ZLV Online

Damages to forest stands are still urgent in some regions of the Czech Republic despite the current trend of continually decreasing SO2 and NOx emissions. Monitoring of the health condition of crowns in forest stands (according to ICP Forests) shows that the Czech Republic has been recently occupying the first place in Europe. Regarding the range of stress factors, one of possible reasons of damages to forest stands appears to be the synergic effect of sulphur, nitrogen and hydrogen ions depositions in combination with the climatic stress. The paper evaluates development of the potential throughfall deposition of hydrogen ions, sulphur and nitrogen in the territory of the Krušné hory Mts. NFR in the period from 2002 – 2005. Potential deposition flows of S, N and H+ are derived from the model calculations of SO2, NOx (NO and NO2) gaseous concentrations, and from their dry and wet deposition flows. The calculation of SO2 and NOx air pollution concentrations was made by using Gauss model of dispersal SYMOS 97. Derivation of dry sulphur and nitrogen depositions dwells on the application of deposition rates within a resistant model. Calculation of wet sulphur and nitrogen depositions (SO4-2 and NO3- components) dwells on parametrizations used in the MESOPUFF II Model. In addition, the calculation makes use of measured meteorological data characterizing dispersal conditions (wind direction and velocity, temperature stratification), concentrations of SO2 and NOx in the air and the chemical composition of atmospheric precipitation. The deposition flows were assessed in a network of reference points (1,257) representing forest stand sites in the territory of the Krušné hory Mts. The deposition field structure is based on the current status of emission and air-pollution loads in the Czech Republic and Europe and on meteorological conditions in the period from 2002 – 2005. The spatial distribution of the potential acid throughfall deposition suggests that the value of critical load of acid throughfall deposition (CLH) for spruce was exceeded on 84 – 91% of the area. In respect of eutrophication, the critical load of nitrogen for coniferous stands (CLN) was exceeded on 65 – 96% of the area.