Stockability, growth, and yield of the circumboreal aspens (Populus tremuloides Michx., P. tremula L).

The authors show elsewhere that quaking aspen (Populus tremuloides Michx.) and its Eurasian counterpart, P. tremula L., form a single circumpolar superspecies when viewed from the standpoint of self-thinning rates and stockability. Here the authors expand their examination to the d.b.h.-age relationships and to growth series measurements from permanent plots of aspen stands of varying densities reported in the literature. They also attempt to account for the curvilinear trend in the self-thinning relationship they detected in young stands that forced them in their first analysis to truncate their usable data set to older stands. The resulting equations satisfy the need for a framework to study variation in aspen stockability. The equations can give useful regional estimates as well, but will need refitting to local data to satisfy needs for finer resolution.