finland ORCID ID:E-mail: andreas.kreutz@wald-rpl.de
  • Aakala, Department of Forest Sciences, University of Helsinki, P.O. Box 27, FI-00014 University of Helsinki, Finland ORCID ID: http://orcid.org/0000-0003-0160-6410 E-mail: tuomas.aakala@helsinki.fi (email)
  • Grenfell, Department of Forest Sciences, University of Helsinki, P.O. Box 27, FI-00014 University of Helsinki, Finland ORCID ID:E-mail: russell.grenfell@gmail.com
  • Kuuluvainen, Department of Forest Sciences, University of Helsinki, P.O. Box 27, FI-00014 University of Helsinki, Finland ORCID ID:E-mail: timo.kuuluvainen@helsinki.fi
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 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 964, category Research article
Liisa Huttunen, Matthew P. Ayres, Pekka Niemelä, Susanne Heiska, Riitta Tegelberg, Matti Rousi, Seppo Kellomäki. (2013). Interactive effects of defoliation and climate change on compensatory growth of silver birch seedlings. Silva Fennica vol. 47 no. 3 article id 964. https://doi.org/10.14214/sf.964
Highlights: The main components affecting growth compensation in silver birch seedlings are the timing and severity of foliage damage; The ability to compensate growth is also dependent upon the limits of temperature and nutrient availability; The responses of birches imply that folivory does not necessarily lead to reduced net productivity under changing climate
Atmospheric warming increases the abundance of insect herbivores and intensifies the risk of defoliation, especially in high latitude forests. At the same time, the effects of increasing temperature and CO2 on plant responses to foliage damage are poorly understood. We examined if previous-year defoliation, varying between 0 and 75% of total leaf area, and different combinations of elevated temperature, CO2 and nutrient availability alter the growth of two-year old silver birch (Betula pendula Roth) seedlings. We measured the greatest height growth in seedlings that were fertilized and defoliated twice at the level of 50% of total leaf area, and subjected to elevated temperature with ambient CO2. The lowest growth was recorded in unfertilized seedlings that were defoliated twice at the level of 25% of total leaf area, and grew under ambient temperature with ambient CO2. The total biomass increased in all seedlings that were fertilized or grew under elevated temperature. The root: shoot ratios were low in defoliated seedlings, or seedlings subjected to fertilization or temperature elevation. Our conclusion is that ability of birches to compensate height growth is highly dependent upon the magnitude and frequency of defoliation on the limits of temperature and nutrient availability. These responses imply that folivory does not necessarily lead to reduced net productivity of trees under changing climate.
  • Huttunen, Section of Ecology, Department of Biology, University of Turku, FI-20014 Turku, Finland ORCID ID:E-mail: liisa.huttunen@utu.fi (email)
  • Ayres, Biological Sciences, Dartmouth College, Hanover, NH 03755, USA ORCID ID:E-mail: matt.ayres@dartmouth.edu
  • Niemelä, Section of Biodiversity and Environmental Science, Department of Biology, University of Turku, FI-20014 Turku, Finland ORCID ID:E-mail: pekka.niemela@utu.fi
  • Heiska, The Finnish Forest Research Institute, Punkaharju Unit, Finlandiantie 18, FI-58450 Punkaharju, Finland ORCID ID:E-mail: susanne.heiska@metla.fi
  • Tegelberg, Digitarium - Digitization Centre of the Finnish Museum of Natural History and the University of Eastern Finland, Joensuu Science Park, P.O. Box 111, FI-80101 Joensuu, Finland ORCID ID:E-mail: riitta.tegelberg@helsinki.fi
  • Rousi, The Finnish Forest Research Institute, Vantaa Unit, P.O. Box 18, FI-01301 Vantaa, Finland ORCID ID:E-mail: matti.rousi@metla.fi
  • Kellomäki, Faculty of Science and Forestry, School of Forest Sciences, University of Eastern Finland, P.O. Box 111, FI-80101 Joensuu, Finland ORCID ID:E-mail: seppo.kellomaki@uef.fi
article id 917, category Research article
Anna Gunulf, Rebecka Mc Carthy, Jonas Rönnberg. (2012). Control efficacy of stump treatment and influence of stump height on natural spore infection by Heterobasidion spp. of precommercial thinning stumps of Norway spruce and birch. Silva Fennica vol. 46 no. 5 article id 917. https://doi.org/10.14214/sf.917
An alternative precommercial thinning technique results in trees being cut higher up the stem compared to the normal method using a brush saw. The aims of this study were to investigate if primary infection of Heterobasidion spp. on precommercial thinning stumps of Norway spruce and birch is influenced by stump height and to test the control efficacy of stump treatment with Phlebiopsis gigantea on precommercial thinning stumps of Norway spruce. Small Norway spruce and birch trees were felled on five sites in southern Sweden and their stumps subjected to natural spore infection. For each species, two treatments of stump height were created: 15 and 100 cm. Half of the Norway spruce stumps were treated with P. gigantea. After two months, 896 stumps were sampled and infection by Heterobasidion spp. was quantified. The height of stumps did not significantly influence infection frequency or size of infection on either tree species. Untreated Norway spruce stumps had an infection frequency of 55% while 31% of the treated stumps were infected. The control efficacy of stump treatment in terms of reduced relative infected area was 61–65%. The area occupied by Heterobasidion spp. on birch stumps was generally small, on average 0.4 cm2 per infected stump, although 15% of the stumps were infected. The risk of primary infection in Norway spruce dominated stands should be considered when precommercial thinning is conducted but the control efficacy and economy of stump treatment warrants further investigation before practical recommendations can be made.
  • Gunulf, Swedish University of Agricultural Sciences, Department of Southern Swedish Forest Research Centre, P.O. Box 49, SE-230 53 Alnarp, Sweden ORCID ID:E-mail: anna.gunulf@slu.se (email)
  • Mc Carthy, Skogsforsk, Ekebo 2250, SE-268 90 Svalöv, Sweden ORCID ID:E-mail: Rebecka.McCarthy@skogforsk.se
  • Rönnberg, Swedish University of Agricultural Sciences, Department of Southern Swedish Forest Research Centre, P.O. Box 49, SE-230 53 Alnarp, Sweden ORCID ID:E-mail: jonas.ronnberg@slu.se
article id 905, category Research article
Katarzyna A. Jadwiszczak, Danuta Drzymulska, Agata Banaszek, Piotr Jadwiszczak. (2012). Population history, genetic variation and conservation status of the endangered birch species Betula nana L. in Poland. Silva Fennica vol. 46 no. 4 article id 905. https://doi.org/10.14214/sf.905
The effective conservation of species requires data on the levels and distribution of genetic diversity within and among populations. In this study, we estimated the genetic variation in three isolated populations of Betula nana in Poland. An analysis of 11 nuclear microsatellites revealed moderate mean heterozygosities (HO=0.556, HE=0.562), low mean number of alleles per locus (A=4.57) and no inbreeding in the total sample. An M-ratio test indicated that each population had experienced a severe bottleneck in the past. Tests for heterozygosity excess revealed that a significant decrease in the numbers of individuals in two populations had occurred quite recently. The large number of private alleles and very restricted number of migrants between populations (Nm=0.35) strongly suggest that genetic drift and geographic isolation are the primary factors responsible for the reduction of genetic variation in the Polish populations of B. nana. We detected two cpDNA haplotypes in the study populations, which can be explained in terms of either the genetic drift acting on the relict localities or a postglacial recolonisation from distinct refugia. Palynological data indicated that one refugium could be located in the Carpathians and their northern foreland. The primary threat to B. nana in Poland is the overgrowth of its habitats by competing species, which has likely resulted in a lack of generative reproduction in the mountain populations.
  • Jadwiszczak, Institute of Biology, University of Białystok, wierkowa 20B, 15-950 Białystok, Poland ORCID ID:E-mail: kszalaj@uwb.edu.pl (email)
  • Drzymulska, Institute of Biology, University of Białystok, wierkowa 20B, 15-950 Białystok, Poland ORCID ID:E-mail:
  • Banaszek, Institute of Biology, University of Białystok, wierkowa 20B, 15-950 Białystok, Poland ORCID ID:E-mail:
  • Jadwiszczak, Institute of Biology, University of Białystok, wierkowa 20B, 15-950 Białystok, Poland ORCID ID:E-mail:
article id 48, category Research article
Jyrki Hytönen, Lasse Aro. (2012). Biomass and nutrition of naturally regenerated and coppiced birch on cutaway peatland during 37 years. Silva Fennica vol. 46 no. 3 article id 48. https://doi.org/10.14214/sf.48
Biomass production and nutrient use of birch thickets with a mixture of willow on a cut away peatland in southern Finland over a period of 37 years was studied. Dense, naturally regenerated 16-year-old birch stands were cut down, fertilized with either wood ash (P 108 and K 339 kg ha–1) or PK fertilizer (P 50 and K 95 kg ha–1) or left unfertilized. The biomass production of the coppiced stands and one uncut stand was monitored for a period of 21 years. Soil nutrient and foliar nutrient concentrations were analyzed several times during the study period. Ash fertilization supplied more nutrients than PK fertilization and increased the soil nutrient amounts more. The foliar phosphorus concentration of birch on control plots indicated a severe phosphorus deficiency which was removed by PK and ash fertilization. Fertilization did not increase nutrient concentrations of the stem (wood + bark) nor the amount of nutrients bound in the biomass. Two energy wood rotations (16+21 years) produced 124–158 Mg ha–1 of leafless, above-ground biomass altogether corresponding to 61–78 Mg ha–1 of carbon. The highest biomass yield was achieved with a rotation of 37 years in the uncut stand (211 Mg ha–1). Corresponding values for mean annual increment (MAI) were 3.4–4.3 Mg ha–1 and 5.7 Mg ha–1. This study shows that the length of the rotation for birch in energy wood production should be longer than 21 years. PK and ash fertilization increased the biomass of coppiced 21-year-old birch by 23 Mg ha–1 and 33 Mg ha–1, respectively.
  • Hytönen, Finnish Forest Research Institute, Kannus, Finland ORCID ID:E-mail: jyrki.hytonen@metla.fi (email)
  • Aro, Finnish Forest Research Institute, Kannus, Finland ORCID ID:E-mail: lasse.aro@metla.fi
article id 46, category Research article
Matti Rousi, Boy J.H.M. Possen, Risto Hagqvist, Barb R. Thomas. (2012). From the Arctic Circle to the Canadian prairies – a case study of silver birch acclimation capacity. Silva Fennica vol. 46 no. 3 article id 46. https://doi.org/10.14214/sf.46
Earlier provenance research has indicated poor success even in short distance transfers (> 2–3° latitude) of silver birch (Betula pendula Roth) southward from their origin. These results may indicate poor adaptability of silver birch to a warming climate. Some of the scenarios for a warming climate in Finland suggest effective heat sums are likely to double in the north and increase 1.5 fold in the south for the period of 2070–2099. Consequently, the outlook for silver birch appears bleak. To study the acclimation of birch to this projected change we established a provenance trial in northeastern Alberta, Canada, at the temperature area currently predicted for Central Finland (lat. 64–66°N) at the turn of this century (1400 dd). Our 10-year experiment showed that all the Finnish provenances (origins 61–67°N) have acclimated well to the warmer growth conditions experienced in Alberta at 54°N. These results suggest that silver birch has the potential to acclimate to thermal conditions predicted for Finland at the end of the 21st century. Our results also indicate that silver birch has the potential as a plantation species in Canada, where the Finnish birch grew faster in the boreal forest region of Canada than local paper birch (Betula papyrifera Marsh.) provenances.
  • Rousi, The Finnish Forest Research Institute, Finland ORCID ID:E-mail: matti.rousi@metla.fi (email)
  • Possen, The Finnish Forest Research Institute, Finland ORCID ID:E-mail:
  • Hagqvist, The Finnish Forest Research Institute, Finland ORCID ID:E-mail:
  • Thomas, University of Alberta, Dept of Renewable Resources, Edmonton & Alberta-Pacific Forest Industries Inc., Boyle, Alberta, Canada ORCID ID:E-mail:
article id 46, category Research article
Matti Rousi, Boy J.H.M. Possen, Risto Hagqvist, Barb R. Thomas. (2012). From the Arctic Circle to the Canadian prairies – a case study of silver birch acclimation capacity. Silva Fennica vol. 46 no. 3 article id 46. https://doi.org/10.14214/sf.46
Earlier provenance research has indicated poor success even in short distance transfers (> 2–3° latitude) of silver birch (Betula pendula Roth) southward from their origin. These results may indicate poor adaptability of silver birch to a warming climate. Some of the scenarios for a warming climate in Finland suggest effective heat sums are likely to double in the north and increase 1.5 fold in the south for the period of 2070–2099. Consequently, the outlook for silver birch appears bleak. To study the acclimation of birch to this projected change we established a provenance trial in northeastern Alberta, Canada, at the temperature area currently predicted for Central Finland (lat. 64–66°N) at the turn of this century (1400 dd). Our 10-year experiment showed that all the Finnish provenances (origins 61–67°N) have acclimated well to the warmer growth conditions experienced in Alberta at 54°N. These results suggest that silver birch has the potential to acclimate to thermal conditions predicted for Finland at the end of the 21st century. Our results also indicate that silver birch has the potential as a plantation species in Canada, where the Finnish birch grew faster in the boreal forest region of Canada than local paper birch (Betula papyrifera Marsh.) provenances.
  • Rousi, The Finnish Forest Research Institute, Finland ORCID ID:E-mail: matti.rousi@metla.fi (email)
  • Possen, The Finnish Forest Research Institute, Finland ORCID ID:E-mail:
  • Hagqvist, The Finnish Forest Research Institute, Finland ORCID ID:E-mail:
  • Thomas, University of Alberta, Dept of Renewable Resources, Edmonton & Alberta-Pacific Forest Industries Inc., Boyle, Alberta, Canada ORCID ID:E-mail:
article id 441, category Research article
Ane Zubizarreta-Gerendiain, Petri Pellikka, Jordi Garcia-Gonzalo, Veli-Pekka Ikonen, Heli Peltola. (2012). Factors affecting wind and snow damage of individual trees in a small management unit in Finland: assessment based on inventoried damage and mechanistic modelling. Silva Fennica vol. 46 no. 2 article id 441. https://doi.org/10.14214/sf.441
In this work, we assessed the factors affecting wind and snow damage of individual trees in a small management unit in western Finland. This was done based on inventoried damage and observed wind speeds and snow loading in storms Pyry and Janika in 2001 and Mielikki in 2002 together with mechanistic model. First, we studied which factors explain the observed damage in individual trees. Secondly, we studied how well the mechanistic model (HWIND) could predict the wind speed needed to uproot individual trees at the margins of permanent upwind edges. We found that Pyry storm caused 70% and Janika and Mielikki 18 and 12% of observed damage. In Janika storm, all trees uprooted. In other storms, both uprooting and stem breakage occurred. Scots pine suffered the most damage. Recently thinned stands on the upwind edges of open areas suffered the most damage. But, damage occurred also on soils with relatively shallow anchorage. HWIND predicted correctly damage for 69% of all uprooted trees. No-uprooting was correctly predicted for 45 and 19% of standing trees (all Scots pines), which were measured within and at the immediate upwind edge of same stands. HWIND model needs further validation at the permanent edges and/or on soils with shallow rooting to improve its prediction accuracy in such conditions.
  • Zubizarreta-Gerendiain, Technical University of Lisbon, School of Agriculture, Forest Research Centre, Lisbon, Portugal ORCID ID:E-mail:
  • Pellikka, University of Helsinki, Dept. of Geosciences and Geography, Helsinki, Finland ORCID ID:E-mail:
  • Garcia-Gonzalo, Technical University of Lisbon, School of Agriculture, Forest Research Centre, Lisbon, Portugal ORCID ID:E-mail:
  • Ikonen, University of Eastern Finland, School of Forest Sciences, Joensuu, Finland ORCID ID:E-mail:
  • Peltola, University of Eastern Finland, School of Forest Sciences, Joensuu, Finland ORCID ID:E-mail: heli.peltola@uef.fi (email)
article id 67, category Research article
Pentti Niemistö, Heikki Korpunen, Ari Laurén, Marika Salomäki, Jori Uusitalo. (2012). Impact and productivity of harvesting while retaining young understorey spruces in final cutting of downy birch (Betula pubescens). Silva Fennica vol. 46 no. 1 article id 67. https://doi.org/10.14214/sf.67
Quite often Norway spruce (Picea abies (L.) Karsten) forms an understorey in birch dominated stands in Finland. Advantageous growth conditions for both storeys are present especially in downy birch (Betula pubescens Ehrh.) stands on drained fertile peatland. The most common way of regenerating mature Downy birch forest is clear cutting and replanting with Norway spruce, even if vital spruce seedlings or saplings was already growing under the birch. The aim of this study is to investigate the impact of retaining young understorey spruces on the productivity of harvesting and on the quality of the remaining stands in downy birch dominated stands with modern cut-to-length (CTL) machinery. Retaining undergrowth spruces decreased productivity of cutting in managed stands (600 stems/ha) by 6–9 per cent and in unmanaged stands (1200 stems/ha) by 11–17 per cent compared with clear cutting, where the understorey is not considered. Compared with the case where no understorey was present, the decrease in productivity was 10–17 per cent and 21–30 per cent respectively. In forwarding, retaining the undergrowth decreased the productivity of loading phases by 7–14 per cent. Harvesting treatment where spruces were retained produced an adequate stand structure for the future growing stock. Using this method, 14–24 per cent of the original spruces were totally destroyed while 25–44 per cent of spruces were destroyed when they were not considered for harvesting. The spatial variation of the remaining spruces was much better in the treatment where spruces were retained. Our study results shows that in this kind of two storey birch–spruce forests, the harvesting treatment where spruces are retained while cutting is the most acceptable and profitable method. It allows for a vital spruce sapling to continue growing, and avoids regeneration and tending costs or other harmful effects of clear-cut areas such as the freezing of young spruce plants and an increase in the ground water table.
  • Niemistö, Finnish Forest Research Institute, Parkano & Joensuu, Finland ORCID ID:E-mail:
  • Korpunen, Finnish Forest Research Institute, Parkano & Joensuu, Finland ORCID ID:E-mail:
  • Laurén, Finnish Forest Research Institute, Parkano & Joensuu, Finland ORCID ID:E-mail:
  • Salomäki, Finnish Forest Research Institute, Parkano & Joensuu, Finland ORCID ID:E-mail:
  • Uusitalo, Finnish Forest Research Institute, Parkano & Joensuu, Finland ORCID ID:E-mail: jori.uusitalo@metla.fi (email)
article id 117, category Research article
Harri Kilpeläinen, Jari Lindblad, Henrik Heräjärvi, Erkki Verkasalo. (2011). Saw log recovery and stem quality of birch from thinnings in southern Finland. Silva Fennica vol. 45 no. 2 article id 117. https://doi.org/10.14214/sf.117
The objective of this study was to examine the timber quality of silver birch (Betula pendula Roth) and European white birch (Betula pubescens Ehrh.) trees in the first and second thinnings in southern parts of Finland, from the viewpoint of sawing of small-diameter, short logs, in particular. The average stem volume of birch was 0.140 m3 in the first thinning stands and 0.206 m3 in the second thinning stands. In planted stands, the trees were larger in the first thinnings but slightly smaller in the second thinnings, compared with naturally regenerated pure birch stands or mixed stands of Norway spruce and birch species. Almost 60% of the harvested and 35% of the remaining stems that could provide saw logs were graded as pulpwood for timber quality due to the occurrence of stem defects. The most common stem defects were multiple crooks and middle crooks. Only minor between-stratum differences were detected in the numbers of defects. Depending on the bucking option, the total percentage of saw and plywood logs from the total birch recovery in the thinning of the sample stands varied between 11.7 and 18.2. The recovery of saw logs was clearly higher in the second thinnings, 12–19%, than in the first thinnings, 8–14%. Of the stand types, saw log recovery was the highest in planted birch stands, 12–19%, but lower in naturally regenerated pure birch stands and mixed stands of Norway spruce and birch. The highest share of saw logs was in the second thinning of planted stands, 17–25%. This study shows that the harvesting recoveries of end-use based timber assortments can be estimated in different kinds of thinning birch stands. Based on tree and log dimensions and stem squality, silver birch firstly from plantations and secondly from mixed stands should be the most interesting source of raw material for the saw milling, furniture and interior product sectors.
  • Kilpeläinen, Finnish Forest Research Institute, Eastern Finland Research Unit, P.O. Box 68, FI-80101 Joensuu, Finland ORCID ID:E-mail:
  • Lindblad, Finnish Forest Research Institute, Eastern Finland Research Unit, P.O. Box 68, FI-80101 Joensuu, Finland ORCID ID:E-mail:
  • Heräjärvi, Finnish Forest Research Institute, Eastern Finland Research Unit, P.O. Box 68, FI-80101 Joensuu, Finland ORCID ID:E-mail: henrik.herajarvi@metla.fi (email)
  • Verkasalo, Finnish Forest Research Institute, Eastern Finland Research Unit, P.O. Box 68, FI-80101 Joensuu, Finland ORCID ID:E-mail:
article id 117, category Research article
Harri Kilpeläinen, Jari Lindblad, Henrik Heräjärvi, Erkki Verkasalo. (2011). Saw log recovery and stem quality of birch from thinnings in southern Finland. Silva Fennica vol. 45 no. 2 article id 117. https://doi.org/10.14214/sf.117
The objective of this study was to examine the timber quality of silver birch (Betula pendula Roth) and European white birch (Betula pubescens Ehrh.) trees in the first and second thinnings in southern parts of Finland, from the viewpoint of sawing of small-diameter, short logs, in particular. The average stem volume of birch was 0.140 m3 in the first thinning stands and 0.206 m3 in the second thinning stands. In planted stands, the trees were larger in the first thinnings but slightly smaller in the second thinnings, compared with naturally regenerated pure birch stands or mixed stands of Norway spruce and birch species. Almost 60% of the harvested and 35% of the remaining stems that could provide saw logs were graded as pulpwood for timber quality due to the occurrence of stem defects. The most common stem defects were multiple crooks and middle crooks. Only minor between-stratum differences were detected in the numbers of defects. Depending on the bucking option, the total percentage of saw and plywood logs from the total birch recovery in the thinning of the sample stands varied between 11.7 and 18.2. The recovery of saw logs was clearly higher in the second thinnings, 12–19%, than in the first thinnings, 8–14%. Of the stand types, saw log recovery was the highest in planted birch stands, 12–19%, but lower in naturally regenerated pure birch stands and mixed stands of Norway spruce and birch. The highest share of saw logs was in the second thinning of planted stands, 17–25%. This study shows that the harvesting recoveries of end-use based timber assortments can be estimated in different kinds of thinning birch stands. Based on tree and log dimensions and stem squality, silver birch firstly from plantations and secondly from mixed stands should be the most interesting source of raw material for the saw milling, furniture and interior product sectors.
  • Kilpeläinen, Finnish Forest Research Institute, Eastern Finland Research Unit, P.O. Box 68, FI-80101 Joensuu, Finland ORCID ID:E-mail:
  • Lindblad, Finnish Forest Research Institute, Eastern Finland Research Unit, P.O. Box 68, FI-80101 Joensuu, Finland ORCID ID:E-mail:
  • Heräjärvi, Finnish Forest Research Institute, Eastern Finland Research Unit, P.O. Box 68, FI-80101 Joensuu, Finland ORCID ID:E-mail: henrik.herajarvi@metla.fi (email)
  • Verkasalo, Finnish Forest Research Institute, Eastern Finland Research Unit, P.O. Box 68, FI-80101 Joensuu, Finland ORCID ID:E-mail:
article id 135, category Research article
Ola Lindroos, Marina Henningsson, Dimitris Athanassiadis, Tomas Nordfjell. (2010). Forces required to vertically uproot tree stumps. Silva Fennica vol. 44 no. 4 article id 135. https://doi.org/10.14214/sf.135
Stumpwood attracts renewed interest due to increased use of forest biomass for bioenergy. In Nordic countries stumps are generally uprooted with crawler excavators, which have strong cranes (ca. 400 kNm gross lift torque), but are not designed for moving in forest terrain. Their use is based on practical experience with available and tested machine types rather than thorough examinations of requirements, partly due to limited knowledge of force requirements for uprooting of stumps. Therefore, in this work mean and maximum forces required to vertically uproot stumps of Norway spruce (Picea abies) and birch (Betula spp.) were quantified together with the effects of various soil types and uprooting methods. The used excavator’s crane-mounted uprooting device enabled comparisons between usage of solely crane force, and a method in which preparatory loosening forces were applied prior to crane force. Uprooting stumps in single pieces proved difficult; 61% split unintentionally. Force requirements were similar across tree species, increasing curve-linearly with stump diameter, and stumps uprooted in a single piece required more force than split stumps. Preparatory loosening reduced crane force requirements and, surprisingly, less force was required to uproot stumps from a mesic, till soil than from a moist, finer-textured soil. No stump required more than 60 kN crane force and functions for maximum force requirements indicate that powerful harvesters and forwarders (gross crane lifting capacity of 273 and 155 kNm, respectively) should be able to uproot all stumps with ≤ 61 cm and ≤ 32 cm diameter, respectively, in one piece. Larger stumps could be managed if it is acceptable that stumps are split before uprooting.
  • Lindroos, Department of Forest Resource Management, Swedish University of Agricultural Sciences, SE-901 83 Umeå, Sweden ORCID ID:E-mail: ola.lindroos@srh.slu.se (email)
  • Henningsson, Komatsu Forest AB, Box 7124, SE-907 04 Umeå, Sweden ORCID ID:E-mail:
  • Athanassiadis, Department of Forest Resource Management, Swedish University of Agricultural Sciences, SE-901 83 Umeå, Sweden ORCID ID:E-mail:
  • Nordfjell, Department of Forest Resource Management, Swedish University of Agricultural Sciences, SE-901 83 Umeå, Sweden ORCID ID:E-mail:
article id 174, category Research article
Akihiro Sumida, Taro Nakai, Masahito Yamada, Kiyomi Ono, Shigeru Uemura, Toshihiko Hara. (2009). Ground-based estimation of leaf area index and vertical distribution of leaf area density in a Betula ermanii forest. Silva Fennica vol. 43 no. 5 article id 174. https://doi.org/10.14214/sf.174
We developed a ground-based method for estimating leaf area index (LAI) and vertical distribution of leaf area density (LAD) for two Betula ermanii plots, combining an allometric method for tree leaf area with the MacArthur–Horn (MH) method using a portable laser rangefinder, including a correction for changes in leaf inclination angle along the vertical gradient measured with a portable digital protractor from a canopy access tower in each plot. Vertical distribution of projected leaf area density obtained by the MH method (LADMH) was transformed to relative distribution for allotting fixed LAI to different heights. Hence, we first developed an allometric method for estimating tree leaf area for LAI determination. Trunk cross-sectional area at branching height (AB) was accurately estimated (r2 = 0.97) from ground-based measurements of tree dimensions. We used this method to apply pipe model allometry between tree leaf area and AB, and estimated LAI (4.56 and 4.57 m2 m–2). We then examined how leaf inclination angle affected estimation of the vertical distribution of actual LAD. Leaf inclination angle measurements revealed that actual LAD in the upper canopy was 1.5–1.8-times higher than LADMH, because of steep leaf inclination, while the correction factor was 1.15–1.25 in the lower canopy. Due to the difference among heights, vertical distribution of LAD estimated with correction for vertical change in leaf inclination was more skewed to the upper canopy than that without correction. We also showed that error in LAD distribution can result if horizontal canopy heterogeneity is neglected when applying the MH method.
  • Sumida, Institute of Low Temperature Science, Hokkaido University, N19W8, Sapporo 060-0819, Japan ORCID ID:E-mail: asumida@lowtem.hokudai.ac.jp (email)
  • Nakai, International Arctic Research Center, University of Alaska Fairbanks, 930 Koyukuk Drive, P.O. Box 757340, Fairbanks, Alaska 99775-7340, USA ORCID ID:E-mail:
  • Yamada, International Meteorological & Oceanographic Consultants Co., Ltd. Kawaguchi-cho 2-6528-87, Choshi, Chiba 288-0001, Japan ORCID ID:E-mail:
  • Ono, Institute of Low Temperature Science, Hokkaido University, N19W8, Sapporo 060-0819, Japan ORCID ID:E-mail:
  • Uemura, Field Science Center for Northern Biosphere, Hokkaido University, Tokuda 250, Nayoro, Hokkaido 096-0071, Japan ORCID ID:E-mail:
  • Hara, Institute of Low Temperature Science, Hokkaido University, N19W8, Sapporo 060-0819, Japan ORCID ID:E-mail:
article id 169, category Research article
Susanne von Bargen, Elise Grubits, Risto Jalkanen, Carmen Büttner. (2009). Cherry leaf roll virus – an emerging virus in Finland? Silva Fennica vol. 43 no. 5 article id 169. https://doi.org/10.14214/sf.169
Cherry leaf roll virus, CLRV, is a plant pathogen that infects a variety of deciduous trees and shrubs in temperate regions. Little is known about its occurrence at high latitudes and especially in Finnish birch species. Still, symptoms that seemed to be associated with CLRV such as vein banding, leaf roll and decline have been observed in birch trees throughout the country since the summer of 2002. Six different birch species, subspecies or varieties, i.e. Betula pubescens subsp. pubescens (downy birch), B. pendula (silver birch), B. nana (dwarf birch), B. pubescens var. appressa (Kiilopää birch), B. pubescens subsp. czerepanovii (mountain birch) and B. pendula var. carelica (curly birch) originating from all over Finland were assessed by immunocapture-reverse transcription-polymerase chain reaction (IC-RT-PCR) for CLRV infection. It was shown that CLRV is widely distributed in B. pendula and B. pubescens throughout the country. Furthermore, dwarf birch, mountain birch, Kiilopää birch and curly birch were confirmed to be previously unkown hosts of CLRV. Genetic analysis of virus sequence variants originating from Finnish birch trees revealed atypical phylogenetic relationships. In contrast to CLRV isolates from birches growing in the United Kingdom and Germany which clustered exclusively within group A, Finnish CLRV isolates belonged either to group B, D or E. Thus, virus population structure in Finnish birches seems to be more variable and host plant dependency seems not to apply for Finnish CLRV isolates.
  • Bargen, Humboldt-Universität zu Berlin, Department für Nutzpflanzen- und Tierwissenschaften, Fachgebiet Phytomedizin, Lentzeallee 55/57, 14195 Berlin, Germany ORCID ID:E-mail: susanne.von.bargen@agrar.hu-berlin.de (email)
