Climate change-controlled dendroecological signal in Pinus pinea in Southern Spain [Póster]

Abstract

Researching the dynamic response to climatic variability of Mediterranean pine forests is a basic issue when evaluating the vulnerability of these ecosystems to climate change-induced abiotic stress. Tree-rings can provide valuable information to approach this purpose. We established five Pinus pinea ring-width chronologies in SW Spain. Tree-growth variability was analyzed using principal component analysis (PCA) for the period 1935-2011. A common climatic signal expressed by the first principal component (PC1) was found. Considering the PC1 scores as a regional chronology, significant correlations with meteorological data were found: correlation was positive for winter-spring precipitation and winter minimum temperatures, and negative for spring maximum temperatures. The PCA, the PC1-climate correlations and the inter-annual ringwidth variability (sensitivity) were computed for successive intervals to check whether the variance explained by the PC1, the climate-growth relationships and the intensity of growth response to climate varied over time. Both sensitivity and shared variance increased over the last decades. The correlation with winter precipitation and temperatures became stronger, spring precipitations lost significance and negative correlation with spring temperatures was enhanced. This indicates that climate became more limiting and a major force controlling growth in the recent decades. In agreement with our findings, meteorological series showed an increase of maximum temperatures in the warmer months, a decrease of minimum temperatures in winter and a marked increase of precipitation variability. Finally, running-interval correlations were performed between PC1 and three P. pinea reference chronologies from Central Spain: correlation increased significantly since the 1970s, indicating an enhanced common macroclimatic signal. Our study highlights the sensitivity of P. pinea to more restrictive climatic conditions and the synchronizing effect of climate change on P. pinea forest growth patterns at regional scale.