DendroGrad: Tree-rings, wood anatomy and hydraulic traits do evaluate long-term CO2-fertilisation effects across environmental gradients on three tropical tree species

Abstract

One of the major challenges in tropical forest ecology and climate change studies is predicting responses of tropical ecosystems to the synergistic effects of different global environmental changes: temperature, atmospheric CO2 levels, nutrient and water availability. The research proposed here will apply state-of-the-art techniques in the field of tropical forest ecology: hydraulic-trait measurements, tree-ring analysis, quantitative wood anatomy, and stable isotope measurements to elucidate temporal and environmental responses of tropical tree growth and functioning. We will quantify these responses at sub-continental scale and evaluate the modifying role of soil fertility and rainfall on hydraulic traits, climatic drivers of tree growth and to assess tree responses to the rise in atmospheric CO2 levels of the last ~150 years. We aim to: (1) assess how hydraulic traits related to drought resistance, and the wood anatomical drivers behind these traits, vary across rainfall and soil fertility gradients; (2) unravel how yearly climatic variation affects tree growth and anatomy and how this climate influence varies over rainfall and soil fertility gradients; and (3) study CO2-fertilization of tree growth and evaluate whether the magnitude of this fertilization is mediated by rainfall and soil fertility. We will assemble a unique dataset on key environmental drivers of performance and function of three widespread tree species and assess how these factors vary over broad resource gradients. Finally, this project will help establish an integrative and cutting-edge research line in the state of São Paulo and train undergraduate, MSc and PhD students in state-of-the-art ecological methods. (AU)