Forest models can be useful tools to improve our understanding of forest dynamics and to evaluate potential impacts of climate change. There is an ongoing debate how drought events influence the dynamics of tropical forests. In this study, we explored the role of changes in precipitation on tropical forests in Madagascar. Therefore, we derived a new parameterization of the process-based forest model FORMIND using local forest inventory measurements. This model was extended by a drought sensitivity module based on a water use efficiency concept.

The objective of this study is to evaluate how different levels of water availability modify forest productivity, and net ecosystem exchange as a function of mean annual precipitation. Our simulation results indicate that a moderate precipitation decline (0%–30% of current precipitation conditions) has only minor impact on forest carbon stocks and exchange. A rainfall decline below 30% of current precipitation conditions would change forest structure considerably.