Patterns of growth dominance in thinned yellow-poplar stands in the southern Appalachian Mountains, USA
Abstract
Growth dominance provides a quantitative description of the relative contribution of individual trees to stand growth. Positive dominance occurs when the largest individuals account for a greater proportion of growth period increment than total biomass. Conversely, negative dominance occurs when the smallest trees account for a greater proportion of the growth period increment than of total biomass. This study uses the relatively new concept of growth dominance to examine long-term changes in tree growth patterns in thinned yellow-poplar (Liriodendron tulipifera L.) in the southern Appalachians. Growth dominance decreased with site index and the interaction between residual relative density and site index but increased with residual relative density and years since thinning. These relationships suggested that discrepancies in growth dominance among varying degrees of residual relative densities, with stands thinned to lower densities displaying negative growth dominance relative to stands receiving less intense thinning treatments, decreased over time. This negative growth dominance indicates that the stand-level growth included a disproportionate increase in growth of nondominant trees. The concept of growth dominance in a management context appears useful for assessing the efficacy of thinning treatments in meeting various management objectives and should be considered a potential tool for quantifying the relative success of management alternatives.