  • Grubits, Humboldt-Universität zu Berlin, Department für Nutzpflanzen- und Tierwissenschaften, Fachgebiet Phytomedizin, Lentzeallee 55/57, 14195 Berlin, Germany ORCID ID:E-mail:
  • Jalkanen, Finnish Forest Research Institute, Rovaniemi Research Unit, P.O. Box 16, FI-96301 Rovaniemi, Finland ORCID ID:E-mail: risto.jalkanen@metla.fi
  • Büttner, Humboldt-Universität zu Berlin, Department für Nutzpflanzen- und Tierwissenschaften, Fachgebiet Phytomedizin, Lentzeallee 55/57, 14195 Berlin, Germany ORCID ID:E-mail:
article id 169, category Research article
Susanne von Bargen, Elise Grubits, Risto Jalkanen, Carmen Büttner. (2009). Cherry leaf roll virus – an emerging virus in Finland? Silva Fennica vol. 43 no. 5 article id 169. https://doi.org/10.14214/sf.169
Cherry leaf roll virus, CLRV, is a plant pathogen that infects a variety of deciduous trees and shrubs in temperate regions. Little is known about its occurrence at high latitudes and especially in Finnish birch species. Still, symptoms that seemed to be associated with CLRV such as vein banding, leaf roll and decline have been observed in birch trees throughout the country since the summer of 2002. Six different birch species, subspecies or varieties, i.e. Betula pubescens subsp. pubescens (downy birch), B. pendula (silver birch), B. nana (dwarf birch), B. pubescens var. appressa (Kiilopää birch), B. pubescens subsp. czerepanovii (mountain birch) and B. pendula var. carelica (curly birch) originating from all over Finland were assessed by immunocapture-reverse transcription-polymerase chain reaction (IC-RT-PCR) for CLRV infection. It was shown that CLRV is widely distributed in B. pendula and B. pubescens throughout the country. Furthermore, dwarf birch, mountain birch, Kiilopää birch and curly birch were confirmed to be previously unkown hosts of CLRV. Genetic analysis of virus sequence variants originating from Finnish birch trees revealed atypical phylogenetic relationships. In contrast to CLRV isolates from birches growing in the United Kingdom and Germany which clustered exclusively within group A, Finnish CLRV isolates belonged either to group B, D or E. Thus, virus population structure in Finnish birches seems to be more variable and host plant dependency seems not to apply for Finnish CLRV isolates.
  • Bargen, Humboldt-Universität zu Berlin, Department für Nutzpflanzen- und Tierwissenschaften, Fachgebiet Phytomedizin, Lentzeallee 55/57, 14195 Berlin, Germany ORCID ID:E-mail: susanne.von.bargen@agrar.hu-berlin.de (email)
  • Grubits, Humboldt-Universität zu Berlin, Department für Nutzpflanzen- und Tierwissenschaften, Fachgebiet Phytomedizin, Lentzeallee 55/57, 14195 Berlin, Germany ORCID ID:E-mail:
  • Jalkanen, Finnish Forest Research Institute, Rovaniemi Research Unit, P.O. Box 16, FI-96301 Rovaniemi, Finland ORCID ID:E-mail: risto.jalkanen@metla.fi
  • Büttner, Humboldt-Universität zu Berlin, Department für Nutzpflanzen- und Tierwissenschaften, Fachgebiet Phytomedizin, Lentzeallee 55/57, 14195 Berlin, Germany ORCID ID:E-mail:
article id 169, category Research article
Susanne von Bargen, Elise Grubits, Risto Jalkanen, Carmen Büttner. (2009). Cherry leaf roll virus – an emerging virus in Finland? Silva Fennica vol. 43 no. 5 article id 169. https://doi.org/10.14214/sf.169
Cherry leaf roll virus, CLRV, is a plant pathogen that infects a variety of deciduous trees and shrubs in temperate regions. Little is known about its occurrence at high latitudes and especially in Finnish birch species. Still, symptoms that seemed to be associated with CLRV such as vein banding, leaf roll and decline have been observed in birch trees throughout the country since the summer of 2002. Six different birch species, subspecies or varieties, i.e. Betula pubescens subsp. pubescens (downy birch), B. pendula (silver birch), B. nana (dwarf birch), B. pubescens var. appressa (Kiilopää birch), B. pubescens subsp. czerepanovii (mountain birch) and B. pendula var. carelica (curly birch) originating from all over Finland were assessed by immunocapture-reverse transcription-polymerase chain reaction (IC-RT-PCR) for CLRV infection. It was shown that CLRV is widely distributed in B. pendula and B. pubescens throughout the country. Furthermore, dwarf birch, mountain birch, Kiilopää birch and curly birch were confirmed to be previously unkown hosts of CLRV. Genetic analysis of virus sequence variants originating from Finnish birch trees revealed atypical phylogenetic relationships. In contrast to CLRV isolates from birches growing in the United Kingdom and Germany which clustered exclusively within group A, Finnish CLRV isolates belonged either to group B, D or E. Thus, virus population structure in Finnish birches seems to be more variable and host plant dependency seems not to apply for Finnish CLRV isolates.
  • Bargen, Humboldt-Universität zu Berlin, Department für Nutzpflanzen- und Tierwissenschaften, Fachgebiet Phytomedizin, Lentzeallee 55/57, 14195 Berlin, Germany ORCID ID:E-mail: susanne.von.bargen@agrar.hu-berlin.de (email)
  • Grubits, Humboldt-Universität zu Berlin, Department für Nutzpflanzen- und Tierwissenschaften, Fachgebiet Phytomedizin, Lentzeallee 55/57, 14195 Berlin, Germany ORCID ID:E-mail:
  • Jalkanen, Finnish Forest Research Institute, Rovaniemi Research Unit, P.O. Box 16, FI-96301 Rovaniemi, Finland ORCID ID:E-mail: risto.jalkanen@metla.fi
  • Büttner, Humboldt-Universität zu Berlin, Department für Nutzpflanzen- und Tierwissenschaften, Fachgebiet Phytomedizin, Lentzeallee 55/57, 14195 Berlin, Germany ORCID ID:E-mail:
article id 226, category Research article
Anneli Viherä-Aarnio, Pirkko Velling. (2008). Seed transfers of silver birch (Betula pendula) from the Baltic to Finland – effect on growth and stem quality. Silva Fennica vol. 42 no. 5 article id 226. https://doi.org/10.14214/sf.226
Silver birch (Betula pendula Roth) seed origins from the Baltic countries, Finland and Russia were compared for survival, growth and stem quality, and the effect of latitudinal seed transfer distance examined in two provenance trials. The trials were located on moist upland forest soils at Tuusula (60°21’N) in southern Finland and at Viitasaari (63°11’N) in central Finland. The material consisted of 21 stand and single tree origins ranging from latitudes 54° to 63°N. Survival, height, dbh, relative stem taper, stem volume/ha and the proportion of trees with a stem defect (vertical branch or forked stem), were assessed when the trees were 22 years old. Significant differences were detected among the origins regarding all the measured traits in both trials. Southern Finnish origins produced the highest volume per unit area in central Finland, whereas Estonian and north Latvian stand seed origins, as well as the southern Finnish plus tree origins, were the most productive ones in southern Finland. The more southern the origin, the higher was the proportion of trees with a stem defect in both trials. The latitudinal seed transfer distance had a significant but relatively small effect on survival, stem volume/ha and proportion of trees with a stem defect. The proportion of trees with a stem defect increased linearly in relation to the seed transfer distance from the south. The relationship of both survival and stem volume/ha to the seed transfer distance was curvilinear. Volume/ha was increased by transferring seed from ca. 2 degrees of latitude from the south. A longer transfer from the south, as well as transfer from the north, decreased the yield.
  • Viherä-Aarnio, Finnish Forest Research Institute, Vantaa Research Unit, P.O. Box 18, FI-01301 Vantaa, Finland ORCID ID:E-mail: anneli.vihera-aarnio@metla.fi (email)
  • Velling, Finnish Forest Research Institute, Vantaa Research Unit, P.O. Box 18, FI-01301 Vantaa, Finland ORCID ID:E-mail:
article id 229, category Research article
Carmen Martín, Teresa Parra, Margarita Clemente-Muñoz, Esteban Hernández-Bermejo. (2008). Genetic diversity and structure of the endangered Betula pendula subsp. fontqueri populations in the south of Spain. Silva Fennica vol. 42 no. 4 article id 229. https://doi.org/10.14214/sf.229
Betula pendula subsp. fontqueri, present in the south of Spain, has been considered in danger of extinction and, for this reason, some regional governments in Spain have included their populations in conservation programmes. In order to establish the genetic structure of the Betula pendula subsp. fontqueri populations, a random amplified polymorphic DNA (RAPD) analysis was carried out. Two B. pubescens populations were included in the study as taxonomic controls. B. pendula subsp. fontqueri populations were clearly differentiated through UPGMA, and showed significant pairwise genetic distance (ΦST) values between all pairs of populations obtained by AMOVA. Genetic diversity found between populations was not correlated to geographical distances. The significant differences among populations must be due to progressive isolation of Betula populations along their paleogeographical history, and more recently to the drastic fragmentation and reduction of some of these populations. The results obtained in this work show clear genetic differences which could be considered in the management of conservation strategies for Betula pendula subsp. fontqueri in its Iberian meridional distribution.
  • Martín, Departamento de Biología Vegetal, Escuela Técnica Superior de Ingenieros Agrónomos de Madrid, Universidad Politécnica de Madrid, Ciudad Universitaria s/n, 28040-Madrid, Spain ORCID ID:E-mail: mariacarmen.martin@upm.es (email)
  • Parra, Departamento de Ciencias y Recursos Agrícolas y Forestales, Universidad de Córdoba, Avda. Linneo s/n, 14004-Córdoba, Spain ORCID ID:E-mail:
  • Clemente-Muñoz, Departamento de Ciencias y Recursos Agrícolas y Forestales, Universidad de Córdoba, Avda. Linneo s/n, 14004-Córdoba, Spain ORCID ID:E-mail:
  • Hernández-Bermejo, Departamento de Ciencias y Recursos Agrícolas y Forestales, Universidad de Córdoba, Avda. Linneo s/n, 14004-Córdoba, Spain ORCID ID:E-mail:
article id 258, category Research article
Ursula Schatz, Henrik Heräjärvi, Kari Kannisto, Matti Rantatalo. (2008). Influence of saw and secateur pruning on stem discolouration, wound cicatrisation and diameter growth of Betula pendula. Silva Fennica vol. 42 no. 2 article id 258. https://doi.org/10.14214/sf.258
The aim of this case study was to compare the impacts of saw and secateur pruning on silver birch (Betula pendula Roth). Data were collected from two saw pruned stands in 2005, and one secateur pruned stand in 2003. All the stands were located in southern Finland. The sample stems were felled, and their butt logs were sawn into flitches, whose knot features and colour defects were measured. In addition, discs were sawn from each stem in order to study the annual ring widths. In this material, pruning with secateurs appeared to cause less colour defects than pruning with a saw. Irrespective of the pruning method used, the colour defects in the stem wood were at their largest in cases where the basal knob or the stem bark appeared to be damaged by pruning. Colour defects spread mainly towards the pith, only in a few cases towards the stem surface. The cicatrisation time of the knots as well as the length of the bark stick remaining inside the stem did not show significant differences between the two pruning methods. Pruning of the lowest living branches appears to have no effect on the diameter growth of silver birch trees.
  • Schatz, Peltotievantie 27, FI-99440 Leppäjärvi, Finland ORCID ID:E-mail:
  • Heräjärvi, Finnish Forest Research Institute, Joensuu Research Unit, P.O. Box 111, FI-80101 Joensuu, Finland ORCID ID:E-mail: henrik.herajarvi@metla.fi (email)
  • Kannisto, Finnish Forest Research Institute, Parkano Research Unit, Kaironiementie 54, FI-39700 Parkano, Finland ORCID ID:E-mail:
  • Rantatalo, Peltotievantie 27, FI-99440 Leppäjärvi, Finland ORCID ID:E-mail:
article id 252, category Research article
Tuomo Kalliokoski, Pekka Nygren, Risto Sievänen. (2008). Coarse root architecture of three boreal tree species growing in mixed stands. Silva Fennica vol. 42 no. 2 article id 252. https://doi.org/10.14214/sf.252
Root system architecture determines many of the vital functions of a tree, e.g. stability of anchorage and resource uptake. The shoot:root ratio is determined through the allocation of resources. Studies on below-ground architectural elements in boreal mixed forests are relatively scarce despite the fact that knowledge on below-ground interactions and allocation changes in relation to stand developmental stage and soil fertility is needed both in ecological and silvicultural research. In this study, sixty tree root systems of three different tree species, Betula pendula, Picea abies and Pinus sylvestris, were excavated in five mixed forest stands in order to quantify differences between the species and sites in terms of rooting behaviour. Root architecture differed greatly between the species, implying different solutions for the functions of root systems. Half of the P. sylvestris had developed a taproot as a response to anchorage needs, while P. abies correspondingly had pronounced secondary growth of proximal roots. Betula pendula had the most extensive root system, illustrating the greater demand of deciduous trees for water. Betula pendula was also the most sensitive to soil fertility: it favoured exploration on the poorest site, as illustrated by the high total root length, whereas on the most fertile site its strategy was to efficiently exploit soil resources through increased branching intensity. The results obtained in this study provide basic knowledge on the architectural characteristics of boreal tree root systems for use by forestry professionals and modellers.
  • Kalliokoski, The Finnish Forest Research Institute, Vantaa Research Unit, P.O. Box 18, FI-01301 Vantaa, Finland ORCID ID:E-mail: tuomo.kalliokoski@metla.fi (email)
  • Nygren, Department of Forest Ecology, P.O. Box 27, FI-00014 University of Helsinki, Finland ORCID ID:E-mail:
  • Sievänen, The Finnish Forest Research Institute, Vantaa Research Unit, P.O. Box 18, FI-01301 Vantaa, Finland ORCID ID:E-mail:
article id 293, category Research article
Conor O'Reilly, Norberto De Atrip. (2007). Seed moisture content during chilling and heat stress effects after chilling on the germination of common alder and downy birch seeds. Silva Fennica vol. 41 no. 2 article id 293. https://doi.org/10.14214/sf.293
The effects of seed moisture content (MC) and heat treatment on the germination response of common alder (Alnus glutinosa) and downy birch (Betula pubescens) seeds were examined. Seeds of each species were adjusted to MC of 7% to 50% MC, then chilled for up to 36 weeks, after which they were allowed to germinate at 15°C with 8 hours lighting per day or 20 (dark)/ 30°C (light). Seed lot effects were evident, but treatment effects were consistent in each lot and species. The response to moist chilling treatments was larger at 15°C than at 20/30°C. Chilling had no effect on germination unless seed MC was >15%, but it was low also at 20% MC. The highest germination was achieved following 24–36 weeks chilling at the optimum or target MC (TMC) levels of about 30% in alder and 35% in birch. In a separate experiment, seeds were fully imbibed (FI) (~50% MC; standard method used in operational practice) or adjusted to TMC levels, after which some seeds of each treatment group were chilled to release dormancy. Following this, the seeds were dried back to TMC levels and then subjected to 60°C for up to 4 hours after which they were allowed germinate under the same conditions described above. Heat treatment damaged the prechilled FI seeds, but no damage occurred to the non-chilled seeds. However, heat stress stimulated germination in the non-chilled FI seeds of both species and the TMC seeds of alder.
  • O'Reilly, UCD School of Biology and Environmental Science, UCD College of Life Sciences, University College Dublin, Belfield, Dublin 4, Ireland ORCID ID:E-mail: conor.oreilly@ucd.ie (email)
  • De Atrip, UCD School of Biology and Environmental Science, UCD College of Life Sciences, University College Dublin, Belfield, Dublin 4, Ireland ORCID ID:E-mail:
article id 319, category Research article
Ulises Diéguez-Aranda, José Antonio Grandas-Arias, Juan Gabriel Álvarez-González, Klaus von Gadow. (2006). Site quality curves for birch stands in north-western Spain. Silva Fennica vol. 40 no. 4 article id 319. https://doi.org/10.14214/sf.319
A model for predicting the height growth of even-aged, birch (Betula pubescens Ehrh.) dominated stands in Galicia (north-western Spain) was developed. Data from stem analysis of 214 trees were used for model construction. Two dynamic site equations derived with the generalized algebraic difference approach (GADA) were tested, which combine compatible site index and height models in one common equation. Both equations are base-age invariant and directly estimate height and site index from any height and age. The fittings were done in one stage using the base-age-invariant dummy variables method. A second-order continuous-time autoregressive error structure was used to correct the inherent autocorrelation of the longitudinal data used in this study. Cieszewski’s model best described the data. This model is therefore recommended for height growth prediction and site classification of birch stands in Galicia.
  • Diéguez-Aranda, Departamento de Ingeniería Agroforestal, Universidad de Santiago de Compostela. Escuela Politécnica Superior, Campus universitario, 27002 Lugo, Spain ORCID ID:E-mail: udieguez@lugo.usc.es (email)
  • Grandas-Arias, Departamento de Ingeniería Agroforestal, Universidad de Santiago de Compostela. Escuela Politécnica Superior, Campus universitario, 27002 Lugo, Spain ORCID ID:E-mail:
  • Álvarez-González, Departamento de Ingeniería Agroforestal, Universidad de Santiago de Compostela. Escuela Politécnica Superior, Campus universitario, 27002 Lugo, Spain ORCID ID:E-mail:
  • Gadow, Institut fur Waldinventur und Waldwachstum, George-Auguts-Universität Göttingen. Büsgenweg 5, D-37077 Göttingen, Germany ORCID ID:E-mail:
article id 328, category Research article
Pedro J. Aphalo, Markku Lahti, Tarja Lehto, Tapani Repo, Aino Rummukainen, Hannu Mannerkoski, Leena Finér. (2006). Responses of silver birch saplings to low soil temperature. Silva Fennica vol. 40 no. 3 article id 328. https://doi.org/10.14214/sf.328
Two-year-old silver birch (Betula pendula) saplings were grown for a third growing season in controlled-environment rooms (dasotrons) at three soil temperatures (5, 10, and 20 °C). All trees grew the first flush of leaves, but the growth of the second flush was almost completely inhibited at the two lower temperatures. The dry weight of the second-flush leaves was 50 times larger at 20 °C than at 5 and 10 °C, with about 100 times more nitrogen. Root growth was less affected than shoot growth. Chlorophyll content, net assimilation rate and stomatal conductance were lower at low soil temperatures. The value of the cytoplasm resistance estimated from the electric impedance spectra was lower at 5 °C than at 10 or 20 °C. Leaf water potential was highest at the lowest soil temperature, and intercellular carbon dioxide concentration was only slightly lower in saplings growing in cooler soil. We conclude that the effect of long-term exposure to cold soil on net assimilation and growth was not caused by stomatal closure alone. It is likely to be additionally mediated by the limited nitrogen acquisition at the low soil temperatures, and perhaps additionally by some other factor. As the growth depression of aboveground parts in response to low soil temperature was more significant in silver birch than what has earlier been found in conifers, the relative changes in air and soil temperature may eventually determine whether birch will become more dominant in boreal forests with climate change.
  • Aphalo, University of Helsinki, Department of Biological and Environmental Sciences ORCID ID:E-mail:
  • Lahti, The Finnish Forest Research Institute ORCID ID:E-mail:
  • Lehto, University of Joensuu, Faculty of Forestry, Box 111, FI-80101 Joensuu, Finland ORCID ID:E-mail: tarja.lehto@joensuu.fi (email)
  • Repo, The Finnish Forest Research Institute ORCID ID:E-mail:
  • Rummukainen, University of Joensuu, Faculty of Forestry, Box 111, FI-80101 Joensuu, Finland ORCID ID:E-mail:
  • Mannerkoski, University of Joensuu, Faculty of Forestry, Box 111, FI-80101 Joensuu, Finland ORCID ID:E-mail:
  • Finér, The Finnish Forest Research Institute ORCID ID:E-mail:
article id 353, category Research article
Jaakko Repola, Hannu Hökkä, Timo Penttilä. (2006). Thinning intensity and growth of mixed spruce-birch stands on drained peatlands in Finland. Silva Fennica vol. 40 no. 1 article id 353. https://doi.org/10.14214/sf.353
The impacts of thinning at various intensities on the growth and mortality of mixed spruce-birch stands were investigated in thinning experiments on spruce swamps in northern and south-eastern Finland. At the time of establishment, three of the stands had recently reached the first commercial thinning stage and four were more advanced. The monitoring period was mainly 15 years, and the thinning intensity varied from heavy thinning (ca. 46 per cent of the basal area removed) to no thinning. Basal area removals of light and moderate thinning were ca. 22% and 39%, respectively. Unthinned plots had the highest volume increment. Light and moderate thinning slightly decreased the 15-year volume increment by, on an average, 1% and 8%, respectively. Heavy thinning led to a greater reduction (22%) in volume increment. The growth response to thinning intensity was evident as a higher relative volume and mean diameter increment of the living trees with decreasing stand density. Part of the volume increment on the unthinned plots was lost through natural mortality. Even light thinning significantly decreased natural mortality.
  • Repola, Finnish Forest Research Institute, Rovaniemi Research Unit, P.O. Box 16, FI-96301 Rovaniemi, Finland ORCID ID:E-mail: jaakko.repola@metla.fi (email)
  • Hökkä, Finnish Forest Research Institute, Rovaniemi Research Unit, P.O. Box 16, FI-96301 Rovaniemi, Finland ORCID ID:E-mail:
  • Penttilä, Finnish Forest Research Institute, Rovaniemi Research Unit, P.O. Box 16, FI-96301 Rovaniemi, Finland ORCID ID:E-mail:
article id 374, category Research article
Jyrki Hytönen, Paula Jylhä. (2005). Effects of competing vegetation and post-planting weed control on the mortality, growth and vole damages to Betula pendula planted on former agricultural land. Silva Fennica vol. 39 no. 3 article id 374. https://doi.org/10.14214/sf.374
Effects of competing vegetation and weed control methods (fibre board mulch, cover crop of clover, various herbicides) on the survival and growth of and vole damage to silver birch (Betula pendula Roth) were analysed based on data from a field experiment established in southern Finland. The cover percentage of competing vegetation and its shading effect were assessed, and seedling size and vitality were recorded several times during the 11-year research period. Mean seedling height and height increment decreased linearly with increasing vegetation cover. Seedling mortality started to significantly increase once the vegetation cover had reached the level of 60–80%. Herbicides significantly retarded increase of weed cover on the initially weedless areas for two to three years, and a cover crop promoted increase in cover percentage. Successful weed control with herbicides significantly increased seedling growth and survival. After 11 years, the average stem volume on the herbicide-treated plots (28.9 m3 ha–1) was 2.5-fold as compared to that of the control plots (11.6 m3 ha–1). Furthermore, seedling mortality on the control plots (21%) was almost 3.5-fold as compared to the seedling mortality on herbicide-treated plots (6%). Having a cover crop proved to be an ineffective weed control method both in terms of seedling growth and survival. The application of mulch had only a slight effect on height increment (0.6 m in 11 years), but on the other hand, it considerably decreased seedling mortality (control: 21%, mulch treatment: 1.5%). These differences were not, however, statistically significant. Small seedling size, high shading class, and high vegetation coverage percentage increased the risk of voles damaging the seedlings.
  • Hytönen, Finnish Forest Research Institute, Kannus Research Station, P.O. Box 44, FI-69101 Kannus, Finland ORCID ID:E-mail: jyrki.hytonen@metla.fi (email)
  • Jylhä, Finnish Forest Research Institute, Kannus Research Station, P.O. Box 44, FI-69101 Kannus, Finland ORCID ID:E-mail:
article id 504, category Research article
Sylvain Jutras, Hannu Hökkä, Virpi Alenius, Hannu Salminen. (2003). Modeling mortality of individual trees in drained peatland sites in Finland. Silva Fennica vol. 37 no. 2 article id 504. https://doi.org/10.14214/sf.504
Multilevel logistic regression models were constructed to predict the 5-year mortality of Scots pine (Pinus sylvestris L.) and pubescent birch (Betula pubescens Ehrh.) growing in drained peatland stands in northern and central Finland. Data concerning tree mortality were obtained from two successive measurements of the National Forest Inventory-based permanent sample plot data base covering pure and mixed stands of Scots pine and pubescent birch. In the modeling data, Scots pine showed an average observed mortality of 2.73% compared to 2.98% for pubescent birch. In the model construction, stepwise logistic regression and multilevel models methods were applied, the latter making it possible to address the hierarchical data, thus obtaining unbiased estimates for model parameters. For both species, mortality was explained by tree size, competitive position, stand density, species admixture, and site quality. The expected need for ditch network maintenance or re-paludification did not influence mortality. The multilevel models showed the lowest bias in the modeling data. The models were further validated against independent test data and by embedding them in a stand simulator. In 100-year simulations with different initial stand conditions, the models resulted in a 72% and 66% higher total mortality rate for the stem numbers of pine and birch, respectively, compared to previously used mortality models. The developed models are expected to improve the accuracy of stand forecasts in drained peatland sites.
  • Jutras, Département des sciences du bois et de la forêt, Université Laval, Ste-Foy, Québec, G1K 7P4, Canada ORCID ID:E-mail:
  • Hökkä, Finnish Forest Research Institute, Rovaniemi Research Station, P.O. Box 16, FIN 96301 Rovaniemi, Finland ORCID ID:E-mail: hannu.hokka@metla.fi (email)
  • Alenius, Finnish Forest Research Institute, Rovaniemi Research Station, P.O. Box 16, FIN 96301 Rovaniemi, Finland ORCID ID:E-mail:
  • Salminen, Finnish Forest Research Institute, Rovaniemi Research Station, P.O. Box 16, FIN 96301 Rovaniemi, 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 576, category Research article
Anneli Viherä-Aarnio, Pirkko Velling. (2001). Micropropagated silver birches (Betula pendula) in the field – performance and clonal differences. Silva Fennica vol. 35 no. 4 article id 576. https://doi.org/10.14214/sf.576
Micropropagated and seed-born silver birches (Betula pendula Roth) were compared for survival, height growth and occurrence of biotic damage (voles, hares, mooses, stem lesions and cankers) in field trials in southern Finland. The material consisted of 11 clones and 10 different lots of seedlings growing in 10 field trials, established in clear-cut forest cultivation areas. The plants were 6–7 years old. The micropropagated and seed-born material types did not significantly differ from each other as regards survival, height growth and frequencies of damage caused by biotic agents. Large and significant differences were, however, detected in survival, height and frequencies of all types of biotic damage between single clones. Careful selection and testing of birch clones in field conditions is recommended before wide-scale commercial micropropagation and practical forest cultivation takes place.
  • Viherä-Aarnio, Finnish Forest Research Institute, Vantaa Research Centre, P.O. Box. 18, FIN-01301 Vantaa, Finland ORCID ID:E-mail: anneli.vihera-aarnio@metla.fi (email)
  • Velling, Finnish Forest Research Institute, Vantaa Research Centre, P.O. Box. 18, FIN-01301 Vantaa, Finland ORCID ID:E-mail:
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)
article id 683, category Research article
Anders Karlsson, Arne Albrektson, Anders Forsgren, Lennart Svensson. (1998). An analysis of successful natural regeneration of downy and silver birch on abandoned farmland in Sweden. Silva Fennica vol. 32 no. 3 article id 683. https://doi.org/10.14214/sf.683
To improve our understanding of factors influencing the success of natural regeneration with downy birch (Betula pubescens Ehrh.) and silver birch (Betula pendula Roth) on abandoned farmlands, a survey was conducted to analyse the effects of site conditions and site preparation characteristics. The study was based on a sample plot inventory conducted in one northern and one southern district of Sweden, in which 29 successfully established, naturally regenerated stands, about to be cleaned or thinned, were assessed. Radical site preparation increased stand density and uniformity of established regeneration, and gave faster initial development, than establishment without site preparation on former leys or meadows. Large proportions of the total sample area were classified as moist, and soils consisting of sand–fine sand or peat were frequent. The frequency of birch stems was highest in mesic sites, and on soils consisting of sand, sand–fine sand or peat. Distances to seed-trees were generally shorter than 80 m, and downy birch was the dominant species in most stands.
  • Karlsson, Swedish University of Agricultural Sciences, Department of Silviculture, S-901 83 Umeå, Sweden ORCID ID:E-mail: anders.karlsson@ssko.slu.se (email)
  • Albrektson, Swedish University of Agricultural Sciences, Department of Silviculture, S-901 83 Umeå, Sweden ORCID ID:E-mail:
  • Forsgren, Swedish University of Agricultural Sciences, Department of Silviculture, S-901 83 Umeå, Sweden ORCID ID:E-mail:
  • Svensson, Swedish University of Agricultural Sciences, Department of Silviculture, S-901 83 Umeå, Sweden ORCID ID:E-mail:
article id 683, category Research article
Anders Karlsson, Arne Albrektson, Anders Forsgren, Lennart Svensson. (1998). An analysis of successful natural regeneration of downy and silver birch on abandoned farmland in Sweden. Silva Fennica vol. 32 no. 3 article id 683. https://doi.org/10.14214/sf.683
To improve our understanding of factors influencing the success of natural regeneration with downy birch (Betula pubescens Ehrh.) and silver birch (Betula pendula Roth) on abandoned farmlands, a survey was conducted to analyse the effects of site conditions and site preparation characteristics. The study was based on a sample plot inventory conducted in one northern and one southern district of Sweden, in which 29 successfully established, naturally regenerated stands, about to be cleaned or thinned, were assessed. Radical site preparation increased stand density and uniformity of established regeneration, and gave faster initial development, than establishment without site preparation on former leys or meadows. Large proportions of the total sample area were classified as moist, and soils consisting of sand–fine sand or peat were frequent. The frequency of birch stems was highest in mesic sites, and on soils consisting of sand, sand–fine sand or peat. Distances to seed-trees were generally shorter than 80 m, and downy birch was the dominant species in most stands.
  • Karlsson, Swedish University of Agricultural Sciences, Department of Silviculture, S-901 83 Umeå, Sweden ORCID ID:E-mail: anders.karlsson@ssko.slu.se (email)
  • Albrektson, Swedish University of Agricultural Sciences, Department of Silviculture, S-901 83 Umeå, Sweden ORCID ID:E-mail:
  • Forsgren, Swedish University of Agricultural Sciences, Department of Silviculture, S-901 83 Umeå, Sweden ORCID ID:E-mail:
  • Svensson, Swedish University of Agricultural Sciences, Department of Silviculture, S-901 83 Umeå, Sweden ORCID ID:E-mail:

