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Effects of genetics on the wood properties of Sitka spruce growing in the UK: bending strength and stiffness of structural timber.

Moore, J R; Mochan, S J; Br�chert, F; Hapca, Adrian Ilie; Ridley-Ellis, Daniel; Gardiner, Barry A; Lee, S J

Authors

J R Moore

S J Mochan

F Br�chert

Adrian Ilie Hapca

Barry A Gardiner

S J Lee



Abstract

Mechanical tests were conducted on structural timber from a 37-year-old Sitka spruce (Picea sitchensis (Bong.) Carr), progeny trial located in Kershope Forest, Cumbria, UK. Values of modulus of rupture (MOR) and global modulus of elasticity (MOEG) in bending and density were compared between timber cut from four of the eight different seed lots which made up the experiment. Three of these seed lots were open-pollinated progeny of selected plus trees, while the fourth consisted of trees grown from an unimproved collection imported from the Queen Charlotte Islands (QCI) in British Columbia, Canada. The progenies from the plus trees were selected for their contrasting growth rates, stem form and wood density relative to the QCI control. Overall, the timber had characteristic values for density, MOR and MOEG consistent with the requirements for the C16 strength class. A significant difference in timber basic density was observed between two of the seed lots; however, there was no difference in MOR or MOEG between any of the seed lots. Most of the variation in strength properties in the study was attributable to differences between individual trees (»40 per cent) and individual pieces of timber from within a tree (»50 per cent), with only a small amount (⪅5 per cent) due to treatment differences. Results indicate that gains in merchantable log volume that have been achieved due to tree breeding do not appear to have been offset by a reduction in the mechanical properties of timber.

Citation

Moore, J. R., Mochan, S. J., Brüchert, F., Hapca, A. I., Ridley-Ellis, D., Gardiner, B. A., & Lee, S. . J. (2009). Effects of genetics on the wood properties of Sitka spruce growing in the UK: bending strength and stiffness of structural timber. Forestry, 82, 491-501. https://doi.org/10.1093/forestry/cpp018

Journal Article Type Article
Publication Date 2009
Deposit Date Apr 10, 2014
Journal jForsetry
Print ISSN 1464-3626
Electronic ISSN 1464-3626
Publisher Oxford University Press
Peer Reviewed Peer Reviewed
Volume 82
Pages 491-501
DOI https://doi.org/10.1093/forestry/cpp018
Keywords structural timber; Sitka spruce (Picea sitchensis (Bong.) Carr); density; modulus of rupture (MOR); modulus of elasticity (MOEG);
Public URL http://researchrepository.napier.ac.uk/id/eprint/6761
Publisher URL http://dx.doi.org/10.1093/forestry/cpp018