Huebner, Cynthia .
A Comparison of the Competitive Ability of Ailanthus altissima (Miller) Swingle (Tree of Heaven) and Acer rubrum L. (Red Maple) Under Different Growing Conditions.
Ailanthus altissima (TOH) is an exotic tree whose invasiveness has been attributed to its competitive ability, which is not yet documented. This research evaluated TOH’s competitive ability when grown with Acer rubrum (RM), a shade-tolerant tree. Two experiments were conducted for 2.5 months each. The first experiment used two light environments (high-light, HL = 1400 umolm-2s-1; low-light, LL = 100 umol-2s-1) and activated carbon to control for TOH’s allelopathic effects. The effect of density was evaluated in an additive series design. The second experiment, a replacement series with a density of 50, used the same two light levels, and added two nitrogen levels and the presence or absence of mycorrhizae. In the first experiment, TOH produced more root and shoot biomass under HL, but only at lower densities (20 and 50). At high densities (100) and HL, TOH root biomass was greater than that of RM. RM root and shoot biomass was greater under LL, but only at densities of 50 and 100. Activated carbon had no effect. Relative yields for both shoot and root biomass differed significantly between RM and TOH under LL, with RM being more competitive for all but 20 density, while TOH’s relative yields were higher under HL except 20 density. In the second experiment, TOH produced more root biomass than RM under HL and both mychorrizae and nitrogen levels. RM produced more shoot biomass than TOH under LL, low nitrogen, and with mycorrhizae, while TOH produced more root biomass under LL, low nitrogen, and no mycorrhizae. Neither TOH nor RM was more competitive based on relative yields under any second-experiment treatments. Thus, TOH was more competitive under HL while RM was more competitive under LL, but this behavior was less evident at low densities and when nitrogen and mycorrhizae levels differed.
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1 - Northern Research Station, USDA Forest Service, 180 Canfield St., Morgantown, WV, 26505, USA
Presentation Type: Oral Paper:Papers for Sections
Location: Council Chambers/SUB
Date: Monday, July 28th, 2008
Time: 8:15 AM