Predicciones del crecimiento en poblaciones de pino laricio (Pinus nigra Arn. ssp. salzmannii) bajo diferentes escenarios futuros de cambio climático

Abstract

Current decreasing precipitation and increasing temperatures, together with the growing likelihood of extreme drought events, may heighten the vulnerability of several tree populations in the Mediterranean. However, the effects of expected climate change on tree growth are poorly understood. We analysed growth pattern in black pine (Pinus nigra) across an altitudinal gradient in the Cuenca Mountain Range (central-eastern Spain). Data on the increment of tree basal area were used to fit climate-growth models. Then, we forecasted future tree growth using as predictors the climate data from CGCM2 and ECHAM4 models, and the IPCC emission scenarios A2 and B2, at a regional scale. We hypothesized that the populations showing the lowest mean growth rates are the most vulnerable to impending climate change. Local climatic data spanning the 20th century, as well as the future (2011-2070) climate projections, yielded a warming trend and increasing extreme drought events. Low-elevation P. nigra stands did not yield the lowest growth rate but showed negative correlations among temperature and climate, and therefore, growth models forecasted growth decline and virtual extinction of these populations. Nonetheless, old-growth and higher-elevation stands yielded steady and slightly declining growth predictions, despite they showed very low mean growth rates. Core populations showed positive growth trends related to positive correlations with winter and autumn temperatures. Our results allow to expect contrasting climate change effects on P. nigra, where some populations are likely to decline, others populations might improve their potential growth, and some old-growth stands could endure long-term persistence in a similar manner as they currently do.