Tropical forests cycle more carbon and water than any other ecosystem, and they play critical roles in determining Earth’s energy balance. Additionally, intact tropical forests are estimated to be Earth’s largest carbon sink, yet the processes controlling tropical forest carbon cycling are not well established. Understanding of carbon and related water and energy exchanges between tropical forests and the atmosphere lags that of other ecosystems, and poor model representation of these processes is the most significant source of terrestrial uncertainty in climate projections. To address these challenges, the Terrestrial Ecosystem Science (TES) program within the Department of Energy’s (DOE) Office of Biological and Environmental Research (BER) is supporting a next-generation ecosystem experiments project in the tropics (NGEE–Tropics).
During the first phase of the 10-year NGEE–Tropics project, researchers will assess what is known about tropical forest ecosystems and how well these processes are represented in models. Several initial field studies are being developed at key sites and globally across the tropics. Pilot studies in Brazil, Panama, and Puerto Rico will link modeling advances with field observations.
Measurements at these sites are designed to fill high-priority knowledge gaps and encompass investigations on (1) forest carbon cycle−hydrology interactions, (2) nutrient limitations on tropical secondary forests, (3) plant functional diversity response to climate change, and (4) regional variability in the causes of tree mortality.
Results from these Phase 1 NGEE–Tropics research activities will guide both model development and additional pantropical fieldwork that will be conducted in Phases 2 and 3.