Untersuchungen zur waldbaulichen Behandlung von Araucaria araucana-Wäldern in Südchile

Weihenstephan

2003

36 Lit. Ang.

Artikel aus einer Zeitschrift

200107041

Waldbau - weltweit : Beiträge zur internationalen Waldbauforschung ; Nr. 192

Felling of Araucaria araucana (Mol.) K. Koch is prohibited in Chile. However this law might be revoked in the near future. If this happens, management concepts must be developed in order to avoid excessive expolitation, as well as to take full advantage of its potential. this study analyses the structure and groth dynamics of A. araucana-N.pumilio virgin forest, as well as the influence of silvicultural treatments on such stands. Nine experimental plots, with diverse basal areas, were examined. These plots (of one hectare each) were established between 1981 and 1982. The virgin forest that was studied (with basal area of approx. 80 m2/ha) has not been influenced by catastrophic disturbances for many centuries and exhibits, on one hectare, an inverse-j diameter distribution, with trees of up to 200 cm in DBH. The existing bamboo coverage in this forest did not hinder the ample establishment and survival of A. araucana seedlings, which are sufficient for adequate ingrowth and the maintenance of its steady state. The reaction of this forest to silvicultural interventions depends on the residual basal area. On plots with "intermediate" residual basal area (50-60 m2/ha), A. araucana has a better reaction than N. pumilio, apparently because the created light conditions are insufficient to initiate a strong growth response in N. pumilio. On these plots, the uneven-aged diameter distribution from 1982 was maintained, ensuring the continuance of a. araucana. On plots where the residual basal area was reduced to 30-40 m2/ha, the additional light was sufficient to produce a very strong response in N. pumilio. Here, the increase in interspecific competition led to repression of A. araucana, mainly in the understory. By 1998, a inverse-j curve should be found. However because of the very strong ingrowth of N. pumilio, the diameter distribution changed in the lower classes. The species ratio in the lower classes also changed against A. araucana. Without further intervention, it is expected that, on these plots, the uneven-aged structure would develop into an even-aged structure with N. pumilio being the dominant species. In general it can be concluded that, in A. araucana forests that have been degraded by man the only chance for the continuance of the species is the sustainable management of its forests and for this, the most adequate silvicultural concept is an uneven-aged management.