The Digital Climatic Atlas and the Ecological and the Forestry Inventory of Catalonia (NE Spain) were analysed to study the climate effect on leaf mass per area (LMA) and leaf area index (LAI) on Quercus ilex L., one of the most widely spread tree species in the Mediterranean region. 195 sites in this region of 31,895 km2 were considered. The relationship between climatic variables (total annual rainfall, mean annual temperature, mean minimum winter temperatures, and mean annual solar radiation) and LMA and LAI were analysed by simple and multiple regressions. LMA was higher in the drier sites and specially in the colder sites. There was also a significant correlation between solar radiation and LMA. On the contrary, LAI values, which were negatively correlated with LMA values, were lower in drier and colder sites, and were not significantly affected by solar radiation. The results highlight that high LMA values do not seem to be a specific protection to dry conditions but to a wide range of environmental stress factors, including low temperatures.

This research was financially supported by MEC projects REN2003- 04871, and CGL2004-01402/BOS from the Spanish Government, by the European project ALARM (Contract 506675, EU sixth framework programme) and by a Fundacio´n BBVA 2004 and a SGR2005-00312 AGAUR-Generalitat de Catalunya grants.

6 páginas, 4 figuras, 1 tabla.

Peer reviewed