Deposition and soil leaching in stands of Norway spruce and European Beech: Results from the Höglwald research in comparison with other European case studies : Höglwald research II interdisciplinary investigations on nitrogen turnover in a nitrogen saturated forest ecosystem

Stands of Norway spruce (Picea abies K.) and European beech (Fagus sylvatica L.) were investigated at the Hoglwald research area, Southern Germany from 1985-1988 and from 1994-1997 in order to determine the effects of tree species on deposition and soil solution fluxes. The results were compared to 15 European case studies representing different deposition levels and site conditions. At the Hoglwald site, which is characterised by a high nitrogen and a moderate sulphur load, throughfall deposition of nitrogen and sulphur compounds was about two-fold higher in spruce stands compared to beech stands. The differences in elemental input were clearly reflected in soil solution chemistry with a higher leaching of nitrate and sulphate in the spruce stands. The turnover of sulphur and nitrogen compounds induced a strong soil internal production of protons especially in the spruce stands. These results are in accordance with the other European case studies. Throughfall deposition and soil leaching of nitrogen and sulphur compounds was generally higher for spruce stands compared to beech stands. The species-related differences were mainly caused by dry deposition and were relatively small in remote areas. The consequences for the forest ecosystem itself and for the hydrosphere are discussed.