Das Projekt "Teilnahme am europaeischen Programm zu oben offenen Kammern" wird vom Umweltbundesamt gefördert und von Fraunhofer-Institut für Umweltchemie und Ökotoxikologie durchgeführt. Objective: to check whether ambient concentrations of atmospheric pollutants cause direct visible damage or induces chronic (non visible) injury to forest trees. General information: the hypothesis here above mentioned will be tested by means of open-top chambers installed in sites remote from industrial and urban areas. These sites are characterized by relatively low average level of air pollution (compared with those occurring in areas where visible injury are undoubtedly attributable to air pollution). Forest trees are grown in a set of open-top chambers with filtered atmosphere. Comparison is done with identical plants grown in chambers with unfiltered atmosphere and with identical plants grown nearby, in open field. This project is part of a European open-top chamber network aiming at verifying the hypothesis at different European sites chosen in such a way that a representative range of ecological as well as air pollution conditions are covered (sites, pollutant exposure, climate conditions, etc.) In view of the necessity to generate comparable data, common experimental protocols are applied.