Das Potenzial der Totholzakkumulation im deutschen Wald | Potential of deadwood accumulation in German forests

Deadwood is an important part of the forest ecosystem. The quantity available depends on the rates of accumulation and of decomposition. A comprehensive pool of data regarding the deadwood stock for Germany is collected by the German national forest inventory. Moreover, the Projection Modelling of Forest Development and Timber Harvesting Potential (WEHAM) adds other important parameters such as growth rates and potential roundwood availability. Using this data, scenarios for the accumulation of deadwood were developed. For the calculation of deadwood decomposition, independent of tree species, a decay constant k = 0.054 was derived for the whole of Germany. The study shows that a long-term stop in timber harvesting in Germany, assuming the proportions of different tree species remained constant, would lead to a saturation of deadwood with a total of 184 m³/ha. If the German forest presented a natural composition of tree species, a deadwood stock of 150 m³/ha at most could be accumulated. Based on these scenarios, rates of accumulation of total dead-wood and of deadwood of large diameter can be calculated taking into account the deadwood stock levels desired and the time span involved. It has been shown that 7.3% of the WEHAM potential roundwood availability must remain in the forest per year if the quantity of deadwood is to be maintained at 11.5 m³/ha. If an increase in the accumulation of deadwood is to be aimed for, the annual input rate together with the desired deadwood stocks are increasingly influenced by the time span involved. Thus shorter time spans with greater stocks of deadwood to be achieved make it possible to approach the WEHAM potential roundwood availability. The results presented in this paper should assist in decision-making concerning stocks of deadwood to be aimed for in the forest and, in the future, serve as a basis for the selection, evaluation and discussion of quantities of dead-wood to be achieved.