Sensitivity of Nothofagus dombeyi tree growth to climate changes along a precipitation gradient in northern Patagonia, Argentina

SUAREZ, M.L.; VILLALBA, R.; MUNDO, I.A.; SCHROEDER, N.

TREES-STRUCTURE AND FUNCTION

SPRINGER

Lugar: Berlin; Año: 2015 vol. 29 p. 1053 - 1067

0931-1890

Key message Recent variations in climate appear toinduce similarities in the responses of N. dombeyigrowth along its entire distribution, supporting globalconvergence in tree growth responses to climatechanges.Abstract Understanding forest responses to climate variationsis urgently needed for anticipating changes in forestcomposition and biodiversity. We use twelve tree-ringchronologies from Nothofagus dombeyi, the dominant treeat mesic-to-humid sites, to characterize climate?growthrelationships along the west-to-east precipitation gradientin Nahuel Huapi National Park, Argentina. A principalcomponents analysis indicates that a large proportion ofcommon variance in tree growth reflects regional-scaleinfluences of climate. Correlation functions between climateand tree-ring indexes show that the critical factorregulating tree growth is spring?summer water deficitinduced by above-average temperature and reduced precipitationduring the growing season. At high elevations,however, tree growth appears to be less sensitive to waterdeficit but comparatively more sensitive to warmer conditions.Temporal trends in climate?tree growth relationshipssupported the occurrence of a dominant large-scaleclimatic response, but also identify changes in climate?growth relationships over time, primarily at wet andhigh-elevation sites. These variations in climate?growthrelationships are interpreted as a convergence process tosimilar patterns in tree growth across the entire precipitationgradient, as wet?cool conditions at high-elevation sitesturned to be less frequent due to drier and warmer yearsduring the late twentieth century. Sampling along environmentalgradients provides a comprehensive view of thepotential range of responses of tree growth to climatewhich is not recorded using traditional dendrochronologicalsampling at marginal, more climate-sensitive sites.The recent changes in the relationships between climateand growth highlight the vulnerability of N. dombeyi toclimate changes across its entire range of distribution inArgentina.