Estudo de anéis anuais de crescimento de árvores como indicadores climáticos em Portugal

Abstract

In the present study a dendroclimatological approach, using dendrochronological techniques, was made in samples taken from Serra da Nogueira (Terra Fria Transmontana) of Quercus pyrenaica Willd, site with the main stand of this species in Portugal. Pinus sylvestris L. e Abies alba Miller, conifers present in the sampling site were analysed and compared simultaneously . The influence of climate was evaluated by comparing total rings, earlywood and latewood indices with monthly climatic data collected at Bragança’s weather station over the period between 1950 and 2008. The correlation between rainfall/temperature and the chronology of the three species were not meaningful enough to allow an evaluation of the past climatic variation over statistical models, that rely on indexed series of tree rings. In comparison to Q. pyrenaica of the same sampling site, P. sylvestris evidenced a different reaction faced to extreme dry periods, stronger during 2004 and 2006. Q. pyrenaica was affected strongly during severe droughts between 1974 and 1976, regarding that the recovery of the south sloped trees is lower than the north sloped trees. Possible ecophysiological arguments are presented to sustain obtained results