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Browsing by discipline "Skogsresursvetenskap och -teknologi (träteknologi)"

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  • Pyörälä, Jiri (2013)
    This study is a part of the research project of uneven-aged forest stands ERIKA by Finnish Institute for Forest Research. The aim of this study was to identify the growth and quality of Norway spruce wood and sawn wood products from uneven-aged forest stands in South Finland. The properties ex-amined were fiber length, wood density, modulus of elasticity and visual grade according to Nordic standards of visual grading. 64 trees were measured for fiber length and sawn wood of 40 trees (355 pc.) was measured for density, modulus of elasticity and visual grading. The variation of fiber length was modeled in respect to distance from pith and ring width using a mixed model. The variation of density, modulus of elasticity and visual grade was analyzed in respect to the within-tree location with two-sided variance analysis. In respect to cambial age and ring width the properties were analyzed by means of regression modeling. According to the results fiber length, density and MOE did not differ significantly from those characteristic to spruce in even-aged stands: most variation was among-tree which gives a reason to think that the changes in within-tree growth rhythm do not affect these proper-ties within an individual tree. Visual grading for sawn wood gave that there was a good amount of class A (~ 20 %) but class C (> 33 %) was more common than class B (> 25 %): Timber was knotty especially near pith and loose knots were dense on lumber boards. Twisting was high near pith in timber boards but did not differ from the usual. There was remarkable amount of compression wood and decay in the material. The within-tree variation of visual grade was equal to the among-tree varia-tion. Due to the small sample size the results are not yet applicable to uneven-aged forests in general, but they give an impression that there might not be any major differences between the quality of even-aged and uneven-aged wood. First of all, the results give light to the characteristics of uneven-aged spruce wood properties that might be of interest for further research.
  • Kyllönen, Kalle (2009)
    The first aim of this study was to find out the moisture content of sawdust in drying and briquetting process. The moisture content of sawdust has an effect on output quality. The moisture content and density of output worked out. The second aim of study was to find out how the feeding volume of dried sawdust and the moisture content of output are influencing together the density of output. The moisture content of input is on average 56,8 +/- 2,3 % and it is homogenous. The moisture content of midput is on average 11,2 +/- 7,9 %. Variation is large. The moisture content of output is depending on moisture content of midput. The moisture content of raw material has an effect on output density. The optimum moisture content is 11 % for high density of output. The feeding volume of dried sawdust has also an effect on output density. Low feeding volume increases and high feeding volume decreases density of output. The density of output is on average 951— 1011 kg/m3 depending on briquette press.The energy content of sawdust is 0,68 MWh/loose m3 and the energy content of briquettes is 3,07 MWh/loose m3. The energy content of sawdust becomes five times better in drying and briquetting process.
  • Väisänen, Erja (2007)
    The study describes the dead branch height of Scots Pines from sawing industry point of view. The regional means for dead branch heights are given in a table, while the lower quartile of dead branch height, the median tree and the upper quartile are given in Box Plots. The grouping regions consist of the existing 13 areas of the Finnish Forestry Centres. Two of these regions are divided into two, making the total number of areas to be reviewed 15. The research material consists of the data gained from the 9th National Forest Inventory of Finland (VMI9), carried out 1996-2003, and also in relation to the data from Southern Finland in the previous National Forest Inventory (VMI8). Over all, dead branch heights on the major regions differ from each other, but in these two inventories the highest means and medians of dead branch height are in different areas within the middle part of Southern Finland. In addition to the absolute dead branch height, the review also shows the relative dead branch height (the ratio of dead branch height to the height of the tree), in those previous areas and as well as in swampy areas, in mature and thinning stands, and in different forest site types with mineral soils. In the areas of most common forest site types (VT and MT et corresponding) the dead branch heights are approximately at the same level, but the relative heights are higher on more poor sites. The effect of the age, height and the diameter of the trees were reviewed, too. Regression lines were calculated for the relationship between the stem part with only dead branches and the height of the tree having different diameter. It was not possible to examine the effect of the regeneration or later treatment method on the dead branch height, because there was no data for them concerning saw log-sized trees. It was also decided not to examine the number of stems in those different groups and their distribution into saw logs, although this information would be possible to calculate out of the data.
  • Pihlajamaa, Tuuli (2010)
    The study is part of Future Biorefinery, the second research program of Forestcluster Ltd. The goal of the program is to find innovative ways to better utilize the raw materials of the forest industry. The aim of the study is to investigate the structure and characters of stump- and rootwood of Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies [L.] Karst.). The aim is to find out if there is any reaction wood in the roots of Scots pine and Norway spruce and what is the proportion of the acetone soluble extractives in the stump- and root wood. The study material consisted of five stems of Scots pine and Norway spruce of various age. Root and stump samples of Scots pine and Norway spruce were collected after cutting the timber from a peatland site in Parkano (62.017°N, 23.017°E), Western Finland. Cutting was done by the Finnish Forest Research Institute (Metla). The samples were taken from the underground parts of roots a three different distances from the root collar. The study was executed as descriptive research. Neither of the species showed traces of actual reaction wood, but some samples showed traces of mild reaction wood. The mild form of reaction wood was more common in the pine roots than in the spruce roots and it did not appear in the samples that were taken from the thinnest parts of roots, i.e. the roots with ca. 2 cm diameter. The acetone soluble extractive content was higher in the pine stumps than in the spruce stumps. In the pine roots the extractives per cent increased towards the root tips. On the spruce roots the extractives per cent decreased at first and then increased near the root tips. The extractives per cent of the bark was higher than of the wood and that applied for both species. Becouse the sample set was rather limited there was no attempt to make any statistic analysis of the data. There is a need for further studies concerning properties of roots and stumps from peatlands. The supply of wood from peatlands is increasing in the future in Finland while the studies on wood properties and extractives of roots have been focused in the mineral soils.