Assessing the effects of global change on the performance of Iberian firs using carbon isotopes analyses in tree rings

Abstract

Linares, J.C., Camarero, J.J. (2010). Assessing the effects of global change on the performance of Iberian firs using carbon isotopes analyses in tree rings. Ecosistemas 19(3):24-40

Assessing the effects of global change on the performance of Iberian firs using carbon isotopes analyses in tree rings. Drought is the main tree-growth limiting factor in the Mediterranean basin. It has been suggested that, in water-limited ecosystems, the global atmospheric CO2 rise might to compensate an increasing drought-induced stomatal closure, without a significant drop in the production rates. In this paper we show data of secondary growth and intrinsic water use efficiency (WUEi) for Abies alba and A. pinsapo trees. We compared populations with and without external decline symptoms. Since the early eighties of the 20th century, the rate of WUEi increase has declined in the sites with  decline  symptoms,  being  currently  below  the  rate  of  CO2 increase. Our data show a good relationship between the time the rate of WUEi increase falls below the CO2 increase, the regional mean temperature increase, the occurrence of several extreme droughts, and generalised radial growth decline.