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Silva Fennica 1926-1997
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Acta Forestalia Fennica
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Articles containing the keyword 'silver birch'.

Category: Research article

article id 10052, category Research article
Pentti Niemistö, Harri Kilpeläinen, Henrik Heräjärvi. (2019). Effect of pruning season and tool on knot occlusion and stem discolouration in Betula pendula – situation five years after pruning. Silva Fennica vol. 53 no. 1 article id 10052. https://doi.org/10.14214/sf.10052
Highlights: The occlusion was the fastest in the case of small living branches of fast growing trees pruned in springtime; Occlusion was quicker after saw pruning than after secateurs pruning, due to shorter knot stubs; Branches that were pruned in living state occluded faster than the ones pruned as dead; Dead branches hit down with a stick occluded slowly.

This paper investigates and models the effects of pruning season and tool on wound occlusion with varying tree and branch characteristics of silver birch (Betula pendula Roth) stems at the pruning height of 0−4 metres. Dates of eight secateurs prunings, three saw prunings and two sticks prunings as well as unpruned control were tested in permanent plots on four sites. Knot occlusion and discolouration in stemwood were measured from about 1600 studied knots of 112 sample trees felled five to six years after pruning in 2010. Knot occlusion rate was modelled according to pruning tool, date, tree growth, and branch characteristics. The occlusion was the fastest in trees pruned in spring or early summer, and the slowest in trees pruned in autumn. Stubs of living branches occluded faster than the dead ones with the same diameter. Saw pruning resulted in clearly better occlusion rates than secateurs pruning, caused by the shorter knot stubs after saw pruning. Hitting dead branches away with a stick resulted in the worst occlusion status. The colour defects spread more often upward from the knot than downward. Discolouration in stemwood was detected more frequently near to the pruned branches than the unpruned ones, and more widely near to the stubs of dead branches than the living ones. Most saw and secateurs pruned branches were completely occluded during the experiment, so these prunings were suitable for all branches under 20 mm in diameter, and for living branches even up to 30 mm in fast-growing trees.

  • Niemistö, Natural Resources Institute Finland (Luke), Natural resources, Kampusranta 9 C, FI-60320 Seinäjoki, Finland ORCID ID:E-mail: pentti.niemisto@luke.fi (email)
  • Kilpeläinen, Natural Resources Institute Finland (Luke), Production systems, Yliopistokatu 6 B, FI-80100 Joensuu, Finland ORCID ID:E-mail: harri.kilpelainen@luke.fi
  • Heräjärvi, Natural Resources Institute Finland (Luke), Production systems, Yliopistokatu 6 B, FI-80100 Joensuu, Finland ORCID ID:E-mail: henrik.herajarvi@luke.fi
article id 9985, category Research article
Antonín Martiník, Robert Knott, Jan Krejza, Jakub Černý. (2018). Biomass production of Betula pendula stands regenerated in the region of allochthonous Picea abies dieback. Silva Fennica vol. 52 no. 5 article id 9985. https://doi.org/10.14214/sf.9985
Highlights: Biomass equations for individual components of above-ground wood biomass estimation are presented for stands at the age of 4, 8, 17 and 22 years; Peak of the mean annual increment was found at the age from 15 to 20 years and reached over 5.0 t ha–1 y–1 of dry biomass; The share of the stem to the total biomass increased with stand age.

The paper deals with production of above-ground biomass of silver birch (Betula pendula Roth) stands in the Czech Republic. One-year biomass dynamics was studied within chronosequence of birch stands at the age of 4–5, 8–9, 17–18 and 22–23 years. With the exception of the youngest stand, which was established by seeding, all experimental birch stands were regenerated naturally after the allochthonous spruce stands. Above-ground biomass (AB) was calculated from plot inventory data and biomass equations were parameterized from destructive sampling of biomass component of sampled trees. Results reveal that the peak of the mean annual increment (MAIABtotal) of birch stands can be expected at the age from 15 to 20 years. Additionally, the stand age, the value of basal area (BA) should be considered as a predictor of stand productivity. If the value of BA varied from 25 to 35 m2 ha–1, the MAI of the birch stands reached the range from 5.0 to 6.5 t of dry biomass per ha y–1 at the age ranging between 15 and 25 years. The stem/branch proportion increased with stand age, the stem relative proportion ranging from 75 to 90% of total above-ground biomass. According to the results of this study, birch stand biomass production and utilization is one of the approaches in terms of forest recovery management in large disturbed areas. Although, no silvicultural treatments were occurred in all analysed stands, the pre-commercial thinning method could increase stand productivity and stability as well.

