RFA2: Forest structure and composition along environmental gradients.
How do forest structure and composition vary in response to plant available water, soil fertility, and disturbance?
Representing tropical forest structure and functional composition, and how they mediate responses to climate and disturbance from ecosystem to Earth-system scales are key innovations that FATES provides to E3SM. During Phase 2 the NGEE-Tropics team will focus on developing accurate representations of forest composition and functional diversity as they relate to water and nutrient availability, and disturbance regimes. To support this activity, we will investigate mechanisms which can lead to stable functional coexistence in FATES. Lastly, RFA2 will also develop a new nutrient-enabled version of FATES, allowing forest functional assembly to vary with competitive interactions for limiting nutrients.
WP2.1: Mechanisms and tradeoffs for differential functional assembly. Our objective is to investigate how trait selection, model assumptions, demographic process representation, and the sampling of trait data and temporal variation within FATES impact the capacity of the model to simulate functionally diverse ecosystems.
WP2.2: Functional composition across plant-available water gradients. We will explore how diversity in tree hydraulic strategies governs forest response to local and regional plant water availability and determines forest structure and functional composition.
WP2.3: Forest structure and function across nutrient gradients. We are developing the empirical basis and FATES algorithms to represent nutrient acquisition, allocation, and demand in tropical trees to enable FATES to simulate key features of tropical forest structure and function across nutrient gradients.
WP2.4 Disturbance Regime Effects on Forest Structure and Dynamics. We aim to develop and test the ability of FATES to predict forest structure and composition in response to landscape-scale disturbances and variation in disturbance regimes, including fire, wind and agricultural land use.