Category: Review article

article id 923, category Review article
Katarzyna A. Jadwiszczak. (2012). What can molecular markers tell us about the glacial and postglacial histories of European birches? Silva Fennica vol. 46 no. 5 article id 923. https://doi.org/10.14214/sf.923
The last glaciation was one of the most severe of the Pleistocene epoch. The development of the Scandinavian ice sheet forced many species to reduce their ranges to areas with favourable climatic conditions. Most European species survived the Last Glacial Maximum in refugia in southern parts of Europe. Cold-tolerant species, such as birch trees and shrubs, could also inhabit western, eastern or central Europe. After climate warming, Holocene recolonisation began. This paper presents a comparative analysis of the genetic variation of four European Betula species to reconstruct their glacial and postglacial histories. Two chloroplast DNA haplotypes dominate within the ranges of all birch species, one haplotype is the most common in western and northwestern Europe, the second haplotype occurs mainly in the eastern and southeastern parts of the continent. This finding suggests that birches have recolonised Europe from the western and the eastern refugia, respectively. Most of Europe was likely populated from higher latitude refugia because there was no evidence of isolation by distance and weak genetic structures were detected. Similar patterns of haplotype distributions within Betula ranges indicate that postglacial recolonisation may be disturbed by interspecies hybridisation.
  • Jadwiszczak, Institute of Biology, University of Bialystok, wierkowa 20B, 15-950 Bialystok, Poland ORCID ID:E-mail: kszalaj@uwb.edu.pl (email)

Category: Research note

article id 927, category Research note
Risto Jalkanen, Carmen Büttner, Susanne von Bargen. (2007). Cherry leaf roll virus abundant on Betula pubescens in Finland. Silva Fennica vol. 41 no. 4 article id 927. https://doi.org/10.14214/sf.927
Virus-related symptoms such as vein banding, leaf roll, chlorosis and subsequent necrosis on birch leaves were increasingly recorded throughout Finland since 2002. They are widespread in this country and have also been detected in northern Norway and Sweden. Symptomatic foliage has so far been found on Betula pendula, B. pubescens, B. pubescens subsp. czerepanovii, and B. nana. A Cherry leaf roll virus (CLRV) specific IC-RT-PCR was applied to young leaves, buds and catkins of symptomatic shoots of nineteen pubescent and one silver birch trees grown in the centre of Rovaniemi, Finland. CLRV was found in seventeen B. pubescens trees. This is the first time that B. pubescens has been confirmed to be a host species for CLRV in Finland. Nor has CLRV been recorded earlier in northern Finland.
  • Jalkanen, Finnish Forest Research Institute, Rovaniemi Research Unit, P.O. Box 16, FI-96301 Rovaniemi, Finland ORCID ID:E-mail: risto.jalkanen@metla.fi (email)
  • Büttner, Humboldt Universität zu Berlin, Institut für Gartenbauwissenschaften, Fachgebiet Phytomedizin, Lentzeallee 55/57, 14195 Berlin, Germany ORCID ID:E-mail: Carmen.Buettner@agrar.hu-berlin.de
  • Bargen, Humboldt Universität zu Berlin, Institut für Gartenbauwissenschaften, Fachgebiet Phytomedizin, Lentzeallee 55/57, 14195 Berlin, Germany ORCID ID:E-mail: susanne.von.bargen@agrar.hu-berlin.de
article id 927, category Research note
Risto Jalkanen, Carmen Büttner, Susanne von Bargen. (2007). Cherry leaf roll virus abundant on Betula pubescens in Finland. Silva Fennica vol. 41 no. 4 article id 927. https://doi.org/10.14214/sf.927
Virus-related symptoms such as vein banding, leaf roll, chlorosis and subsequent necrosis on birch leaves were increasingly recorded throughout Finland since 2002. They are widespread in this country and have also been detected in northern Norway and Sweden. Symptomatic foliage has so far been found on Betula pendula, B. pubescens, B. pubescens subsp. czerepanovii, and B. nana. A Cherry leaf roll virus (CLRV) specific IC-RT-PCR was applied to young leaves, buds and catkins of symptomatic shoots of nineteen pubescent and one silver birch trees grown in the centre of Rovaniemi, Finland. CLRV was found in seventeen B. pubescens trees. This is the first time that B. pubescens has been confirmed to be a host species for CLRV in Finland. Nor has CLRV been recorded earlier in northern Finland.
  • Jalkanen, Finnish Forest Research Institute, Rovaniemi Research Unit, P.O. Box 16, FI-96301 Rovaniemi, Finland ORCID ID:E-mail: risto.jalkanen@metla.fi (email)
  • Büttner, Humboldt Universität zu Berlin, Institut für Gartenbauwissenschaften, Fachgebiet Phytomedizin, Lentzeallee 55/57, 14195 Berlin, Germany ORCID ID:E-mail: Carmen.Buettner@agrar.hu-berlin.de
  • Bargen, Humboldt Universität zu Berlin, Institut für Gartenbauwissenschaften, Fachgebiet Phytomedizin, Lentzeallee 55/57, 14195 Berlin, Germany ORCID ID:E-mail: susanne.von.bargen@agrar.hu-berlin.de
article id 927, category Research note
Risto Jalkanen, Carmen Büttner, Susanne von Bargen. (2007). Cherry leaf roll virus abundant on Betula pubescens in Finland. Silva Fennica vol. 41 no. 4 article id 927. https://doi.org/10.14214/sf.927
Virus-related symptoms such as vein banding, leaf roll, chlorosis and subsequent necrosis on birch leaves were increasingly recorded throughout Finland since 2002. They are widespread in this country and have also been detected in northern Norway and Sweden. Symptomatic foliage has so far been found on Betula pendula, B. pubescens, B. pubescens subsp. czerepanovii, and B. nana. A Cherry leaf roll virus (CLRV) specific IC-RT-PCR was applied to young leaves, buds and catkins of symptomatic shoots of nineteen pubescent and one silver birch trees grown in the centre of Rovaniemi, Finland. CLRV was found in seventeen B. pubescens trees. This is the first time that B. pubescens has been confirmed to be a host species for CLRV in Finland. Nor has CLRV been recorded earlier in northern Finland.
  • Jalkanen, Finnish Forest Research Institute, Rovaniemi Research Unit, P.O. Box 16, FI-96301 Rovaniemi, Finland ORCID ID:E-mail: risto.jalkanen@metla.fi (email)
  • Büttner, Humboldt Universität zu Berlin, Institut für Gartenbauwissenschaften, Fachgebiet Phytomedizin, Lentzeallee 55/57, 14195 Berlin, Germany ORCID ID:E-mail: Carmen.Buettner@agrar.hu-berlin.de
  • Bargen, Humboldt Universität zu Berlin, Institut für Gartenbauwissenschaften, Fachgebiet Phytomedizin, Lentzeallee 55/57, 14195 Berlin, Germany ORCID ID:E-mail: susanne.von.bargen@agrar.hu-berlin.de
article id 659, category Research note
Anneli Viherä-Aarnio, Pirkko Velling. (1999). Growth and stem quality of mature birches in a combined species and progeny trial. Silva Fennica vol. 33 no. 3 article id 659. https://doi.org/10.14214/sf.659
The growth and stem quality of silver birch (Betula pendula), downy birch (B. pubescens) and paper birch (B. papyrifera) were compared in a 32-year-old field trial in southern Finland. The material consisted of different unselected stand origins and progenies of phenotypically selected plus trees of silver and downy birch from southern Finland and differing stand origins of paper birch from the North-West Territories, Canada. Growth, yield and a number of stem quality traits, including taper, sweep, stem defects, heights of different crown limits and length of the veneer timber part of the stem were measured or observed. The native Finnish silver and downy birches were superior to paper birch in terms of both yield and stem quality, silver birch being the best. Progenies of silver birch plus trees were better than the stand origin, indicating that the former are able to reach high quality veneer log size in a shorter time than unselected material. The cultivation of paper birch can not be considered viable in Finland.
  • Viherä-Aarnio, The Finnish Forest Research Institute, Vantaa Research Centre, P.O. Box 18, FIN-01301 Vantaa, Finland ORCID ID:E-mail: anneli.vihera-aarnio@metla.fi (email)
  • Velling, The Finnish Forest Research Institute, Vantaa Research Centre, P.O. Box 18, FIN-01301 Vantaa, Finland ORCID ID:E-mail:
article id 659, category Research note
Anneli Viherä-Aarnio, Pirkko Velling. (1999). Growth and stem quality of mature birches in a combined species and progeny trial. Silva Fennica vol. 33 no. 3 article id 659. https://doi.org/10.14214/sf.659
The growth and stem quality of silver birch (Betula pendula), downy birch (B. pubescens) and paper birch (B. papyrifera) were compared in a 32-year-old field trial in southern Finland. The material consisted of different unselected stand origins and progenies of phenotypically selected plus trees of silver and downy birch from southern Finland and differing stand origins of paper birch from the North-West Territories, Canada. Growth, yield and a number of stem quality traits, including taper, sweep, stem defects, heights of different crown limits and length of the veneer timber part of the stem were measured or observed. The native Finnish silver and downy birches were superior to paper birch in terms of both yield and stem quality, silver birch being the best. Progenies of silver birch plus trees were better than the stand origin, indicating that the former are able to reach high quality veneer log size in a shorter time than unselected material. The cultivation of paper birch can not be considered viable in Finland.
  • Viherä-Aarnio, The Finnish Forest Research Institute, Vantaa Research Centre, P.O. Box 18, FIN-01301 Vantaa, Finland ORCID ID:E-mail: anneli.vihera-aarnio@metla.fi (email)
  • Velling, The Finnish Forest Research Institute, Vantaa Research Centre, P.O. Box 18, FIN-01301 Vantaa, Finland ORCID ID:E-mail:
article id 659, category Research note
Anneli Viherä-Aarnio, Pirkko Velling. (1999). Growth and stem quality of mature birches in a combined species and progeny trial. Silva Fennica vol. 33 no. 3 article id 659. https://doi.org/10.14214/sf.659
The growth and stem quality of silver birch (Betula pendula), downy birch (B. pubescens) and paper birch (B. papyrifera) were compared in a 32-year-old field trial in southern Finland. The material consisted of different unselected stand origins and progenies of phenotypically selected plus trees of silver and downy birch from southern Finland and differing stand origins of paper birch from the North-West Territories, Canada. Growth, yield and a number of stem quality traits, including taper, sweep, stem defects, heights of different crown limits and length of the veneer timber part of the stem were measured or observed. The native Finnish silver and downy birches were superior to paper birch in terms of both yield and stem quality, silver birch being the best. Progenies of silver birch plus trees were better than the stand origin, indicating that the former are able to reach high quality veneer log size in a shorter time than unselected material. The cultivation of paper birch can not be considered viable in Finland.
  • Viherä-Aarnio, The Finnish Forest Research Institute, Vantaa Research Centre, P.O. Box 18, FIN-01301 Vantaa, Finland ORCID ID:E-mail: anneli.vihera-aarnio@metla.fi (email)
  • Velling, The Finnish Forest Research Institute, Vantaa Research Centre, P.O. Box 18, FIN-01301 Vantaa, Finland ORCID ID:E-mail:

Category: Article

article id 7178, category Article
Matti Keltikangas, Pekka Tiililä. (1968). Koivun ja kuusen istutuksen keskinäinen edullisuusjärjestys käenkaali-mustikkatyypin metsämailla. Acta Forestalia Fennica vol. 82 no. 5 article id 7178. https://doi.org/10.14214/aff.7178
English title: The economic sequence of silver birch (Betula pendula) and Norway spruce (Picea abies) when planting Oxalis-Myrtillus type forest land.

The present study proposes to calculate the economic sequence of two of Finland’s three main tree species, Norway spruce (Picea abies (L.) H. Karst.) and silver birch (Betula pendula Roth) when planted on Oxalias-Myrtillus type sites where both species are equally suitable, on biological grounds. In addition, the accuracy and applicability of the present Finnish yield tables to an economic comparison is tested. Benefit/cost ratio was selected as criterion of profitableness. All future net incomes and costs were discounted into the planting time and added together. The ratio between the discounted net revenues and the discounted investment costs (later called profit ratio) was the criterion. There is no reliable method to forecast the future wood prices, therefore two price ratios, birch veneer timber to spruce pulpwood and birch cordwood to spruce pulpwood, were chosen as free variables. The economic sequence of the tree species was determined as the function of these variables.

The main conclusions are, first, that under the present price ratios spruce appears to be the better choice for the forest owner, and the most promising policy for changing the situation seems to decrease the production costs of plants in birch nurseries. Second, the present Finnish yield tables are not consistent or accurate enough to enable any sufficiently reliable economic comparisons of tree species in artificial regeneration. The possible error of difference between two rather uncertain estimates is big. More work is needed to construct a uniform system of yield tables covering all main tree species, all site types, all macro climate conditions and all types of regeneration.

The PDF includes a summary in English.

  • Keltikangas, ORCID ID:E-mail:
  • Tiililä, ORCID ID:E-mail:
article id 7167, category Article
Veijo Heiskanen. (1966). Tutkimuksia rauduskoivikon karsimisen kannattavuudesta. Acta Forestalia Fennica vol. 81 no. 2 article id 7167. https://doi.org/10.14214/aff.7167
English title: Studies on the profitability of pruning of common birch (Betula pendula) stands.

The objective of the present investigation was to clarify the profitability of pruning silver birch (Betula verrucosa, now Betula pendula Roth) in the growing of raw material for veneer industry. Calculations were made on the grade, value, and price of pruned and untreated butt logs as well as on costs of pruning and the development of pruned trees.

The grade distribution of unpruned veneer butt logs, the grade distribution of the veneer yield, and consequently, the value of veneer yield and log prices at the plant are considerably better than those of average logs. The grade, value and price increased with increasing diameter. The value and price of pruned butt logs depended primarily on the difference between the turning pruning diameters, and their increase with decreasing pruning diameter and increasing turning diameter. The value of pruned butt logs is always considerably higher than that of unpruned logs. The increase in the value correlates to the pruning and turning diameters, and is, for example, in rotary-cut logs which have been pruned when 10 cm in diameter 80–130%.

Pruning increases the stumpage in naturally regenerated silver birch stands on Oxalis-Myrtillus site by 2,000–3,000 Fmk/ha when employed at 20 years of stand age and rotary cutting at 60–80 years of age respectively. The average pruning costs on Oxalis-Myrtillus site are 51–57 Fmk/ha.

The PDF includes a summary English.

  • Heiskanen, ORCID ID:E-mail:
article id 7167, category Article
Veijo Heiskanen. (1966). Tutkimuksia rauduskoivikon karsimisen kannattavuudesta. Acta Forestalia Fennica vol. 81 no. 2 article id 7167. https://doi.org/10.14214/aff.7167
English title: Studies on the profitability of pruning of common birch (Betula pendula) stands.

The objective of the present investigation was to clarify the profitability of pruning silver birch (Betula verrucosa, now Betula pendula Roth) in the growing of raw material for veneer industry. Calculations were made on the grade, value, and price of pruned and untreated butt logs as well as on costs of pruning and the development of pruned trees.

The grade distribution of unpruned veneer butt logs, the grade distribution of the veneer yield, and consequently, the value of veneer yield and log prices at the plant are considerably better than those of average logs. The grade, value and price increased with increasing diameter. The value and price of pruned butt logs depended primarily on the difference between the turning pruning diameters, and their increase with decreasing pruning diameter and increasing turning diameter. The value of pruned butt logs is always considerably higher than that of unpruned logs. The increase in the value correlates to the pruning and turning diameters, and is, for example, in rotary-cut logs which have been pruned when 10 cm in diameter 80–130%.

Pruning increases the stumpage in naturally regenerated silver birch stands on Oxalis-Myrtillus site by 2,000–3,000 Fmk/ha when employed at 20 years of stand age and rotary cutting at 60–80 years of age respectively. The average pruning costs on Oxalis-Myrtillus site are 51–57 Fmk/ha.

The PDF includes a summary English.

  • Heiskanen, ORCID ID:E-mail:
article id 7166, category Article
J. E. Hårdh. (1966). Trials with carbon dioxide, light and growth substances on forest tree plants. Acta Forestalia Fennica vol. 81 no. 1 article id 7166. https://doi.org/10.14214/aff.7166

Growth-promoting effects of enhanced caron dioxide levels upon forest tree seedlings grown in plastic houses was studied in 1964 and 1965 in the Forest Breeding Foundation in Haapastensyrjä near Loppi in Southern Finland. In both years more vigorous height and weight growth, and development of root system was achieved when the CO2 concentration was increased to 0.2% than in the normal conditions (CO2 0.03%). The CO2 concentration was increased by burning propane in the plastic houses. Burning continued for four hours per day either at 8–10 and 14–16 a clock or 6–10 a clock. Growth was not affected by the time of the treatment, and it was equally high in 0.1% and 0.2% concentrations.

Treatment of the seedlings with 100–200 ppm gibberellic acid (GA) increased the height growth of healthy, well-rooted seedlings. Treatment with a concentrated (600 ppm) dosage, as well as treatment with a combination of GA and 1-naphtyl acetic acid (NAA) caused serious defects in grafts of Scots pine (Pinus sylvestris L.). GA treatments did not induce flower formation in pine. Red light during the night seemed to enhance growth of grafts of silver birch (Betula pendula Roth) and Norway spruce (Picea abies (L.) H. Karst.).

The PDF includes a summary in Finnish.

  • Hårdh, ORCID ID:E-mail:
article id 7165, category Article
Veijo Heiskanen. (1966). Tutkimuksia koivujen vikaisuuksista, niiden vaikutuksesta sorvaustulokseen sekä niiden huomioonottamisesta laatuluokituksessa. Acta Forestalia Fennica vol. 80 no. 3 article id 7165. https://doi.org/10.14214/aff.7165
English title: Studies on the defects of birch, their influence on the quality and quantity of rotary cut veneer, and their consideration in veneer birch grading.

The objective of this paper was to study the influence of defects of Betula pendula Roth and Betula pubescens Ehrh. on the quality, value and quantity of veneer cut produced by rotary cutting, to prepare grading rules for veneer birch and to determine the minimum quality for veneer birch, and to assess the quality and quantity of veneer yield in rotary cutting of bolts of different grades. Data for the study was collected in 1953-1963 from six plywood factories in Finland.

The effect of knot marks, knot bumps, dry and rotten knots, sound knots, sweep and crookedness, upright limbs, heart rot, open and overgrown scars and bark peeling defects in the bolt on the quality and yield of veneer is described. Recommendations for grading rules were defined on the basis of the result. The rules include three grades, for which certain defects are allowed. In the first grade are accepted bolts, which of the veneer yield included at least 30% of veneer of grades A and B when all jointing and end-clipped sheets were taken into account. In the second grade were accepted bolts, which of the main part of the veneer yield still is surface veneer on the basis of the wood quality. Of the third-grade bolts at least one third of the veneer yield ought to be surface veneer.

The PDF includes a summary in English.

  • Heiskanen, ORCID ID:E-mail:
article id 7119, category Article
Paavo J. Ollinmaa. (1960). Eräistä ojitetuilla soilla kasvavan puun fysikaalisista ominaisuuksista. Acta Forestalia Fennica vol. 72 no. 2 article id 7119. https://doi.org/10.14214/aff.7119
English title: Physical properties of wood growing on drained peatlands.

