BASE-CATION DEPOSITION IN EUROPE .2. ACID NEUTRALIZATION CAPACITY ANDCONTRIBUTION TO FOREST NUTRITION

An assessment was made of the capacity of base cations to neutralize a cid deposition and of the contribution of base cation deposition to fo rest nutrition in Europe. In large parts of southern Europe more than 50% of the potential acid deposition was found counteracted by deposit ion of non-sea salt Mg2+ + Ca2+ + K+. In central and northwestern Euro pe, base cation deposition usually amounted to less than 25% of the ac id input. Smallest base cation deposition relative to potential acid d eposition was found in southern Scandinavia, Denmark, northern Germany and The Netherlands. A similar spatial pattern was found for the neut ralization of acid anions in precipitation. Whereas in Scandinavia wea thering is the dominant supplier of base cation to forest soils, in ea stern and southern Europe, forests mainly rely on atmospheric depositi on for the supply of base cations. Using error propagation, the random and systematic error in acid neutralization capacity for an average g rid cell of 10 x 20 km was estimated to equal 45-55% and 50-55%, respe ctively. (C) 1997 Elsevier Science Ltd.