Forest management and conservation of Nothofagus forests in south Patagonia, Argentina.

P PERI; G MARTÍNEZ PASTUR; MV LENCINAS

Hobart, Tasmania (Australia)

Conferencia; Old Forests: New management; 2008

Nothofagus forests in south Patagonia (Santa Cruz and Tierra del Fuego provinces, Argentina) that cover 1.05 millions hectares are being used in multiple ways, for example timber production, cattle grazing, firewood extraction, tourism and recreation activities, and conservation. Between 700 and 1000 ha of the forest has been logged annually with a mean log volume of 63.2 thousand m3 yr-1. The sustainable management of these forests has been legally declared as an objective. However, there are a number of issues in Nothofagus forest management that may affect long-term sustainability: the lack of long-term policies and planning, weak control from the government, incomplete implementation of management plans and silvicultural practices, and livestock damage to regeneration. In this context, we propose an industry adaptation to a biodiversity program with an alternative regeneration method. In N. pumilio forest, the proposed method leaves 30% of the timber-quality forest area as aggregated retention and 15 m² ha-1 basal area (BA) as dispersed retention. Instead this regeneration method maintained the same yield rate as the first cut of the shelterwood cut system, the harvesting costs decreased and the original diversity of primary forest was better conserved. Furthermore, N. antarctica forests have been used as silvopastoral systems where natural pastures grown under the tree canopy are grazed by cattle and sheep. There are ecological and economic interactions (positive and/or negative) between the woody, non-woody and animal components of these systems. Data on above- and below biomass, carbon and nutrient accumulation in different tree components, dry matter production and quality of pastures, wood production from thinning schedules, animal performance (stocking rates, live weight gains) and regeneration have been evaluated to determine the impact of silvopastoral system practices. A Monitoring Program was established to reach an equilibrium between economic and biodiversity conservation. Thus, in harvested stands it has been evaluating the ecological functionality of the applied regeneration system such as forest structure, climate changes, ecophysiology of regeneration dynamics, habitat quality, abiotic cycles, and insect, understorey and birds biodiversity.