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- Högberg, Karl-Anders, et al.
(författare)
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The potential for the genetic improvement of sawn timber traits in Picea abies
- 2014
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Ingår i: Canadian Journal of Forest Research. - : NRC Research Press. - 0045-5067 .- 1208-6037. ; 44:4, s. 273-280
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Tidskriftsartikel (refereegranskat)abstract
- This study evaluated the potential for the selective genetic improvement of the structural quality traits important in sawn Norway spruce (Picea abies (L.) Karst.) timber based on early and nondestructively assessed field traits. From a 34-year-old Norway spruce trial situated in southern Sweden, 401 butt logs were sampled and sawn to produce two 50 × 100 mm boards that were dried to an 18% moisture content. Structural quality traits were assessed, and genetic parameters were estimated, including additive genetic variance, heritability, and their genetic correlations with field traits. Board twisting, density, and modulus of elasticity (MOE, stiffness) were found to have appreciable heritabilities (0.23–0.44). Board twist was found to have a strong genetic correlation with grain angle measured under bark in the field (0.93), and both board MOE and density exhibited strong genetic correlations with field-assessed pilodyn penetration (–0.75 and –0.91, respectively). Although these observations were made on a thinning material comprising mainly juvenile wood, they nonetheless suggest grain angle and pilodyn penetration to be promising candidates as selection criteria for Norway spruce breeding. Heritabilities of other sawn timber traits were lower and the genetic correlations between these traits and field traits were also lower, variable, and had large estimation errors.
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| 2. |
- Johansson, Marie, 1973-, et al.
(författare)
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Properties of materials from Birch – Variations and relationships : Part 2. Mechanical and physical properties
- 2013
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Birch regarded as Sweden’s third largest tree species. The two birch species, Silver- and Downy birch represents about 12% of total Swedish timber volume. For forestry, birch an important tree species which today mainly used for the manufacture of pulp and paper.The aim of this project was to describe mechanical and physical properties of birch. The properties that have been studied are stiffness, bending strength, shrinkage, spiral gran angle, density and microfibril angle in the cell wall and vessel cells, from different parts of the birch stems grown at different rates. The mapped properties have been compared also with those of other tree species, mainly spruce. The long term aim is to increase the knowledge of the birch wood properties to provide better predict their impact on products as well as provide a basis for better utilization of Swedish birch raw material and hopefully using birch as future structural timber.Three birch stands with different growth was chosen: Two stands where the birch growth has been different in a mixed forests stand of spruce and pine, and a fast growing stand with improved birch seedlings. Samples were taken from four different heights in the trees. The main thing that has been analyzed is the bending strength, modulus of elasticity, shrinkage coefficients in different directions and spiral grain. The mechanical tests are carried out on tines that are 20 x 20 x 300 mm and the fiber angle measurements were carried out on discs. These results have supplemented by the results of analyzes conducted with lnnventias SilviScan instruments that are able to recognize variations of year ring wood properties. Some of these are density, and microfibril angle, which is also included in this report.The results show that the wood from normal growth and fast growth improved birch receive equivalent wood properties. The results also show that birch wood properties are slightly better than that in Norway spruce.The material in this project was limited to only three stands and 11 sampled trees and therefore it can´t provide complete answers to the birch trees different wood properties. Limitations include genetic origin, growth rate, earlier silvicultural treatment and number of sample trees.
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