9630397 Bazzaz The central role of competition in the ecology and evolution of plant is a widely accepted concept. Yet, our understanding of the mechanisms of competition is quit limited, in part because it does not have a strong mechanistic basis. This project proposes a novel, multi- level approach to the study of plant competition. The approach combines a new method for characterizing physiological aspects of resource competition with traditional growth analyses and demographic techniques. The system chosen for the study is competitive interactions in experimentally established field monocultures of two birch species, (Betula alleghaniensis and B. populifolia), that differ in their requirements for light, water and nutrients. Resource uptake and stand development will be monitored for two years. A third year will be devoted to processing plant and soil samples and to modeling and synthesizing data. The results will allow us to assess the magnitude and relative importance of competition for light and nutrients at various stages of stand development, and to empirically test a number of current hypotheses regarding resource competition among plants. The research will be an important step in bridging the gap between well-developed phenomenological models of plant competition and stand development, and the physiological mechanisms of competition.
