Effects of acid deposition on Dutch forest ecosystems

Effects of elevated S and N deposition on the solution chemistry of Dutch forest soils are mainly manifested by increased concentrations of Al associated with increased concentrations of SO4 and NO4. Presumed critical Al/base cation ratios are often exceeded below 20 cm soil depth. There is also evidence that elevated N deposion during the last decades affected the forest nutrient status and caused large changes in forest vegetation. About half of the Dutch forests have absolute shortage of P and relative Mg deficiencies compared to foliar N contents. Evidence from field studies of a relationship between soil acidification and nutrient imbalances in the soil and the foliage on one hand and the vitality of forests on the other hand is, however, lacking.