Delta(13)C and tree-ring width reflect different drought responses in Quercus ilex and Pinus halepensis

• Published in: Oecologia 2003-12, Vol.137 (4), p.512-518
• Main Authors: Ferrio, J P, Florit, A, Vega, A, Serrano, L, Voltas, J
• Format: Article
• Language: English
• Subjects: Adaptation, Physiological; Carbon Isotopes - analysis; Climate; Disasters; Mediterranean Region; Pinus - growth & development; Pinus - physiology; Quercus - growth & development; Quercus - physiology; Rain; Water-Electrolyte Balance - physiology
• ISSN: 0029-8549
• DOI: 10.1007/s00442-003-1372-7

Holm oak (Quercus ilexL.) and Aleppo pine (Pinus halepensisMill) are representative of two different functional types of trees extensively found in the Mediterranean: evergreen sclerophyllous and drought-adapted conifers. The former is considered a partially drought-tolerant species, whereas the latter is a typically drought-avoiding, water-saving species. We postulated that contrasting strategies in response to water deficits in Q. ilex and P. halepensis would lead to a differential sensitivity to changes in water availability. To test this hypothesis, we compared the response of both species in growth rate (measured as radial increments) and intrinsic water use efficiency WUE(i), as inferred from carbon isotope discrimination (Delta(13)C) in wood samples] among sites from different provenance regions in NE Spain. We found significant differences in Delta(13)C and growth among provenance regions, partly explained by contrasting water availability. Wood Delta(13)C was positively related with precipitation and the ratio between precipitation and potential evapotranspiration (P/ E). However, these relationships were stronger in P. halepensis (for P / E, r(2)=0.67, P