Fine root studies in two old growth spruce forests affected by "'Waldsterben" in Bavaria. Fine roots of healthy and declining Norway spruce (Picea abies) were investigated. ' We observed fewer active mycorrhizae a.ssociated with affected spruce in two old growth forests. It has been bypotbesised that air pollution is damaging the needles resulting in less photosynthate and that the reduction of active mycorrhizae is due to such an initial weakening of the tree. Einleitung