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Genetic improvement of shape stability in Norway spruce and Scots pine sawn timber

Hallingbäck, Henrik (2010). Genetic improvement of shape stability in Norway spruce and Scots pine sawn timber. Diss. (sammanfattning/summary) Uppsala : Sveriges lantbruksuniv., Acta Universitatis Agriculturae Sueciae, 1652-6880 ; 2010:22
ISBN 978-91-576-7499-9
[Doctoral thesis]

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Poor shape stability of sawn softwood timber, causes substantial economic losses for sawmills and the building industry. Sawn timber twist is regarded to be the most severe deformation and has been shown to be controlled by intrinsic wood properties like wood shrinkage and spiral grain angle. The aim of the studies this thesis is based upon was to investigate the possibility to improve sawn timber shape stability, by genetic selection of genotypes of Norway spruce (Picea abies L. Karst.) and Scots pine (Pinus sylvestris L.) with a favourable spiral grain angle. Genetic parameters were estimated for the spiral grain angle in the mature wood of trees in four progeny trials (age 27–36 years) and two clonal trials (age 19 years) of Norway spruce. In addition, in a 36-year-old Scots pine progeny trial, the grain angle was measured and shape stability traits of the boards sawn from sampled trees were assessed. The estimates of genetic standard deviation (0.7°–0.9°) and heritability (0.29–0.42) in the mature wood of both species suggested that grain angle could be altered by genetic selection. The grain angle measured in single annual rings of Scots pine showed substantial phenotypic correlations (0.54–0.70) with the twist of small sawn timber dried to a 12% moisture content. As an example, twist could potentially be reduced by 0.3°–0.7° by selecting 20% of the parents displaying the lowest grain angle, thereby appreciably decreasing the percentage of excessively twisted boards. Grain angle under bark exhibited non-significant genetic correlations, close to zero, with growth traits, stem form, and branch traits in both species, and with pilodyn penetration in Norway spruce, suggesting that genetic selection for this trait would not generate any appreciable response in the other traits. The results of the studies imply that the grain angle measured under bark is utilisable in terms of genetic parameter estimation and for predicting the twist propensity of small sawn timber. This suggests that there is potential to improve sawn timber shape stability by genetic selection for a lower grain angle under bark and thus reducing the twist of sawn timber.

Authors/Creators:Hallingbäck, Henrik
Title:Genetic improvement of shape stability in Norway spruce and Scots pine sawn timber
Series Name/Journal:Acta Universitatis Agriculturae Sueciae
Year of publishing :2010
Number of Pages:52
ALLI. Hallingbäck, H.R., Jansson, G. & Hannrup, B. (2008). Genetic parameters for grain angle in 28-year-old Norway spruce progeny trials and their parent seed orchard. Annals of Forest Science 65(3),301p1-301p8. II. Hallingbäck, H.R., Jansson, G. & Hannrup, B. (2010). Genetic correlations between spiral grain and growth and quality traits in Picea abies. Canadian Journal of Forest Research 40, 173-183. III. Högberg, K-A., Persson B., Hallingbäck, H.R. & Jansson, G. Relationships between early assessments of stem and branch properties and sawn timber traits in a Scots pine progeny trial. Submitted. IV. Hallingbäck, H.R., Jansson G., Hannrup, B. & Fries, A., Which annual rings to assess grain angles in breeding of Scots pine for improved shape stability of sawn timber? Submitted.
Place of Publication:Uppsala
ISBN for printed version:978-91-576-7499-9
Publication Type:Doctoral thesis
Full Text Status:Public
Agrovoc terms:picea abies, pinus sylvestris, forest trees, genetic variation, heritability, sawnwood, wood properties, wood defects
Keywords:forest genetics, genetic variation, heritability, Picea abies, Pinus sylvestris, sawn timber, spiral grain, twist, warp, wood properties
Permanent URL:
ID Code:2241
Department:(NL, NJ) > Dept. of Plant Biology and Forest Genetics (until 131231)
Deposited By: Henrik Hallingbäck
Deposited On:02 Mar 2010 00:00
Metadata Last Modified:02 Dec 2014 10:17

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