The objective of the investigation was to determine the differences between faultless timber grown on a peatland before and after draining, in respect of compressive strength to the grain, volume weight, and shrinkage. In addition, the influence of the boundary zone between the close-ringed wood formed before draining and the wide-ringed wood produced after draining on strength of the timber was studied. The material consisted of 15 sample trees of Scots pine (Pinus sylvestris L.), Norway spruce (Picea abies (L.) Karst.), white birch (Betula pubescens Ehrh.) and silver birch (B. Pendula Roth).

The volume weight of wood of the tree species in ascending order is; spruce, pine, white birch, silver birch. The volume weight of Scots pine seems to decrease from the butt end upwards, while no trend was revealed for spruce. In the coniferous trees, the wide-ringed wood formed subsequent to draining was slightly lighter than the close-ringed wood produced prior draining. No distinct trend was seen in the birch species. The volume weight of pine and spruce increased with decreasing width of the growth rings up to a certain limit, after which the conditions inverted.

The compressive strength of the different kinds of wood seems to increase from the butt end upwards, but after height of two meters it begins to decrease considerably. In birch, this point of inversion is in somewhat greater height. In spruce timber, the compressive strength parallel to the grain is lowest for wood which contains exclusively wide-ringed wood formed after draining. The boundary zone between the woods formed before and after draining is very distinguishable, but has no remarkable influence on the compressive strength parallel to the grain. Shrinkage of close-ringed wood is higher in all three principal directions than that of wide-ringed wood. This can be explained by the variations in volume weight and fibrillar orientation of the tracheid walls.

The PDF includes a summary in English.

  • Ollinmaa, ORCID ID:E-mail:
article id 7119, category Article
Paavo J. Ollinmaa. (1960). Eräistä ojitetuilla soilla kasvavan puun fysikaalisista ominaisuuksista. Acta Forestalia Fennica vol. 72 no. 2 article id 7119. https://doi.org/10.14214/aff.7119
English title: Physical properties of wood growing on drained peatlands.

The objective of the investigation was to determine the differences between faultless timber grown on a peatland before and after draining, in respect of compressive strength to the grain, volume weight, and shrinkage. In addition, the influence of the boundary zone between the close-ringed wood formed before draining and the wide-ringed wood produced after draining on strength of the timber was studied. The material consisted of 15 sample trees of Scots pine (Pinus sylvestris L.), Norway spruce (Picea abies (L.) Karst.), white birch (Betula pubescens Ehrh.) and silver birch (B. Pendula Roth).

The volume weight of wood of the tree species in ascending order is; spruce, pine, white birch, silver birch. The volume weight of Scots pine seems to decrease from the butt end upwards, while no trend was revealed for spruce. In the coniferous trees, the wide-ringed wood formed subsequent to draining was slightly lighter than the close-ringed wood produced prior draining. No distinct trend was seen in the birch species. The volume weight of pine and spruce increased with decreasing width of the growth rings up to a certain limit, after which the conditions inverted.

The compressive strength of the different kinds of wood seems to increase from the butt end upwards, but after height of two meters it begins to decrease considerably. In birch, this point of inversion is in somewhat greater height. In spruce timber, the compressive strength parallel to the grain is lowest for wood which contains exclusively wide-ringed wood formed after draining. The boundary zone between the woods formed before and after draining is very distinguishable, but has no remarkable influence on the compressive strength parallel to the grain. Shrinkage of close-ringed wood is higher in all three principal directions than that of wide-ringed wood. This can be explained by the variations in volume weight and fibrillar orientation of the tracheid walls.

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  • Ollinmaa, ORCID ID:E-mail:
article id 7476, category Article
Leo Heikurainen. (1958). Sekametsiköiden juuristoista ojitetulla suolla. Acta Forestalia Fennica vol. 67 no. 2 article id 7476. https://doi.org/10.14214/aff.7476
English title: Root systems of mixed forest in drained peatlands.

Draining transforms root systems of trees growing in peatlands towards the ones growing on mineral soil. However, even after efficient draining the root systems differ from the root systems of trees growing on mineral soil. This investigation concentrates on root systems of forests of similar mire types growing in similar draining conditions but having different tree species compositions. The peatland, situated in Pieksämäki in Southern Finland, was drained in 1937. Sample plots, measured in 1956, consisted of mixed forest of Scots pine (Pinus sylvestris L.), Norway spruce (Picea abies L. Karst.) and birch (Betula sp.) in different compositions, and were in natural condition.

The sedge pine bog studied in this investigation was shown to have larger total amount of roots and mycorrhiza than in previously studied dwarf shrub pine bogs. This reflects better growth conditions of the better site. The depth of root system was, however, similar. Root systems of birch were deeper than those of the coniferous tree species. Differences between Scots pine and Norway spruce were small. Corresponding differences between the species were found in the density and total number of mycorrhizas. The abundance of mycorrhizas in the roots of birch increased in deeper layers of peat, but decreased especially in spruce roots. In earlier studies the abundance of mycorrhizas decreased in the roots growing in deeper layers in pure Scots pine stands, but no such variation was seen in this study. The result suggest that the deep root system of birch may affect also the root systems of the coniferous trees. On the other hand, birch roots can have advantage over the coniferous trees.

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  • Heikurainen, ORCID ID:E-mail:
article id 7463, category Article
Paavo J. Ollinmaa. (1955). Koivun vetopuun anatomisesta rakenteesta ja ominaisuuksista. Acta Forestalia Fennica vol. 64 no. 3 article id 7463. https://doi.org/10.14214/aff.7463
English title: On the anatomical structure and properties of the tension wood in birch.

The investigation concerns with the strength of the eccentric growth accompanying formation of tension wood in silver birch  (Betula pendula Roth.) and downy birch (Betula pubescens Ehrh.), behaviour of wood in wood-working machines and its macroscopic characteristics, its microscopic and sub-microscopic structure, chemical composition, resistance against certain chemicals, physical properties, and the strength characteristics of wood.

The most detrimental properties of tension wood used in wood working industry are high longitudinal shrinkage, warping, twisting and checking. The wooliness of the cut is unwanted, for instance, in plywood and furniture. In pulp industry tension wood is better raw material than normal wood because it yields more and purer cellulose than normal wood. However, it has poorer strength properties.

The PDF includes a summary in English.

  • Ollinmaa, ORCID ID:E-mail:
article id 7463, category Article
Paavo J. Ollinmaa. (1955). Koivun vetopuun anatomisesta rakenteesta ja ominaisuuksista. Acta Forestalia Fennica vol. 64 no. 3 article id 7463. https://doi.org/10.14214/aff.7463
English title: On the anatomical structure and properties of the tension wood in birch.

The investigation concerns with the strength of the eccentric growth accompanying formation of tension wood in silver birch  (Betula pendula Roth.) and downy birch (Betula pubescens Ehrh.), behaviour of wood in wood-working machines and its macroscopic characteristics, its microscopic and sub-microscopic structure, chemical composition, resistance against certain chemicals, physical properties, and the strength characteristics of wood.

The most detrimental properties of tension wood used in wood working industry are high longitudinal shrinkage, warping, twisting and checking. The wooliness of the cut is unwanted, for instance, in plywood and furniture. In pulp industry tension wood is better raw material than normal wood because it yields more and purer cellulose than normal wood. However, it has poorer strength properties.

The PDF includes a summary in English.

  • Ollinmaa, ORCID ID:E-mail:
article id 7400, category Article
P. S. Tikka. (1949). Perä-Pohjolan koivikoiden laadusta. Acta Forestalia Fennica vol. 57 no. 4 article id 7400. https://doi.org/10.14214/aff.7400
English title: Quality of birch (Betula sp.) stands in the northernmost Finland.

The quality of birch (Betula sp.) stands in Perä-Pohjola in Northern Finland is low due to the harsh environment, unsuitable sites for the species and unsatisfactory silvicultural state. A total of 236 sample trees were felled and measured in 8 sample plots. The trees were over 80 years old.

Only third of the stand volume of birch in the stands had adequate quality for merchantable timber. This is due to birch growing often in sites unsuitable for the species, the low density of the stands, the small average size of stems, and the low amount of large sized trees. These problems may contribute to the fact that birch seem to be susceptible to decay. The trees have often grown from sprouts, which leads often to poor stem form and decay. The volume and quality of both pure and mixed birch stands was sufficient only in the most fertile sites. Also, decay was more common in poor sites.

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  • Tikka, ORCID ID:E-mail:
article id 7359, category Article
V. T. Aaltonen. (1942). Muutamia kasvukokeita puuntaimilla. Acta Forestalia Fennica vol. 50 no. 6 article id 7359. https://doi.org/10.14214/aff.7359
English title: Growth studies on tree seedlings.

The aim of the study was to investigate effect of growth conditions on germination and growth of Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies (L.) Karst.) seedlings in greenhouse conditions. Germination of seeds becomes markedly slower as the soil temperature decreases. It seems that low temperatures affect more Norway spruce than Scots pine. When temperature rises, the fresh weight of the seedlings increases more in pine seedlings than in spruce seedlings. Accordingly, lower temperatures affect less the weight growth of spruce seedling than that of pine seedlings.

An experiment testing how root competition affect germination showed that adjacent seedlings decrease germination of seeds more than shading with branches. The effect was strongest on pine and spruce seedlings when the shading tree species was fast growing birch (Betula sp.). On the other hand, shading affected most height growth of birch seedlings. Growing space can vary in relatively large range without it affecting greatly tree growth.

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  • Aaltonen, ORCID ID:E-mail:
article id 7356, category Article
Peitsa Mikola. (1942). Koivun vesomisesta ja sen metsänhoidollisesta merkityksestä. Acta Forestalia Fennica vol. 50 no. 3 article id 7356. https://doi.org/10.14214/aff.7356
English title: Silvicultural usefulness of sprouting of birch.

Birches’ (Betula sp.) ability to grow sprouts is low. The stump grows root collar and stump shoots, but the stump shoots are not proper stump shoots that will grow from the space between wood and bark. The buds are situated very low in the base, even under the ground. In this study, no actual root shoots could be found. Also the bushy alpine birches seem to be formed from stump and root collar shoots.

In Southern Finland silver birch (Betula pendula Roth) is more common than downy birch (Betula pubescens Ehrh.) in dry upland forest sites, while downy birch is common in fresh mineral soil forests and peatlands. In Northern Finland downy birch is the dominant birch species. Of the two species downy birch has markedly better capacity to form stump and root collar shoots both in Northern and Southern Finland. In general, birches grow sprouts much more strongly in Northern Finland.

Growth of the shoots is fastest during the first year after the felling of the parent tree and slows down gradually. The stump shoots may get separated from the stump when the stump decays, and the decay may also spread to the shoots. It is common that the shoots have no own roots, and die along with the stump. The shoots may have own root system or use roots of the parent tree that have stayed alive, in the latter case decay spreads almost always from the stump to the shoot. Whether the tree was felled with axe or saw had no effect on sprouting, probably because the sprouting buds are situated in the base of the tree. The larger stumps had usually fewer sprouts than smaller stumps. The fertility of the site seemed to have little effect on sprouting, but more moist sites formed more sprouts.

Forest regeneration using sprouts may be possible in peatlands for firewood production. on mineral soil sites birch does not suit for coppicing. The proportion of trees originating from sprouts decreases strongly by the time. Consequently, in Southern Finland sprouts have little effect on regeneration of birch. In Northern Finland sprouting is the most important way of regeneration.

The PDF includes a summary in German.

  • Mikola, ORCID ID:E-mail:
article id 7356, category Article
Peitsa Mikola. (1942). Koivun vesomisesta ja sen metsänhoidollisesta merkityksestä. Acta Forestalia Fennica vol. 50 no. 3 article id 7356. https://doi.org/10.14214/aff.7356
English title: Silvicultural usefulness of sprouting of birch.

Birches’ (Betula sp.) ability to grow sprouts is low. The stump grows root collar and stump shoots, but the stump shoots are not proper stump shoots that will grow from the space between wood and bark. The buds are situated very low in the base, even under the ground. In this study, no actual root shoots could be found. Also the bushy alpine birches seem to be formed from stump and root collar shoots.

In Southern Finland silver birch (Betula pendula Roth) is more common than downy birch (Betula pubescens Ehrh.) in dry upland forest sites, while downy birch is common in fresh mineral soil forests and peatlands. In Northern Finland downy birch is the dominant birch species. Of the two species downy birch has markedly better capacity to form stump and root collar shoots both in Northern and Southern Finland. In general, birches grow sprouts much more strongly in Northern Finland.

Growth of the shoots is fastest during the first year after the felling of the parent tree and slows down gradually. The stump shoots may get separated from the stump when the stump decays, and the decay may also spread to the shoots. It is common that the shoots have no own roots, and die along with the stump. The shoots may have own root system or use roots of the parent tree that have stayed alive, in the latter case decay spreads almost always from the stump to the shoot. Whether the tree was felled with axe or saw had no effect on sprouting, probably because the sprouting buds are situated in the base of the tree. The larger stumps had usually fewer sprouts than smaller stumps. The fertility of the site seemed to have little effect on sprouting, but more moist sites formed more sprouts.

Forest regeneration using sprouts may be possible in peatlands for firewood production. on mineral soil sites birch does not suit for coppicing. The proportion of trees originating from sprouts decreases strongly by the time. Consequently, in Southern Finland sprouts have little effect on regeneration of birch. In Northern Finland sprouting is the most important way of regeneration.

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  • Mikola, ORCID ID:E-mail:
article id 7336, category Article
R. Sarvas. (1937). Kuloalojen luontaisesta metsittymisestä : Pohjois-Suomen kuivilla kankailla suoritettu metsäbiologinen tutkielma. Acta Forestalia Fennica vol. 46 no. 1 article id 7336. https://doi.org/10.14214/aff.7336
English title: Natural regeneration of burned areas. Forest biological study in dry mineral soil sites in Northern Finland.

Natural regeneration has been common in Northern Finland, where forest fires have been usual, and the large areas make artificial regeneration expensive. The regeneration, and for instance tree species composition and density of the stand, cannot been controlled. In Northern Finland there is little demand for Betula sp. which is often abundant in the burnt areas. The unburned forests are generally Scots pine (Pinus sylvestris L.) or Norway spruce (Picea abies (L.) H. Karst.) dominated mixed forests with single Betula sp. trees.

The fire destroys birch for the most part in the Vaccinium site type, but the surviving trees produce enough seeds to regenerate the areas. The largest trees of Scots pine usually survive the fires. Pine has good seed years in the north only every 8th or 10th year. Spruce is totally destroyed in the forest fire and the seedlings grow poorly as primary species. The seedling stands are usually dominated by Scots pine and birch, but birch seedlings grow in batches, and do not hinder growth of pine. The drier Calluna site type stands are dominated by Scots pine. Birch seedlings may be abundant in the beginning, but most of them do not survive. Abundant emergent pine trees prevent the growth of seedlings especially in the dry site types, and they should be thinned to guarantee regeneration. Sowing results are better few years after the fire. The birch seedling should be removed from the seedling stands.

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  • Sarvas, ORCID ID:E-mail:
article id 7315, category Article
Erkki Laitakari. (1934). Koivun juuristo. Acta Forestalia Fennica vol. 41 no. 2 article id 7315. https://doi.org/10.14214/aff.7315
English title: The root system of birch (Betula pubescens and B. verrucosa).
English keywords: mixed stand; forest site type

About 40% forest in Finland are mixed stands that have birch (Betula pubescens and B. verrucosa) as one of the species. The aim of this research was to study the structure of root system of birch and compare it to the other main tree species in Finland.

The root systems were dug out and measured in 28 sample plots in Southern and Central Finland, representing different forest site types. Birch roots correspond 30‒100% of the volume of the stem, the largest root systems being in the sandy soils or peatlands. Also the longest lateral roots can be found at these sites. The size variation of root system of birch is larger than in Scots pine (Pinus sylvestris L.), and the vertical root system is in general smaller in birch. Birch seems to be better than pine able to adapt its root system to the existing conditions. The smallest root systems were found in the good forest site types, but the roots grow in the good sites denser than in the poor sites. The lateral roots of the main tree species in Finland, birch, Scots pine and Norway spruce (Picea abies (L.) H. Karst.) grow in different depths, which decreases the competition between the species. This finding gives support to cultivation of mixed stands.

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  • Laitakari, ORCID ID:E-mail:
article id 7297, category Article
A. L. Backman. (1934). Om den Åländska skogens förhistoria. Acta Forestalia Fennica vol. 40 no. 20 article id 7297. https://doi.org/10.14214/aff.7297
English title: Early history of forests in Åland, Finland.

The paper presents preliminary results of paleobotanical studies on vegetation in Åland, south-west Finland. The investigations concentrated on studying arrival of tree species and stratigraphy of peatlands. According to the studies, some plant fossils found in the peat (Ceratophyllum submersum, Sparagnium neglectum, Najas flexilis) indicate that climate of the region has earlier been warmer than at the present. The present forests in Åland are dominated by coniferous species, but the pollen analysis of the peat indicate that Norway spruce (Picea abies (L.) H. Karst.) became a common species in the region about by the time of Christ’s birth. The species has reached its present distribution in Åland relatively late. The pollen analyses give relatively little information about the arrival of birch (Betula sp.) and Scots pine (Pinus sylvestris L.), but it seems obvious that occurrence of birch reached its culmination just before spruce. During the warm period common alder (Alnus glutinosa (L.) Gaertn.) was the most important species, and also pollen of oak (Quercus robur L.), kinden (Tilia cordata L.) and elm (Ulmus sp.) was relatively common in the peat of some of the studied peatlands. An interesting finding was the pollen of Carpinus betulus in many sites in Åland.

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  • Backman, ORCID ID:E-mail:
article id 7291, category Article
Paul Wallden. (1934). Tutkimuksia koivupuun anatoomisen rakenteen ja teknillisten ominaisuuksien keskinäisestä riippuvuudesta solumittauksien perusteella. Acta Forestalia Fennica vol. 40 no. 14 article id 7291. https://doi.org/10.14214/aff.7291
English title: Studies on relationship between anatomical structure and technical properties of birch wood.

Birch wood is used widely in wooden structures where mechanical strength is needed. The aim of the research was to study the influence of the relative share of mechanically weak tracheids, and length of the wood fibers on specific gravity and bending strength of downy birch (Betula pubescens Ehrh.) wood. According to the results, the strength of wood is strongly dependent on the relative share of tracheids, and length of the libriform cells. The strength of the wood increases when the share of tracheids decreases and the length of libriform cells increases. The specific gravity can be used as an indication of the strength of wood, especially if it is possible to analyze the structure of the wood.

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  • Wallden, ORCID ID:E-mail:
article id 7290, category Article
K. J. Valle. (1934). Fennoskandian koivuvyöhykkeen eläinmaantieteellisestä merkityksestä. Acta Forestalia Fennica vol. 40 no. 13 article id 7290. https://doi.org/10.14214/aff.7290
English title: The zoogeographical significance of the birch zone in Fennoscandia.

The subarctic-subalpine mountain birch forest zone discerns Fennoscandia from other northern regions. The zone offers protection against wind to animal life, protects soil from evaporation and increases humidity. The article reviews distribution of vertebrate and butterfly species in the birch forest zone. There are no vertebrates that occur solely in the birch forest zone, and only few live mostly in the zone. Many species live either both on the birch forest zone and the treeless fell area above it, or in the birch forest zone and coniferous zone below it. Similarly, no butterflies occur only in the birch forest zone, but the zone is the main habitat for some species. Consequently, the subarctic-subalpine birch forest zone cannot be considered to be an independent ecozone but a transitional zone between regio silvatica and regio arctica that is nearer to the northern coniferous zone than the fell region

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  • Valle, ORCID ID:E-mail:
article id 7287, category Article
Erkki K. Cajander. (1934). Havaintoja eräällä myrskytuhoalueella. Acta Forestalia Fennica vol. 40 no. 10 article id 7287. https://doi.org/10.14214/aff.7287
English title: Observations in a storm damage area.

A big storm hit Finland in 12.10.1933, and caused forest damages especially in the coasts of the Gulf of Finland and Baltic Sea, and in the eastern part of the country. In these areas the wind felled about 75,000‒85,000 m3 timber trees in the state lands. The extent of the wind damage was measured in forest area of 1,500 hectares in Lapinjärvi in Southern Finland. The wind had felled 42% of the Scots pine (Pinus sylvestris L.), 70% of the Norway spruce (Picea abies (L.) H. Karst.) and 44% of the Betula sp. trees. Thus, Norway spruce had been most susceptible for wind damage. That extensive damages in Norway spruce seed tree stands risk the regeneration in the area. Natural regeneration of Norway spruce using seed trees may, therefore, be questioned. The seed tree areas on hills, and especially hollows next to the hills were susceptible for wind damage. A denser border stand protects sparsely stocked seed tree area. The damages were also smaller in older seed tree areas, where the trees and ground vegetation had had time to recover after the felling. The felled spruce and birch trees had often stem rot.

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  • Cajander, ORCID ID:E-mail:
article id 7276, category Article
Paul Walldén. (1933). Eräs puun laadun tunnus. Acta Forestalia Fennica vol. 39 no. 5 article id 7276. https://doi.org/10.14214/aff.7276
English title: Bending strength of birch wood.

According to earlier studies, the weight of the wood may be a useful quality when aim is to create such wooden structures where small weight is combined with maximum mechanical strength. Of the northern tree species, Scots pine (Pinus sylvestris L.), Norway spruce (Picea abies (L.) H. Karst.) and birch (Betula sp.), birch has the highest bending strength. The main focus of this study was to find out if there is correlation between the specific gravity of cell wall substance and bending strength of the birch wood, and if the specific gravity of cell wall substance could be used as indication of the quality of the wood.

Dominant trees from 55 years old birch (Betula sp.) stand was selected for bending tests. The bending strength did not vary in birch as much as in many other tree species. The highest bending strength was achieved near the specific gravity class s=0,65, and it can be concluded that when the specific gravity falls below S=0,57, the wood’s technical quality is not sufficient. The article includes a literature review on the subject.

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  • Walldén, ORCID ID:E-mail:
article id 7226, category Article
W. Sukatschew. (1929). Betula Cajanderii sp.n. Acta Forestalia Fennica vol. 34 no. 13 article id 7226. https://doi.org/10.14214/aff.7226
English title: Betula Cajanderii sp.n. (Cajander birch).
Original keywords: Betula Cajanderii; Birke
English keywords: Betula Cajanderii; birch

Different birch species hybridize very easily with each other and identifying the species of an individual tree is difficult. The article gives the description of one variant from Russia and the author suggests naming it after Prof. Cajander.

The volume 34 of Acta Forestalia Fennica is a jubileum publication of professor Aimo Kaarlo Cajander.

  • Sukatschew, ORCID ID:E-mail:
article id 7226, category Article
W. Sukatschew. (1929). Betula Cajanderii sp.n. Acta Forestalia Fennica vol. 34 no. 13 article id 7226. https://doi.org/10.14214/aff.7226
English title: Betula Cajanderii sp.n. (Cajander birch).
Original keywords: Betula Cajanderii; Birke
English keywords: Betula Cajanderii; birch

Different birch species hybridize very easily with each other and identifying the species of an individual tree is difficult. The article gives the description of one variant from Russia and the author suggests naming it after Prof. Cajander.

The volume 34 of Acta Forestalia Fennica is a jubileum publication of professor Aimo Kaarlo Cajander.

  • Sukatschew, ORCID ID:E-mail:
article id 7207, category Article
N. A. Hildén. (1926). Koivun kuutioimisesta massataulukoiden avulla Pohjois-Karjalasta kootun aineiston nojalla. Acta Forestalia Fennica vol. 32 no. 2 article id 7207. https://doi.org/10.14214/aff.7207
English title: Preparation of volume table of birch, based on data collected in North Karelia.

Sample trees of Betula sp. were felled in North Karelia in different forest site types. The stands, both mixed and pure stands, had been regenerated in areas where shifting cultivation had been practiced. Sample trees represented breast height diameters up to 43 cm. Diameter was measured in distances of 1/10 of the height of the tree to calculate the stem form. The form factor was higher for the good forest site types than the poor sites. The volume tables were calculated based on the assumption that diameter does not affect the form factor. Comparing the volume table to the original data, it was found that the table seems to form a successful fitting of the data. Control data proved that the method seems to give a good fitting to the used data. Thus, the volume table can be used to measure volume of birch stands in North Karelia.

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  • Hildén, ORCID ID:E-mail:
article id 5616, category Article
Hannu Hökkä, Virpi Alenius, Timo Penttilä. (1997). Individual-tree basal area growth models for Scots pine, pubescent birch and Norway spruce on drained peatlands in Finland. Silva Fennica vol. 31 no. 2 article id 5616. https://doi.org/10.14214/sf.a8517

Models for individual-tree basal area growth were constructed for Scots pine (Pinus sylvestris L.), pubescent birch (Betula pubescens Ehrh.) and Norway spruce (Picea abies (L.) Karst.) growing in drained peatland stands. The data consisted of two separate sets of permanent sample plots forming a large sample of drained peatland stands in Finland. The dependent variable in all models was the 5-year basal area growth of a tree. The independent tree-level variables were tree dbh, tree basal area, and the sum of the basal area of trees larger than the target tree. Independent stand-level variables were stand basal area, the diameter of the tree of median basal area, and temperature sum. Categorical variables describing the site quality, as well as the condition and age of drainage, were used. Differences in tree growth were used as criteria in reclassifying the a priori site types into new yield classes by tree species. All models were constructed as mixed linear models with a random stand effect. The models were tested against the modelling data and against independent data sets.

  • Hökkä, ORCID ID:E-mail:
  • Alenius, ORCID ID:E-mail:
  • Penttilä, ORCID ID:E-mail:
article id 5611, category Article
Arja Lilja, Timo Kurkela, Sakari Lilja, Risto Rikala.. (1997). Nursery practices and management of fungal diseases in forest nurseries in Finland. A review. Silva Fennica vol. 31 no. 1 article id 5611. https://doi.org/10.14214/sf.a8512

The purpose of this article was to collate the literature on fungal diseases that occur on seedlings in forest nurseries. It describes the symptoms of the diseases, the infection pattern of each fungus and the possibilities of controlling the diseases. As background a short introduction is given on forests and nursery practices in Finland.

