GLOBAL CHANGE CHALLENGES THE ENVIRONMENT THREATENING NATURE S ABILITY TO PROVIDE ECOSYSTEM SERVICES. ECOTONES HAVE BEEN IDENTIFIED AS IMPORTANT REGIONS TO MONITOR THE EFFECTS OF ENVIRONMENTAL AND HUMAN PRESSURES ON ECOSYSTEMS. CHANGES FROM NATURAL AND ANTHROPOGENIC PROCESSES MAY CAUSE A SHIFT IN SPECIES COMPOSITION AND VEGETATION STRUCTURE THAT OCCUR ACROSS ECOTONE TRANSITIONS. TO MONITOR CHANGES IN VEGETATION STRUCTURE GLOBALLY SATELLITE DATA ON ECOSYSTEM STRUCTURE WILL BE NEEDED. ONE SOURCE OF THIS INFORMATION WILL BE THE UPCOMING GLOBAL ECOSYSTEM DYNAMICS INVESTIGATION (GEDI) MISSION. SCHEDULED FOR LAUNCH LATE 2018 GEDI WILL PROVIDE BILLIONS OF HIGH-SPATIAL RESOLUTION MEASUREMENTS OF CANOPY STRUCTURE. THE OVERALL GOAL OF THIS PROPOSAL IS TO EXPLORE THE POTENTIAL OF GEDI DATA TO CHARACTERIZE CHANGES IN VEGETATION STRUCTURE ACROSS ECOTONES. IN PARTICULAR I WILL FOCUS ON ECOTONE TRANSITIONS WITHIN FOUR ECOREGIONS IN GABON USING LIDAR DATA COLLECTED BY THE LAND VEGETATION AND ICE SENSOR (LVIS) THE AIRBORNE SIMULATOR OF GEDI DURING NASA S AFRISAR EXPERIMENT. LVIS DATA ALONG WITH FIELD INFORMATION AND TERRESTRIAL LIDAR SCANS WILL BE USED TO DEVELOP AND TEST APPROACHES THAT IDENTIFY AND QUANTIFY STRUCTURAL VARIABILITY ACROSS ECOTONES. AN IMPORTANT OUTPUT OF THIS RESEARCH WILL BE THE DEVELOPMENT OF AN APPROACH FOR MAPPING ECOTONE STRUCTURE USING SPACEBORNE LIDAR DATA COLLECTED BY THE GEDI INSTRUMENT. THIS STUDY WILL CONTRIBUTE TO THE LARGER VISION OF CREATING A BENCHMARK MAP OF ECOTONE STRUCTURE OF THE EARTH THAT WILL ENABLE AN EVALUATION OF ECOTONE RESPONSE TO INCREASING ENVIRONMENTAL AND HUMAN PRESSURES IN THE FUTURE.