There is large variation in wood characteristics, which contradicts the expectations of the consumers for the uniform quality. For example in Scots pine (Pinus sylvestris L.), heartwood timber is more resistant than the sapwood against the biological degradation due to rot fungi. Moreover, the outer heartwood is more durable than the inner heart-wood. Besides the within-tree variation, there is large variation between individual trees in the durability as well as in the concentration of protective extractives in the heart-wood. The wide natural variation in wood quality traits can be seen as a source to be exploited. For example, durable wood could be used in outdoor-structures, where decay resistance is needed. However, to find the most durable heartwood is a demanding task, where indirect measures are needed. The development of fast and reliable non-destructive methods for grading of heartwood timber could be based on the strong rela-tionship between the decay resistance and the concentration of extractives. It would be possible, with an appropriate measurement technique such as FT-NIR spectroscopy, to grade existing heartwood according to its concentration of e.g. phenolic compounds. One aim of our studies has been to participate in the development work to predict the extractive content and consequently the durability of the Scots pine heartwood material. A uniform natural durability, including a prediction of service life, would add the value of wooden products.
Keywords: Decay resistance, heartwood extractives, natural variation, timber, grading
Authors
Harju A.M.
innish Forest Research Institute, Punkaharju Research Unit, Punkaharju
Venäläinen M.
innish Forest Research Institute, Punkaharju Research Unit, Punkaharju
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