Emission of biogenic volatile organic compounds:: An overview of field, laboratory and modelling studies performed during the 'Tropospheric Research Program' (TFS) 1997-2000

The present paper summarises results on the emission of biogenic volatile organic compounds (BVOC) achieved within the frame of the national'German Tropospheric Research Programme' (TFS) between 1997 and 2000. Field measurements were carried out at the meteorological monitoring station `Hartheimer Wald' located in the vicinity of Freiburg (upper Rhine valley), Germany, within a pine plantation dominated by Scots pine (Pinus sylvestris L.). The measured BVOC emission rates were used to determine the daily and seasonal variation of BVOC emission and its dependence on important meteorological and plant physiological parameters. In parallel, laboratory experiments using young trees of pine (P. sylvestris), poplar (Populus tremula xP. alba) and pedunculate oak (Quercus robur L.) were performed, and the influence of abiotic (e.g., light, temperature, seasonality, flooding) factors on the biosynthesis and emission of BVOC was quantified. Based on these data, emission algorithms were evaluated and a process-oriented numerical model for the simulation of the isoprene emission by plants was developed. In addition, newly calculated land use and tree species distributions were used for the calculation of an actual BVOC emission inventory of Germany.