Vulnerabilidad frente a la sequía de repoblaciones de dos especies de pinos en su límite meridional en Europa

Abstract

Sanchez-Salguero, R., Navarro-Cerrillo, R.M., Camarero, J.J., Fernandez-Cancio, A., Swetnam, T.W., Zavala, M.A. (2012). Vulnerability to drought of two pine species in plantations at the rear edge of Europe. Ecosistemas 21(3):31-40. Doi.: 10.7818/ECOS.2012.21-3.05 Climate change causes an increase of extreme weather events such as droughts that can trigger processes of forest decline, especially in drought prone areas such as the southern limit of distribution of tree species. The vulnerability of Mediterranean mountain plantations to drought is conditioned by this climatic variability, which ultimately affects growth, vigor and long-term persistence. In this paper, we analyze the impact of several recent droughts (1994, 1995, 1999 and 2005) on the radial growth and vigor of two pine species (Pinus sylvestris, Pinus nigra) in a semi-arid mountain at southeastern Iberian Peninsula (Sierra Filabres), near their rear-edge limit. We used dendrochronological and defoliation data to quantify, by means of logistic and linear mixed models, growth and vigor changes at both individual and species scales in response to stand structure, site conditions (competition) and drought. In the Iberian southeast, a temperature rise and a decrease in spring precipitation have led to drier conditions during the late twentieth century. Defoliation levels and reductions in growth were higher in the species more vulnerable to drought-induced xylem embolism (P. sylvestris) than in the most resistant one (P. nigra). The radial growth was favored by wet conditions in late spring (May) and early summer (June) in both species. The growth of defoliated trees responded more to water deficit and competition than that of less defoliated trees. Climate and competition were the two main factors driving growth. The sharp growth reduction and widespread defoliation were the main components of the decline episodes described in the studied pine plantations. Current decline in pine plantations in the southeastern Iberian Peninsula, where these stands experience severe and frequent droughts, calls into question their persistence in the face of the forecast climatic scenarios for the current century, characterized by warmer and more arid conditions.