Dominant patterns of tree growth in North-western Argentina: Their relationships with climate.

E. FERRERO; R. VILLALBA

Malargüe, Mendoza

Simposio; Regional Climate Variations in South America over the late Holocene.; 2006

PAGES

Mountain topography in North-western Argentina (NOA) originates a wide range of environmental gradients along which tree growth responds diferentially to climate. Thus, tree growth can be influenced by temperature (in moist, cool sites), or by precipitation (dry, warm sites). Since 1980´s two species fron the montane forests have been studied: Juglans australis ("nogal criollo" Juglandaceae) and Cedrela lilloi ("cedro rosado" Meliaceae). Up to now, 34 tree-ring width chronologies have been developed from these species. Previous studies indicate large differencies of interannual variations in tree growth between sites and a wide variety of responses to climate across different environments.In this presentation we determine the range of tree growth responses of Juglans and Cedrela to climatic variations in NOA. We emphasized the identification of common signals between sites and species, in order to determine the dominant patterns of tree growth and their relationships with climate. Based on the similarity in interannual growth variations between sites, individual chronologies were grouped into regional chronologies. This procedure is expected to enhance the regional climatic signal present in the tree-ring records. The regional signal in the chronologies is strengthen when a large number of samples fron environmentally similar sites is included in a common record, wich eventually will lead to better reconstructions of the past climate variations in the NOA region.