Input of chemical elements to the forest ecosystem on the carpathian foothills (s. Poland)

Atmospheric inputs of elements (macro, micro nutrients and pollutants) to the pinebeech forest (Ratanica stream catchment, Carpathian Foothills, S Poland) were examined in the years 1991-1995. The input embraced bulk precipitation and throughfall. Chemical composition of precipitation was largely influenced by air pollution in the catchment. Four factors can be distinguished responsible for the raised ionic inputs to the forest: (1) long-range transport of pollutants bringing principally H^+, NO[3]^-, SO[4]^2-, CI^- and Pb^2+, (2) local emissions from domestic heating (mainly Zn^2-, Cd^2+ and Ca^2+), (3) local dust emissions from fields and roads (K^+, Mg^2+, Ca^2+), and (4) agriculture (NH[4]^+, PO[4]^3-). Concentrations and loads of some ions (SO[4]^2-, CI^-, Pb^2+, Cd^2+) to the forest tended to decline over the study period. Element inputs in bulk precipitation to the Ratanica catchment were moderately high, generally lower than those to polluted areas of Europe (Germany), and hig her the inputs to the relatively unpolluted regions (Scandinavia). In relation to forests of central and northern Poland, the inputs estimated were, as a rule, great. Sulphur and nitrogen loads to the study forest did not exsceed threshold values for the Carpathian Foothills. Chronic pollution of the forest ecosystem in Ratanica catchment seems to be responsible for transformations of lichen flora and herb layer composition. Gradual acidification of upper soil layers was found to occur in Ratanica stream catchment. Continuous atmospheric deposition has also led to heavy metal accumulation in the soil. Acid precipitation and substantial quantities of heavy metals may pose a threat to the forest ecosystem. Any further nitrogen input to the Ratanica forest may cause demands for the element to be exceeded, and the ecosystem to collapse.