Financial analysis of the thinning decision with consideration of biodiversity, using the example of spruce in Saxony | Zur finanziellen Analyse der Waldpflegeentscheidung bei Berücksichtigung der Biodiversität, dargestellt am Beispiel der Fichte in Sachsen

Stand growth, competition, stability, and wood quality are usually the focus of traditional investigations into stand treatment. Although needed for a stand-adequate intermediate harvest, they are not entirely satisfactory as they are superimposed by crucial economic influences such as the timber market, prices of production factors, objectives of the forest owners and societal demands. Due to the fact that thinning is future-oriented, the decisions taken in this context are controlled by a dynamic magnitude: Changes in the natural environment have to be complied with in the same way as changes in economic premises and the forest owners’ objectives.The financial analysis of thinning regimes is based on an intermediate investment theory, especially theFAUSTMANN formula as an integer construct. It aids in deducing the hypotheses. However, the analysis itself turns out to be problematic since theFAUSTMANN model relies on model assumptions by which the features of thinning regimes tend to be faded out rather than substantiated. Therefore, an attempt has been made to approach a solution to the problem by means of simulations.The stand simulator SILVA 2, simulating stand growth in dependence on various thinning regimes and at the same time calculating the costs and revenues for the individual operations, proved to be suitable. Hence, payments series may be derived and holding values determined which are relevant to the decision to be taken. For the simulation experiments 40-, 60-, 70-, and 90-year-old spruce stands were selected at the time the decision was taken. The variables involved were type of thinning, thinning intensity and interval as well as the guiding rate of return of the forest owners.The financial analysis was extended by including public services, demonstrated by the example of biodiversity. For this purpose the technique according toKLEMPERER was applied, which considers changes in biodiversity and the opportunity costs thus accruing.Finally, the ten statements derived from the simulations for the selection of optimal thinning regimes are presented for peer reviewal.