9310049 MORAN Clearance of large tracts of tropical forests like those in the Amazon Basin has potential impacts on many processes ranging from loss of biological diversity to changes in atmospheric chemistry that affect global temperature and precipitation patterns. Considerable attention has been devoted to identifying rates and patterns of deforestation, but much less scholarly inquiry has been given to assessing the degree to which native tree species reestablish themselves in cleared areas. The investigative team undertaking this research project have engaged in research on regeneration rates in two parts of the Amazon Basin where soils are relatively rich in nutrients. This project will expand the comparative framework for this line of research by using similar methods to investigate three sites with soils containing fewer nutrients. Two of the sites are in the Zona Bragantina of Brazil; the other is in the Rio Negro Basin in Colombia. Thematic Mapper digital data from Landsat satellites will be analyzed in concert with field-based investigations of land-use change and management practices in the study sites to identify spatial and temporal patterns of clearance and regeneration. This project will make contributions to general knowledge from both substantive and methodological perspectives. It will add to understandings about the processes of forest clearance and regeneration in different environments, thereby providing the basis for making more accurate regional adjustments in models of carbon exchange. It also will continue exploration of new ways to integrate remotely sensed and ground-based data for large areas, a methodological thrust that will enhance and expand capabilities for data acquisition across large areas. ***