I am interested in ecosystem functioning and interactions between ecology and the environment with a specific interest on the impact of climate change on tropical forests. My latest research focused on the long-term responses of tropical trees to climate and increasing atmospheric [CO2] levels. In these studies I used tree rings and stable isotopes (δ13C, δ18O), which allow the reconstruction of historical responses of trees to climate over long time intervals and may tell us what to expect for the future. This also provides clues concerning to the resilience of tropical forests to predicted climate change. I am further interested in the reconstruction of past climates, and the use of isotopes as tracers for changes in the climate system. Recently, I started using oxygen isotope analysis of tree ring cellulose as a tracer for historical changes in the hydrological cycle of the Amazon.