Intraspecific variability of monoterpene composition emitted by Quercus ilex leaves

Intraspecific variation in the composition of monoterpenes emitted from Que rcus ilex L. leaves was investigated in southern France by screening the em issions 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 alpha -pinene, beta- pinene, sabinene, m yrcene, and limonene but in distinctly different proportions. Of the survey ed trees, 71% emitted mainly pinenes (60-80%), 21% had higher proportions o f limonene (30-80%), and 8% had higher proportions of myrcene (60-90%) in t heir emissions. For a given tree, the proportions were similar for leaves o f different ages and different crown positions, and remained unchanged thro ughout different seasons.