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
FRANCO, M.G.; BARRERA, M.D.; MARTÍNEZ-PASTUR, G.J.; MUNDO, I.A.
Conferencia; AmeriDendro 2016 - Third American Dendrochronology Conference; 2016
Silvicultural proposals adjusted to different forest type dynamic are critical for the improvement of natural resources management practices. Forest management proposals for Nothofagus betuloides ?guindo? are scarce and tree ring analysis, which can be a powerful tool to perform higher precision analysis in slow growing species, have not been included in studies concerning silvicultural interventions. The aim of this work was to determine and analyse, using dendrochronological techniques, radial and diametric growth in a N. betuloides stand in Tierra del Fuego which was subjected to different thinning combination treatments. Thinning from bellow was conducted in 1993 and 2000, applying four and two thinning levels in each intervention, thus resulting in eight thinning combinations. Growth differences were evaluated both through visual and statistical analysis, considering ring width, basal area increment, percentage growth change and periodic annual increment. Thinning intensities showed differentiated effects on radial growth and heavier thinning treatments resulted in higher growth rates (3,31 mm.year-1 in ratio and 10,73 cm2.year-1 in basal area), being significantly higher than the unthinned treatment (0,68 mm.year-1 and 1,64 cm2.year-1). However, low density stands showed higher growth increments, suggesting that growth is not only determined by thinning intensity but also by post-intervention stand density. The differentiated effect of the first thinning was nullified by the second intervention, indicating that this species responds well to very intense interventions. These results indicate that it´s possible to reduce the number of non-commercial thinning and, in consequence, the cost of application of the silvicultural system. However, no significant diameter differences were detected among treatments twelve years after the second intervention. In consequence, recommendations about the most convenient thinning intensity cannot be made based on these results. Further studies should be carried out to determine the optimal thinning density, including economical aspects, and to evaluate managed stands stability.