Response of spruce stands in national parks of southern Poland to air pollution in 1998-2005

The purpose of this study was to describe changes in the deposition of air pollutants and the response of spruce trees in the period of 1998-2005. The investigation was carried out in twelve sites, mainly national parks. Air pollution level, that is, SO2, NO2, and O-3 concentrations in the air, as well as throughfall and soil solution chemical composition was analysed. The reaction of trees was described based on a stand health parameter, that is, defoliation. A decrease in the concentration of SO2 and NO2 in the investigated period was observed. In most of the analysed sites, ozone concentrations in the growing season exceeded the level regarded as harmful to plants. Annual loads of nitrogen and sulphur reaching the forest soil exceeded 10 kg/ha. The data collected for the analysed period confirmed that the health status of forests at the investigated sites did not show a general tendency towards improvement. Also, no dependency between the air pollution level and defoliation rate was found.