MAPPING OF THE ACIDITY CRITICAL LOADS FOR FOREST ECOSYSTEMS IN THE KYSUCE AND ORAVA REGIONS

The aim of our research was mapping the critical loads of acidity (CL) for forest ecosystems in the Kysuce and Orava region, where the problem of non-native forest decline became really actual in the last years. The widespread Steady State Mass Balance (SSMB) approach was applied for spatial mapping of CLs. The maps and histograms of critical loads of sulphur and nitrogen for the most prevailing tree species in the subject region (spruce, beech, fir and pine) are presented. Spatial distribution of critical load exceedance was obtained by comparison of the calculated critical limits with the values of sulphur and nitrogen depositions modelled for time span of 2000 - 2005. The evaluation of maps calculated by SSMB proved total exceedance of acidity CL at 13,7% within the whole Kysuce and Orava area. The highest values of exceedance are related to the soils with low potential of the basic cations weathering (podzol, acid and pseudogley soils). Local calculation for the research plot Sadibolovci (901 m a. s. l.) was realized by multi-layer steady-state PROFILE model. It was found that critical load calculated by PROFILE model is a little enhanced at research plot Sadibolovci, which means that acid input from the atmosphere is higher than the buffering ability of forest soils against acidification. Based on that fact between 10 to 20 percent of the trees at this locality could be weakened or even seriously damaged as a result of some chemical changes within the forest ecosystems.