Intraclonal Variation in Wood Density of Trembling Aspen in Alberta

Four trees from each of three putative clones of trembling aspen (Populus tremuloides Michx.) at one site in north-central Alberta were sampled to determine the patterns of wood density variation within stems and within clones. Sample disks were removed at five heights from each tree to examine variation among cardinal directions and across the southern radius at each height. Although only three clones were sampled, there were significant differences (0.05 level) among clones. Wood density tends to be high at the bottom of the tree, decreases to a minimum at midheight, then increases again near the top of the tree. In the radial direction, wood density is high near the pith (at all heights), decreases, then increases again in the mature wood zone (after rings 15-20+). Average wood density values within the twelve stems varied from 0.348 g/cc to 0.402 g/cc.