Können Windwurfschäden vermindert werden? Eine Analyse von Einflussgrössen

Abstract

Can windthrow damage be minimized? An analysis of predictors The paper deals with different influencing factors that determine storm damage to forests and the question how this damage can be minimized. The influence factors include tree-related parameters like species, tree height and h/d-relation, terrain-related parameters (encompassing wind speed and soil condition), and type of forest management as well as stand structure. The analysis of a multitude of studies including empirical as well as mechanistic models reveals that coniferous species, especially Norway spruce, show a higher vulnerability towards storm damage than broadleaves. Many investigations point at a significant influence of tree height on storm damage probability, while the h/d-value does not have the same importance. Besides that, the influence of management operations, stand structure and surrounding forest stands as well as the vulnerability of selection forests (“plenter forest”) are analysed. Silvicultural treatment, mostly timing and intensity of the interventions, plays a role for determining damage severity, as well as soil water content (waterlogged soils) and exposure towards the main wind direction. Plenter forests appeared not to be very vulnerable to storm damage in the existing investigations in Switzerland, however, due to the lack of sufficient data, a general superiority of these uneven-aged forests compared to even-aged ones cannot be proved at the moment. Based on a discussion on the importance of the different parameters, measures to reduce storm damage to forests are discussed. Hereby mainly the choice of tree species, the limitation of the dominant height of forest stands as well as early and intensive thinning are investigated.