I am working at the frontier between biological and environmental sciences, at the interface with global change. My major contributions to current debates have been in the study of the dynamics of forests, particularly carbon and water cycles. I have worked in Boreal, temperate, tropical and Mediterranean forests and in deserts. I have worked in Europe, USA, Australia, Brazil, Peru and Africa. I have authored about 200 peer-reviewed papers. I am currently the leader of two 1.5 million-pound projects (a- the effects of nitrogen deposition on the carbon balance of Sitka spruce forests, and b- the effects of drought in accelerating mortality of trees in the Mediterranean), and I am also interested in the mechanisms of drought-induced mortality in the tropics. I also work closely with the forestry sector on a large range of themes, including the regional modelling of growth and carbon sequestration using a combination of modelling, data assimilation and remote sensing.