Trait Acclimation Mitigates Mortality Risks of Tropical Canopy Trees under Global Warming

Area of Science:

• Ecology
• Plant Physiology
• Climate Change Science

Background:

• Global change significantly impacts tropical forests, with ongoing debate on tree mortality versus mitigating factors like CO2 fertilization and trait acclimation.
• The role of physiological trait acclimation in tropical trees' response to warming remains largely unquantified.

Purpose of the Study:

• To quantify the potential of trait acclimation to mitigate negative effects of warming on tropical canopy tree growth and survival.
• To incorporate trait acclimation into a physiological tree growth model for predicting tropical forest resilience.

Main Methods:

• Applied a physiological tree growth model with trait acclimation via an optimization approach.
• Simulated tree carbon gain under predicted 21st-century temperatures (25-35°C) and CO2 concentrations (390-800 ppm).
• Focused on traits with high plasticity (leaf photosynthetic capacity, total leaf area, stem sapwood area) for maximizing carbon gain.

Main Results:

• Full trait acclimation increased simulated carbon gain by 10-20% and maximum tolerated temperature by up to 2°C.
• Trait acclimation reduced the risk of tree death under predicted warming scenarios.
• Model indicated that acclimation cannot prevent tree death during extreme heat and drought events at current CO2 levels.

Conclusions:

• Functional trait acclimation can enhance tropical tree resilience to warming.
• Incorporating trait acclimation into field studies and predictive models is crucial for understanding tropical forest responses to climate change.