Application of the magic model to the Norway spruce stand at Solling, Germany

magic (Model of Acidification of Groundwaters In Catchments) is a long-term process-oriented model for soil and water acidification. The model consists of a set of chemical equilibria between soil and soil solution and an accounting of annual fluxes and pools of major anions and cations in the ecosystem. magic was applied to the dataset from the 105-year-old Norway spruce stand at Solling, central Germany. The primary aim was to evaluate the relative roles of forest management and acid deposition on soil acidification as expressed by the pool of exchangeable base cations (base saturation). Future scenarios of management and deposition reduction were investigated, and the model indicated that with a 75% reduction in deposition, soils would recover with respect to present day values if the forest is left, or removed and converted to grassland, but would continue to acidify if the forest was removed and replanted.