Â鶹ÒùÔº

Uniform and intensive forest management approaches threaten European forest biodiversity. There are many different ways to manage forests, but the effects of different combinations of approaches are not well understood.

An international research team led by the universities of Göttingen, Germany, and Jyväskylä, Finland, has investigated how the Triad forest management framework can support biodiversity conservation in European beech forests. This framework proposes to balance economic and ecological objectives by dividing forest landscapes into three distinct zones: intensively managed forest for timber production, unmanaged areas for biodiversity conservation, and extensively managed forest for supporting biodiversity while producing timber.

The researchers collected data from these three management categories and developed "virtual forest landscapes" for analysis. The results are in Proceedings of the National Academy of Sciences.

The research team quantified the effects of using different proportions of the three management zones in a landscape on the diversity of a wide range of species groups—including birds, beetles, plants, lichens and fungi. The original data, which were collected from nine sites in France, Germany, Italy and Czechia, were classified following the Triad forest management categories: intensively managed forests (with clearcutting—meaning harvesting all or nearly all the trees from an area), unmanaged areas (no harvesting in recent years) and extensively managed forest (partial harvests without clearcutting and dominated by native tree species).

"The originality of our method was to develop 'virtual' landscapes using computer analysis, in which data could be resampled. It enabled us to create landscapes that vary in proportion of extensively, intensively, and unmanaged forests, and explore the whole range of possibilities," says researcher Dr. Peter Schall, University of Göttingen.

The researchers found that species diversity was highest in landscapes composed of 60% unmanaged and 40% intensively managed forests. Diversity was lowest in purely intensively managed landscapes, but extensively managed forests contributed little to support species richness. However, it would be unrealistic to have 60% unmanaged forests in Europe due to the rising demand for wood, which is why the authors suggest focusing on improving the ecological performance of extensive management.

"To preserve forest biodiversity in Europe, we recommend increasing the proportion of unmanaged forests and promoting forest heterogeneity in extensive management—for instance by providing a mosaic of open and closed forest patches and keeping large old trees and deadwood in the forests," explains Dr. Rémi Duflot, University of Jyväskylä.

"Our study showed that it is possible to maintain a certain proportion of forest area dedicated to timber production without compromising overall forest biodiversity," adds Schall.