Input of Sulphur and Acidity in Three Spruce Stands in the Vicinity of a Strong SO2-Source

Deposition measurements (flux rates) in three spruce stands in the vicinity of a strong SO2 source are discussed concerning the role of long range transport/local sources, input of air pollutants and reactions of trees on input of H+. High total deposition rates of H+, deriving from the SO2 emissions of the paper mill to a great extent, are resulting in high leaching rates of Ca and K (Mg,Mn) out of the canopy. Although CECeff. of soils indicate strong acidification of all sites, the exchangeable pool of cations (Ca, Mg, K Mn) seems to be sufficient for buffering 20–35 % of total H+ input in the canopy. Total deposition rates of S and H+ exceed critical load levels by far. Official air pollution measurements according to TA Luft are insufficient for a complete description of the stress situation of forest ecoysystems due to air pollutant intake.