Mon, Aug 02, 2021:On Demand
Background/Question/Methods
Drought can act over seasons to decades and beyond, with notable examples in tropical forests evident in the recent past, as well as in a range of possible futures this century. However, studying drought responses by trees and forests over ecologically meaningful timescales is challenging. This is especially true at stand scale, where both inter- and intra-specific variations in growth, drought-induced tree mortality rates and acclimation among different plant physiological traits can all influence long-term biogeochemical and ecological trajectories, with large potential global impact. As part of our attempts to address this challenge, we synthesise recent findings from the world’s only multi-decadal (20 yrs) and stand-scale (1 ha treatment) throughfall exclusion experiment in tropical forest, situated in eastern Amazonia.
Results/Conclusions We quantify and analyse: (i) how different physiological traits (metabolic, hydraulic) exert control upon growth and how this changes during drought; (ii) how traits differ in their capacity to acclimate under long-term drought stress, and how taxonomic identity and tree size influence these processes; (iii) how new high-resolution laser-based structural analysis is transforming our quantification of metabolic, structural and growth responses to drought; and (iv) how drought alters overall water use and water stress at individual tree and stand-scale, over different timescales. The results connect a series of new findings that inform short- and long-term influences of future drought on tropical forest structure, function and composition. They also highlight the importance of accounting for diversity across physiological trait responses and species identity.
Results/Conclusions We quantify and analyse: (i) how different physiological traits (metabolic, hydraulic) exert control upon growth and how this changes during drought; (ii) how traits differ in their capacity to acclimate under long-term drought stress, and how taxonomic identity and tree size influence these processes; (iii) how new high-resolution laser-based structural analysis is transforming our quantification of metabolic, structural and growth responses to drought; and (iv) how drought alters overall water use and water stress at individual tree and stand-scale, over different timescales. The results connect a series of new findings that inform short- and long-term influences of future drought on tropical forest structure, function and composition. They also highlight the importance of accounting for diversity across physiological trait responses and species identity.