GENETIC VARIATION IN WOOD MECHANICAL PROPERTIES OF CALYCOPHYLLUM SPRUCEANUM AT AN EARLY AGE IN THE PERUVIAN AMAZON

摘要

Calycophyllum spruceanum (Benth.) Hook. f. ex Shum. is an important timber species of the Peruvian Amazon Basin. Due to overexploitation in natural populations, users are turning to young trees of potentially lower quality. Therefore, variation in juvenile wood properties should be investigated to determine whether wood quality can be maintained or, if necessary, improved by breeding. A provenance/ progeny test was established to evaluate genetic variation in growth and wood properties of young trees, the strength of their genetic control, as well as their interrelationships both at the genetic and phenotypic levels. This paper presents results obtained for ultimate crushing strength (aL), the static compliance coefficient (sn) in longitudinal compression, the dynamic sn in the longitudinal direction (determined by ultrasound), and air-dry density at 39 months. Results indicate that the mechanical properties of juvenile wood of this species are adequate for structural uses. There was significant variation in all wood properties due to families within provenances, and in all but dynamic S_11 due to provenances. Families accounted for a larger percentage of the total phenotypic variance than provenances. Heritability estimates were higher for sigma_L and static sn than for dynamic sn and density. Genetic correlations indicate that selecting trees with denser wood and/or faster growth would have a positive effect on some mechanical properties. A non-destructive ultrasonic method appeared suitable for estimating juvenile wood strength and stiffness of this species.