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Silva Fennica 1926-1997
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Articles containing the keyword 'bark'.

Category: Research article

article id 9938, category Research article
Jyrki Hytönen, Egbert Beuker, Anneli Viherä-Aarnio. (2018). Clonal variation in basic density, moisture content and heating value of wood, bark and branches in hybrid aspen. Silva Fennica vol. 52 no. 2 article id 9938. https://doi.org/10.14214/sf.9938
Highlights: Hybrid aspen clones differed in their moisture content, ash content, basic density and heating value; Stem wood had lower ash content, basic density and effective heating value than stem bark; There was significant vertical variation in wood and bark along the stem in moisture content and basic density.

Hybrid aspen (Populus tremula × P. tremuloides) is one of the fastest growing tree species in Finland. During the mid-1990s, a breeding programme was started with the aim of selecting clones that were superior in producing pulpwood. Hybrid aspen can also be grown as a short-rotation crop for bioenergy. To study clonal variation in wood and bark properties, seven clones were selected from a 12-year-old field trial located in southern Finland. From each clone, five trees were harvested and samples were taken from stem wood, stem bark and branches to determine basic density, effective heating value, moisture and ash content. Vertical within-tree variation in moisture content and basic density was also studied. The differences between clones were significant for almost all studied properties. For all studied properties there was a significant difference between wood and bark. Wood had lower ash content (0.5% vs. 3.9%), basic density (378 kg m–3 vs. 450 kg m–3) and effective heating value (18.26 MJ kg–1 vs. 19.24 MJ kg–1), but higher moisture content (55% vs. 49%) than bark. The values for branches were intermediate. These results suggest that the properties of hybrid aspen important for energy use could be improved by clonal selection. However, selecting clones based on fast growth only may be challenging since it may lead to a decrease in hybrid aspen wood density.

  • Hytönen, Natural Resources Institute Finland (Luke), Natural resources, Teknologiakatu 7, FI-67100 Kokkola, Finland ORCID ID:E-mail: jyrki.hytonen@luke.fi (email)
  • Beuker, Natural Resources Institute Finland (Luke), Production systems, Vipusenkuja 6, FI-57200 Savonlinna, Finland ORCID ID:E-mail: egbert.beuker@luke.fi
  • Viherä-Aarnio, Natural Resources Institute Finland (Luke), Production systems, Latokartanonkaari 9, FI-00790 Helsinki, Finland ORCID ID:E-mail: anneli.vihera-aarnio@luke.fi
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 1713, category Research article
Lars-Göran Stener, Lars Rytter, Gunnar Jansson. (2017). Effects of pruning on wood properties of planted silver birch in southern Sweden. Silva Fennica vol. 51 no. 2 article id 1713. https://doi.org/10.14214/sf.1713
Highlights: Pruning silver birch trees increased the production of defect-free wood outside the knots; Most wood defects were found inside the knots; Pruned birch trees provide butt logs with higher value than unpruned trees.

Pruning was performed at midsummer in two genetically homogenous and managed planted silver birch stands in southern Sweden – one aged 9 and one aged 10 years. Wood defects were analysed 10 years thereafter, using the five uppermost twigs of the stems up to a height of 30 dm. The number of trees examined at each site was around 70, of which half were pruned. The main findings were that: a) compared to unpruned trees, pruned trees produced more defect-free wood outside the knots; b) most wood defects were found inside the knots; and c) wood defects like rot and bark ingrowth were similar for pruned and unpruned trees, while discolouration was marginally higher for pruned trees inside knots but similar outside knots. Overall, the results confirm previous findings that pruned birch trees will provide butt logs with higher value than unpruned trees.