  • Lilja, ORCID ID:E-mail:
  • Kurkela, ORCID ID:E-mail:
  • Lilja, ORCID ID:E-mail:
  • Rikala., ORCID ID:E-mail:
article id 5582, category Article
Jonathan J. Ruel, Matthew P. Ayres. (1996). Variation in temperature responses among populations of Betula papyrifera. Silva Fennica vol. 30 no. 2–3 article id 5582. https://doi.org/10.14214/sf.a9227

How will global warming affect southern populations of boreal trees? In paper birch, Betula papyrifera (Betulaceae), alpine trees with an evolutionary history of relatively cool summers may be more sensitive to climate warming than valley populations. We evaluated this scenario by growing seedlings from different populations in four temperature treatments (mountain field site, valley field site, and two greenhouse rooms).

Populations from low elevations germinated earlier and had higher germination success than population from high elevations (16.8 vs. 22.0 d; 72% vs. 11%). At the valley site, seedlings from native populations grew faster than seedlings from higher elevations (mean ± SE = 0.25 ± 0.02 vs. 0.09 ± 0.04 mm · cm-1 · d-1) while at the mountain site, all seedlings grew at similar rates. Seedling grown in cooler environments had higher root : shoot ratios, perhaps to compensate for temperature limitations in nutrient uptake by roots. Leaf area varied among populations but was not affected by environmental differences across the field sites. Net photosynthetic rates at valley temperatures were higher for seedlings grown in the valley than for seedling grown in the mountains or the warm greenhouse (12.0 vs. 10.3 and 5.8 μmoles · m-2 · s-1), perhaps due to adaptive phenotypic adjustments. Climatic warming could rapidly produce important phenotypic changes in birch trees (e.g. decreased root : shoot ratio, reduced growth in alpine populations). On a longer time-scale, warming could also result in genetic changes as natural selection favours valley genotypes in alpine sites where they are presently rare.

  • Ruel, ORCID ID:E-mail:
  • Ayres, ORCID ID:E-mail:
article id 5573, category Article
Ilkka Vanha-Majamaa, Raili Suominen, Tiina Tonteri, Eeva-Stiina Tuittila. (1996). Seedling establishment after prescribed burning of a clear-cut and a partially cut mesic boreal forest in southern Finland. Silva Fennica vol. 30 no. 1 article id 5573. https://doi.org/10.14214/sf.a9218

The prescribed burning of a 7.3 ha clear-cut and a 1.7 ha partially cut forest (volume 150 m3/ha) was carried out in Evo (61 °12'N, 25°07'E) on 1 June 1992. The forest was a mesic Myrtillus site type forest dominated by Norway spruce (Picea abies (L.) H. Karst.). Practically all the trees and the above-ground parts of the understorey vegetation died in the fire, while the mor layer was thinned by an average of 1.5 cm.

A study was made on the change of germinated seedling population in time and their dependence on environmental factors. Seedlings of Norway spruce, Scots pine (Pinus sylvestris L.), silver birch (Betula pendula Roth), pubescent birch (B. pubescens Ehrh.) and rowan (Sorbus aucuparia L.) were inventoried in 1993 and in 1994 on permanent plots, four times per growing season. Autoregression models were used to compare regeneration of tree species in the burned forest with regeneration in the burnt clear-cut area, and to study the effect of distance from nearest seed source to regeneration.

The average number of seedlings germinating in 1993 was higher than in 1994, probably because of differences between these consecutive years in regard to the amount of seed rain and weather conditions. The number of Norway spruce and rowan seedling was higher inside the forest area than in the clear-cut area. The distance to the bordering forest and to the closest seed tree did not explain the result. It is suggested that the more stable microclimatic conditions under the shade of dead tree promote germination and seedling establishment in the forest area. As rowan is a bird-dispersed species, it is likely that dead trees help the dispersal of rowan seed by providing birds place to sit and defecate. The shade provided by dead trees may influence the further succession of the tree stand and vegetation composition and diversity.

  • Vanha-Majamaa, ORCID ID:E-mail:
  • Suominen, ORCID ID:E-mail:
  • Tonteri, ORCID ID:E-mail:
  • Tuittila, ORCID ID:E-mail:
article id 5573, category Article
Ilkka Vanha-Majamaa, Raili Suominen, Tiina Tonteri, Eeva-Stiina Tuittila. (1996). Seedling establishment after prescribed burning of a clear-cut and a partially cut mesic boreal forest in southern Finland. Silva Fennica vol. 30 no. 1 article id 5573. https://doi.org/10.14214/sf.a9218

The prescribed burning of a 7.3 ha clear-cut and a 1.7 ha partially cut forest (volume 150 m3/ha) was carried out in Evo (61 °12'N, 25°07'E) on 1 June 1992. The forest was a mesic Myrtillus site type forest dominated by Norway spruce (Picea abies (L.) H. Karst.). Practically all the trees and the above-ground parts of the understorey vegetation died in the fire, while the mor layer was thinned by an average of 1.5 cm.

A study was made on the change of germinated seedling population in time and their dependence on environmental factors. Seedlings of Norway spruce, Scots pine (Pinus sylvestris L.), silver birch (Betula pendula Roth), pubescent birch (B. pubescens Ehrh.) and rowan (Sorbus aucuparia L.) were inventoried in 1993 and in 1994 on permanent plots, four times per growing season. Autoregression models were used to compare regeneration of tree species in the burned forest with regeneration in the burnt clear-cut area, and to study the effect of distance from nearest seed source to regeneration.

The average number of seedlings germinating in 1993 was higher than in 1994, probably because of differences between these consecutive years in regard to the amount of seed rain and weather conditions. The number of Norway spruce and rowan seedling was higher inside the forest area than in the clear-cut area. The distance to the bordering forest and to the closest seed tree did not explain the result. It is suggested that the more stable microclimatic conditions under the shade of dead tree promote germination and seedling establishment in the forest area. As rowan is a bird-dispersed species, it is likely that dead trees help the dispersal of rowan seed by providing birds place to sit and defecate. The shade provided by dead trees may influence the further succession of the tree stand and vegetation composition and diversity.

  • Vanha-Majamaa, ORCID ID:E-mail:
  • Suominen, ORCID ID:E-mail:
  • Tonteri, ORCID ID:E-mail:
  • Tuittila, ORCID ID:E-mail:
article id 5557, category Article
Klaus Silfverberg. (1995). Forest regeneration on nutrient-poor peatlands: Effects of fertilization, mounding and sowing. Silva Fennica vol. 29 no. 3 article id 5557. https://doi.org/10.14214/sf.a9208

The effects of wood ash and PK fertilization on natural regeneration and sowing of Scots pine (Pinus sylvestris L.) were studied in field experiments on nitrogen-poor (Ntot 0.87–1.26%) peat substrates. The study material was derived from three drained, nutrient-poor pine mires (64°52’ N, 25°08’ E) at Muhos, near Oulu, Finland. The experimental fields were laid out in 1985 as a split-split-plot design including the following treatments; mounding, natural regeneration and sowing and fertilization; PK (400 kg ha-1) and wood ash (5,000 kg ha-1). The seedlings were inventoried in circles in July–August 1991.

Changes in the vegetation were small and there were no statistical differences due to the fertilization treatments in the ground vegetation. PK or ash fertilization did not cause vegetation changes harmful to Scots pine regeneration on nitrogen-poor peatlands. Both sowing and fertilization significantly increased the number of pine seedlings, but not their height. Wood ash increased seedling number more than PK fertilizer. The number of seedlings varied from 7,963 (control) to 42,781 ha-1 (mounding + sowing + ash). The seedling number was adequate for successful regeneration even on non-mounded, non-fertilized naturally regenerated plots.

The number of birch seedlings varied more than that of pine (370–25,927 ha-1). Mounding especially increased the number of birches. The difference between PK fertiliser and ash was less pronounced than that for pine. In addition, to the field studies the effects of ash and PK fertilizer on the germination of Scots pine seeds was studied in a greenhouse experiment. Soaking in ash solutions strongly reduced seed germination, while the PK solution was less harmful.

  • Silfverberg, ORCID ID:E-mail:
article id 5551, category Article
Jyrki Hytönen, Pekka Rossi, Anna Saarsalmi. (1995). Biomass production and nutrient uptake of short-rotation plantations. Silva Fennica vol. 29 no. 2 article id 5551. https://doi.org/10.14214/sf.a9202

The biomass production and nutrient uptake of silver birch (Betula pendula Roth), downy birch (Betula pubescens Erhr.), grey alder (Alnus incana (L.) Moench), native willows Salix triandra L. and S. phylicifolia L. and exotic willows S. x dasyclados and S. ’Aquatica’ growing on a clay mineral soil field (Sukeva) and on two cut-away peatland areas (Piipsanneva, Valkeasuo) were investigated.

Biomass production of downy birch was greater than that of silver birch, and the biomass production of the native willows greater than that of the exotic ones. The performance of S. phylicifolia was the best of the studied willow species. Exotic willows were susceptible to frost damage and their winter hardiness was poor. The production of all species was lower on the clay mineral soil field than on the cut-away peatland areas. Fertilization of birches and alder – on the double dose given to the willows – increased biomass production. After 6 growing seasons the leafless biomass production of fertilized silver birch at Piipsanneca was 21 t ha-1 (at Valkeasuo 34 t ha-1) and of grey alder 24 t ha-1, and that of S. triandra after five growing seasons 31 t ha-1, S. phylicifolia 38 t ha-1 and of S. x dasyclados 16 t ha-1.

6-year-old stands of silver birch bound more nutrients per unit biomass than downy birch stands. Grey alder bound more N, Ca and Co but less Mn and Zn per unit biomass than silver and downy birch. On the field more P was bound in grey alder per unit biomass compared to downy birch. The willows had more K per unit biomass than the other tree species, and the exotic willow species more N than the native ones. Less N, K and Mg were bound per unit biomass of S. phylicifolia compared to the other tree species.

  • Hytönen, ORCID ID:E-mail:
  • Rossi, ORCID ID:E-mail:
  • Saarsalmi, ORCID ID:E-mail:
article id 5551, category Article
Jyrki Hytönen, Pekka Rossi, Anna Saarsalmi. (1995). Biomass production and nutrient uptake of short-rotation plantations. Silva Fennica vol. 29 no. 2 article id 5551. https://doi.org/10.14214/sf.a9202

The biomass production and nutrient uptake of silver birch (Betula pendula Roth), downy birch (Betula pubescens Erhr.), grey alder (Alnus incana (L.) Moench), native willows Salix triandra L. and S. phylicifolia L. and exotic willows S. x dasyclados and S. ’Aquatica’ growing on a clay mineral soil field (Sukeva) and on two cut-away peatland areas (Piipsanneva, Valkeasuo) were investigated.

Biomass production of downy birch was greater than that of silver birch, and the biomass production of the native willows greater than that of the exotic ones. The performance of S. phylicifolia was the best of the studied willow species. Exotic willows were susceptible to frost damage and their winter hardiness was poor. The production of all species was lower on the clay mineral soil field than on the cut-away peatland areas. Fertilization of birches and alder – on the double dose given to the willows – increased biomass production. After 6 growing seasons the leafless biomass production of fertilized silver birch at Piipsanneca was 21 t ha-1 (at Valkeasuo 34 t ha-1) and of grey alder 24 t ha-1, and that of S. triandra after five growing seasons 31 t ha-1, S. phylicifolia 38 t ha-1 and of S. x dasyclados 16 t ha-1.

6-year-old stands of silver birch bound more nutrients per unit biomass than downy birch stands. Grey alder bound more N, Ca and Co but less Mn and Zn per unit biomass than silver and downy birch. On the field more P was bound in grey alder per unit biomass compared to downy birch. The willows had more K per unit biomass than the other tree species, and the exotic willow species more N than the native ones. Less N, K and Mg were bound per unit biomass of S. phylicifolia compared to the other tree species.

  • Hytönen, ORCID ID:E-mail:
  • Rossi, ORCID ID:E-mail:
  • Saarsalmi, ORCID ID:E-mail:
article id 5542, category Article
Leena Ryynänen, Anneli Viherä-Aarnio. (1995). Growth, crown structure and seed production of birch seedlings, grafts and micropropagated plants. Silva Fennica vol. 29 no. 1 article id 5542. https://doi.org/10.14214/sf.a9193

Growth, crown structure, flowering and seed production of silver birch (Betula pendula Roth) seedlings, grafts and micropropagated plants was compared during four years in a polythene greenhouse experiment. The growth of the seedlings was clearly the most vigorous and that of the grafts the weakest, the micropropagated plants being intermediate. The seedlings had the highest and the grafts the lowest number of branches before cutting the tops of the plants, but the differences between the material types were no more significant after cutting the tops. The grafts had significantly shorter and thinner branches than the seedlings and the micropropagated plants, whereas the differences in branch length and branch thickness between the latter two groups were not significant. The grafts started flowering at the age of two years, one year earlier than the other two types of material. At the age of four years the micropropagated plants had abundant seed production, about 75% of that of the seedlings and about two times higher than that of the grafts. Thus, the micropropagated plants can be used instead of grafts when establishing polythene greenhouse seed orchards of birch.

  • Ryynänen, ORCID ID:E-mail:
  • Viherä-Aarnio, ORCID ID:E-mail:
article id 5541, category Article
Anneli Viherä-Aarnio. (1994). Performance of micropropagated plants of silver birch (Betula pendula) in a field trial. Silva Fennica vol. 28 no. 4 article id 5541. https://doi.org/10.14214/sf.a9181

Micropropagated and seed-borne plants of sliver birch (Betula pendula Roth) were compared for survival and growth in a field trial at the age of six years. Three clones for micropropagation were selected from open-pollinated progenies of selected southern Finnish plus trees at the age of 17 and 20. The three seed-borne lots were of southern Finnish stand origin. The best two lots of the experiment as regards the height and diameter growth at the age of six were the clones. The best of these differed significantly from the best-growing seed-grown lot. The weakest lot of the experiment was also a clone which was clearly slow-growing with a dense and bushy crown. Survival of the material was high (mean = 94%), and there was no damage caused by voles and elks, for example. The results clearly show that the selection of material for clonal propagation should be done carefully. The clones should also be tested for performance in the field before propagation on a large scale.

  • Viherä-Aarnio, ORCID ID:E-mail:
article id 5538, category Article
Anneli Viherä-Aarnio, Leena Ryynänen. (1994). Seed production of micropropagated plants, grafts and seedlings of birch in a seed orchard. Silva Fennica vol. 28 no. 4 article id 5538. https://doi.org/10.14214/sf.a9178

Seed production of micropropagated plants, seedlings and grafts of Silver birch (Betula pendula Roth) in a polyethylene greenhouse experiment was followed for five years. The grafts started flowering and seed production at the age of two years, one year earlier than other two types of material. At the age of three the seed production of both micropropagated plants and seedlings was already more than two times higher than that of the grafts. Variation between the clones was high and plant type x clone interaction was significant. At the age of four, in 1993, seed production was high in all three types of material. Seed production of the micropropagated plants was two times higher than that of the grafts but about 75% of that of the seedlings. In 1994 seed production of all three plant types was very low, which shows large variation between different years. The early development of the plant material types suggests that micropropagated plants have higher seed production than grafts and could well be used instead of grafts in polythene greenhouse seed orchards.

  • Viherä-Aarnio, ORCID ID:E-mail:
  • Ryynänen, ORCID ID:E-mail:
article id 5536, category Article
Roar Skuterud, Jon Dietrichson. (1994). Budburst in detached birch shoots (Betula pendula) of different varieties winter-stored in darkness at three different temperatures. Silva Fennica vol. 28 no. 4 article id 5536. https://doi.org/10.14214/sf.a9176

Budburst timing and the relationship to storage temperature and duration were investigated in four varieties (entries) of 1–2 metres tall silver birch (Betula pendula Roth) trees. A total of 2,160 shoots were sampled, and the material stores in darkness at 0, 3 or 6 °C from November 29, 1993. When the shoots were placed in storage, they had been through a period of 29 days with temperatures below 0°C (since October 15). By that time the autumn dormancy was assumed already broken, and the trees were expected to respond to increased temperature by bud development. On January 4, 1994, and on four subsequent dates, January 19, February 1, March 4 and March 17, shoots were taken out of storage and set in growth chambers at 9, 12 or 15°C. The time to budburst was recorded.

Duration of storage, storage temperatures and varieties were all highly significant for budburst. The interaction terms were of less statistical importance. Based on the contrast between the three different growth chamber environments, three different methods were used to calculate the threshold temperatures for each entry. In spite of the pre-selection of variable budburst performers, the threshold values, varying between 0°C to -2°C, could not be shown to be statistically different. According to the results, the time of budburst changes in accordance with both winter and spring temperatures, being extremely early after a mild winter and warm spring, given sufficient autumn chilling. The similarities in the threshold temperatures indicate that the ranking in earliness between varieties will most likely be the same from year to year without regard to climate change.

  • Skuterud, ORCID ID:E-mail:
  • Dietrichson, ORCID ID:E-mail:
article id 5521, category Article
Taneli Kolström, Seppo Kellomäki. (1993). Tree survival in wildfires. Silva Fennica vol. 27 no. 4 article id 5521. https://doi.org/10.14214/sf.a15682

The survival of forest tree species in wildfires was examined on two burned stands. Norway spruce (Picea abies (L.) H. Karst.) and birches (Betula spp.) proved to be sensitive to the effects of wildfire; almost all individuals of these tree species were killed by the fires. Scots pine (Pinus sylvestris L.) was more tolerable to the effects of wildfire; i.e. one out of five Scots pines survived. Fire tolerance increased as tree size increased.

The PDF includes an abstract in Finnish.

  • Kolström, ORCID ID:E-mail:
  • Kellomäki, ORCID ID:E-mail:
article id 5478, category Article
Seppo Kellomäki, Marja Kolström. (1992). Computations on the management of seedling stands of Scots pine under the influence of changing climate in southern Finland. Silva Fennica vol. 26 no. 2 article id 5478. https://doi.org/10.14214/sf.a15639

Model computations on the management of Scots pine (Pinus sylvestris L.) at the seedling stage showed that a rising temperature due to the suggested climate change could increase the competition capacity of birch species (Betula pendula) more than Scots pine, whose growth could even decline during the course of a rise in temperature. A temperature rise could, thus, bring the time of removal of birches forward when aiming at Scots pine timber stands composed of these tree species. The increasing proportion of birches makes the removal of birches even more urgent and emphasizes the need for careful management of Scots pine stands under rising temperatures. The first thinning of Scots pine is generally brought forward; this is particularly the case when wide spacing is applied in planting. A furthrer rise in temperature magnifies the above patterns by reducing further the competitive capacity of Scots pine in relation to birches.
The PDF includes an abstract in Finnish.

  • Kellomäki, ORCID ID:E-mail:
  • Kolström, ORCID ID:E-mail:
article id 5475, category Article
Jyrki Hytönen. (1992). Allelopathic potential of peatland plant species on germination and early seedling growth of Scots pine, silver birch and downy birch. Silva Fennica vol. 26 no. 2 article id 5475. https://doi.org/10.14214/sf.a15636

The potential alleopathic inhibitive effects of aqueous extracts of 13 peatland plant species on germination, radicle and seedling growth of Scots pine (Pinus sylvestris L.), silver and downy birch (Betula pendula Roth., B. pubescens Ehrh.) were studied. Freshly cut plant parts were finely ground, mixed with distilled water and agitated. The proportions of fresh plant mass in the mass-based extracts varied within the range of 1, 5, 10 and 20% (w/w). The seeds were germinated in petri dishes moistened with the plant extracts. In a separate experiment growth of birch seedlings irrigated with the extracts was studied.

Ledum palustre, Vaccinium uliginosum and Empetrum nigrum extracts, and in certain experiments extracts of other species, inhibited the germination of Scots pine and birch seeds. Results from the different experiments were not, however, fully consistent. None of the low (1% w/w) extract concentrations had any effect on germination. Strong extract concentrations (20% w/w) inhibited germination of pine seedlings significantly. The extracts affected only slightly the growth of potted birch seedlings.

The PDF includes an abstract in Finnish.

  • Hytönen, ORCID ID:E-mail:
article id 5463, category Article
Öje Danell. (1991). Survey of past, current and future Swedish forest tree breeding. Silva Fennica vol. 25 no. 4 article id 5463. https://doi.org/10.14214/sf.a15621

The paper gives an introduction of the tree breeding program of Sweden that started in 1936 by the establishment of an association for the tree breeding. In 1967 the Institute of Forest Improvement was founded and it replaced the earlier association. The main species in the programme have been Scots pine (Pinus sylvestris L.), Norway spruce (Picea abies (L.) H. Karst.), lately also birch (mainly Betula pendula Roth.) and lodgepole pine (Pinus contorta). In addition, limited breeding has been done also with hybrid aspen (Populus tremula x P. tremuloides), oak (Quercus), larch (Larix), black spruce (Picea mariana) and a few other native and exotic species. The dominating initial effort has been to select plustrees in natural stands and use them for production of reforestation material. In addition, a considerable body of tests was built. The paper lists the status of breeding material of the different tree species and introduces the medium and short-term breeding programmes.

  • Danell, ORCID ID:E-mail:
article id 5432, category Article
Risto Rikala, Helen J. Jozefek. (1990). Effect of dolomite lime and wood ash on peat substrate and development of tree seedlings. Silva Fennica vol. 24 no. 4 article id 5432. https://doi.org/10.14214/sf.a15586

Effect of dolomite lime and wood ash (0, 0.5, 1, 2, 4, 8 and 16 kg m-3) on the chemical composition of low humified Sphagnum peat was studied. Germination of Scots pine (Pinus sylvestris L.), Norway spruce (Picea abies (L.) H. Karst.) and silver birch (Betula pendula Roth) and the subsequent growth of these seedlings were investigated in a greenhouse experiment. Nutrient concentrations in shoots and roots of pine seedlings were also analysed. The pH of peat increased asymptotically from 3.8 to about 7.0 with increasing lime regimen and to about 8.0 with increasing ash regimen. Wood ash linearly increased electrical conductivity and P, K, and Ca concentrations of peat. Rate of germination, within 7 days, of pine and spruce was best at low pH (<5) while birch seeds had a slightly higher pH optimum (4–6). Germination capacity, within 21 days, was not affected by pH or application regimen of either lime or ash. Pine and spruce seedlings grew best with lime and ash doses of 0.5–2.0 kg m-3, the pH of peat being 4–5. Lime and ash treatments did not affect the growth of birch seedlings, but wood ash increased nutrient concentration of pine seedlings.

The PDF includes an abstract in Finnish.

  • Rikala, ORCID ID:E-mail:
  • Jozefek, ORCID ID:E-mail:
article id 5423, category Article
Eliisa Särkilahti, Terho Valanne. (1990). Induced polyploidy in Betula. Silva Fennica vol. 24 no. 2 article id 5423. https://doi.org/10.14214/sf.a15577

Seeds of ten different Betula species were treated with colchicine solution during germination, to induce duplication of the chromosome set. The species included in the study were B. pendula, B. pubescens, B. papyrifera subcordata, B. papyrifera papyrifera, B. papyrifera occidentalis, B. populifolia, B. alleghaniensis, B.n igra, B. glandulosa and B. nana. The total number of individually labelled, colchicine-treated trees was 1,550. Colchicine treatment induced changes in morphological features, especially in the leaves. These features proved to be good indicators of polyploidization. The experiments produced 687 polyploid trees, 287 of which are still alive. The polyploid Betula trees offer possibilities of studying the significance of the genome dosage for the growth, breeding, adaptability and evolution of Betula.

The PDF includes an abstract in Finnish.

  • Särkilahti, ORCID ID:E-mail:
  • Valanne, ORCID ID:E-mail:
article id 5411, category Article
Eero Paavilainen. (1990). Effect of refertilization of pine and birch stands on a drained fertile mire. Silva Fennica vol. 24 no. 1 article id 5411. https://doi.org/10.14214/sf.a15563

Refertilization with PK, about 15 years after the first fertilizer application, increased tree growth and the amount of nutrients in tree litter in Scots pine (Pinus sylvestris L.) and birch (mainly Betula pubescens Erhr.) stands on a drained fertile mire in Northern Finland (65°34 N’, 25°42’ E). The increase in growth and nutrient contents after refertilization was greatest in the mature pine stand where the application of nitrogen and micronutrients gave an additional response compared to the PK-application.

The PDF includes an abstract in Finnish.

  • Paavilainen, ORCID ID:E-mail:
article id 5411, category Article
Eero Paavilainen. (1990). Effect of refertilization of pine and birch stands on a drained fertile mire. Silva Fennica vol. 24 no. 1 article id 5411. https://doi.org/10.14214/sf.a15563

Refertilization with PK, about 15 years after the first fertilizer application, increased tree growth and the amount of nutrients in tree litter in Scots pine (Pinus sylvestris L.) and birch (mainly Betula pubescens Erhr.) stands on a drained fertile mire in Northern Finland (65°34 N’, 25°42’ E). The increase in growth and nutrient contents after refertilization was greatest in the mature pine stand where the application of nitrogen and micronutrients gave an additional response compared to the PK-application.

The PDF includes an abstract in Finnish.

  • Paavilainen, ORCID ID:E-mail:
article id 5369, category Article
Helen J. Jozefek. (1989). The effect of varying levels of potassium on the frost resistance of birch seedlings. Silva Fennica vol. 23 no. 1 article id 5369. https://doi.org/10.14214/sf.a15528

Seven hundred one-year-old Betula pendula Roth seedlings were given different concentrations of potassium fertilizer. Over the study period seedlings were subjected to artificial growing and dormant phases. Frost resistance of the seedlings was assessed by artificial freezing tests and electrical impedance measurements on stem cuttings. In general, high concentrations of potassium fertilizer reflected a low tolerance to frost. Pre-freezing impedance readings decreased with increasing potassium fertilizer dosages. Results from pre-freezing impedance measurements were found to be in broad agreement with the hypothesis that high impedance readings indicate a frost hardy tissue whereas low readings imply the opposite.

The PDF includes an abstract in Finnish.

  • Jozefek, ORCID ID:E-mail:
article id 5344, category Article
Ilari Lumme. (1988). Early effects of peat ash on growth and mineral nutrition of the silver birch (Betula pendula) on a mined peatland. Silva Fennica vol. 22 no. 2 article id 5344. https://doi.org/10.14214/sf.a15501

Two-year-old silver birch (Betula pendula Roth) seedlings were fertilized with three peat ash dosages (10, 50 and 150 metric t/ha) and planted at three densities (2,000, 10,000 and 25,000 seedlings/ha). The peat and mineral soil were mixed together by deep ploughing before peat ash application. The results indicate that the 10 t/ha of peat ash may be too low a dosage and 150 t/ha too high for the silver birch seedlings. The 50 t/ha ash dosage increased growth markedly, obviously due to an enhancement in soil and foliar P, Mg and Ca content, soil pH, microbial activity and mobilization of soil organic nitrogen. Both foliar and soil P were already enhanced with the 10 t/ha peat ash dosage. The K content of the peat ash was low, however, and it may be that fertilizer K should be applied later.

The PDF includes a summary in Finnish.

