Nachhaltige Naturwaldbewirtschaftung in Bergregenwäldern Südecuadors : Eine Option zur Erhaltung von Biodiversität?

Weihenstephan

2003

17 Lit. Ang.

Artikel aus einer ZeitschriftUnselbständiges Werk

200107042

In southern Ecuador, exploitation of natural mountain forests for timber and transformation into pastures are common ways of land-use systems that cause losses of biodiversity. Protection by conservation of virgin mountain forests is certainly the best way to prevent losses of biodiversity. However, where exploitation from the local communities continues on a large-scale, protection by conservation has no successful prospects. One of the objectives of a comprehensive scientific work in South Ecuador supported by the German Research Foundation, DFG, is to find out alternative land-use strategies in the sense "of natural forest management" which can be an option for the conservation of biodiversity in this region. For the design of such land-use strategies, the current situation in the tropical mountain rain forest of Estación Cientifica San Francisco in South Ecuador (1800 - 2100 m NN) was analysed. In four watersheds of a size of 8, 10, 13, and 20 hectare, based on sampling by strips of 10 m width, eight transects with a total area of 4,5 ha were established. Within each transect all woody species with DBH > 10 cm were recorded. The abundance of the individuals with DBH > 10 cm was high with more than 1,000 trees per hectare. For those trees the basal area varied between 27 m2/ha and 33 m2/ha for the different transects. When taking into consideration only the group of economically valuable species (Prumnopitys montana, Podocarpus oleifolius, Tabebuia chrysantha and Cedrela sp. and others), the number of potential crop trees (PCT) having a DBH > 20 cm was 33 per hectare, of which only four individuals having a adequate harvest size of above 40 cm DBH. Thus, the number of the vigorous PCT is considered too low for a sustainable and profitable natural forest management. Therefore, emphasis should be put on trees in an abundant number such as the PCT of the smaller DBH in order to develop a silvicultural transformation system that aims at raising the proportion and dimension of valuable species. Design and application of such system are discussed.