RESPONSE OF 6 EUROPEAN FOREST SITES TO DECIDED AND PROPOSED AIR POLLUTANT EMISSION REDUCTIONS

Two acid deposition scenarios were simulated for six European forest s ites situated in Germany, Denmark, Russia, Switzerland, Spain and Irel and. Three models were used in combination; the RAINS (Regional Acidif ication INformations and Simulation) model, the SAFE (Simulating Acidi fication in Forest Ecosystems) model and the MakeDep model. The scenar ios used were based on results from international negotiations (the Os lo and Sofia protocols) and on calculations of what could br! achieved using the best available technology at a reasonable cost. The paramet ers chosen for studying the course of acidification were base saturati on, BC:Al molar ratio in soil solution and pH. Furthermore, the sites were compared with respect to deposition regimes as well as loll excha nge and weathering rates, nutrient uptake and nutrient cycling. The re sults show, that all sires have undergone acidification. Three of the sites show BC:Al molar ratios below or very close to the threshold val ue of 1. Currently accepted reductions in S and N emissions will lead to a halt in acidification in all cases and a partial regeneration of the soil buffer capacity in some cases. Introducing maximum feasible r eductions would improve soil conditions remarkably at all six sites. T he differences in degree and course of acidification can be derived fr om J differences in weathering rate and soil buffer capacity as well a s from the deposition regimes. Detailed information on future anthropo genic base cation deposition is shown to be less important for the out come of the scenarios than expected. (C) 1998 Elsevier Science Ltd. Al l rights reserved.