The overall goal of my research program is to understand the ecological processes governing the dynamics of tree communities in temperate and tropical forests. My focus is explicitly on the mechanisms that cause changes in relative abundance and diversity of tree species through time and across gradients of soil resource availability. Examples of some of the boader questions that my lab group addresses include: What are the mechanisms - both the particular environmental factors and process responses to those factors -- that cause landscape-level variation in forest composition? How do anthropogenic effects on soil resources manifest through these mechanisms? How can hundreds of tree species, all of which use the same resources, co-exist in wet tropical forests? Why isn't there just one or a few dominant tree species in these systems? To address these types of questions, my lab group designs field experiments to calibrate individual-based, species-specific models of tree performance (e.g. mortality, growth, reproduction, dispersal) in relation to plant resource availability and biotic interactions. The models, specified as simple equations with coefficients of biological meaning, are integrated, analyzed, and simplified to develop general theory of the environmental constraints and processes that cause patterns at the forest community and landscape levels.