Growth responses to climate across environmental gradients in subtropical forests from South America

FERRERO, M.E.; VILLALBA, R.; DE MEMBIELA, M.; RIPALTA, AL.

Tucson, AZ

Conferencia; Second American Dendrochonology Conference; 2013

In subtropical northwestern Argentina (22-20°S; 64-66°W), changes in forest composition reflect the large diversity of environmental conditions resulting from interactions between topography and regional climate. The dominant patterns of interannual variations in 15 tree-ring chronologies (including four subtropical species: Juglans australis, Cedrela lilloi, Alnus acuminata and Schinopsis lorentzii) developed along an elevation gradient from the dry-warm Chaco lowlands to the wet-cool montane Yungas were determined using principal component analysis (PCA). At a large, regional scale tree growth is largely modulated by climate. However, different species may respond differentially according to climatic conditions along the elevation gradient. At the most climatically severe sites, species response to climate variations are similar. In contrast, mild environments display a large diversity in tree-growth responses to climate reflecting differences in both local environmental conditions and physiology of the species.