How do ecological processes structure temperate and tropical plant communities? Our research emphasis is on the ecology of temperate and tropical terrestrial ecosystems, particularly forests but including shrub and herbaceous plant communities of Lake Michigan sand dune habitats. Among the features of primary interest to us are plant growth, primary productivity, patterns of biomass distribution, regeneration, and species diversity and distribution. Many of our field studies have been and continue to be in tropical locations, e.g., Venezuela, Puerto Rico, northern Australia, Zaire, Uganda, and Kenya. Increasingly our focus has been on the water-stressed types of tropical forest, such as dry forest, highly seasonal or monsoon forest, and floodplain forest, and the manner in which the vegetation responds to water stress. In the temperate zone our work has been concentrated in the Great Lakes region with focus on beech-maple, oak-hickory, white pine, northern white cedar, and jack pine forest types. Several of our projects have concerned the interactions among people, animals, and plants and conservation/management strategies for assuring co-existence under disturbed conditions. The basic underlying objective in all of our studies has been to elucidate fundamental aspects of ecosystem structure and function, including those that can be applied to the development of strategies for resource management and conservation.