Environmental controls on ozone fluxes in a poplar plantation in Western Europe

摘要

Tropospheric O_3 is a strong oxidant that may affect vegetation and human health. Here we report on the O_3 fluxes from a poplar plantation in Belgium during one year. Surprisingly, the winter and autumn O_3 fluxes were of similar magnitude to ones observed during most of the peak vegetation development. Largest O_3 uptakes were recorded at the beginning of the growing season in correspondence to a minimum stomatal uptake. Wind speed was the most important control and explained 44% of the variability in the nighttime O_3 fluxes, suggesting that turbulent mixing and the mechanical destruction of O_3 played a substantial role in the O_3 fluxes. The stomatal O_3 uptake accounted for a seasonal average of 59% of the total O_3 uptake. Multiple regression and partial correlation analyses showed that net ecosystem exchange was not affected by the stomatal O_3 uptake.