Low-intensity elective logging of tropical forests is a promising means of according tropical forests economic value, thus providing a financial incentive for their retention. Currently lacking, but vital, are good data on the demography of timber species in order to make selective harvesting of tropical timber species sustainable. This study will examine in detail the ecology and demography of mahogany (Swietenia macrophylla), a valuable hardwood species in the Neotropics. Dr. Hubbell will study the demography of mahogany in (1) pristine forest, (ii) in recently logges forests, and (iii) forest logged 20 years ago. Demographic data from pristine forest will identify the factors responsible for controlling the abundance of mahogany in natural populations. Demographic data from the recently logged forest will provide data on immediate mortality of individuals during logging, and estimates of residual stocking after logging. The demography of mahogany in forest logging twenty year ago will provide data on the long-term response of natural populations to selective logging. Information from this study will aid in assessing the sustainability of current logging operations, and through simulation models, developing better forest management practises. Dr. Hubbell will also assist in forming a long-term research program by (i) training Bolivian nationals in data collection and analysis techniques, and (ii) establishing permanent forest inventory plots, which will provide the basis for future research on other potentially commercial species.