  • Stener, The Forestry Research Institute of Sweden, Ekebo 2250, 268 90 Svalöv, Sweden ORCID ID:E-mail: lars-goran.stener@skogforsk.se (email)
  • Rytter, The Forestry Research Institute of Sweden, Ekebo 2250, 268 90 Svalöv, Sweden ORCID ID:E-mail: lars.rytter@skogforsk.se
  • Jansson, The Forestry Research Institute of Sweden, Uppsala Science Park, 751 83 Uppsala, Sweden ORCID ID:E-mail: gunnar.jansson@skogforsk.se
article id 1071, category Research article
Ursula Kretschmer, Nadeschda Kirchner, Christopher Morhart, Heinrich Spiecker. (2013). A new approach to assessing tree stem quality characteristics using terrestrial laser scans. Silva Fennica vol. 47 no. 5 article id 1071. https://doi.org/10.14214/sf.1071
Highlights: Minimal deviations of the bark surface can be detected and visualized based on terrestrial laser scan data; Additionally the geometrical properties of bark scars and branched knots can be assessed; Two methods using two different approaches are presented: (1) a method using intensity data and (2) a method using bark surface models.
This paper presents an approach to assess and measure bark characteristics as indicators of wood quality using terrestrial laser scan data. In addition to the detection and measurement by use of the intensity information of the scan data a new approach was established. Bark surface models are calculated for each tree. They offer the representation of the bark as a height model. The reference is the tree stem approximated by a chain of cylinders. Minimal deviations of the bark surface can be detected and visualized and the geometrical properties of bark scars and branched knots can be assessed. Results of the measurement of 18 scars are presented using the two approaches: (1) a method using intensity data or (2) using bark surface models. The selection of the adequate approach depends on the stem characteristics. In a next step, methods for automatic measurement of bark scars will be developed.
  • Kretschmer, Chair of Forest Growth, Albert-Ludwigs-University Freiburg, Tennenbacher Str. 4, 79106 Freiburg, Germany ORCID ID:E-mail: ursula.kretschmer@iww.uni-freiburg.de (email)
  • Kirchner, VOLKE Consulting Engineers GmbH, Schätzweg 7-9, 80935 München, Germany ORCID ID:E-mail: nadeschda.kirchner@volke.muc.de
  • Morhart, Chair of Forest Growth, Albert-Ludwigs-University Freiburg, Tennenbacher Str. 4, 79106 Freiburg, Germany ORCID ID:E-mail: christopher.morhart@iww.uni-freiburg.de
  • Spiecker, Chair of Forest Growth, Albert-Ludwigs-University Freiburg, Tennenbacher Str. 4, 79106 Freiburg, Germany ORCID ID:E-mail: instww@uni-freiburg.de
article id 296, category Research article
Samuel Roturier, Sofia Bäcklund, Maria Sundén, Urban Bergsten. (2007). Influence of ground substrate on establishment of reindeer lichen after artificial dispersal. Silva Fennica vol. 41 no. 2 article id 296. https://doi.org/10.14214/sf.296
Methods to improve the recovery of reindeer lichen after soil disturbance or overgrazing are being sought for areas where reindeer are herded. The effects of four substrates – mineral soil, moss, twigs and pine bark – on the establishment of lichen fragments after total removal of the vegetation were thus studied in a middle-aged pine stand and a clear-cut, both located in a lichen-rich pine-heath. Cladina mitis fragments of two sizes were manually dispersed in 1 m2 quadrats and their movements from their respective dispersal points were registered after one year. The natural re-establishment of lichens in the quadrats was monitored over three years by using digital pictures. In the forest stand, no significant differences were detected in either the fragment movement or the lichen establishment between the different substrates, but the fragment size had positive effects on both parameters. In the clear-cut, the moss substrate was the most suitable not only for the artificially dispersed lichens to fasten to, but also for the natural settlement of lichens from the surrounding lichen mat. More lichen thalli fastened to the bark and twigs substrates than to the mineral soil, but the settlement of lichens from the surrounding was greater on bare mineral soil substrate. The results indicate that artificial dispersal of lichen thalli on an appropriate substrate could be a successful strategy for promoting lichen recovery.
  • Roturier, SLU, Vindeln Experimental Forests, Svartberget Fältstation, SE-922 91 Vindeln, Sweden ORCID ID:E-mail: samuel.roturier@esf.slu.se (email)
  • Bäcklund, ORCID ID:E-mail:
  • Sundén, ORCID ID:E-mail:
  • Bergsten, SLU, Dept of Forest Ecology, SE-901 83 Umeå, Sweden ORCID ID:E-mail:
article id 316, category Research article
Sonja Vospernik. (2006). Probability of bark stripping damage by red deer (Cervus elaphus) in Austria. Silva Fennica vol. 40 no. 4 article id 316. https://doi.org/10.14214/sf.316
Bark stripping by red deer (Cervus elaphus) causes considerable damage to Austrian forests, however, the incidence of bark stripping was never examined from large scale survey data. In this manuscript we present a logistic regression model for bark stripping damage (static model) and a model for recent (5-year period) bark stripping damage to previously undamaged trees (dynamic model) developed from Austrian National Forest Inventory data. Both models showed bark stripping damage to be most frequent in core red deer habitat areas and less frequent in less suitable habitat. Damage was concentrated at elevations of 400–1200 m and in alluvial forests (only static model). Norway spruce (Picea abies), European ash (Fraxinus excelsior), Sweet chestnut (Castanea sativa) and Sorbus spp. had 11–12 times more injuries than all the other species. Red deer preferred the smallest trees with a breast height diameter of 5 cm for bark stripping and damage probability decreased rapidly for trees with a breast height diameter greater than 25 cm. Our static model showed a maximum of bark stripping damage in stands with a mean height of 20 m. In the dynamic model the probability for bark stripping damage decreased with decreasing mean height. Also, in the static model the probability for bark stripping damage increased with increasing spruce proportion and with increasing stand density whereas in the dynamic model the proportion of previous bark stripping damage was a good predictor. Goodness of fit and discrimination of both models were good. In combination with forest growth models, the bark stripping models can be used to predict the risk of damage associated with different forest and habitat management options.
  • Vospernik, University of Natural Resources and Applied Life Sciences, Institute of Forest Growth Research, Department of Forest and Soil Sciences, Peter-Jordan-Stra§e 82, A-1190 Vienna, Austria ORCID ID:E-mail: sonja.vospernik@boku.ac.at (email)

