2024 Abstracts

The Past and Future of NGEE Tropics Measurements and ModEx


Nate McDowell1* (nate.mcdowell@pnnl.gov), Jeffrey Warren2, Chonggang Xu3, Alistair Rogers4, Kolby Jardine4, Stuart Davies5, Daniel Zuleta5, Zachary Robbins3, Cynthia Wright6, Rutuja Chitra-Tarak3, Alfonso Zambrano5, Bruno Gimenez7, Crist Santos7, Gustavo Spanner7, Regison Oliveira7, Niro Higuchi7, Robinson Negron-Juarez4, Mizanur Rahman1, Kurt Solander3, Julien Lamour8, Joe Wright5, Michael Keller6, Jeffrey Chambers4,9, NGEE Tropics team


1Pacific Northwest National Laboratory, Richland, WA; 2Oak Ridge National Laboratory, Oak Ridge, TN; 3Los Alamos National Laboratory, Los Alamos, NM; 4Lawrence Berkeley National Laboratory, Berkeley, CA; 5Smithsonian Tropical Research Institute, Panama City, Panama; 6USDA Forest Service; 7National Institute of Amazonian Research, Manaus, Amazonas, Brazil; 8French National Centre for Scientific Research, France; 9University of California–Berkeley, CA



Next-Generation Ecosystem Experiments (NGEE) Tropics has promoted leaps forward in understanding of tropical tree function from root to global scales using deliberate integration of empirical and numerical approaches. The empirical work has tested numerous hypotheses regarding tropical tree function at the site level, the data of which are being employed for model development. Functionally Assembled Terrestrial Ecosystem Simulator (FATES) efforts have simultaneously resulted in large advances in mechanistic representation of forest function. One critical next step is to emphasize efforts on model-experiment (ModEx) hypotheses from tissue to pantropical scales. To test FATES’s capability to simulate physiological and demographic processes, the model will be evaluated at five sites located across Malaysia, Panama, and Brazil, where extensive water- and carbon-related traits and processes are being measured at root to whole-tree scales. These simulations allow rigorous evaluation if the model gets the right answers for the right reasons and simultaneously allows tests of alternative mechanisms underlying variation in carbon and water fluxes and demography. At the pantropical scale, the team is utilizing long-term networks of forest demographics, carbon storage, nutrient availability, and functional traits to provide the basis for empirical and numerical hypotheses. Finally, remotely sensed datasets are being used for model parameterization of biomass, wind disturbance, and land use at large scales. Here, the team summarizes the existing and planned datasets, model developments, and associated ModEx efforts and highlights the key next steps to achieve the goal of generating a process-rich model that accounts for carbon dioxide, climate, and land-use impacts on the pantropical carbon sink.