An optimal management of mountain forests is economically viable, maintains and ensures the protection against natural hazards, creates good conditions for regeneration and maintains stand increment in the long-term at high levels. These requirements pose complex optimization tasks for managers. During the last 10 years, an increasing trend towards very strong interventions emerged, because this seems economically advantageous in the short-term. However, experience shows that these patch cuts remain free of regeneration for a long period. In the long run this practice could prolongate forest regeneration for many years and reduce timber growth. The aim of this research project is to estimate, for Norway spruce and silver fir-Norway spruce forests, if such disadvantageous impacts occur and if yes, at which magnitude. A simple tool will be developed that depicts the determining factors and allows quantifying increment losses.
The increment of single Norway spruce trees will be estimated with statistical models, on the basis of permanent plot data. The existing data on tree growth will be supplemented with dendroecological methods gained in 6 to 10 case studies, to cover increment release reactions of spruce after strong interventions. In an empirical study the regeneration on cleared sites and on sites with selective management, with the last intervention before > 8 years, will be assessed. This should enable quantifying a possible delay of regeneration.
- Samuel Zürcher (project leader), Fachstelle für Gebirgswaldpflege, Maienfeld
- Dr. Riet Gordon, Amt für Wald und Naturgefahren, Chur