Natural variation in wood properties of Alnus acuminata H.B.K. grown in Colombia

Ninety-nine Andean alder (Alnus acuminata H.B.K.) trees were sampled from eleven regions in Colombia and Venezuela to determine the pattern of wood property variation between regions, between altitude within regions, between trees, and within a tree. A 5-mm-diameter increment core was extracted from each tree at breast height. The core was used to evaluate wood density and the dynamic compliance coefficient in the longitudinal direction. Based on mean regional values, wood density varied from 314 kg/m3 to 409 kg/m3; and dynamic compliance coefficient varied from 91 x 10-6 MPa-1 to 136 x 10-6 MPa-1. Single-tree values ranged from 249 kg/m3 to 446 kg/m3 for wood density, and from 81 x 10-6 MPa-1 to 187 x 10-6 MPa-1 for the compliance coefficient, respectively. The analysis of variance indicated that both wood properties vary considerably between geographic locations, between trees, and within a tree. The wood density tends to increase linearly from pith to bark, although there were differences in the magnitude of increase between regions. Finally, tree characteristics (tree height and diameter at breast height) were not related to wood properties.