Natural VOC emissions from forests in Poland

On the basis of the last inventory of forests and climatic conditions in Po land, a national evaluation of the emissions of reactive volatile organic c ompounds (VOCs) was carried out. Calculations took into account the composi tion and age structure of forests as well as the temperature dependencies o f VOC emission rate for the main European forest-forming tree species. In t he case of isoprene, the dependence on illumination level and day length wa s also taken into account. Estimations were made for all 49 administrative regions of Poland. Depending on weather conditions in different years, the total VOC emission of Polish forests can be in the range 186-763 kt yr(-1). For instance, for a moderately warm year, 1992, it was estimated at 440.6 kt, which represents 25% of the total VOC emissions in Poland. (C) 1999 Els evier Science Ltd.