EFFECTS OF ACID DEPOSITION ON DUTCH FOREST ECOSYSTEMS

Effects of elevated S and N deposition on the solution chemistry of Du tch forest soils are mainly manifested by increased concentrations of Al associated with increased concentrations of SO4 and NO4. Presumed c ritical Al/base cation ratios are often exceeded below 20 cm soil dept h. There is also evidence that elevated N deposion during the last dec ades affected the forest nutrient status and caused large changes in f orest vegetation. About half of the Dutch forests have absolute shorta ge of P and relative Mg deficiencies compared to foliar N contents. Ev idence from field studies of a relationship between soil acidification and nutrient imbalances in the soil and the foliage on one hand and t he vitality of forests on the other hand is, however, lacking.