Methane (CH4) is a potent greenhouse gas that is naturally produced in wetlands and terrestrial-aquatic interfaces (TAIs) through microbial methanogenesis. CH4 can be transported directly into the atmosphere via soil-atmosphere diffusion, a pathway that is understood. In contrast, a more understudied CH4 transport pathway is through tree stems. Recent advances in CH4 analysis have enabled us to discover that trees act as physical conduits of CH4, but the magnitude of this CH4 flux remains uncertain, especially in the upland forests of TAIs. (Barba et al., 2024; Pangala et al., 2013) Furthermore, tree stem CH4 fluxes can vary between species, making estimation difficult. (Moisan et al., 2024) To better constrain stem CH4 fluxes, we have designed a comparative study of Acer saccharinum and co-occurring Quercus species in the Ottawa National Wildlife Refuge. Our objective is to compare stem CH4 fluxes across species using static stem gas-chamber measurements at different heights along the stem. CH4 Fluxes will be measured during a period of natural inundation in the late spring of 2026, through the fall of 2026. Our results will contribute to pre-treatment measurements for the DELUGE (Disturbance and Ecohydrological Upland Great Lakes Ecosystems) ecosystem-scale manipulative experiment. In this poster, we will present experimental and methodological design, site characterization, and preliminary results.
