Dynamics of woody debris in a beech stand (Fagus sylvatica L.) in Solling. Input, causes and decomposition of woody debris

In a 8 ha beech (Fagus sylvatica) stand of about 160 years in Solling, south Lower Saxony, the input and decomposition of woody debris were observed over a period of 12 years. Since the beginning of the investigation input has increased. In 2000 the volume of the coarse woody debris was 50,9 m 3 ha I (Tab. 4). Storm and the white rot resulting fungus Fomes fomentarius were identified as causes of mortality (Fig. 1). The infestation of Fomes fomentarius increased and resulted in death of single trees (Fig. 3). The oldest, still identifiable, strongly decomposed logs fell down 1970. Under the given climatic conditions the decomposition period is about 40 years. The determined volume of woody debris is in the range of the amounts from natural beech forests and natural forest reserves. The results indicate that the amount and origin of mortality as well as the mortality pattern depend on the age of the stand. On the basis of the properties of woody debris a decomposition key will be presented.