Uncertainty in climate sensitivity of tropical forests is a major constraint in predicting 21st century climate change impacts. Long-term responses are determined by resilience, which is the ability of a forest to absorb disturbances and re-organize under change (through tree mortality and recruitment) to maintain similar functioning and structure. This project aims to disentangle this resilience by quantifying short-term and long-term shifts in forest properties and by focussing on a most enigmatic ecoregion: the Congo Basin. We will build a multi-temporal dataset consisting of three data types: forest inventory data, tree functional traits, and fossil charcoal. The dataset will be geographically integrated by concentrating data collection on existing permanent forest inventory plots. This will allow quantification of changes in Congo Basin forests at multiple time scales: (i) the repeated plot inventory data itself will reveal decadal-scale changes in the carbon balance and biodiversity, while (ii) radiocarbon dating and identification of fossil charcoal assemblages will reveal century-scale and millennial-scale changes in biodiversity. The wide array of measured tree traits will allow in-depth analysis of changes in functional composition across time scales. This project has the ambition to force important breakthroughs in multiple scientific fields and provide the much-needed leverage to force better (inter)national protection and conservation of DRCongo’s forests.