  • Martiník, Department of Silviculture, Faculty of Forestry and Wood Technology, Mendel University in Brno, 613 00 Brno, Czech Republic ORCID ID: https://orcid.org/0000-0002-5906-8830 E-mail: martinik@mendelu.cz (email)
  • Knott, Department of Silviculture, Faculty of Forestry and Wood Technology, Mendel University in Brno, 613 00 Brno, Czech Republic ORCID ID:E-mail: robert.knott@mendelu.cz
  • Krejza, Global Change Research Institute CAS, v.v.i., Bělidla 4a, 603 00 Brno, Czech Republic ORCID ID:E-mail: krejza.j@czechglobe.cz
  • Černý, The Forestry and Game Management Research Institute, Research Station at Opočno, Na Olivě 550, 517 73 Opočno, Czech Republic ORCID ID:E-mail: cerny@vulhmop.cz
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 1559, category Research article
Karol Bronisz, Mike Strub, Chris Cieszewski, Szymon Bijak, Agnieszka Bronisz, Robert Tomusiak, Rafał Wojtan, Michał Zasada. (2016). Empirical equations for estimating aboveground biomass of Betula pendula growing on former farmland in central Poland. Silva Fennica vol. 50 no. 4 article id 1559. https://doi.org/10.14214/sf.1559
Highlights: We developed equations for aboveground biomass components of young silver birch stands on post-agricultural lands in central Poland for single tree level; Simplified equations were based exclusively on diameter at ground level or breast height, while expanded ones were based on the appropriate diameter and tree height; For large trees, diameter at breast height is a more appropriate explanatory variable than diameter at ground level; Biomass estimations based on models from neighboring countries were consistent with our results.

We determined empirical models for estimating total aboveground as well as stem, branches, and foliage dry biomass of young (age up to 16 years) silver birch (Betula pendula Roth.) growing on the post-agricultural lands. Two sets of allometric models for trees with a height below or above 1.3 m (small and large trees respectively) were developed. Simplified models were elaborated based exclusively on appropriate tree diameter (diameter at ground level for small trees, diameter at breast height for large trees), while expanded models also included tree height. Total aboveground biomass was estimated as the sum of biomass of all tree components. To assure additivity of the developed equations, the seemingly unrelated regression approach for the final model fitting was used. Expanded models in both tree groups were characterized by a better fit to the data (R2 for total aboveground biomass for small and large trees equaled 0.8768 and 0.9752, respectively). Diameter at breast height appeared to be a better predictor than diameter at ground level – simplified models had better fit for large trees (R2 for total aboveground biomass equals 0.9611) than for small ones (R2 = 0.7516). The developed equations provide biomass predictions consistent with available Latvian, Estonian, Finnish, Swedish, and Norwegian models for silver birch.

