Intraspecific variability of monoterpene composition emitted by Quercus ilex leaves

Intraspecific variation in the composition of monoterpenes emitted from Quercus ilex L. leaves was investigated in southern France by screening the emissions of 146 trees and by examining the effects of season, age, and crown position of leaves on the composition of emissions. All trees emitted the same blend of monoterpenes, mainly apinene, b-pinene, sabinene, myrcene, and limonene but in distinctly different proportions. Of the surveyed trees, 71% emitted mainly pinenes (60-80%), 21% had higher proportions of limonene (30-80%), and 8% had higher proportions of myrcene (60-90%) in their emissions. For a given tree, the proportions were similar for leaves of different ages and different crown positions, and remained unchanged throughout different seasons.