Spatiotemporal changes in climate-growth relationships for Nothofagus dombeyi in

SUAREZ, MARIA LAURA

Vancouver, Canada

Conferencia; AmeriDendro; 2008

Tree-Ring Lab, UBC - Tree-ring Society

Climate-growth relationships have improved the knowledge of forest growth responses to past climatic variations, and have contributed to the analysis of  future growth responses under global warming. For species highly affected by recent climatic events, such as Nothofagus dombeyi, there is an urgent need  to understand climate-growth relationships and their variability across environmental gradients. In this study climate-growth relationships were analyzed using dendrochronological techniques for three sites within two contrasting extreme environments. Individuals of N. dombeyi belonging to the main canopy were cored, and master chronology for each site was developed. Residual chronologies were used to analyze growth-climate relationships for each site. The climate data used were monthly temperature and precipitation data. Temporal changes in climate-growth relationships were analyzed using evolutionary and moving interval analyses. Standard  and residual chronologies for N. dombeyi were reliable for analyzing growth variability and its relationship with regional climate in Patagonia. Nothofagus dombeyi showed a strong negative relationship with temperature and a strong positive relationship with precipitation during the growing season. However, the climate-growth relationship was variable between stands, not only in relation the months with significant correlation but also in the strength of the relationshipl. Surprisingly, all stands growing on wet sites showed  a stronger relationship with precipitation than those registered for xeric sites. At a temporal scale, climate-growth relationships for xeric sites seems to be changing during the last decades to greater  temperature sensitivity since the 1970’s. Dendrochronological analysis for N. dombeyi provide a good perspective of climate-growth variability in northern Patagonia at both local and regional scales. The strong relationship between radial growth with temperature and precipitation shows that N. dombeyi growth is affected by interannual climatic variation. Moreover, the changes in climate response suggests that there is high probability  that this species will be affected by future climatic events.