  • Bronisz, Laboratory of Dendrometry and Forest Productivity, Faculty of Forestry, Warsaw University of Life Sciences – SGGW, Nowoursynowska 159, 02-787 Warsaw, Poland ORCID ID:E-mail: karol.bronisz@wl.sggw.pl (email)
  • Strub, Warnell School of Forestry and Natural Resources, University of Georgia, Athens, GA, 30605, USA ORCID ID:E-mail: strub@mcfns.com
  • Cieszewski, Warnell School of Forestry and Natural Resources, University of Georgia, Athens, GA, 30605, USA ORCID ID:E-mail: thebiomat@gmail.com
  • Bijak, Laboratory of Dendrometry and Forest Productivity, Faculty of Forestry, Warsaw University of Life Sciences – SGGW, Nowoursynowska 159, 02-787 Warsaw, Poland ORCID ID:E-mail: szymon.bijak@wl.sggw.pl
  • Bronisz, Laboratory of Dendrometry and Forest Productivity, Faculty of Forestry, Warsaw University of Life Sciences – SGGW, Nowoursynowska 159, 02-787 Warsaw, Poland ORCID ID:E-mail: agnieszka.bronisz@wl.sggw.pl
  • Tomusiak, Laboratory of Dendrometry and Forest Productivity, Faculty of Forestry, Warsaw University of Life Sciences – SGGW, Nowoursynowska 159, 02-787 Warsaw, Poland ORCID ID:E-mail: robert.tomusiak@wl.sggw.pl
  • Wojtan, Laboratory of Dendrometry and Forest Productivity, Faculty of Forestry, Warsaw University of Life Sciences – SGGW, Nowoursynowska 159, 02-787 Warsaw, Poland ORCID ID:E-mail: rafal.wojtan@wl.sggw.pl
  • Zasada, Laboratory of Dendrometry and Forest Productivity, Faculty of Forestry, Warsaw University of Life Sciences – SGGW, Nowoursynowska 159, 02-787 Warsaw, Poland ORCID ID:E-mail: michal.zasada@wl.sggw.pl
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 322, category Research article
Jaakko Repola. (2006). Models for vertical wood density of Scots pine, Norway spruce and birch stems, and their application to determine average wood density. Silva Fennica vol. 40 no. 4 article id 322. https://doi.org/10.14214/sf.322
The purpose of this study was to investigate the vertical dependence of the basic density of Scots pine, Norway spruce, and birch stems, and how such dependence could be applied for determining the average stem wood density. The study material consisted of 38 Scots pine (Pinus sylvestris), 39 Norway spruce (Picea abies [L.] Karst.) and 15 birch (Betula pendula and Betula pubescens) stands located on mineral soil sites in southern Finland. The stem material mainly represented thinning removal from stands at different stages of development. The linear mixed model technique, with both fixed and random effects, was used to estimate the model. According to the fixed part of the model, wood density was dependent on the vertical location along the stem in all three tree species. Wood density in pine decreased from the butt to the top, and the gradient in wood density was steep at the butt but decreased in the upper part of the stem. The vertical dependence was similar in birch, but the density gradient was much smaller. For spruce the vertical dependence of the basic density was moderate. The model can be calibrated for a tree stem when one or more sample disks are measured at freely selected heights. Using treewise calibrated predictions of the vertical density dependence and measured stem diameters, almost unbiased estimates, and lower prediction errors than with traditional methods, were obtained for the average stem wood density. The advantages of the method were greater for pine with a strong vertical dependence in basic density, than for spruce and birch.
  • Repola, Finnish Forest Research Institute, Rovaniemi Research Unit, Eteläranta 55, FI-96300 Rovaniemi, Finland ORCID ID:E-mail: jaakko.repola@metla.fi (email)
article id 581, category Research article
Henrik Heräjärvi. (2001). Technical properties of mature birch (Betula pendula and B. pubescens) for saw milling in Finland. Silva Fennica vol. 35 no. 4 article id 581. https://doi.org/10.14214/sf.581
The purpose of this study was to investigate the variation in selected technical properties of mature (age > 60 years) birch stems in southern and central Finland. Technical properties were defined as the natural external characteristics that cause differences in the usability of a certain section of stem in the mechanical wood industry, saw milling in particular. On mineral soils, birch stems in mixed stands were slightly larger than those in pure birch stands. On peatlands, however, birch stems in pure stands were larger than those in mixed stands. The average stem form of silver birch was straighter than that of white birch. Small-sized log sections of white birch, as well as those of codominant silver birch, typically contain many dead knots. On mineral soils, coniferous admixture had a positive effect on self-pruning of white birch. Self-pruning of silver birch was as good in pure birch stands as in mixed stands of spruce and birch. Occurrence of decay did not differ significantly between the two birch species. Not only silver birch, due to the growth and yield of the stand, but also vigorous and good-quality white birch, because of the possibility to provide high-quality logs, can be maintained profitably as an admixture in coniferous forests until final cutting.
  • Heräjärvi, The Finnish Forest Research Institute, Joensuu Research Centre, P.O. Box 68, FIN-80101 Joensuu, Finland ORCID ID:E-mail: henrik.herajarvi@metla.fi (email)

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 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 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 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 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 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 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 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 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 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.

The PDF includes a summary in Finnish.

  • Raulo, 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:

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