Forstbetriebliche Schadholzlagerbestände nach natürlichen Störungsereignissen - Verfahren zur nationalen Schätzung

Natural disturbances such as fire, drought, insect calamities and storm events have now become a central issue for Germany's forests and forestry companies. Economic damage due to reduced revenues after natural disturbances with high levels of damaged timber is taking on considerable proportions. In order to decouple the sale of damaged timber from severe natural disturbance events, forestry companies store large quantities of damaged wood, sometimes over periods of several years. The central aim of this work is to develop a method for estimating forest companies’ timber storage after severe natural disturbance events at the national level. This work is based to a large extent on the results of Zimmermann et al. (2018) and Zimmermann et al. (2021). For this purpose, the empirical operational data of the federal forestry test network (TBN-Forst) in connection with the natural disturbance events Lothar (1999) and Kyrill (2007) are transferred in several steps to a national timber storage model. The key input variables are the disturbance-related additional felling quantities (DAMcomp), the inflows into damaged timber storage (TSAcomp) and the outflows from damaged timber storage (TSOcomp) at the company level over a multi-year observation period. The individual steps of this study for transferring the operational information to estimate timber storage at the national level are structured as follows: In step 1, national disturbance-related additional felling quantities (DAMnat) are derived. Step 2 shows the inflows into damaged timber storage (TSAnat). Step 3 shows how a national timber storage model can be parameterized from the inflow and temporal course of the outflows from the damaged timber storage (TSOnat). The procedure for scaling the national tiber storage model is presented in step 4. The timber storage model is scaled on the basis of the national inflows into the damaged timber storage, which are derived from the national disturbance-related additional felling quantities. National timber storage is estimated for the natural disturbance events Lothar, Kyrill and the damage complex storm/drought/bark beetle...