Individual and stand growth of Austrocedrus chilensis in El Bolsón, Río Negro, Argentina.

This paper studies volume and dry matter growth at tree and stand level in two Austrocedrus chilensis (Don.) Florin et Boutleje (ciprés de la cordillera) stands with structural differences. One stand is located at the Reserva Forestal Loma del Medio-Río Azul (LM) while the other is at the Reserva Provincial El Guadal (EG), nearby El Bolsón city (Río Negro). EG stand has more A. chilensis’ density and basal area than LM. Dominant and codominant trees were cored for age determination and to develop the mean tree-ring series. All sample cores were cross-dated and tree-ring series were smoothed using moving average with a 10 years period to remove high frequency variations. Smoothed series were used to compute individual and stand growth. Tree ring series at EG showed an accelerated early growth followed by an even diminishing. Diameter growth ranged from 0.2 to 1.5 cm.yr-1. Instead, LM series reflected a more competitive environment as diameter growth showed lesser variability (0.2 to 0.7 cm.yr-1). This suggests that LM stand establishment and early growth did not occur in open-growth conditions, as it was observed in EG. The relationship between DBH and height showed lower slope at EG, which reflects a poor site quality. Different patterns in individual early growth conditioned the age of maximum mean annual increment both in volume and dry matter. Silvicultural treatments on stands as those studied in this paper would show different responses, not only due to site differences but because of stand establishment conditions also.

Key words: Austrocedrus chilensis, growth, tree-ring, volume, biomass.