Category: Research note

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

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

  • Liepiņš, Latvian State Forest Research Institute “Silava”, 111 Rigas Str., LV 2169, Salaspils, Latvia ORCID ID:E-mail: janis.liepins@silava.lv (email)
  • Ivanovs, Latvian State Forest Research Institute “Silava”, 111 Rigas Str., LV 2169, Salaspils, Latvia ORCID ID:E-mail: janis.ivanovs@silava.lv
  • Lazdiņš, Latvian State Forest Research Institute “Silava”, 111 Rigas Str., LV 2169, Salaspils, Latvia ORCID ID:E-mail: andis.lazdins@silava.lv
  • Jansons, Latvian State Forest Research Institute “Silava”, 111 Rigas Str., LV 2169, Salaspils, Latvia ORCID ID:E-mail: jurgis.jansons@silava.lv
  • Liepiņš, Latvian State Forest Research Institute “Silava”, 111 Rigas Str., LV 2169, Salaspils, Latvia ORCID ID:E-mail: kaspars.liepins@silava.lv
article id 37, category Research note
D. N. Avtzis, F. A. Aravanopoulos. (2011). Host tree and insect genetic diversity on the borderline of natural distribution: a case study of Picea abies and Pityogenes chalcographus (Coleoptera, Scolytinae) in Greece. Silva Fennica vol. 45 no. 1 article id 37. https://doi.org/10.14214/sf.37
Picea abies (L.) Karst. and Pityogenes chalcographus constitute a commonly observed host tree–insect association in Eurasia, with the natural distribution of the bark beetle overlapping that of Norway spruce. The southernmost borderline of their distributions occurs in the Elatia forest (Mt. Rodopi, Greece), where these interacting organisms may experience severe conditions due to the effects of climate change. In order to assess the dynamics of this host tree–insect association, the genetic diversity of both organisms was studied. In contrast to previous studies, the assessment of molecular diversity was based on the same mitochondrial gene (Cytochrome Oxidase One) sequence for both host and pest. This analysis revealed a remarkably higher genetic diversity of P. chalcographus compared to that of P. abies, something that renders the insect capable not only of adapting to novel environmental conditions, but even of shifting to other host species. On the contrary, P. abies presented a narrow genetic base, a potential drawback at the southern-most region of the species natural distribution. Synthesizing the preliminary outcome for both organisms, it appears that P. chalcographus exhibits an evolutionary advantage over P. abies, something that should be considered when planning conservation strategies for the relict forest of Elatia.
  • Avtzis, Aristotle University of Thessaloniki, Laboratory of Forest Genetics and Tree Breeding, Thessaloniki, Greece ORCID ID:E-mail: dimitrios.avtzis@gmail.com (email)
  • Aravanopoulos, Aristotle University of Thessaloniki, Laboratory of Forest Genetics and Tree Breeding, Thessaloniki, Greece ORCID ID:E-mail:

Category: Article

article id 7467, category Article
Matti Nuorteva. (1956). Hakkuiden vaikutuksesta kaarnakuoriaisten esiintymiseen eräällä metsäalueella Etelä-Hämeessä. Acta Forestalia Fennica vol. 65 no. 4 article id 7467. https://doi.org/10.14214/aff.7467
English title: Effect of fellings on bark beetle population in a forest area in Southern Finland.

Bark beetle populations live usually in a balance in natural forests, and outbreaks occur seldom. The populations have been found to increase in managed forests. Fellings affect the structure of the forests, which influence the living conditions of the insects, and produce material for reproduction. In this study the occurrence of bark beetles was studied in a forest area in Etelä-Häme in Southern Finland using line plot survey.

The forests in the area were Norway spruce (Picea abies L. Karst.) dominated. Over third of the 140 sample plots studied were in forests which had never been cut or it was over ten years to the last logging. Bark beetles of 26 different species were found in 66 of the sample plots. The most common species was six-toothed spruce bark beetle (Pityogenes chalcographus L.), which was due to the abundance of growth material suitable for the species in the area. New species in the area were common double-eyed spruce bark beetle (Polygraphus polygraphus L.), Pityophthorus micrographus L., and Dryocetes-beetle (either Dryocetes autographus or D. hectographus). The fellings increased the occurrence of beetles. The amount and quality of logging residue affected the abundance of the insects.