  • Lumme, ORCID ID:E-mail:
article id 5305, category Article
Timo Pukkala. (1987). Simulation model for natural regeneration of Pinus sylvestris, Picea abies, Betula pendula and Betula pubescens. Silva Fennica vol. 21 no. 1 article id 5305. https://doi.org/10.14214/sf.a15462

In the model the regeneration process is derived into three subprocesses: birth, growth and mortality of seedlings. The main emphasis is on the birth process where the following phases are simulated: seed crop, quality of seeds, maturity of seeds, predation of seeds and germination. The parameters are based on data published in Finland. Part of the parameters are obtained directly from the investigations and part is proposed by the author. The model can be calibrated by changing parameter values. The simulation is made with the help of random numbers which have the same means as the estimates and the same distributions as the residuals of the equations used in simulation. The time step of the model is one year. The number of emerged seedlings in one year is obtained by multiplying the seed crop with the probabilities that the seed passes different phases of the birth process. Because of stochasticity the regeneration period is simulated several times. From the results it is possible to evaluate the risk and succeeding probability of the regeneration. The main drawbacks of the simulation method are the lack of empirical parameters and the difficulty of testing. The model could be further developed by including spatiality into the model.

The PDF includes an abstract in Finnish.

  • Pukkala, ORCID ID:E-mail:
article id 5305, category Article
Timo Pukkala. (1987). Simulation model for natural regeneration of Pinus sylvestris, Picea abies, Betula pendula and Betula pubescens. Silva Fennica vol. 21 no. 1 article id 5305. https://doi.org/10.14214/sf.a15462

In the model the regeneration process is derived into three subprocesses: birth, growth and mortality of seedlings. The main emphasis is on the birth process where the following phases are simulated: seed crop, quality of seeds, maturity of seeds, predation of seeds and germination. The parameters are based on data published in Finland. Part of the parameters are obtained directly from the investigations and part is proposed by the author. The model can be calibrated by changing parameter values. The simulation is made with the help of random numbers which have the same means as the estimates and the same distributions as the residuals of the equations used in simulation. The time step of the model is one year. The number of emerged seedlings in one year is obtained by multiplying the seed crop with the probabilities that the seed passes different phases of the birth process. Because of stochasticity the regeneration period is simulated several times. From the results it is possible to evaluate the risk and succeeding probability of the regeneration. The main drawbacks of the simulation method are the lack of empirical parameters and the difficulty of testing. The model could be further developed by including spatiality into the model.

The PDF includes an abstract in Finnish.

  • Pukkala, ORCID ID:E-mail:
article id 5269, category Article
Leena Ryynänen, Martti Ryynänen. (1986). Propagation of adult curly-birch succeeds with tissue culture. Silva Fennica vol. 20 no. 2 article id 5269. https://doi.org/10.14214/sf.a15448

The curly-grained trait of Betula pendula Roth is inheritable, but it is persumably not question of only one Mendelian gene since, for instance, there are a number of different types of curly-birch. The progeny obtained from controlled crossing between two curly-birch individuals do not all posses the curly-grained trait.

Plantlets were produced from adult curly-birch (Betula pendula var. carelica). Murashige and Skoog’s medium was used as the culture medium. Growth was initiated on a medium containing 1 mg/l BAP. Bud formation was induced using a medium containing 10 mg/l BAP and 0.2 mg/l NAA. Development of shoots was achieved on a medium containing ½ x Murashige and Skoog’s macrominerals and sucrose, 1/1 x Murashige and Skoog’s microminerals and vitamins, and 0.5 mg/l BAP and 0.5 mg/l IAA. The medium used for inducing root formation was the same as above, but without any growth regulators. The results indicate that adult deciduous trees can be best propagated through tissue culture when the least differentiated cells, i.e. the initial cells of the promeristem, are used as the startin material. The axillary buds provide easily available study material which can be prepared with little difficulty and are continuously renewed.

The PDF includes a summary in Finnish.

  • Ryynänen, ORCID ID:E-mail:
  • Ryynänen, ORCID ID:E-mail:
article id 5266, category Article
Matti Kärkkäinen. (1986). Malli männyn, kuusen ja koivun puuaineen oksaisuudesta. Silva Fennica vol. 20 no. 2 article id 5266. https://doi.org/10.14214/sf.a15445
English title: Model of knottiness of wood material in pine, spruce and birch.

A computer model was developed for predicting knottiness of wood material of Scots pine (Pinus sylvestris L.), Norway spruce (Picea abies (L.) H. Karst.) and birch (Betula sp). The prediction included location of knots, their size and quality, i.e. if they are dead or living knots. The model suits best for tree species where branches are born at the base of shoots, in Finland such tree species is Scots pine.

The usefulness of the model was tested in the prediction of knots in wooden elements of joinery industry. According to the results, the shape of cross section affects the surface quality of elements. Especially useful is a quadratic cross section as it increases the probability to get a knotless surface.

The PDF includes an abstract in English.

  • Kärkkäinen, ORCID ID:E-mail:
article id 5261, category Article
Matti Kärkkäinen. (1986). Koivuvaneritukkien ja -runkojen arvosuhteet. Silva Fennica vol. 20 no. 1 article id 5261. https://doi.org/10.14214/sf.a15440
English title: Value relations of birch veneer logs and stems in Finland.

A model was developed in order to describe the peeling of veneer for determining value relationship for birch veneer logs and stems. The model was based on selling prices of veneer and other products as well as processing costs. The model was utilized for determining the effect of various input variables on the log value.

According to the results, the effect of tree size was important for the value of raw material. Even knottiness had an effect although only in the higher manufacturing costs of knotty veneer were taken into account. Pruning was a method to increase substantially the proportion of knotless veneer.

The PDF includes an abstract in English.

  • Kärkkäinen, ORCID ID:E-mail:
article id 5261, category Article
Matti Kärkkäinen. (1986). Koivuvaneritukkien ja -runkojen arvosuhteet. Silva Fennica vol. 20 no. 1 article id 5261. https://doi.org/10.14214/sf.a15440
English title: Value relations of birch veneer logs and stems in Finland.

A model was developed in order to describe the peeling of veneer for determining value relationship for birch veneer logs and stems. The model was based on selling prices of veneer and other products as well as processing costs. The model was utilized for determining the effect of various input variables on the log value.

According to the results, the effect of tree size was important for the value of raw material. Even knottiness had an effect although only in the higher manufacturing costs of knotty veneer were taken into account. Pruning was a method to increase substantially the proportion of knotless veneer.

The PDF includes an abstract in English.

  • Kärkkäinen, ORCID ID:E-mail:
article id 5258, category Article
Pirkko Romakkaniemi. (1986). The susceptibility of Betula pendula and B. pubescens saplings to stem spot disease on different soils. Silva Fennica vol. 20 no. 1 article id 5258. https://doi.org/10.14214/sf.a15437

The susceptibility of Betula pendula Roth and B. pubescens Ehrh. Saplings to stem spot disease caused by Godronia multispora J.W. Groves and Fusarium avenaceum (Fr.) Sacc. was studeied. B. pendula proved to be more susceptible than B. pubescens on all studied soils, especially on peat. G. multispora was more pathogenic than F. avenaceum. Inoculations with G. multispora in the spring and summer induced smaller cancers than in the autumn.

The PDF includes an abstract in Finnish.

  • Romakkaniemi, ORCID ID:E-mail:
article id 5258, category Article
Pirkko Romakkaniemi. (1986). The susceptibility of Betula pendula and B. pubescens saplings to stem spot disease on different soils. Silva Fennica vol. 20 no. 1 article id 5258. https://doi.org/10.14214/sf.a15437

The susceptibility of Betula pendula Roth and B. pubescens Ehrh. Saplings to stem spot disease caused by Godronia multispora J.W. Groves and Fusarium avenaceum (Fr.) Sacc. was studeied. B. pendula proved to be more susceptible than B. pubescens on all studied soils, especially on peat. G. multispora was more pathogenic than F. avenaceum. Inoculations with G. multispora in the spring and summer induced smaller cancers than in the autumn.

The PDF includes an abstract in Finnish.

  • Romakkaniemi, 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 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 5249, category Article
Jari Parviainen. (1985). Istuttamalla perustetun nuoren männikön, kuusikon, siperianlehtikuusikon ja rauduskoivikon kasvu. Silva Fennica vol. 19 no. 4 article id 5249. https://doi.org/10.14214/sf.a15428
English title: Growth of young Scots pine, Norway spruce, siberian larch and silver birch plantations.

Early growth of four different tree species (Pinus sylvestris L., Picea abies (L.) H. Karst., Larix sibirica Ledeb and Betula pendula Roth) 16–23 years after planting were compared in a field experiment of 16 square plots established on a stony, grove-like upland (Oxalis-Myrtillus forest type) in Southern Finland. This study gives additional results to the publication Folia Forestalia 386/1979.

At this early stage, the growth of the spruce stand was clearly slower than that of the other species for all parameters to be measured (height, diameter, and volume growth). Height growth was most rapid in the silver birch stand and diameter growth in the larch stand. No clear differences were found in the mean volume of the 100 thickest trees in the stand between the larch and silver birch.

The PDF includes a summary in English.

  • Parviainen, ORCID ID:E-mail:
article id 5236, category Article
Pirkko Romakkaniemi-Niemelä. (1985). Rauduskoivun runkosolukon RC-arvo talveentumisasteen osoittajana. Silva Fennica vol. 19 no. 2 article id 5236. https://doi.org/10.14214/sf.a15415
English title: RC-value of stem tissue of silver birch as an indicator of cold acclimation.

The aim of this study was to examine the development of the cold acclimation of silver birch (Betula pendula Roth) seedlings. The effect of fertilization was also studied. The seedlings were two-year-old. As a comparison stump sprouts from the near-by forest were used. The seedlings were treated in temperatures of +5°C (= control), –5°C and –15°C four times with conductivity measurements and with ocular inspection.

There were no significant differences in cold acclimation between different fertilization treatments or between the fertilized seedlings and stump sprouts. This may have been due to the rapid cooling rate. The cold acclimation of the seedlings was registered well by the changes in the relative conductivity values. The differences between the relative conductivity values of different temperature treatments in August and the beginning of September were significant. However, in the end of September and especially October the values no longer differed significantly. Correlation proved good between the relative electrical conductivity tests and the ocular inspections of the damages.

The PDF includes a summary in English.

  • Romakkaniemi-Niemelä, ORCID ID:E-mail:
article id 5233, category Article
Leo Heikurainen. (1985). Verhopuuston vaikutus kuusitaimikon kehitykseen. Silva Fennica vol. 19 no. 1 article id 5233. https://doi.org/10.14214/sf.a15412
English title: The influence of birch nurse crop (Betula pubescens) on the growth of Norway spruce (Picea abies) seedling stands on drained peatlands.

Young Norway spruce (Picea abies (L.) H. Karst.) are susceptible to early summer frost damage. Birch (Betula pubescens Ehrh.) naturally colonize rich or fairly rich drained peatlands after clear cutting, and can provide protection for developing seedlings. The report describes the development of spruce stands after various types of handing of the birch nurse crops.

Different proportions of birch and spruces did not have any influence on the spruce stand production. In cases where the nurse crop stand is removed when the spruce stand age was 20 years and height 4 m the spruce suffered badly but recovered with time, reaching the spruce stand growing under a nurse stand within the next 20 years. The height growth of spruce depends on the density of the nurse stand, especially on fertile sites. The development of diameter growth also depends on the density of the nurse trees. Removal of the nurse stand in spruce stands on the sites concerned should be done when the spruce stand is 20 years old and at the height of 4 m.

The PDF includes a summary in English.

  • Heikurainen, ORCID ID:E-mail:
article id 5221, category Article
Aleksandr P. Jevdokimov. (1984). Visakoivun kasvatus Neuvostoliiton luoteisosissa. Silva Fennica vol. 18 no. 3 article id 5221. https://doi.org/10.14214/sf.a15400
English title: Experiences of curly birch growing in north-western Russia.

Curly birch (Betula pendula var. carelica (Merklin) Hejtmanek) is widely distributed over north-western part or Russia, including the Baltic Soviet Republics and Belorussia. Experiences of growing this decorative species in Soviet Karelia and Leningrad region are presented. Commonly used classifications of the species are described, and recommendations for management of curly birch cultures and production of planting stock in greenhouses are given.

The PDF includes a summary in English.

  • Jevdokimov, ORCID ID:E-mail:
article id 5206, category Article
Matti Kärkkäinen. (1984). Miten koivuun tulisi suhtautua metsätaloudessa? Silva Fennica vol. 18 no. 1 article id 5206. https://doi.org/10.14214/sf.a15385
English title: The proper attitude towards birch in forestry.

A literature survey based on Nordic literature deals with the biology, use, harvesting and economy of birch (Betula sp.). According to the results, the easily quantified hard facts are against cultivation of birch: lower growth, poorer production of valuable assortments, lower price of pulp, higher planting costs, and higher harvesting and transport costs than for conifers. The soft facts, which may be true, are not easily measured or their importance evaluated: the possible improvement of soil, decreasing risk of insect and fungi attacks, shelter against frost etc. Due to the differences in the nature of the facts the discussion of cultivation of birch will probably continue.

The PDF includes a summary in English.

  • Kärkkäinen, ORCID ID:E-mail:
article id 5202, category Article
Kari Löyttyniemi. (1983). Flight periods of some birch timber insects. Silva Fennica vol. 17 no. 4 article id 5202. https://doi.org/10.14214/sf.a15185

Flight periods of insects breeding on birch (Betula sp.) timber were observed by means of window flight traps baited with freshly cut birch logs in five locations in Finland from 1972 to 1976. Only few species were caught during the study. In general, these species were on the wing during midsummer, although flight periods of some of them were relatively long. Scolytus ratzeburgi Jans. caused harmful staining of wood within a month from attack, but the damage by the wood-boring pests remained negligible throughout the first storage summer.

The PDF includes a summary in Finnish.

  • Löyttyniemi, ORCID ID:E-mail:
article id 5188, category Article
Eljas Pohtila, Tapani Pohjola. (1983). Vuosina 1970-1972 Lappiin perustetun aurattujen alueiden viljelykokeen tulokset. Silva Fennica vol. 17 no. 3 article id 5188. https://doi.org/10.14214/sf.a15171
English title: Results from the reforestation experiment on ploughed sites established in Finnish Lapland during 1970–1972.

The objective of the study was to compare different reforestation methods on ploughed areas in Finnish Lapland. Four species were compared: Scots pine (Pinus sylvestris L.), Norway spruce (Picea abies (L.) H. Karst.), silver birch (Betula pendula Roth) and Siberian larch (Larix sibirica Ledeb.). The experiments were established in different parts of Lapland on different types of sites in 1970–72.

In Scots pine there was a difference of 15 percentage points in survival of seedlings between the best and worst methods of regeneration. Containerized seedlings and paper pot seedlings had the best survival rates. In Norway spruce the respective difference between sowing and planting was about 20 percentage points. In favour of planting. The survival rate can be increased by about 20 percentage points by selecting the right tree species. The average height varied from 25 cm (the sowed Norway spruce) to 179 cm (the planted silver birch) after 10 growing seasons. The birch was planted at the most fertile sites only. The longer time passed from the afforestation the clearer was the effect of the local growing conditions on the development of the seedlings. The elevation of the site was one factor seemed to influence the success of the seedlings.

The PDF includes a summary in English.

  • Pohtila, ORCID ID:E-mail:
  • Pohjola, ORCID ID:E-mail:
article id 7044, category Article
O. J. Lukkala. (1920). Lehdeksien tekotapa Lounais-Suomessa ja sen metsähoidollinen merkitys. Acta Forestalia Fennica vol. 16 no. 2 article id 7044. https://doi.org/10.14214/aff.7044
English title: The silvicultural influences of collecting leaf fodder in South-West Finland.

In South-West Finland the usual method to make leaf fodder for cattle has been to cut the branches and collect the new sprouts again next year. According to this review, the most common tree species to be topped is Betula sp. Downy Birch (Betula pubescens Ehrh.) grows shoots easier than silver birch (B. pendula Roth). The topped forests are usually small and situated near the settlements, next to the fields and meadows. The birch trees are typically cut when they are 15-20 years old. Regularly topped birch rots easily and seldom exceeds 50 years. The capacity to grow shoots depends on the age of the tree, site and time of the cutting. The risk for rotting can be decreased by removing only part of the shoots and cutting the shoots a short distance from the base of the shoot. Collecting leaf fodder decreased in Finland, and was common only in the South-West Finland and Åland.

The PDF includes a summary in German.

  • Lukkala, ORCID ID:E-mail:
article id 7044, category Article
O. J. Lukkala. (1920). Lehdeksien tekotapa Lounais-Suomessa ja sen metsähoidollinen merkitys. Acta Forestalia Fennica vol. 16 no. 2 article id 7044. https://doi.org/10.14214/aff.7044
English title: The silvicultural influences of collecting leaf fodder in South-West Finland.

In South-West Finland the usual method to make leaf fodder for cattle has been to cut the branches and collect the new sprouts again next year. According to this review, the most common tree species to be topped is Betula sp. Downy Birch (Betula pubescens Ehrh.) grows shoots easier than silver birch (B. pendula Roth). The topped forests are usually small and situated near the settlements, next to the fields and meadows. The birch trees are typically cut when they are 15-20 years old. Regularly topped birch rots easily and seldom exceeds 50 years. The capacity to grow shoots depends on the age of the tree, site and time of the cutting. The risk for rotting can be decreased by removing only part of the shoots and cutting the shoots a short distance from the base of the shoot. Collecting leaf fodder decreased in Finland, and was common only in the South-West Finland and Åland.

The PDF includes a summary in German.

  • Lukkala, ORCID ID:E-mail:
article id 7044, category Article
O. J. Lukkala. (1920). Lehdeksien tekotapa Lounais-Suomessa ja sen metsähoidollinen merkitys. Acta Forestalia Fennica vol. 16 no. 2 article id 7044. https://doi.org/10.14214/aff.7044
English title: The silvicultural influences of collecting leaf fodder in South-West Finland.

In South-West Finland the usual method to make leaf fodder for cattle has been to cut the branches and collect the new sprouts again next year. According to this review, the most common tree species to be topped is Betula sp. Downy Birch (Betula pubescens Ehrh.) grows shoots easier than silver birch (B. pendula Roth). The topped forests are usually small and situated near the settlements, next to the fields and meadows. The birch trees are typically cut when they are 15-20 years old. Regularly topped birch rots easily and seldom exceeds 50 years. The capacity to grow shoots depends on the age of the tree, site and time of the cutting. The risk for rotting can be decreased by removing only part of the shoots and cutting the shoots a short distance from the base of the shoot. Collecting leaf fodder decreased in Finland, and was common only in the South-West Finland and Åland.

The PDF includes a summary in German.

  • Lukkala, ORCID ID:E-mail:
article id 5155, category Article
K. M. Bhat, Matti Kärkkäinen. (1982). Wood anatomy and physical properties of the wood and bark in Betula nana growing in Finland. Silva Fennica vol. 16 no. 1 article id 5155. https://doi.org/10.14214/sf.a15070

Eighty Betula nana samples were collected from three swamp sites. In the butt portion of the dwarf shrub the average number of growth rings was 12 and the average diameter of the sprouts 6 mm. The basic density of wood was 457 kg/m3 and that of bark 544 kg/m3. The proportion of bark was 32–38% of weight or volume. The vessel elements and fibres were short and their diameter small. The proportion of vessels was 15%, that of fibres 70% and that of rays 15%.

The PDF includes a summary in Finnish.

  • Bhat, ORCID ID:E-mail:
  • Kärkkäinen, ORCID ID:E-mail:
article id 7042, category Article
Yrjö Ilvessalo. (1920). Kasvu- ja tuottotaulut Suomen eteläpuoliskon mänty-, kuusi- ja koivumetsille. Acta Forestalia Fennica vol. 15 no. 4 article id 7042. https://doi.org/10.14214/aff.7042
English title: Growth and yield tables for the Scots pine, Norway spruce and birch in the southern part of Finland.

The first proper growth and yield tables were prepared in Finland already in 1872, but they have been used little as the needs of forestry and forest sciences increased. One of the problems of the old yield tables was how the site quality classes are determined. The new growth and yield tables use the forest site type classification, which enables the use of same site types for all tree species. This makes it possible to compare the growth of different tree species in same kind of sites. The tables also use stem frequency distribution series. In the first stage, the tables were prepared for Southern and Central Finland.

The PDF includes a summary in German.

  • Ilvessalo, ORCID ID:E-mail:
article id 5147, category Article
J. Eriksson, J. Bergholm, K. Kvist. (1981). Injury to vegetation caused by industrial emissions of boron compounds. Silva Fennica vol. 15 no. 4 article id 5147. https://doi.org/10.14214/sf.a15374

At immediate surroundings of a fiberglass plant in Central Sweden, vegetation shows toxicity symptoms. Soils and birch (Betula pendula Roth) leaves were sampled. The soil was analysed for water soluble and organic bound boron, carbon, nitrogen, and pH. Vegetation was analysed for total boron. Both fractions of boron in the soils increased towards the factory. Organic bound boron increased irregularly because of its strong correlation to carbon content which varied in the area. The C/N ratio increased nearer the industry due to the harmful effect of boron on the decomposition of organic matter. No relation between pH and the distance from the emission source was visible, but B/C ratio was found to increase with increasing pH of the soil. Boron levels in birch leaves were elevated very much close to the factory. The geographical distribution of high levels of boron in birch, corresponded well with high values in soils, and also with the main wind directions. The limit values for visible injury on birch were found to be around 5 ppm of water-soluble boron in soil and around 200 ppm in leaves.

  • Eriksson, ORCID ID:E-mail:
  • Bergholm, ORCID ID:E-mail:
  • Kvist, ORCID ID:E-mail:
article id 5115, category Article
K. M. Bhat, Matti Kärkkäinen. (1981). Variation in structure and selected properties of Finnish birch wood. II. Silva Fennica vol. 15 no. 2 article id 5115. https://doi.org/10.14214/sf.a15056

The anatomical variation of a lateral root was compared with that of the stem of the same tree at breast height by concentrating on the intrelationships of certain anatomical features in Betula pendula and B. pubescens. The results showed that root wood has several essential features of stem wood, such as gelatinous fibres, growth eccentricity, scalariform perforation plates in the vessels and pith flecks. However, some of the anatomical differences are significant. The differences between the species were more pronounced in the root than in the stem anatomy.

The PDF includes a summary in Finnish.

  • Bhat, ORCID ID:E-mail:
  • Kärkkäinen, ORCID ID:E-mail:
article id 5115, category Article
K. M. Bhat, Matti Kärkkäinen. (1981). Variation in structure and selected properties of Finnish birch wood. II. Silva Fennica vol. 15 no. 2 article id 5115. https://doi.org/10.14214/sf.a15056

The anatomical variation of a lateral root was compared with that of the stem of the same tree at breast height by concentrating on the intrelationships of certain anatomical features in Betula pendula and B. pubescens. The results showed that root wood has several essential features of stem wood, such as gelatinous fibres, growth eccentricity, scalariform perforation plates in the vessels and pith flecks. However, some of the anatomical differences are significant. The differences between the species were more pronounced in the root than in the stem anatomy.

The PDF includes a summary in Finnish.

  • Bhat, ORCID ID:E-mail:
  • Kärkkäinen, ORCID ID:E-mail:
article id 5113, category Article
K. M. Bhat, Matti Kärkkäinen. (1981). Wood anatomy and physical properties of wood and bark in Betula tortuosa Ledeb. Silva Fennica vol. 15 no. 2 article id 5113. https://doi.org/10.14214/sf.a15054

Ten trees of mountain birch (Betula tortuosa Ledeb, now Betula pubescens subsp. czerepanovii) with an average age of 39 years were sampled in northern Lapland in Finland. The average green density of wood was 589 kg/m3 and that of bark 941 kg/m3. The basic densities were 520 kg/m3 and 559 kg/m3, respectively. The basic density increased only little from the pith to the surface. In contrast, the number of bars in the perforation plates of the vessels increased considerably in the same direction. The average number of bars was 17.3.

The PDF includes a summary in Finnish.

  • Bhat, ORCID ID:E-mail:
  • Kärkkäinen, ORCID ID:E-mail:
article id 5097, category Article
K. M. Bhat, Ari Ferm, Matti Kärkkäinen. (1981). On the properties of one-year shoots of Betula pubescens Ehrh. and Salix spp. Silva Fennica vol. 15 no. 1 article id 5097. https://doi.org/10.14214/sf.a15038

Downy birch (Betula pubescens Ehrh.) trees growing on a drained peatland were cut during dormancy. The properties of the one-year old shoots produced by the stumps were measured in the autumn after one growing season. The one-year old willow shoots (a mixture of Salix phylicifolia L., S. pentandra L. and S. caprea L.) were collected from an abandoned field.

The basic density of unbarked shoots was 443 kg/m3 for birch and 346 kg/m3 for willow. The basic density of the bark was much higher than that of the wood. The effect of shoot length on the properties was small with the exception of cellular proportions. The fibre percentage increased and vessel percentage decreased with increasing shoot length.

The PDF includes a summary in Finnish.

  • Bhat, ORCID ID:E-mail:
  • Ferm, ORCID ID:E-mail:
  • Kärkkäinen, ORCID ID:E-mail:
article id 5096, category Article
K. M. Bhat, Matti Kärkkäinen. (1981). Variation in structure and selected properties of Finnish birch wood. IV. Silva Fennica vol. 15 no. 1 article id 5096. https://doi.org/10.14214/sf.a15037

Length variation of fibres and vessels was studied in the branches, stems and roots of Betula pendula Roth and B. pubescense Ehrh. The cells were significantly shorter in the branches and roots than in the stems. There was no significant difference in the cell length between the upper and lower radii of the branches and roots. The length increased from the pith to the surface and decreased in the branches and stems from the base onwards. In the roots the length increased in that direction. The differences between the tree species were small although the cells of B. pubescens were a little longer.

The PDF includes a summary in Finnish.

  • Bhat, ORCID ID:E-mail:
  • Kärkkäinen, ORCID ID:E-mail:
article id 5096, category Article
K. M. Bhat, Matti Kärkkäinen. (1981). Variation in structure and selected properties of Finnish birch wood. IV. Silva Fennica vol. 15 no. 1 article id 5096. https://doi.org/10.14214/sf.a15037

Length variation of fibres and vessels was studied in the branches, stems and roots of Betula pendula Roth and B. pubescense Ehrh. The cells were significantly shorter in the branches and roots than in the stems. There was no significant difference in the cell length between the upper and lower radii of the branches and roots. The length increased from the pith to the surface and decreased in the branches and stems from the base onwards. In the roots the length increased in that direction. The differences between the tree species were small although the cells of B. pubescens were a little longer.

The PDF includes a summary in Finnish.

