Forests absorb 30% of current annual CO2 emissions through photosynthesis and growth, with tropical forests storing the majority of global live biomass in forests. However, due to climate warming, their ability to act as carbon sinks is uncertain, and they could even become carbon sources as trees stressed by climate extremes die and release their carbon back into the ecosystem. Here we will work within a unique FACE (free-air CO2 enrichment) experiment in the Brazilian tropics: AmazonFACE. This experiment will simulate the atmospheric CO2 composition of the near future (50 year). The project’s overall goal is to improve our understanding of how forest dynamics and elevated CO2 concentrations impact the microclimate buffering capacity in tropical rainforests. The project's five main research objectives are methodological and ecological and are anticipated to lead to at least three substantial scientific breakthroughs: an improved understanding of how forest dynamics affect the microclimate buffering; quantified aboveground biomass allocation in 3D through terrestrial laser scanning and model parameterisation to test the influence of elevated CO2 on forest carbon use. This project is a collaborative effort between UGent and USP that brings together the knowledge of both groups to work on this interdisciplinary project.