The sensitivity of central European mountain forests to scenarios of climatic change: Methodological frame for a large-scale risk assessment

The methodological framework of a large-scale risk assessment for Austrian forests under scenarios of climatic change is presented. A recently develop ed 3D-patch model is initialized with ground-true soil and vegetation data from sample plots of the Austrian Forest Inventory (AFI). Temperature and p recipitation data of the current climate are interpolated from a network of more than 600 weather stations to the sample plots of the AFI. Vegetation development is simulated under current climate ("control run") and under cl imate change scenarios starting from today's forest composition and structu re. Similarity of species composition and accumulated biomass between these two runs at various points in time were used as assessment criteria. An ad ditive preference function which is based on Saaty's AHP is employed to syn thesize these criteria to an overall index of the adaptation potential of c urrent forests to a changing climate. The presented methodology is demonstr ated for a small sample from the Austrian Forest Inventory. The forest mode l successfully simulated equilibrium species composition under current clim atic conditions spatially explicit in a heterogenous landscape based on gro und-true data. At none of the simulated sites an abrupt forest dieback did occur due to climate change impacts. However, substantial changes occured w ith regard to species composition of the potential natural vegetation (PNV) .