Regeneration dynamics in manager Nothofagus forests of Patagonia: variable retention and shelterwood cuts implications

MARTÍNEZ PASTUR, G; LENCINAS, MV; CELLINI, JM; BARRERA, M; PERI, P

Bariloche, Argentina

Congreso; VI Southern Connection Congress; 2010

When a new silvicultural method was proposed, foresters in Patagonia used the regeneration as the decisive indicator to evaluate it. For this, silvicultural research projects focus their studies on the regeneration dynamics, but also in remnant overstory stability, understory and soil nutrient changes, eco-physiology, micro-environments influence, micro-climate and browsing. Most of these studies were conducted in long-term research plots. The present work presents ten years results of regeneration dynamics, and their silvicultural implications of the two main regeneration treatments: shelterwood cuts (SC) and variable retention (VR). Results showed that: (1) seedlings were established after the harvesting and few of the plants of primary forests survived; (2) establishment and growth were related to canopy closure, and magnitude of micro-climate and soil properties changes; (3) remnant overstory stability were deficient in SC and dispersed retention, but was stable into the aggregated retention, influencing over establishment and growth; (4) understory and micro-environments in the harvested areas significantly influence over regeneration dynamics; (5) cattle and guanaco browsing not limited the regeneration, but influence over growth during the first years after the harvesting. Both theoretical proposals regenerated the stands, but SC homogenizes the growing conditions in the stands and VR maintained some of the original heterogeneity of the primary forests