The PDF includes a summary in German.

  • Nuorteva, ORCID ID:E-mail:
article id 7372, category Article
Vilho Seppänen. (1942). Sahatukkien teosta aikatutkimuksen valossa. Acta Forestalia Fennica vol. 50 no. 19 article id 7372. https://doi.org/10.14214/aff.7372
English title: Time studies on making of saw logs.

A time study was conducted in saw log harvesting site in state forests of Evo in Southern Finland in 1934. Felling was performed in teams of two loggers. Two teams were observed. The work was divided into several stages of work: felling, branching, cross-cutting, barking and making of top log. On the site grew Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies (L.) Karst.).

The daily working hours not including breaks was in average 5 hours and 33 minutes. The most time-consuming stage of the work was barking of the stem (55% of working time for Scots pine and 47% for Norway spruce), followed by felling (22.5% for pine and 19.4% for spruce), branching (11.7% and 21.6%) and cross-cutting (11.3% and 11.8%). Temperature affects barking strongly. Scots pine is slower to bark than Norway spruce. Similarly, butt and middle logs are slower to bark than top logs. It took in average 79.02 min to process one solid m3 of timber with bark and 91.45 min without bark.

The PDF includes a summary in German.

  • Seppänen, ORCID ID:E-mail:
article id 7212, category Article
P. Kokkonen. (1927). Über das Verhältnis der Winterfestigkeit des Roggens zur Dehnbarkeit und Dehnungsfestigkeit seiner Wurzeln. Acta Forestalia Fennica vol. 33 no. 3 article id 7212. https://doi.org/10.14214/aff.7212
English title: On the relation between the hibernation of rye and the extensibility and the tensile strength of its roots.

In attempts to improve the autumn cereals, wheat and rye, hibernation plays an essential role. Those varieties that hibernate well should be marketed and others rejected. Concerning roots, it seems that varieties that hibernate well have more extent root system than those hibernating poorly.

Four varieties of rye were chosen for experiments, two that knowingly hibernate well and two that don’t. The experiments were grown in the Botanical gardens of the university and at the same time in experiment field in Tikkurila.

The results proof that plant hibernating well have more extensible roots than others and hence they survive better in frosting soil that extents.

The PDF contains a summary in English and in Finnish.

  • Kokkonen, ORCID ID:E-mail:
article id 5613, category Article
Mikko Peltonen, Kari Heliövaara, Rauno Väisänen. (1997). Forest insects and environmental variation in stand edges. Silva Fennica vol. 31 no. 2 article id 5613. https://doi.org/10.14214/sf.a8514

Distribution and occurrence of bark beetles and other forest insects in relation to environmental variation were analysed by multivariate methods. Eight different forest edges were studied using 10 x 10 m sample plots that formed 200 m linear transects perpendicular to the forest edge. Forest edge affected the distribution of insect species only in the edges between mature, non-managed spruce stands and clear cuts or young seedling stands, but not in the pine stands. The occurrence of the selected forest insects mainly depended on variables associated with the amount and quality of suitable woody material. The most significant environmental variables were forest site type, crown canopy coverage, tree species, number of stumps, number of dead spruce trunks and amount of logging waste at site. Quantitative classification of species and sample plots showed that some specialized species (Xylechinus pilosus, Cryphalus saltuarius, Polygraphus poligraphus and P. subopacus) adapted to mature spruce forests, tended to withdraw from the forest edge to interior stand sites. By contrast many generalized species (Pityogenes chalcographus, P. quadridens, Pissodes spp., Hylurgops palliatus, Tomicus piniperda, Dryocoetes spp. and Trypodendron lineatum) benefitted from cuttings and spread over stand borders into mature forest.

  • Peltonen, ORCID ID:E-mail:
  • Heliövaara, ORCID ID:E-mail:
  • Väisänen, ORCID ID:E-mail:
article id 5395, category Article
Mirja Kortesharju, Jouko Kortesharju. (1989). Studies on epiphytic lichens and pine bark in the vicinity of a cement works in northern Finland. Silva Fennica vol. 23 no. 4 article id 5395. https://doi.org/10.14214/sf.a15553

