Forest ecosystems are known to be important sources of Biogenic Volatile Organic Compounds (BVOC). Due to their large emissions and their high reactivity with the main oxidants (OH, O3, NO3) in the atmosphere, these BVOCs play an important role in atmospheric chemistry. In order to be able to quantify net formation of oxidants and aerosols from BVOCs, the physicochemical oxidation and aerosol formation and/or growth have to be well understood.