INSTITUTO ARGENTINO DE NIVOLOGIA, GLACIOLOGIA Y CIENCIAS AMBIENTALES
Unidad Ejecutora - UE
congresos y reuniones científicas
Radial growth response of Nothofagus betuloides to different thinning intensity levels in Tierra del Fuego, Argentina
M. G. FRANCO; BARRERA, MARCELO D; GUILLERMO J. MARTÍNEZ PASTUR; IGNACIO A. MUNDO
Conferencia; Third American Dendrochronology Conference; 2016
Ianigla - CCT Mendoza
Silvicultural proposals for different forest types are crucial to improve management practices and to adjust them to natural dynamics. Forest management proposals for Nothofagus betuloides (guindo) are scarce and tree ring analysis, which can be a powerful tool to perform high precision analysis for slow growing species, have not been included in silvicultural proposals. The objective of this study was to determine the radial growth response of N. betuloides to different thinning intensity levels using dendrochronological techniques. Thinnings from bellow were conducted in 1993 (four thinning levels) and 2000(two thinning levels), resulting in eight thinning combinations, which were compared with a control treatment. Growth differences were evaluated both through visual and statistical analysis, considering ring widths, basal area increments, percentage of growth change and periodic annual increments. Thinning intensities showed differential effects on radial growth, where heavy thinning treatments resulted in higher individual growth rates (3.31 mm.year-1 and 10.73 cm2year-1) than the control treatment (0.68 mm.year-1 and 1.64 cm2year-1). Beside this, low density plots showed higher growth increments, suggesting that growth is not only determined by thinning intensity but also by post-intervention plot density. The differentiated effect of the first thinning was masked by the second intervention, indicating that this species responds tointense interventions. These results indicate that it is possible to reduce the number of non-commercial thinning and, in consequence, the cost of application of the silvicultural system. However, no significant differences in stem diameter were detected among treatments twelve years after the second intervention. Thus, recommendations about the most convenient thinning intensity cannot be made based on these results, being necessary long-term studies. Further studies should be carried out to determine the optimal thinning density, including economic aspects, and to evaluate managed stands stability andcrown development that can have influence in further individual growth and commercial timber products.