The element content (Ca, Mg, K, Na, Fe, Mn, Zn, Cu, Pb, S) of Scots pine (Pinus sylvestris L.) bark and Bryoria lichens, as well as the occurrence and coverage of epiphytic lichens and the length of Bryoria species, were studied in the vicinity of Kolari cement works, NW Finland. Fruticose Bryoria species had the highest coverage on pine trunks at a distance of 2 km or more from the cement works. At a distance of 1 km the foliose – or even crustose – Parmeliopsis species were most abundant, while nearer to the works lichens were almost completely absent. The length of Bryoria was reduced at distances of less than 2 km from the cement works. The calcium content in Bryoria species increased very steeply close to the works; by a factor of 60 at a distance of 1 km compared to 16 km. No corresponding increase in other elements was observed near the cement works. All the elements studied in pine bark showed a significant negative correlation with distance, and a significant positive correlation with the calculated dust deposition levels. There were only minor differences between the north and south of the pine trunks, or the side facing or away from the works. Pine bark analysis is recommended for element accumulation studies.

The PDF includes an abstract in English.

  • Kortesharju, ORCID ID:E-mail:
  • Kortesharju, ORCID ID:E-mail:
article id 5277, category Article
Kirsi Maasalo. (1986). Pihlajan puuaineen ominaisuuksia. Silva Fennica vol. 20 no. 3 article id 5277. https://doi.org/10.14214/sf.a15456
English title: Properties of the wood of the rowan tree (Sorbus aucuparia).

The basic density of the wood of the rowan tree (Sorbus aucuparia L.) is almost the same along the stem but that of the bark is increasing along the stem. The moisture content of the wood and of the bark is increasing along the stem. Its strength in the bending and in the compression is high. The volume shrinkage is high.

The PDF includes an abstract in Finnish

  • Maasalo, ORCID ID:E-mail:
article id 5213, category Article
Bo Långström. (1984). Windthrown Scots pines as brood material for Tomicus piniperda and T. minor. Silva Fennica vol. 18 no. 2 article id 5213. https://doi.org/10.14214/sf.a15392

In the 1980 and 1981, windthrown and felled Scots pine (Pinus sylvestris L.) were examined at 8 localities in Sweden. The number and length of egg galleries as well as the number of exit holes of Tomicus piniperda (L.) and T. minor (Hart.) were recorded on sample sections (30 m in length) distributed at 3 m intervals on the 37 fallen pine stems, which were successfully colonized by the beetles. In addition, 78 uprooted pines were surveyed in 6 localities. Most trees were attacked by T. piniperda, but only a few by T. minor. Successful colonization often resulted in the production of several thousand beetles per tree, the maximum being approximately 1,800. The attack density of T. piniperda seldom exceeded 200 egg galleries/m3 bark area, and the brood production usually remained below 1,000 beetles/m3. Much higher figures were obtained or T. minor. In T. piniperda, the rate of reproduction (i.e. the number of exit holes /egg gallery) decreased rapidly with increasing attack density, whereas T. minor seemed to be less sensitive to intraspecific competition.

The PDF includes a summary in Finnish.

  • Långström, ORCID ID:E-mail:
article id 5187, category Article
Fuhe Luo. (1983). Determination of stem value. Silva Fennica vol. 17 no. 3 article id 5187. https://doi.org/10.14214/sf.a15170

A dynamic programming approach toward stem value estimation for standing Scots pine (Pinus sylvestris L.) trees was developed. The determination of the saw log value was based on the sawing pattern and on the final products composition. The combination of taper curve models and bark models providing taper curves both over bark and under bark, which constituted the basis of the optimum stem scaling. A computer program was developed to determine the optimum log sequence of the stem aiming at maximizing the value of the final products. To examine the reliability of the computation system, 445 Scots pine sample trees from 29 stands were used as a test material. The stem values of sample trees were calculated in two ways: 1) with 12 measured diameters, and 2) with 12 estimated diameters derived from measured tree characteristics. In both cases the values of the intermediate diameters were calculated via cubic spline interpolation.

The PDF includes a summary in Finnish.

  • Luo, 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 5119, category Article
Kari Puukko. (1981). Okakaarnakuoriaisen, Ips acuminatus Gyll. (Coleoptera, Scolytidae) levinneisyyden nykyinen eteläraja Suomessa. Silva Fennica vol. 15 no. 2 article id 5119. https://doi.org/10.14214/sf.a15060
English title: The southern border of the present distribution of Ips acuminatus Gyll. In Finland.

Ips acuminatus Gyll. (Coleoptera, Scolytidae) is a bark beetle that causes deep bluing in thin-barked Scots pine (Pinus sylvestris L.) pulpwood. It has been shown that this decreases pulp yield. The purpose of this study was to map the southern border of the distribution of Ips acuminatus in Finland. It was found that there have been changes in the distribution of this species during the last three decades. Ips acuminatus has now disappeared from southern Finland. On the basis of the sample plots (134 cutting areas) the southern border of this pest lies on the line running through the towns Vaasa–Seinäjoki–Äänekoski–Jyväskylä–Pieksämäki–Savonlinna–Punkaharju. A certain degree of localisation was observed in the occurrence of I. acuminatus in its distribution area, for instance, differences in its occurrence frequency in cutting areas and even in log and cutting residue piles in the sample cutting area.

