The effect of elevated CO2 and temperature on forest growth is studied by applying a variety of growth models to szenarios produced by weather generators. Forest yield and carbon budgets of European forests is examined with a summary model. In this context the process of upscaling to the regional level is investigated. Our main contributions consist in applying the forest growth models TRAGIC++ and TREEDYN3 at coniferous and decidious forests at selected European sites and to study acclimation effects of the forest ecosystems. The project is carried out in close cooperation with the Center for Environmental Systems Research at the University of Kassel.