Canadian Forest Service Publications
Genetic improvement of white spruce mechanical wood traits – early screening by means of acoustic velocity. 2013. Lenz, P.; Auty, D.; Achim, A.; Beaulieu, J.; MacKay, J. Forests 4:575-594.
Issued by: Canadian Wood Fibre Centre
Catalog ID: 34926
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There is a growing interest to use acoustic sensors for selection in tree breeding to ensure high wood quality of future plantations. In this study, we assessed acoustic velocity as a selection trait for the improvement of mechanical wood properties in two 15- and 32-year-old white spruce (Picea glauca [Moench.] Voss) genetic tests. Individual heritability of acoustic velocity was moderate and of the same magnitude as heritability of wood density. Considerable genetic gain could be expected for acoustic velocity and a measure combining velocity and wood density. The relationship between acoustic velocity and cellulose microfibril angle (MFA) was strong on the genetic level and selection based on velocity could effectively improve MFA, which is one of the most important determinants of wood mechanical properties. Although low, the positive relationship between acoustic velocity and tree height presents an interesting opportunity for the improvement of both tree growth and wood quality. On the phenotypic level, MFA was more strongly correlated to acoustic velocity in mature trees than in young trees. The addition of easily obtainable traits such as diameter at breast height (DBH), height-to-diameter ratio as well as wood density to velocity determinations could improve models of MFA at the young and the mature age. We conclude that juvenile acoustic velocity is an appropriate trait to select for wood quality in a tree breeding context.
Plain Language Summary
The wood from boreal conifers is primarily used to make structural building components where mechanical properties such as stiffness play an important role. The programs originally developed for the genetic improvement of conifers were essentially aimed at increasing growth and adaptability. However, recent studies show a negative relationship between rapid growth and the mechanical properties of wood, hence the need to take this into consideration in tree improvement programs.
The purpose of this study, carried out for white spruce, was to find a simple, quick and low-cost method for selecting young (15-year-old) trees with the best mechanical properties. To this end, the researchers demonstrated that using an acoustic sensor to measure the speed of sound waves in the trunk gives a good indication of these properties. This technique is therefore a useful tool for selecting trees with the best mechanical properties.
Because these characteristics are hereditary, measuring sound propagation can be used in genetic improvement programs to obtain trees with better mechanical properties for future plantations. Early evaluation makes it possible to accelerate these programs.