Abstract

BAVA, J. O.  and  LOPEZ BERNAL, P. M.. Group selection cuts in Tierra del Fuego lenga forests. Quebracho (Santiago del Estero) [online]. 2006, n.13, pp.77-86. ISSN 0328-0543.

In order to characterize the group selection system on lenga (Nothofagus pumilio) forests in Tierra del Fuego (Argentina), three trials were located in the Fagnano lake basin. The cutting criteria were: to generate gaps (initiation cuts); to liberate saplings (liberation cuts) and to promote the growth of young well formed poles (conduction cuts). These criteria were adjusted to economic aims, felling mainly individuals with useful logs, and the cut was complemented with the felling or ringing of individuals of low lumber production aptitude. There were conservation aims too: trees bigger than 80 cm BHD were preserved, the boundaries of peats were protected and the cut on high slopes was avoided. The diameter of gaps remained lower than the height of dominant trees, and special attention was paid to avoid the coalescence between gaps. The cut remain lower than 30 % of the stand BA. Though the trials were realized in similar structures, there were differences up to 100 % in the available volume of merchantable logs obtained in each of them. This fact was reflected in the amount of opened gaps per hectare, but not in its size. The trial with the most intense cut (28 % of the BA) produced the double of merchantable wood that the other two. This wood comes mainly from conduction cuts. The average relationship between merchantable and non merchantable (ring-shaped) trees was 4 to 1.

Keywords : Nothofagus pumilio; Unevenaged management; Cutting criteria; Harvesting, products.