Anthropogenic acidification effects in primeval forests in the Transcarpathian Mts., western Ukraine

The precipitation chemistry, deposition, nutrient pools and composition of soils and soil water, as well as an estimate of historical deposition of sulphur (S) and inorganic nitrogen (N) for the period 1860-2008, were determined in primeval deciduous and coniferous forests at the sites Javornik and Pop Ivan, respectively. Measured S throughfall inputs of 10 kg ha-1 year-1 in 2008 were similar to those estimated for the period 1900-1950 at both sites. The highest estimated S inputs were in the 1980s. Measured bulk deposition of N in 2008 was lower at Pop Ivan (5.6 kg ha-1 year-1) compared to javornik (12 kg ha-1year-1) Significantly lower NO3 deposition was both estimated and measured at Pop Ivan. Higher soil base cation concentrations were observed at well-buffered Javornik underlain by flysch (Ca pool of 2046 kg ha-1 and base saturation of 29%) compared to Pop Ivan underlain by crystalline schist (Ca pool of 186 kg ha-1 and base saturation of6.5%). The soil pool of organic carbon (C) was higher at Pop Ivan (212 t ha-1) compared to Javornik (127 t ha-1 ). The C concentration was positively correlated with organic N in the soil (p<0.001) at both sites, but the mass average C/N ratio in the forest floor was lower at Javornik (22) than at Pop Ivan (26). High N leaching of 17 kg ha-1 year-1 at the 90 cm depth was measured in the soil water at Javornik, suggesting high mineralization and nitrification rates in old growth deciduous forests in the area. Despite relatively low Al concentrations in the soil water, a low soil water Bc/Al ratio (0.9) (Bc = Ca + Mg + K) was found in the upper mineral soil at Pop Ivan. This suggests that the spruce forest ecosystems in the area are vulnerable to anthropogenic acidification and to the adverse effects of Al on forest root systems.