RFA1: Climate change effects on tree function, stress response, and mortality.
How do drought and elevated temperature related to climate change impact tree physiology and mortality?
Phase 2 research will focus on advancing understanding of water sourcing, hydrodynamics, tree canopy exchange of CO2 and water, carbon storage, plant respiration, defense strategies, and damage associated with elevated tree mortality risks. RFA1 will provide new understanding and model representation of physiological processes that enable FATES to more accurately predict forest functional response, damage, and tree mortality as a response to drought and elevated temperature.
Plant water sourcing. Using existing and new data collected pantropically, we will improve mechanistic representation in FATES of water extraction patterns and their direct linkages to soil texture, tree root distribution, plant hydraulic traits, and hydraulic stress.
Plant hydraulics and carbohydrate dynamics. We will advance understanding and model accuracy regarding the responses of plant hydrodynamics, gas exchange, and carbon metabolism to drought and elevated temperatures.
Leaf and canopy processes. Through model development and measurement we will advance the representation of physiological processes at the leaf and canopy scales to improve projections of tropical forest responses to rising temperatures and drought.
Whole plant respiration and defense. We will advance understanding and model representation of plant respiratory response to elevated temperature and drought, and carbon balance, and costs associated with functional defenses against the negative effects of environmental stressors.
Damage and elevated mortality risk. Our aim is to determine the mechanistic links and improve relevant processes in FATES between embolism, carbon storage, crown damage and subsequent tree mortality.
Figure 1. A set of integrated measurements and monitoring systems are being further developed for all RFA1 field sites (Manaus, Panama, Lambir Hills, Daintree), as illustrated here for the Manaus “hillslope site,” to ensure comprehensive comparative studies of the impact of temperature and moisture stress on tree ecophysiology across sites.