SOIL INVESTIGATIONS ON THE NEEDLE LOSS OF NORWAY SPRUCE (PICEA-ABIES [L] KARST) AT ALPINE CALCAREOUS SITES

In order to find probable causes for damages on Norway spruce in the calcareous Alps, soil and nutritional investigations were conducted in Norway spruce stands located along one elevation profile at the Wank mountain Bavarian Alps. The results indicate that the anthropogenic deposition is very low in this area, and that does not impose a burden on the Norway spruce. The nutritional supply of K, Mg, and Ca is optimal. Due to the low water storing capacity, the soil frequently dries out in summer, and the trees suffer from nitrogen and phosphorus deficiency. The needle loss correlates along the elevation profile with P-contents both in the needles and in the soil. Therefore, a causal relation is assumed between needle loss and P deficiencies. As P is stored predominantly in the humus, the amount of the humus plays an important role for the P-supply. The humus at the Wank has been affected decisively by the exploitation history of the area (grazing, game, litter use).