EVALUATION OF BIODIVERSITY FOR MULTI-PURPOSE FOREST MANAGEMENT USING A NON-LINEAR OPTIMIZATION APPROACH

The paper applies a non-linear optimization approach to evaluate biodiversity in the multi¬purpose modelling of forest management. An even-aged forest of pure Norway spruce was generated from large-scale inventory data of the Black Forest of southwest Germany. The effects of different management alternatives including five conversion schemes, two traditional age-class and single-tree- selection systems and a "Do-nothing" strategy were simulated using the forest growth model "BWINPro- S". Optimal allocation of management strategies to the forest area was found subject to the hard constraints of "area" and "protection" and the chance constraint "wood even flow". A utility function representing the value of biodiversity was estimated based on the opportunity costs of different biodiversity levels. The upper and lower boundaries of the function were determined by successive optimization runs. Subsequently, the obtained monetary value of biodiversity was directly integrated into the optimization of a particular forest to identify the optimal allocation of management schemes to entire forest enterprise. Conservation or "Do-Nothing" was the most desirable scenario combined with the partial establishment of beech regeneration. Economic and silvicultural consequences of the optimal multi-purpose forest management plan were discussed and compared to the alternative business-as-usual strategies.