ABSTRACT

Isoprene is a reactive volatile organic compound (VOC), the annual global biogenic emissions of which are the largest of the non-methane VOC. Since isoprene emissions are partly temperature-driven, understanding the relationship between isoprene emission and climate must be improved. Isoprene emission was measured in Quercus crispula, the second-most dominant isoprene-emitting tree species in Japan. Four mature Q. crispula trees were exposed to artificial warming of their roots and branches at approximately 5°C warmer than ambient temperatures. Four un-warmed control trees were also measured and compared for their emissions over the course of five months. Basal emission rates of isoprene (defined as a normalized emission rate under standard light and temperature conditions) was calculated and compared between warmed and control branches. The basal emission rates varied from 0.17 to 38.5 nmol m^-2 s^-1 (average; 10.4 nmol m^-2 s^-1) over the seasons. However, the basal emission rate did not significantly differ between warmed and control leaves.