Aleppo pine vulnerability to climate stress is independent of site productivity of forest stands in southeastern Spain

24 Pág.

Forest management adaptation to climate change requires identifying the previously most vulnerable stands and the possible climate impacts on forests. This study evaluates whether site index, as an indicator of forest productivity, is related to climate–growth responses and assesses the way in which local site factors modulate climate–tree growth relationships. Tree-ring width series and soil characteristics were obtained from six Pinus halepensis stands with different site indices and similar climate. Dendrochronological methods were used to compare tree climate–growth responses among sites and to study temporal trends in inter-annual growth variability and climate– growth relationships (before and after 1970). The influence of topographic and soil features on tree growth was assessed by means of partial least squares. Stands with low site indices tended to present higher mean sensitivities and greater percentages of missing rings, this relation being modulated mainly by clay percentage and nutrient status in soil. Climate is the major Aleppo pine radial growth driver in the study area with similar growth–climate relationship among sites. Radial growth was mainly influenced by spring temperature and precipitation and previous autumn–winter precipitation. This relationship was stronger after 1970 than before this year, showing also a 2-month advancement of the most influential climate variables after 1970, from May to March. These results and the increasing temporal trend found in mean sensitivity after 1970 highlight the vulnerability of these stands to climate change. Site index was not found to be directly related to stand vulnerability, although local site factors modulate in part the tree-growth response. © Springer-Verlag Berlin Heidelberg 2014.

The study was partially supported by the Spanish Ministry of Science and Innovation through projects SUM2008-00002-00-00, AGL2011-29701-C02.01 and AGL2010.21153.C02.01 and by the Spanish National Institute for Agricultural and Food Research and Technology (INIA) with Project AT10-007. We gratefully acknowledge Angel Bachiller and Enrique Garriga for assisting in fieldwork and Raquel Onrubia for helping in cores cross-dating. We thank the Spanish Meteorological Agency (AEMET) for providing climate data.

Peer reviewed