EXPLORATORY STUDY OF GAS FLUXES IN TREES AT VARYING HEIGHTS, SEASONS, AND ELEVATION AT THE SMITHSONIAN ENVIRONMENTAL RESEARCH CENTER, MARYLAND, UNITED STATES

Methane emissions from vegetation are an important, but poorly constrained, term in the global methane budget. This study aimed to elucidate sources and mechanisms of methane emissions from trees by comparing methane to radon, a radioactive gas that is naturally present in soil and groundwater, across different tree species, chamber heights, seasons, and other variables. Emissions were greater at the lower chamber height than at the upper chamber, and higher in the summer than in the winter, indicating the role of warmer temperatures on ecosystem emissions. Because of the similarities observed between radon and methane, and the substantial amount of both gases measured at the base of the tree, we suspect soils to be the primary source of methane emissions from trees. In assessing the contribution of trees to climate change, knees should be considered because they contribute a substantial amount of very potent greenhouse gas to the atmosphere.