  • Bhat, ORCID ID:E-mail:
  • Kärkkäinen, ORCID ID:E-mail:
article id 5095, category Article
K. M. Bhat, Matti Kärkkäinen. (1981).  . Silva Fennica vol. 15 no. 1 article id 5095. https://doi.org/10.14214/sf.a15036
English title: Variation in structure and selected properties of Finnish birch wood. III.

Variation of cellular proportion within the same growth rings counted from the pith of the stems and branches in four trees of Betula pendula Roth was studied. The fibre percentage decreased from breast height to the crown and then increased in the branches. The reverse trend was found in the percentage of vessels and parenchyma, although the latter varied relatively little. No statistically significant differences were found in the percentages of fibres, vessels and rays within the same growth rings counted from the pith between the stems and branches. In both the stem and the branches, the proportion of fibres increased and that of vessels and rays decreased from the pith to the surface. Even crown formed wood differed from that of stem formed. 

The PDF includes a summary in Finnish. 

  • Bhat, ORCID ID:E-mail:
  • Kärkkäinen, ORCID ID:E-mail:
article id 5091, category Article
K. M. Bhat. (1980). Variation in structure and selected properties of Finnish birch wood. I. Silva Fennica vol. 14 no. 4 article id 5091. https://doi.org/10.14214/sf.a15032

Variation of wood characteristics was studied in two mature trees of Betula pendula Roth and two of B. pubescens Ehrh. by stressing the interrelationships of some of the structural features, basic density and shrinkage. Correlation analysis revealed that basic density was related to some of the variables studied, viz: number of rings (age) and distance from pith, height from the ground, ring width, fibre length and double wall thickness. Multiple regression equation showed that age from pith and height from the ground explained 80% of variation of basic density in B. pendula. Two structural variables, viz: fibre wall thickness and ring width accounted for only 28% of variation of basic density in B. pubescens. No significant relations could be found between shrinkage and any of the wood parameters measured in B. pendula while some of the relationships were significant in B. pubescens. However, only 55% of variation of volumetric shrinkage was explained by two related factors, viz: basic density and moisture content while only 35% of variation of tangential shrinkage was explained by ring width and fibre width. Increase in fibre length was highly associated with the increase in fibre width, double wall thickness and vessel length in either species.

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  • Bhat, ORCID ID:E-mail:
article id 5091, category Article
K. M. Bhat. (1980). Variation in structure and selected properties of Finnish birch wood. I. Silva Fennica vol. 14 no. 4 article id 5091. https://doi.org/10.14214/sf.a15032

Variation of wood characteristics was studied in two mature trees of Betula pendula Roth and two of B. pubescens Ehrh. by stressing the interrelationships of some of the structural features, basic density and shrinkage. Correlation analysis revealed that basic density was related to some of the variables studied, viz: number of rings (age) and distance from pith, height from the ground, ring width, fibre length and double wall thickness. Multiple regression equation showed that age from pith and height from the ground explained 80% of variation of basic density in B. pendula. Two structural variables, viz: fibre wall thickness and ring width accounted for only 28% of variation of basic density in B. pubescens. No significant relations could be found between shrinkage and any of the wood parameters measured in B. pendula while some of the relationships were significant in B. pubescens. However, only 55% of variation of volumetric shrinkage was explained by two related factors, viz: basic density and moisture content while only 35% of variation of tangential shrinkage was explained by ring width and fibre width. Increase in fibre length was highly associated with the increase in fibre width, double wall thickness and vessel length in either species.

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  • Bhat, 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.

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  • Meriluoto, ORCID ID:E-mail:
article id 5084, category Article
K. M. Bhat, Matti Kärkkäinen. (1980). Distinguishing between Betula pendula Roth. and Betula pubescens Ehrh. on the basis of wood anatomy. Silva Fennica vol. 14 no. 3 article id 5084. https://doi.org/10.14214/sf.a15025

It was concluded on the basis of the anatomical investigations of four mature trees that Betula pendula Roth can be distinguished from B. pubescens Ehrh. using the number of bars per scalariform perforation plate as an identification factor. If the average number of bars is more than 17.6, the sample is probably from B. pubescens, and if less, from B. pendula. The accuracy can be slightly improved by using the vessel frequency as another factor.

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  • Bhat, ORCID ID:E-mail:
  • Kärkkäinen, ORCID ID:E-mail:
article id 5084, category Article
K. M. Bhat, Matti Kärkkäinen. (1980). Distinguishing between Betula pendula Roth. and Betula pubescens Ehrh. on the basis of wood anatomy. Silva Fennica vol. 14 no. 3 article id 5084. https://doi.org/10.14214/sf.a15025

It was concluded on the basis of the anatomical investigations of four mature trees that Betula pendula Roth can be distinguished from B. pubescens Ehrh. using the number of bars per scalariform perforation plate as an identification factor. If the average number of bars is more than 17.6, the sample is probably from B. pubescens, and if less, from B. pendula. The accuracy can be slightly improved by using the vessel frequency as another factor.

The PDF includes a summary in Finnish.

  • Bhat, ORCID ID:E-mail:
  • Kärkkäinen, ORCID ID:E-mail:
article id 5083, category Article
Matti Kärkkäinen. (1980). Havaintoja koivutukkien epäpyöreydestä ja pituusmittaeroista. Silva Fennica vol. 14 no. 3 article id 5083. https://doi.org/10.14214/sf.a15024
English title: Observations on the out-of-roundness and deviations from nominal lengths of birch logs.
English keywords: Betula; birch; logs; roundness; diameter

A material of 478 birch logs were measured. The horizontal diameter was on average larger than the vertical one, the difference increasing with the increasing diameter. The reason was supposed to be the effect of sweep and out-of-roundness of logs. The difference between the actual and nominal length increased with the increasing lengths, but decreased with increasing diameter.

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  • Kärkkäinen, ORCID ID:E-mail:
article id 5082, category Article
K. M. Bhat. (1980). Pith flecks and ray abnormalities in birch wood. Silva Fennica vol. 14 no. 3 article id 5082. https://doi.org/10.14214/sf.a15023

Samples that had extensive pith flecks, caused by the larvae of Dendromyza betulae (now Phytobia betulae E.Kang), were collected from two trees of Betula pendula Roth and two B. pubescens Erhr. The age of the trees varied from 45 to 56 years. The effect of larvae injury on the rays was studied. The width of affected rays in both species was more than twice that of normal rays. The height and frequency also increased considerably. When describing the anatomy of Betula species the pith flecks should be treated with caution in order to avoid confusion and misinterpretation. 

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  • Bhat, ORCID ID:E-mail:
article id 5082, category Article
K. M. Bhat. (1980). Pith flecks and ray abnormalities in birch wood. Silva Fennica vol. 14 no. 3 article id 5082. https://doi.org/10.14214/sf.a15023

Samples that had extensive pith flecks, caused by the larvae of Dendromyza betulae (now Phytobia betulae E.Kang), were collected from two trees of Betula pendula Roth and two B. pubescens Erhr. The age of the trees varied from 45 to 56 years. The effect of larvae injury on the rays was studied. The width of affected rays in both species was more than twice that of normal rays. The height and frequency also increased considerably. When describing the anatomy of Betula species the pith flecks should be treated with caution in order to avoid confusion and misinterpretation. 

The PDF includes a summary in Finnish. 

  • Bhat, ORCID ID:E-mail:
article id 5082, category Article
K. M. Bhat. (1980). Pith flecks and ray abnormalities in birch wood. Silva Fennica vol. 14 no. 3 article id 5082. https://doi.org/10.14214/sf.a15023

Samples that had extensive pith flecks, caused by the larvae of Dendromyza betulae (now Phytobia betulae E.Kang), were collected from two trees of Betula pendula Roth and two B. pubescens Erhr. The age of the trees varied from 45 to 56 years. The effect of larvae injury on the rays was studied. The width of affected rays in both species was more than twice that of normal rays. The height and frequency also increased considerably. When describing the anatomy of Betula species the pith flecks should be treated with caution in order to avoid confusion and misinterpretation. 

The PDF includes a summary in Finnish. 

  • Bhat, ORCID ID:E-mail:
article id 5082, category Article
K. M. Bhat. (1980). Pith flecks and ray abnormalities in birch wood. Silva Fennica vol. 14 no. 3 article id 5082. https://doi.org/10.14214/sf.a15023

Samples that had extensive pith flecks, caused by the larvae of Dendromyza betulae (now Phytobia betulae E.Kang), were collected from two trees of Betula pendula Roth and two B. pubescens Erhr. The age of the trees varied from 45 to 56 years. The effect of larvae injury on the rays was studied. The width of affected rays in both species was more than twice that of normal rays. The height and frequency also increased considerably. When describing the anatomy of Betula species the pith flecks should be treated with caution in order to avoid confusion and misinterpretation. 

The PDF includes a summary in Finnish. 

  • Bhat, ORCID ID:E-mail:
article id 5065, category Article
Juhani Niiranen. (1980). Methods used in cutting propagation of forest trees in Finland. Silva Fennica vol. 14 no. 1 article id 5065. https://doi.org/10.14214/sf.a15006

Cutting propagation of forest trees has recently been done in Finland mainly by the Foundation for Forest Tree Breeding. The aim has been to develop methods which could be used in forest nurseries for large scale production of rooted cuttings. Methods are being developed for tree species which seem to offer possibilities for economically profitable vegetative propagation. The most important tree species has been Norway spruce (Picea abies (L.) RH. Karst.), and also larches (Larix sp.), lodgepole pine (Pinus contorta), birches (Betula sp.), alders (Alnus sp.) and hybrid aspen (Populus tremula x P. tremuloides) are propagated. The sensitive rooting phase takes place in plastic greenhouses which have ventilation on the roof top, mist irrigation equipment and separate heating systems for the air and the ground. Methods used for cutting propagation of Norway spruce, lodgepole pine, larch species and broadleaved trees are described.

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  • Niiranen, ORCID ID:E-mail:
article id 5011, category Article
Kullervo Etholén. (1978). Kokemuksia visakoivun kasvatuksesta Lapissa. Silva Fennica vol. 12 no. 4 article id 5011. https://doi.org/10.14214/sf.a14865
English title: Experimental growing of curly birch in Finnish Lapland.
Original keywords: visakoivu; Lappi; puunkasvatus

The aim of the present study was to register the curly birch (Betula pendula f. carelica Sok.) plantations established in Lapland and to determine their location and present condition. The information was obtained by means of interviews and visual observations.

In Lapland, the growing of curly birch started in 1950’s and the early 1960’s. During this period, in the different supervisory areas of Lapland, the National Board of Forestry established curly birch stands totalling approximately 30 ha, including about 34,000 seedlings. The bulk of the plantations have been destroyed by animals. On the other hand, the curly birch experimental stands established by the Finnish Forest Research Institute have thrived. The private sector of Forest Management has been engaged in the production of seedlings on a large scale and, as a result of this, curly birch trees are frequently seen as ornamentals in Rovaniemi and in other localities in Lapland. When taken care of, curly birch thrives in Lapland and produces I-class curly wood.

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  • Etholén, ORCID ID:E-mail:
article id 5010, category Article
Jyrki Raulo, Reino Saarnio, Timo Ylitalo. (1978). Visakoivun karsittujen oksien kyljestyminen ja värivian leviäminen niistä runkoon. Silva Fennica vol. 12 no. 4 article id 5010. https://doi.org/10.14214/sf.a14864
English title: Sealing-off of pruned branch stumps in curly birch and subsequent spread of discoloration into the stemwood.

The material used in this study was collected in 1975 from a 41-years old curly birch (Betula pendula f. carelica Sok.) stand in Southern Finland, which had been pruned 12 years earlier. While the stand was thinned, 26 felled trees were selected for further study to study occurrence of discoloration originating from of pruned branches.

The study material included 35 pruned branch stumps and 38 naturally pruned branch stumps of curly birch. The mean diameter of the former was 31 mm and of the latter, only 15 mm. Of the pruned branch stumps, 23% had become completely sealed-off within 12 years. The discoloration had spread into the stem as little from pruned branch stumps as from naturally pruned ones even though the former were greater in diameter. Advanced rot was not found in any of the samples studied.

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  • Raulo, ORCID ID:E-mail:
  • Saarnio, ORCID ID:E-mail:
  • Ylitalo, ORCID ID:E-mail:
article id 5009, category Article
Risto-Veikko Pätiälä, Kari Blomberg, Juhani Paakkanen, Sulo Piepponen. (1978). Havaintoja raudus- ja visakoivun mahlan sokeripitoisuudesta. Silva Fennica vol. 12 no. 4 article id 5009. https://doi.org/10.14214/sf.a14863
English title: Carbohydrates in the sap of silver birch and its curly grained form.
Original keywords: rauduskoivu; visakoivu; sokerit; mahla

Carbohydrates of the sap of six curly and four silver birches (Betula pendula f. carelica Sok. and B. pendula Roth) were analysed by gas chromatography as trimethylsilyl derivates both from hydrolysed and unhydrolyzed samples. Sorbitol was identified from silver birch sap only. In each of the two groups there were glucose and fructose. No other carbohydrates were discovered. The hydrolysis had no influence on the results.

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  • Pätiälä, ORCID ID:E-mail:
  • Blomberg, ORCID ID:E-mail:
  • Paakkanen, ORCID ID:E-mail:
  • Piepponen, ORCID ID:E-mail:
article id 5009, category Article
Risto-Veikko Pätiälä, Kari Blomberg, Juhani Paakkanen, Sulo Piepponen. (1978). Havaintoja raudus- ja visakoivun mahlan sokeripitoisuudesta. Silva Fennica vol. 12 no. 4 article id 5009. https://doi.org/10.14214/sf.a14863
English title: Carbohydrates in the sap of silver birch and its curly grained form.
Original keywords: rauduskoivu; visakoivu; sokerit; mahla

Carbohydrates of the sap of six curly and four silver birches (Betula pendula f. carelica Sok. and B. pendula Roth) were analysed by gas chromatography as trimethylsilyl derivates both from hydrolysed and unhydrolyzed samples. Sorbitol was identified from silver birch sap only. In each of the two groups there were glucose and fructose. No other carbohydrates were discovered. The hydrolysis had no influence on the results.

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  • Pätiälä, ORCID ID:E-mail:
  • Blomberg, ORCID ID:E-mail:
  • Paakkanen, ORCID ID:E-mail:
  • Piepponen, ORCID ID:E-mail:
article id 5008, category Article
Jyrki Raulo, Gustaf Sirén. (1978). Neljän visakoivikon päätehakkuun tuotos ja tuotto. Silva Fennica vol. 12 no. 4 article id 5008. https://doi.org/10.14214/sf.a14862
English title: Yield in volume and money of final cutting in four curly birch stands.
Original keywords: visakoivu; tuotos; laatu

Curly birch (Betula pendula f. carelica Sok.) is characterized by large variations in stem form and the internal structure of the wood, and is generally divided in to four types on the basis of visible external stem characteristics. First plantation experiments in Finland in the 1920’s in experimental areas of the Finnish Forest Institute, had become ripe for cutting and were felled. The study material of this study consists of one 52-year old and three 42–43 -year old stands of curly birch.

The yield suitable for plywood manufacture from the oldest stand was 34,777 kg/ha and that of curly grained branch wood 39,452 kg/ha. The corresponding figures of the other stands were, on average 24,219 and 57,271 kg/ha. The yield from the stands were sold at the present-day price. The result was economically better than from any other forest tree species grown in Finland. The younger stands were obviously cut too early. It was concluded that the genetic quality of the seedlings used in the plantations in the 1920’s and 1930’s was not very high.

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  • Raulo, ORCID ID:E-mail:
  • Sirén, ORCID ID:E-mail:
article id 5007, category Article
Olavi Huuri. (1978). Visaseura. Silva Fennica vol. 12 no. 4 article id 5007. https://doi.org/10.14214/sf.a14861
English title: Curly Birch Society.
Original keywords: Visaseura; visakoivu; järjestöt

Curly birch, a curly grained variety of birch (Betula pendula f. carelica Sok.), has fetched a higher price than any other Finnish tree species on account of its rarity and decorativeness. Curly graininess has been found in Finland in addition to silver birch, also in Alnus glutinosa and Sorbus aucuparia.

The Curly Birch Society was founded in Finland in 1956. Its purpose is to promote the cultivation and use of curly birch, and to coordinate the activities of curly birch cultivators, forest industry and research. The society has made excursions and held informative meetings every year. Furthermore, the society has arranged exhibitions and participated in more extensive agricultural and forestry fairs.

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  • Huuri, ORCID ID:E-mail:
article id 4984, category Article
Jyrki Raulo. (1978). Forestation chain for birch (Betula pendula Roth) in Finland. Silva Fennica vol. 12 no. 1 article id 4984. https://doi.org/10.14214/sf.a14838

During the 1970’s an average of 4 million Betula pendula (Roth) seedlings have been planted annually in Finland. The activities connected with the planting of this tree species, the selection of forestation sites, site preparation, planting out the seedlings and follow-up work on the forestation sites are briefly reviewed in the article. The manuscript is based on the studies into the breeding, seedling production and planting techniques of B. pendula started by the Finnish Forest Research Institute already in 1960’s, as well as on practical observations made at the planting sites. A list of some of the Finnish studies concerning B. pendula which have been published in English and studies with a summary in English is included.

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  • Raulo, ORCID ID:E-mail:
article id 4962, category Article
Matti Keltikangas, Kustaa Seppälä. (1977). Ojitusalueiden hieskoivikoiden kasvatus taloudellisena vaihtoehtona. Silva Fennica vol. 11 no. 1 article id 4962. https://doi.org/10.14214/sf.a14813
English title: The economics of growing downy birch stands on drained peatlands in Finland.

The aim of this study was to determine under what conditions and with what premises the growing of Betula pubescens Ehrh. is an economically competitive alternative to the growing of Scots pine (Pinus sylvestris L.) in drained peatlands. The basic material consisted of all drainage projects in Ostrobothnia in Western Finland in 1937–38 and 1957–59, according to the archives of the Central Board of Forestry Tapio, including such areas that were at least moderately fertile and had birch dominated young stands or no tree cover. A total of 202 sample plots were measured.

According to the results, the discounted timber yield of the thinned B. pubescens stands is about 10% greater than that of untreated stands. The removing of birch seedlings and the subsequent growing of fully stocked Scots pine is more profitable than growing B. pubescens stands only if the establishment and subsequent development of the pine stand involve no costs. If the site in question is a fertile open drained peatland, establishment of a pine stand is obviously a better financial proposition than a naturally regenerated birch stand. However, if there is already a fully stocked young birch stand on the site, it is more economical to let it grow using a shortish rotation time.

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  • Keltikangas, ORCID ID:E-mail:
  • Seppälä, ORCID ID:E-mail:
article id 4930, category Article
Tapio Lehtiniemi. (1976). Ionisoivan säteilyn vaikutus varastokuivien ja liotettujen metsäpuiden siementen idäntään ja taimien alkukehitykseen. Silva Fennica vol. 10 no. 1 article id 4930. https://doi.org/10.14214/sf.a14772
English title: Effect of ionizing radiation on the germination of storage-dry and soaked forest tree seeds and on the initial development of seedlings.

The study was carried out in order to find out the changes taking place in germination of seeds in certain tree species as a function of gamma irradiation, the height growth of the seedlings produced and the types of phenotypic mutants possibly found in the generation that had received radiation. The tree species studied were Pinus sylvestris L., Picea abies (L.) H. Karst., Betula verrucosa (Betula pendula Roth), B. Pubescens Ehrh., Alnus glutinosa (L.) Gaertn. and Alnus incana (L.) Moench.

Soaked seeds that had received a rather small dose of radiation germinated usually better than storage-dry seeds, B. pubescens being an exception. The damages observed in germination, height growth and the relative number of mutants were greater the higher the irradiation doses. The LD50 dose (germination, 28 days) was as follows in the case of the different tree species (storage dry/soaked): P. Sylvestris 1,500-2,000/2500-3,000, P. abies 1,000-1,500/4,000-4,500, B. pendula 9,500-10,000/7,000-7,500, B. pubescens >10,000/7,500-8,000 and A. Glutinosa 10,000/8,500-9,000 rad. Mass production of different mutants of deciduous trees for ornamental purposes, for example, appears to be easy using gamma-irradiation. On the other hand, the possibility of increasing tree growth remains open for further study.

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  • Lehtiniemi, ORCID ID:E-mail:
article id 4930, category Article
Tapio Lehtiniemi. (1976). Ionisoivan säteilyn vaikutus varastokuivien ja liotettujen metsäpuiden siementen idäntään ja taimien alkukehitykseen. Silva Fennica vol. 10 no. 1 article id 4930. https://doi.org/10.14214/sf.a14772
English title: Effect of ionizing radiation on the germination of storage-dry and soaked forest tree seeds and on the initial development of seedlings.

The study was carried out in order to find out the changes taking place in germination of seeds in certain tree species as a function of gamma irradiation, the height growth of the seedlings produced and the types of phenotypic mutants possibly found in the generation that had received radiation. The tree species studied were Pinus sylvestris L., Picea abies (L.) H. Karst., Betula verrucosa (Betula pendula Roth), B. Pubescens Ehrh., Alnus glutinosa (L.) Gaertn. and Alnus incana (L.) Moench.

Soaked seeds that had received a rather small dose of radiation germinated usually better than storage-dry seeds, B. pubescens being an exception. The damages observed in germination, height growth and the relative number of mutants were greater the higher the irradiation doses. The LD50 dose (germination, 28 days) was as follows in the case of the different tree species (storage dry/soaked): P. Sylvestris 1,500-2,000/2500-3,000, P. abies 1,000-1,500/4,000-4,500, B. pendula 9,500-10,000/7,000-7,500, B. pubescens >10,000/7,500-8,000 and A. Glutinosa 10,000/8,500-9,000 rad. Mass production of different mutants of deciduous trees for ornamental purposes, for example, appears to be easy using gamma-irradiation. On the other hand, the possibility of increasing tree growth remains open for further study.

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  • Lehtiniemi, ORCID ID:E-mail:
article id 4924, category Article
Teklé Kapustinskaité. (1975). Puuston kasvu ja turpeen tuhkapitoisuus ojitetuilla soilla. Silva Fennica vol. 9 no. 3 article id 4924. https://doi.org/10.14214/sf.a14766
English title: Ash content of peatland soils and stand growth in connection with drainage.

The ash content has been found to correlate with the fertility of peatlands. Relationship between height of 80-year-old stands and ash content of peat in topmost 30 cm layer was examined in Lithuanian conditions. On drained peatlands with ash content of peat from 3% to 8% pine stands increase in height. Ash content of peat being about 7% Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies (L.) H. Karst.) stands on drained sites are found to be of equal height. Ash content of peat more than 8–9% has no significant effect on growth of pine or spruce stands. Birch (Betula verrucosa (B. Pendula Roth.) and Betula pubescens Erhrh.), stands are less sensitive to ash content of peat compared with other species. Black alder (Alnus glutinosa L. Gaertn.) stands occurred in sites with ash content of peat more than 8–10%. The height of the stands become equal both in drained and undrained sites in the cases where ash content of peat is about 16–18%. Ash (Fraxinus exelsior L.) stands attain high productivity on drained sites with ash content of peat about 20%.

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  • Kapustinskaité, ORCID ID:E-mail:
article id 4924, category Article
Teklé Kapustinskaité. (1975). Puuston kasvu ja turpeen tuhkapitoisuus ojitetuilla soilla. Silva Fennica vol. 9 no. 3 article id 4924. https://doi.org/10.14214/sf.a14766
English title: Ash content of peatland soils and stand growth in connection with drainage.

The ash content has been found to correlate with the fertility of peatlands. Relationship between height of 80-year-old stands and ash content of peat in topmost 30 cm layer was examined in Lithuanian conditions. On drained peatlands with ash content of peat from 3% to 8% pine stands increase in height. Ash content of peat being about 7% Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies (L.) H. Karst.) stands on drained sites are found to be of equal height. Ash content of peat more than 8–9% has no significant effect on growth of pine or spruce stands. Birch (Betula verrucosa (B. Pendula Roth.) and Betula pubescens Erhrh.), stands are less sensitive to ash content of peat compared with other species. Black alder (Alnus glutinosa L. Gaertn.) stands occurred in sites with ash content of peat more than 8–10%. The height of the stands become equal both in drained and undrained sites in the cases where ash content of peat is about 16–18%. Ash (Fraxinus exelsior L.) stands attain high productivity on drained sites with ash content of peat about 20%.

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  • Kapustinskaité, 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.

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  • Kärkkäinen, ORCID ID:E-mail:
article id 4876, category Article
Tapio Lehtiniemi, Juhani Sarasto. (1973). Kokemuksia rauduksen istutuksesta ojitetuille soille. Silva Fennica vol. 7 no. 1 article id 4876. https://doi.org/10.14214/sf.a14706
English title: Betula verrucosa plantations on peat.

The aim of the present study was to assess whether two-year old Betula verrucosa Ehrh. (now Betula pendula Roth.) transplants can be used in afforestation of drained peatlands and what factors affect the development of the young trees. The seedlings were planted in 1967. The site was repair planted next spring due to mortality caused by a undefined fungal disease, and the plantations were fertilized with NPK fertilizer (soil application. The seedlings were measured twice a year until the autumn 1970.

Only 28% of the original transplants, and 73.4% of the repair plantations were alive in 1970. In some cases, fertilization improved the results, while in others it was detrimental to the trees or had no effect on survival. According to peat analysis, the poor survival and development of the plants could be due to the too high ratios of N/Ca and N/P. Stunted or dead trees displayed often necrosis caused by Godronia multispora. According to the experiences, Betula verrucosa plantations are inferior to those obtained with Scots pine (Pinus sylvestris L.). In addition, the results indicate that in old draining areas calcium and phosphorus are often too low in comparison to nitrogen.

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  • Lehtiniemi, ORCID ID:E-mail:
  • Sarasto, ORCID ID:E-mail:
article id 4876, category Article
Tapio Lehtiniemi, Juhani Sarasto. (1973). Kokemuksia rauduksen istutuksesta ojitetuille soille. Silva Fennica vol. 7 no. 1 article id 4876. https://doi.org/10.14214/sf.a14706
English title: Betula verrucosa plantations on peat.

The aim of the present study was to assess whether two-year old Betula verrucosa Ehrh. (now Betula pendula Roth.) transplants can be used in afforestation of drained peatlands and what factors affect the development of the young trees. The seedlings were planted in 1967. The site was repair planted next spring due to mortality caused by a undefined fungal disease, and the plantations were fertilized with NPK fertilizer (soil application. The seedlings were measured twice a year until the autumn 1970.