It is considered that the most important reasons for these changes in distribution are the increase in logging and changes in the location of cutting sites, and resulting competition for breeding material for the increased population of bark beetles. Furthermore, the long-distance transport of unpeeled logs from the north across the present southern borders may, in the future, contribute to local changes in the southern distribution of Ips acuminatus.

The PDF includes a summary in English.

  • Puukko, 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 5089, category Article
Seppo Kellomäki. (1980). Alustavia mittaustuloksia kuivauksen ja liotuksen vaikutuksesta kuorellisen mänty- ja kuusipuutavaran kuoren paksuuteen. Silva Fennica vol. 14 no. 4 article id 5089. https://doi.org/10.14214/sf.a15030
English title: Preliminary results of the effect of drying and soaking of the bark thickness of Scots pine and Norway spruce.

On the basis of a limited material, the drying of Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies (L.) H. Karst.) timber at room temperature decreased the thickness of the bark proportionally to the decrease in the moisture content. The decrease was the greatest in the middle portion of the trunk. In the spruce material, the decrease in bark thickness was exceeded by the shrinkage of the wood. During soaking, the bark thickness of both tree species decreased, too, contrary to the presupposed hypothesis. In both cases, the shrinkage was the greatest in the middle portion of the trunk. In the spruce material, the decrease in bark thickness was exceeded by the shrinkage of the wood. Possible explanation for the phenomenon is discussed.

The PDF includes a summary in English.

  • Kellomäki, ORCID ID:E-mail:
article id 5074, category Article
Jukka Selander, Matti Nuorteva. (1980). Feromonivalmisteen käyttö kirjanpainajien torjumiseksi kuolevassa kuusikossa. Silva Fennica vol. 14 no. 2 article id 5074. https://doi.org/10.14214/sf.a15015
English title: Use of synthetic pheromones for the control of spruce bark beetle in a heavily infested Norway spruce stand.

The dying-off of more trees in an over-aged Norway spruce (Picea abies (L.) H. Karst.) stand caused by Ips-bark beetles was reduced by a pheromone preparation, ipslure. 20 preparations placed in trapping bolts captured more than 13,700 specimens of Ips typographus L. and Ips duplicatus Sahlb., which alone corresponded to a saving of five old trees in this valuable exhibition and seed collection stand. Attractance of ipslure to the following predators of bark beetles was also examined; Thanasimus formicarius, T. rufipes, Epuracea bickhardti, Rhizophagus ferrugineus, Pityophagus ferrugineus.

The PDF includes a summary in English.

  • Selander, ORCID ID:E-mail:
  • Nuorteva, ORCID ID:E-mail:
article id 5034, category Article
Matti Kärkkäinen. (1979). Pinotilavuusmääräinen kuorintahäviö koneellisesti ladotuissa pinoissa. Silva Fennica vol. 13 no. 2 article id 5034. https://doi.org/10.14214/sf.a14891
English title: Barking loss of mechanically loaded piles.

In this study the loose volume of 58 piles of pulpwood were measured before and after barking by rotary ring barker. The volume was 2,121 m3. A recommendation is made, based on the results of the study, concerning the barking loss from piled wood: for green Scots pine (Pinus sylvestris L.) pulpwood, 8.8% of the stacked volume; for seasoned pine pulpwood, 6.1% of the stacked volume; and 8.0% for birch (Betula sp.) pulpwood, green and seasoned. The amount of bark left on bolts was small for pine bolts, namely 0.33%, but quite large for birch bolts, 2.84% of the green weight.

The PDF includes a summary in English.

  • Kärkkäinen, ORCID ID:E-mail:
article id 5034, category Article
Matti Kärkkäinen. (1979). Pinotilavuusmääräinen kuorintahäviö koneellisesti ladotuissa pinoissa. Silva Fennica vol. 13 no. 2 article id 5034. https://doi.org/10.14214/sf.a14891
English title: Barking loss of mechanically loaded piles.

In this study the loose volume of 58 piles of pulpwood were measured before and after barking by rotary ring barker. The volume was 2,121 m3. A recommendation is made, based on the results of the study, concerning the barking loss from piled wood: for green Scots pine (Pinus sylvestris L.) pulpwood, 8.8% of the stacked volume; for seasoned pine pulpwood, 6.1% of the stacked volume; and 8.0% for birch (Betula sp.) pulpwood, green and seasoned. The amount of bark left on bolts was small for pine bolts, namely 0.33%, but quite large for birch bolts, 2.84% of the green weight.

