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Articles containing the keyword 'Betula spp'.

Category: Research article

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 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 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 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:

Category: Article

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 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:

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