Only 28% of the original transplants, and 73.4% of the repair plantations were alive in 1970. In some cases, fertilization improved the results, while in others it was detrimental to the trees or had no effect on survival. According to peat analysis, the poor survival and development of the plants could be due to the too high ratios of N/Ca and N/P. Stunted or dead trees displayed often necrosis caused by Godronia multispora. According to the experiences, Betula verrucosa plantations are inferior to those obtained with Scots pine (Pinus sylvestris L.). In addition, the results indicate that in old draining areas calcium and phosphorus are often too low in comparison to nitrogen.

The PDF includes a summary in English.

  • Lehtiniemi, ORCID ID:E-mail:
  • Sarasto, ORCID ID:E-mail:
article id 4784, category Article
Matti Leikola, Pentti Pylkkö. (1969). Verhopuuston tiheyden vaikutus metsikön minimilämpötiloihin hallaöinä. Silva Fennica vol. 3 no. 1 article id 4784. https://doi.org/10.14214/sf.a14570
English title: Influence of stand density on the minimum temperatures during frost nights.

The objective of this investigation was to study the influence of stand density of white birch (Betula pubescens Ehrl.) on the minimum temperatures in the stand during the growing season, and the actual minimum temperatures of the leading shoot of Norway spruce (Picea abies (L.) H. Karst.) seedlings growing in the open. The 40-year-old uniform white birch stand was situated in 142 m above the sea level in Southern Finland. The stand was treated with thinnings of three different densities in 1961.

Air temperature was recorded in four sample plots at heights of 0.1 m, 0.5 m, 1.0 m, 2 m and 4 m. In the stand of moderate density, temperatures were measured at heights of 6.0 m, and in the stand of full density at 6.0 m, 8.0 m and 10.0 m.

The temperature differences between stands of various densities proved to be rather small. Especially the thinnest stand differed very little from the open area. The soil surface has in all cases been warm compared with the higher air layers indicating meadow-fog-type by Geier (1965). On cloudy or windy weather all the temperature profiles in the various stands resembled each other. The difference between the air temperature and temperature of the spruce shoot was greatest at midnight and decreased steadily thereafter.

The problem in using shelter stands for spruce regeneration areas is that optimum shelter stand density is difficult to define. Already a thin shelter stand causes drawbacks to the young seedlings, but in order to be effective enough against early frosts, the shelter stand should be comparatively dense.

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  • Leikola, ORCID ID:E-mail:
  • Pylkkö, ORCID ID:E-mail:
article id 4745, category Article
Ilmari Schalin. (1967). Microfungi in the humus layer of pine, spruce and birch stands in southern Finland. Silva Fennica vol. 1 no. 2 article id 4745. https://doi.org/10.14214/sf.a14455

This study elucidates the composition of the microfungal populations of the humus layer of tree forest types – Vaccinium type with Scots pine (Pinus sylvestris L.), Myrtillus type with Norway spruce (Picea abies (L.) H. Karst.) and Oxalis-Myrtillus type with birch (Betula sp.). The results indicate that the microfungi encountered in these sites bear close resemblances. The number of species increased but little towards the more fertile sites from VT to OMT. The main difference was limited to the quantitative relationships between the species.

The microfungal density in the humus layer was greatest in VT, and only slightly less in MT and OMT, in this order. In all the sampling areas, occurrence of the microfungi reached a maximum in the middle of summer, at a time when the maximum temperatures were registered in the humus. The quantitative abundance during the early autumn bears a relation to the yield of litter.

The microfungi most commonly encountered in all sampling areas were those of rapid growth, Mucor, Morierella and Penicillium species, along with Trichoderma, a little slower in growth, and actively decomposing cellulose. Mucor fungi, favouring moisture, were most abundant in the early summer and in the autumn. The Mortierella and Penicillium species, which survive dryness, were most abundant in the middle of the summer. The former is twice as common in MT and OMT than in VT, and the latter twice as common in VT as in OMT.

Scopulariopsis and Verticillium species were found regularly in MT and OMT. One Acremonium species was found almost exclusively in VT, and some Aspergillus and Mycogene in OMT alone. Sterilia mycelia was relatively abundant in MT and OMT in particular. Different kinds of yeast fungi were encountered generally in MT and OMT.

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  • Schalin, ORCID ID:E-mail:
article id 7523, category Article
Alpo Luomajoki. (1999). Differences in the climatic adaptation of silver birch (Betula pendula) and downy birch (B. pubescens) in Finland based on male flowering phenology. Acta Forestalia Fennica no. 263 article id 7523. https://doi.org/10.14214/aff.7523

Male flowering was studied at the canopy level in 10 silver birch (Betula pendula Roth) stands from 8 localities and 14 downy birch (B. pubescens Ehrh.) stands from 10 localities in Finland in 1963–73. Distribution of cumulative pollen catches was compared to the normal Gaussian distribution. The basis for timing of flowering was the 50% point of the anthesis-fitted normal distribution. To eliminate effects of background pollen, only the central, normally distributed part of the cumulative distribution was used. Development was measured and tested in calendar days, in degree days (> 5°C) and in period units. The count of the parameters began in March 19.

Male flowering in silver birch occurred from late April to late June depending on latitude, and flowering in downy birch took place from early May to early July. The heat sums needed for male flowering varied in downy birch stands latitudinally but there was practically no latitudinal variation in silver birch flowering. The amount of male flowering in stands of the both species were found to have a large annual variation but without any clear periodicity.

The between years pollen catch variation in stands of either birch species did not show any significant latitudinal correlation in contrast to Norway spruce stands. The period unit heat sum gave the most accurate forecast of the timing of flowering for 60% of the silver birch stands and for 78.6% of the downy birch stands. Silver birch seems to have a local inclination for a more fixed flowering date compared to downy birch, which could mean a considerable photoperiodic influence on flowering time of silver birch. The species had different geographical correlations.

Frequent hybridization of the birch species occurs more often in Northern Finland than in more southerly latitudes. The different timing in the flowering causes increasing scatter in flowering times in the north, especially in the case of downy birch. Thus, the change of simultaneous flowering of the species increases northwards due to a more variable climate and higher altitudinal variation. Compared with conifers, the reproduction cycles of the two birch species were found to be well protected from damage by frost.

  • Luomajoki, ORCID ID:E-mail:
article id 7523, category Article
Alpo Luomajoki. (1999). Differences in the climatic adaptation of silver birch (Betula pendula) and downy birch (B. pubescens) in Finland based on male flowering phenology. Acta Forestalia Fennica no. 263 article id 7523. https://doi.org/10.14214/aff.7523

Male flowering was studied at the canopy level in 10 silver birch (Betula pendula Roth) stands from 8 localities and 14 downy birch (B. pubescens Ehrh.) stands from 10 localities in Finland in 1963–73. Distribution of cumulative pollen catches was compared to the normal Gaussian distribution. The basis for timing of flowering was the 50% point of the anthesis-fitted normal distribution. To eliminate effects of background pollen, only the central, normally distributed part of the cumulative distribution was used. Development was measured and tested in calendar days, in degree days (> 5°C) and in period units. The count of the parameters began in March 19.

Male flowering in silver birch occurred from late April to late June depending on latitude, and flowering in downy birch took place from early May to early July. The heat sums needed for male flowering varied in downy birch stands latitudinally but there was practically no latitudinal variation in silver birch flowering. The amount of male flowering in stands of the both species were found to have a large annual variation but without any clear periodicity.

The between years pollen catch variation in stands of either birch species did not show any significant latitudinal correlation in contrast to Norway spruce stands. The period unit heat sum gave the most accurate forecast of the timing of flowering for 60% of the silver birch stands and for 78.6% of the downy birch stands. Silver birch seems to have a local inclination for a more fixed flowering date compared to downy birch, which could mean a considerable photoperiodic influence on flowering time of silver birch. The species had different geographical correlations.

Frequent hybridization of the birch species occurs more often in Northern Finland than in more southerly latitudes. The different timing in the flowering causes increasing scatter in flowering times in the north, especially in the case of downy birch. Thus, the change of simultaneous flowering of the species increases northwards due to a more variable climate and higher altitudinal variation. Compared with conifers, the reproduction cycles of the two birch species were found to be well protected from damage by frost.

  • Luomajoki, ORCID ID:E-mail:
article id 7657, category Article
Matti Rousi. (1990). Breeding forest trees for resistance to mammalian herbivores - a study based on European white birch. Acta Forestalia Fennica no. 210 article id 7657. https://doi.org/10.14214/aff.7657

Resistance to browsing by mammals differs among birch species, and among origins and families of European white birch (Betula pendula Roth). The variation in resistance is large even among individual seedlings of the same family.

On the surface of the bark of European white birch seedlings there are resin droplets, and the number of droplets is strongly and positively correlated with resistance to browsing by hares. The resistance of European white birch apparently is not expensive metabolically because the rapid growth rate of seedlings was positively correlated with hare resistance, and no correlation was found between seedling size and vole resistance. In cafeteria experiments voles and hares were very discriminating in their feeding on birch seedlings. In field experiments, however, environmental heterogeneity partly masked differences in vole resistance among birch families. Fertilization of seedlings seems not to have a clear effect on resistance to hares. On the other hand, there were indications that greenhouse temperature had an effect on resistance to voles. Practical forestry applications of differences in resistance, e.g. use of species hybrids and clonal forestry, are discussed. The prospects for resistance breeding are good.

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  • Rousi, ORCID ID:E-mail:
article id 7657, category Article
Matti Rousi. (1990). Breeding forest trees for resistance to mammalian herbivores - a study based on European white birch. Acta Forestalia Fennica no. 210 article id 7657. https://doi.org/10.14214/aff.7657

Resistance to browsing by mammals differs among birch species, and among origins and families of European white birch (Betula pendula Roth). The variation in resistance is large even among individual seedlings of the same family.

On the surface of the bark of European white birch seedlings there are resin droplets, and the number of droplets is strongly and positively correlated with resistance to browsing by hares. The resistance of European white birch apparently is not expensive metabolically because the rapid growth rate of seedlings was positively correlated with hare resistance, and no correlation was found between seedling size and vole resistance. In cafeteria experiments voles and hares were very discriminating in their feeding on birch seedlings. In field experiments, however, environmental heterogeneity partly masked differences in vole resistance among birch families. Fertilization of seedlings seems not to have a clear effect on resistance to hares. On the other hand, there were indications that greenhouse temperature had an effect on resistance to voles. Practical forestry applications of differences in resistance, e.g. use of species hybrids and clonal forestry, are discussed. The prospects for resistance breeding are good.

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  • Rousi, ORCID ID:E-mail:
article id 7655, category Article
Leena Finér. (1989). Biomass and nutrient cycle in fertilized and unfertilized pine, mixed birch and pine and spruce stands on a drained mire. Acta Forestalia Fennica no. 208 article id 7655. https://doi.org/10.14214/aff.7655

At the beginning of the investigation period the total biomass of the Scots pine (Pinus sylvestris L.) stands on the ordinary sedge pine mire was 48 t/ha. The biomass of the mixed stands of Scots pine and birch (Betula pubescens Erhr.) on the herbrich sedge pine mire was 91 t/ha, out of which 60% was from pine. The biomass of the Norway spruce (Picea abies (L.) H. Karst.) on the Vaccinium-Myrtillus spruce mire was 148 t/ha. The average annual net increment of the stand biomass was 5.8 t/ha in the unfertilized pine stand and 6.7 t/ha in the NPK and micronutrient fertilized one during the six-year investigation period. The corresponding figures in the mixed stand were 7.2 t/ha and 7.6 t/ha. The net increment of the biomass in the unfertilized spruce stand was 6.9 t/ha and in the fertilized 8.4 t/ha. A considerable proportion of the net increment was lost to the ground as litter in all stands.

The nitrogen, phosphorus, potassium, magnesium, iron, manganese, zinc, copper and boron cycles were investigated. The annual nitrogen uptake from the soil was 26–42 kg/ha, that of phosphorus 2.5–3.4 kg/ha, potassium 4.5–12 kg/ha, calcium 12–29 kg/ha, magnesium 2–4 kg/ha, iron 1.4–6.6 kg/ha, manganese less than 2 kg/ha and the other nutrients only some grams. Only part of the fertilized nutrients was fixed in the stand.

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  • Finér, ORCID ID:E-mail:
article id 7575, category Article
Robert T Brown, Peitsa Mikola. (1974). The influence of fruticose soil lichens upon the mycorrhizae and seedling growth of forest trees. Acta Forestalia Fennica no. 141 article id 7575. https://doi.org/10.14214/aff.7575

Water extracts of six common soil lichens, Cladonia alpestris, C. rangiferina, C. arbuscula (sylvatica), C. pleurota, Cetraria islandica, Stereocaulon paschale, inhibited growth of ectomycorrhizae of Pinus sylvestris (L.). Of 17 fungi (12 mycorrhizal) tested, many were inhibited while others were scarcely influenced or even occasionally stimulated by the extracts. Cladonia alpestris extract inhibited most fungi while C. rangiferina showed much less influence.

In pure culture synthesis experiments, 32P uptake of Pinus sylvestris was significantly reduced by C. alpestris extract. Different species of fungi showed widely variant abilities to pick up 32 P. in nursery experiments, much more vigorous growth of P. sylvestris and Picea abies (L.) H. Karst. was obtained on plots without C. alpestris than on paired plots covered with it. Betula verrucosa (B. pendula Roth) showed no difference. Under natural forest conditions, P. sylvestris seedlings grow much more rapidly where C. alpestris had been eliminated by road building or reindeer grazing than do seedlings only one meter distant under undisturbed C. alpestris cover. It is suggested that by properly controlled reindeer grazing, establishment and early growth of P. sylvestris on Cladonia sites can be much enhanced. By the time that C. alpestris could become re-established the pine seedlings would have grown large enough to suffer little from reindeer grazing. This study shows the continuity of the major components of the forest tundra biome – the dependence of pines, mycorrhizae, lichens, and reindeer and their predators (human or otherwise) upon each other for a healthy existence.

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  • Brown, ORCID ID:E-mail:
  • Mikola, ORCID ID:E-mail:
article id 7610, category Article
Matti Leikola. (1969). The influence of environmental factors on the diameter growth of forest trees : Auxanometric study. Acta Forestalia Fennica no. 92 article id 7610. https://doi.org/10.14214/aff.7610

The influence of various environmental factors on the diameter growth of trees has been studied based on data collected by following daily increment of trees and various environmental factors during the growing season in 1964–1967. The field work was carried out in two experimental stands, a Scots pine (Pinus sylvestris L.) stand and a mixed stands growing birch (Betula sp.), Norway spruce (Picea abies (L.) H. Karst.) and Scots pine, in Southern Finland.

The results show that the temperature sums preceding the beginning of diameter growth were of the same magnitude in the years studied, which indicates dependence in the relationship. Formation of new xylem cells took place in the pine stem ca. every third day when the diameter growth was most active. No summer growth inhibition was detected in diameter growth.

None of the cumulative temperature sums tried determined the time of cessation of diameter growth. In several cases, positive correlation was found between the length of the growing season and the width of the annual ring formed. When studying the relationships between the diameter increment and the environmental factors, it was found that diameter increment was totally masked in the records by the hydrostatic changes in the stem. Relationships between the diameter increment and the environmental factors of the second day preceding growth were found to be poor. In studying the deviations of the recorded daily increments from the regression surface, no clear general trend was seen for pine and spruce, but clear diminishing trend toward the end og the growing season could be seen for birch in 1967.

  • Leikola, ORCID ID:E-mail:
article id 4732, category Article
Juhani Päivänen. (1966). Sateen jakaantuminen erilaisissa metsiköissä. Silva Fennica no. 119 article id 4732. https://doi.org/10.14214/sf.a14290
English title: Distribution of rainfall in different types of forest stands.

Stand precipitation and stemflow studies became necessary in connection with hydrologic studies, for instance, to explain the deviations resulting from rains in the ratios between the water content of peat and the groundwater level, throughfall during rains of variable heaviness, and effect of stand treatment on soil moisture level. In this project the distribution of rainfall in stands differing in species composition and density was studied in Central Finland in 1963–1965 in fifteen stand precipitation sample plots. In addition, rain gauges were situated under individual Scots pine (Pinus sylvestris L.), Norway spruce (Picea abies (L.) H. Karst.) and birch (Betula sp.) trees.

The average precipitation in the open was 4.8 mm, the corresponding precipitation in the stand was 77% for birch, 71% for pine and 62% for spruce. Measurements of stemflow from individual sample trees showed that less than ¼ mm (about 1.5%) during a 15 mm rain in a pine stand. In the spruce stands stemflow is negligible. A part of the sample plots was in drained peatlands with a dense vegetation of small shrubs. The shrub layer retention was about 10% even during heavy rain. In a small forest clearing, the bordering effect of the forest was seen up to the distance of 5 metres from the edge of the forest. During the period of study, on an average 3% more precipitation was recorded in the clearing than in the open, the difference being probably due to the stronger wind effect in the open.

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  • Päivänen, ORCID ID:E-mail:
article id 4730, category Article
Erkki Lähde. (1966). Kokeita selluloosan hajaantumisnopeudesta erilaisissa metsiköissä. Silva Fennica no. 119 article id 4730. https://doi.org/10.14214/sf.a14288
English title: Experiments on the decomposition rate of cellulose in different stands.

The aim of this project was to investigate the cellulose decomposition rate in the soil on the ecological conditions created by different tree species, particularly birch (Betula sp.) and Norway spruce (Picea abies (L.) H. Karst.). Therefore, comparable sample plots were established in adjoining birch and spruce stands. Data on the stands, the vegetation, and the soil in the sample plots were collected. The experiment was carried out in the Ruotsinkylä Experimental Forest near Helsinki in Southern Finland.

Five pieces (3x5x0.15 cm) of cellulose (bleached sulphite pulp) were dried, weighed, and fastened in a row into a nylon bag. The bags were placed into the soil at a slant so that the upmost piece of cellulose was in the depth of 0–1.5 cm and the bottom one 6–7.5 cm. The weight losses of the pieces were measured after periods ranging from 6 to 12 months.

The results show that even within the same forest type, decomposition is much more rapid in birch stands than in spruce stands. In all the stands the decomposition rate decreased rapidly with increasing depth. The difference between birch and spruce stand, as well as the decrease with increasing depth, was probably mainly due to different thermal conditions.

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  • Lähde, ORCID ID:E-mail:
article id 4652, category Article
Kullervo Kuusela. (1956). Hakkuilla käsiteltyjen koivikoiden rakenteesta ja kasvusta. Silva Fennica no. 90 article id 4652. https://doi.org/10.14214/sf.a9115
English title: On the structure and growth of birch stands treated with cutting.

The study is continuation of the earlier structure and growth studies of Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies (L.) H. Karst.) in Forest Research Institute. The material represents birch stands (Betula verrucosa, now B. pendula, and B. Pubescens L.) in Southern Finland. The stands were treated with different fellings, and in regard to their silvicultural condition classified as good, satisfactory and unsatisfactory. Height of the trees, height of living crown, volume, increment and volume increment and development of stem diameter series was measured.

The most characteristic difference between the silviculturally good and poor stands was that the the annual increment of the good stands concentrated into large size trees, and the increment of unsatisfactory stands into small and inferior trees.

It is concluded that if the aim of stand treatment is to produce large and high quality volume increment, the most favourable stand volume of  birch stands, compared with naturally normal stand volume, seems to be 90-85% at the age of 41-55 years, and 80-70% at the age of 56-65 years. If growth of large size trees is aimed at, the maximum number of the dominant trees per hectares cannot be more than 400 at the age of 50-60 years.

The article includes a summary in English.

  • Kuusela, ORCID ID:E-mail:
article id 4652, category Article
Kullervo Kuusela. (1956). Hakkuilla käsiteltyjen koivikoiden rakenteesta ja kasvusta. Silva Fennica no. 90 article id 4652. https://doi.org/10.14214/sf.a9115
English title: On the structure and growth of birch stands treated with cutting.

The study is continuation of the earlier structure and growth studies of Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies (L.) H. Karst.) in Forest Research Institute. The material represents birch stands (Betula verrucosa, now B. pendula, and B. Pubescens L.) in Southern Finland. The stands were treated with different fellings, and in regard to their silvicultural condition classified as good, satisfactory and unsatisfactory. Height of the trees, height of living crown, volume, increment and volume increment and development of stem diameter series was measured.

The most characteristic difference between the silviculturally good and poor stands was that the the annual increment of the good stands concentrated into large size trees, and the increment of unsatisfactory stands into small and inferior trees.

It is concluded that if the aim of stand treatment is to produce large and high quality volume increment, the most favourable stand volume of  birch stands, compared with naturally normal stand volume, seems to be 90-85% at the age of 41-55 years, and 80-70% at the age of 56-65 years. If growth of large size trees is aimed at, the maximum number of the dominant trees per hectares cannot be more than 400 at the age of 50-60 years.

The article includes a summary in English.

  • Kuusela, ORCID ID:E-mail:
article id 4652, category Article
Kullervo Kuusela. (1956). Hakkuilla käsiteltyjen koivikoiden rakenteesta ja kasvusta. Silva Fennica no. 90 article id 4652. https://doi.org/10.14214/sf.a9115
English title: On the structure and growth of birch stands treated with cutting.

The study is continuation of the earlier structure and growth studies of Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies (L.) H. Karst.) in Forest Research Institute. The material represents birch stands (Betula verrucosa, now B. pendula, and B. Pubescens L.) in Southern Finland. The stands were treated with different fellings, and in regard to their silvicultural condition classified as good, satisfactory and unsatisfactory. Height of the trees, height of living crown, volume, increment and volume increment and development of stem diameter series was measured.

The most characteristic difference between the silviculturally good and poor stands was that the the annual increment of the good stands concentrated into large size trees, and the increment of unsatisfactory stands into small and inferior trees.

It is concluded that if the aim of stand treatment is to produce large and high quality volume increment, the most favourable stand volume of  birch stands, compared with naturally normal stand volume, seems to be 90-85% at the age of 41-55 years, and 80-70% at the age of 56-65 years. If growth of large size trees is aimed at, the maximum number of the dominant trees per hectares cannot be more than 400 at the age of 50-60 years.

The article includes a summary in English.

  • Kuusela, ORCID ID:E-mail:
article id 4652, category Article
Kullervo Kuusela. (1956). Hakkuilla käsiteltyjen koivikoiden rakenteesta ja kasvusta. Silva Fennica no. 90 article id 4652. https://doi.org/10.14214/sf.a9115
English title: On the structure and growth of birch stands treated with cutting.

The study is continuation of the earlier structure and growth studies of Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies (L.) H. Karst.) in Forest Research Institute. The material represents birch stands (Betula verrucosa, now B. pendula, and B. Pubescens L.) in Southern Finland. The stands were treated with different fellings, and in regard to their silvicultural condition classified as good, satisfactory and unsatisfactory. Height of the trees, height of living crown, volume, increment and volume increment and development of stem diameter series was measured.

The most characteristic difference between the silviculturally good and poor stands was that the the annual increment of the good stands concentrated into large size trees, and the increment of unsatisfactory stands into small and inferior trees.

It is concluded that if the aim of stand treatment is to produce large and high quality volume increment, the most favourable stand volume of  birch stands, compared with naturally normal stand volume, seems to be 90-85% at the age of 41-55 years, and 80-70% at the age of 56-65 years. If growth of large size trees is aimed at, the maximum number of the dominant trees per hectares cannot be more than 400 at the age of 50-60 years.

The article includes a summary in English.

  • Kuusela, ORCID ID:E-mail:
article id 4644, category Article
Vilho Antero Kolehmainen. (1955). Havaintoja kulotuksen merkityksestä metsiemme uudistamisessa. Silva Fennica no. 85 article id 4644. https://doi.org/10.14214/sf.a9106
English title: Effect of prescribed burning in the forest regeneration.

Prescribed burning has reported to avail forest regeneration, for instance, by releasing nutrients for the use of seedlings, changing the pH of the soil and decreasing competition of ground vegetation. The aim of the study was to find out if the effects could be verified. Sample plots were measured in the experimental area of Tuomarniemi, in Central Finland, both in previously burned and untreated seedling stands and young forests. The main species in the sample plots was Scots pine (Pinus sylvestris L.).

According to the results, prescribed burning prepares the soil for regeneration. Germination percentage of the seeds is higher on the burned soil. All the species, Scots pine, Norway spruce (Picea abies (L.) Karst.) and birch species (Betula sp.) grow faster. Prescribed burning increases the amount of birch seedlings by improving its regeneration compared to unburned sites. The seed trees survive burning better if they are tall and have short crown, and have thick bark. In general, prescribed burning improves regeneration in seed tree stands.

The article includes a summary in German.

  • Kolehmainen, ORCID ID:E-mail:
article id 4579, category Article
Reino Kalliola. (1942). Pyhätunturin kansallispuiston kasvillisuudesta ja kasvistosta. Silva Fennica no. 59 article id 4579. https://doi.org/10.14214/sf.a9083
English title: Vegetation and flora in the Pyhätunturi National Park.

The article is based on the writer’s visits in the area in 1933 and 1939. Pyhätunturi national park was established in 1938. The fell of Pyhätunturi rises up to 540 meters above the sea level, and 357 meters above the surrounding area. The soil is predominantly stony, and the rock is quartzite. The climate is continental with low rainfall. This results in a barren area, where array of plant species is limited with the exception of few gorges with fertile river valleys. The forests have remained mostly in natural state.

Vegetation is arranged in three zones: forested area, subalpine fell birch area and alpine bare top of the fell. Scots pine (Pinus sylvestris L.) forms timberline more often than Norway spruce (Picea abies (L.) H. Karst.). Coniferous forests rise up to 365 meters on the northern slopes and up to about 385 on the southern slopes of the fell. It is followed by fell birch zone (Betula tortuosa, now Betula pubescens subsp. Czerepanovii) up to about 450-475 meters on the eastern and northern slopes, and 475-490 meters on the western slopes. The most common forest site type is Empetrum-Myrtillus site type. Herb-rich spruce swamps along the rivers have highest diversity of species. The article describes the plant species found in forests, peatlands, fell birch zone and top of the fell in detail. In all 162 different vascular plant species and 16 non-indigenous species were found in the area.

The article includes an abstract in German.

  • Kalliola, ORCID ID:E-mail:
article id 4569, category Article
Martti Tertti. (1939). Näkökohtia kuusimetsän hoidosta. Silva Fennica no. 52 article id 4569. https://doi.org/10.14214/sf.a13976
English title: Forest management of Norway spruce forests.

Silva Fennica issue 52 includes presentations held in professional development courses, arranged for foresters working in public administration in 1938. The presentations focus on practical issues in forest management and administration, especially in regional level. The education was arranged by Forest Service.

This presentation describes different types of fellings in Norway spruce (Picea abies (L.) H. Karst.) forests in different forest site types. The use of thinning from below and above, clear cutting of Norway spruce stands, and thinning of mixed forests with birch (Betula sp.) are discussed.

  • Tertti, ORCID ID:E-mail:

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