STAND DEVELOPMENT IN ASPEN CLONES

The growth of trembling aspen (Populus tremuloides Michx.) sprouts in two separate clones was measured annually for 6 years and at year 12 (site 1) and for 5 years and at year 11 (site 2) following sprout initiation. Over 98% of the stems were established within the first growing season after cutting. By the end of the first growing season, height-frequency histograms were positively skewed and coefficients of variation of height were 56 and 60% for sites 1 and 2, respectively, reflecting the presence of many small and few large stems. By the 3rd year after establishment, over 50% mortality of stems occurred and the coefficients of variation of height had declined to approximately 47% for both sites. Although the results of this study may not have widespread implications because of the limited number of clones, the pattern of stand development observed in aspen was similar to that documented for even-aged monospecific stands of nonclonal woody species, with the possible exception that self-thinning occurred at a more rapid rate in aspen.