The PDF includes a summary in English.

  • Kärkkäinen, ORCID ID:E-mail:
article id 5005, category Article
Matti Kärkkäinen. (1978). Kuorinnan vaikutus pinon tiiviyteen. Silva Fennica vol. 12 no. 3 article id 5005. https://doi.org/10.14214/sf.a14859
English title: The effect of barking on the pile density.

According to the available literature, the times when pulpwood limbing was made by axe and barking by hand tools, barking either had no effect on the pile density (if limbing quality was good) or increased pile density (if limbing was bad). When rotary barking machines are used, the branch stumps remain intact during barking. Therefore, if there are branch stumps in the pulpwood, barking decreases the pile density. Nowadays, when power saw limbing is a common practice in Finland, barking presumably greatly decreases the pile density, due to the fact that in power saw limbing branch stumps are numerous and high. Therefore, the method to estimate the solid volume of a pile of unbarked pulpwood are not applicable to barked pulpwood without modification.

The PDF includes a summary in English.

  • Kärkkäinen, ORCID ID:E-mail:
article id 5003, category Article
Hannu Saarenmaa. (1978). Kaarnakuoriaisten (Col., Scolytidae) esiintyminen eräässä kanadanmajavan (Castor canadensis Kuhl) aiheuttaman tulvan seurauksena kuolleessa metsikössä. Silva Fennica vol. 12 no. 3 article id 5003. https://doi.org/10.14214/sf.a14857
English title: The occurrence of bark beetles (Col., Scolytidae) in a dead spruce stand flooded by beavers (Castor canadensis Kuhl.) .

 

The aim of the study was to determine which kinds of insects had infected the Norway spruce (Picea abies (L.) H. Karst.) in different stands killed by flooding caused by beavers (Castor canadensis Kuhl), and if there was any danger that they would subsequently cause damage in the surrounding forests. The effect of tree diameter and certain stand characteristics on the fauna of dead trees are discussed. The occurrence of different insect combinations and qualifications for their coexistence were studied.

Pityogenes chalcographus L., Trypodendron lineatum O., Hylurgops palliatus Gyll. and Dryocetes autographus Ratz. occurred most abundantly. 20 phloem or wood boring species were observed in 5 regular succession types. Secondary species occurred in a virgin stand while Ips typographus L. was found at the edge of a felling area. Owing to the flooding, species preferring moist conditions were abundant. In this case damages had not spread to the surrounding forests which, however, might be possible under certain conditions.

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  • Saarenmaa, ORCID ID:E-mail:
article id 4948, category Article
Matti Kärkkäinen. (1976). Puun ja kuoren tiheys ja kosteus sekä kuoren osuus koivun, kuusen ja männyn oksissa. Silva Fennica vol. 10 no. 3 article id 4948. https://doi.org/10.14214/sf.a14794
English title: Density and moisture content of wood and bark, and bark percentage in the branches of birch, Norway spruce and Scots pine.

In the study the proportion of branch samples of various diameter were studied. The branches were taken from small trees to be harvested by total tree chipping method. The material consisted of 1,056 branch samples of birch (Betula verrucosa, now B. pendula Roth, and Betula pubescens Erhr.), Norway spruce (Picea abies (L.) H. Karst.) and Scots pine (Pinus sylvestris L.) at intervals of 20 cm along each branch.

With exception of the basic density of bark, there was a relation between all the other properties which were studied and the diameter. Even when the effect of diameter was eliminated, in many cases the effect of the distance of the samples from the stem became apparent.

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  • Kärkkäinen, ORCID ID:E-mail:
article id 4877, category Article
Pertti Laatikainen. (1973). Jyrsinturve ja kuorihumus männyn kylvötaimien kasvualustoina muovihuoneessa. Silva Fennica vol. 7 no. 1 article id 4877. https://doi.org/10.14214/sf.a14707
English title: Milled peat and milled bark as substrate for Scots pine seedlings in greenhouses.

The purpose of this study was to compare the development of Scots pine (Pinus sylvestris L.) seedlings sown on substrates off milled peat and milled bark. Mille peat, ordinary milled bark, milled inner bark waste, and a mixture of milled peat and milled bark in the ratio of 1:1, were all compared in the plastic greenhouse. In addition, two fertilization applications were used with milled park: ordinary surface fertilization and double surface fertilization. The germination and development were measured twice during the summer.

It is concluded that milled bark seems to be a rather useful substrate for use in plastic greenhouses, as long as its special requirements are taken into consideration. In the first measurement, there were no differences between the treatments, in the second measurements seedlings growing on a mixture of peat and bark were slightly more developed than the others. Growth of the seedlings was slightly better in ordinary milled bark. Double surface fertilization increased disease and mortality compared to ordinary fertilization.

