GROWTH OF POPULUS-TROMULOIDES IN ASSOCIATION WITH CALAMAGROSTIS-CANADENSIS

Three experiments were conducted to examine the effects of Calamagrost is canadensis (Michx.) Beauv. on the growth of Populus tremuloides Mic hx. Containerized seedlings of P. tremuloides were transplanted into l arge pots and subjected to (1) three soil temperatures (20, 12, and 6 degrees C), (2) root competition with C. canadensis, or (3) presence o r absence of C. canadensis litter, each at two nutrient regimes. In th e first experiment, significant differences (p = 0.0001) in pre-and ne o-formed leaf area and root and shoot dry weights were observed for pl ants subjected to the three different soil temperatures. In experiment two, the presence of C. canadensis significantly (p < 0.001) reduced total biomass, plant height, and root collar calliper of P. tremuloide s. In the third experiment, a significant interaction (p = 0.027) betw een C. canadensis litter and nutrient regime was observed, with the gr eatest inhibitory effect on P. tremuloides growth resulting from litte r at the low nutrient regime. Low soil temperature had the strongest n egative effect on P. tremuloides of the four factors investigated. How ever, direct competition with C. canadensis, low nutrient conditions, and C. canadensis litter likely would add to the growth suppression of P. tremuloides by this grass. The results of this study have signific ant implications for the management of P. tremuloides after harvesting .