LAUSR

Abstract12 years old trees from 20 progenies/provenances of Japanese larch (Larix kaempferi, [Lamb.] Carr.), planted in Quebec, were sampled to study the variation in selected mechanical properties. Two standard wood samples and one 10-mm diameter increment core were taken from each tree at breast height. The parallel-to-grain compliance coefficient and ultimate crushing strength were evaluated on the standard samples at air-dry conditions. The dynamic compliance coefficient was measured on increment cores using an ultrasonic wave propagation method. Differences in all mechanical properties among progenies/provenances were significant. Lowest static compliance coefficient and highest ultimate crushing strength were found in progenies/provenances 8934, 7795, 7283, 8962, 8907, 7794, and 8939, being the most interesting for a lumber end-use. Among them, progenies/provenances 7283, 8934, 7794, 7795, 8962, and 8907 also showed lowest dynamic compliance coefficient. The latter coefficient tended to be lowest near the pith and then increased outward towards the bark. There was also a highly significant correlation between static mechanical properties, and a moderate correlation between static and dynamic compliance coefficients. Ultimate crushing strength was moderately correlated to wood density.