The PDF includes a summary in English.

  • Laatikainen, ORCID ID:E-mail:
article id 4746, category Article
Kari Löyttyniemi. (1967). Tikaskuoriaisesta (Trypodendron lineatum Oliv., Col., Scolytidae) kuorellisen havupuutavaran pilaajana. Silva Fennica vol. 1 no. 2 article id 4746. https://doi.org/10.14214/sf.a14456
English title: Damages caused to timber with bark by spruce ambrosia beetle (Trypodendron lineatum) in Finland.

The paper studied the effect of felling time and conditions in the forest depot of timber to damages caused by spruce ambrosia beetle (Trypodendron lineatum Oliv.) to coniferous timber with bark, both experimentally and observing forest depots in Finland. Effects of fellings was studied by studying the abundance of the beetles in logging residue.

The results show that the spruce ambrosia beetles favour timber felled during the late autumn and winter, stored in a shaded place in the forest. In addition, new spruce stumps maintain and increase the beetle population. Fellings in the forest will increase population during the next year and cause damages in forest depot of timber nearby, because the insect breeds in the stumps. The experiments showed that it is possible to diminish the damages caused by the beetle to timber with bark by spraying with insecticides, and timing the fellings and transport of timber so that there is no timber in the forest in the spring during the time when the insect swarms.

The PDF includes a summary in German.

  • Löyttyniemi, ORCID ID:E-mail:
article id 4736, category Article
Matti Nuorteva. (1967). Hakkuutähteissä elävien hyönteisten käyttömahdollisuuksista hakkuun ajankohdan määrittämisessä. Silva Fennica vol. 1 no. 1 article id 4736. https://doi.org/10.14214/sf.a14446
English title: Potential in using determination of insect species breeding in the logging residue to estimate the time of the logging.

Degree of decomposition of logging residue, and decay in stumps have been used in forest inventories to estimate the time of the felling. In this paper, a method was developed to use insects breeding in the logging residue to determine how long ago the felling took place. The method is based on the arrival and rate of development of the different species of bark beetles that breed in the logging residue.

The most suitable insect species to be used in the purpose of timing the age of logging residue were defined, and their occurrence in different tree species and fellings performed at different times of the year were described. The species can be easily identified by gallery systems characteristic to the species.

It is concluded that the method does not suit for broadleaved species, because there is no common insects suitable for this purpose. Also, the time of swarming of the insects depends on the weather conditions in the spring, which makes it difficult to give definite dateshe progress of the spring has to be taken into account when the occurrence of the insects is used in the determination of the time of the felling. In addition, local conditions, such as shading, affect drying of the branches, and can influence the occurrence of the insects. For Scots pine and Norway spruce the age of the logging residue can be determined precisely only at most two years back.

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

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

The PDF includes a summary in English.

  • Ojansuu, ORCID ID:E-mail:
article id 7574, category Article
Olavi Isomäki. (1974). Sahateollisuuden kuorintajätteiden käyttömahdollisuudet. Erityisesti käyttö maanparannusaineena ja kasvualustana. Acta Forestalia Fennica no. 140 article id 7574. https://doi.org/10.14214/aff.7574
English title: Using possibilities of barking waste in sawmill industry specially using as a soil improver and substrate for plants.

Residue of the wood is good raw material for pulp and board industries, but the question of the use of barking waste still remains to a great extent unsolved. This research deals with the possibilities to utilize the barking waste of sawmill industry in general and, in particular, its use as a soil improver and substrate for plants. It also explains the industrial manufacturing method of composted bark, bark humus, developed by the author as well as the properties of bark humus and the economy of bark humus and the economy of manufacturing.

The PDF includes a summary in Finnish.

  • Isomäki, ORCID ID:E-mail:
article id 7574, category Article
Olavi Isomäki. (1974). Sahateollisuuden kuorintajätteiden käyttömahdollisuudet. Erityisesti käyttö maanparannusaineena ja kasvualustana. Acta Forestalia Fennica no. 140 article id 7574. https://doi.org/10.14214/aff.7574
English title: Using possibilities of barking waste in sawmill industry specially using as a soil improver and substrate for plants.

Residue of the wood is good raw material for pulp and board industries, but the question of the use of barking waste still remains to a great extent unsolved. This research deals with the possibilities to utilize the barking waste of sawmill industry in general and, in particular, its use as a soil improver and substrate for plants. It also explains the industrial manufacturing method of composted bark, bark humus, developed by the author as well as the properties of bark humus and the economy of bark humus and the economy of manufacturing.

The PDF includes a summary in Finnish.

  • Isomäki, ORCID ID:E-mail:

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