PNNL

Abstract

Vegetated terrestrial and wetland ecosystems are among the largest natural sources and sinks of greenhouse gases to the atmosphere, but the mechanisms by which plants mediate methane production, consumption, and transport remain elusive (Rosentreter et al., 2023). Gas transport through the spongy stem tissues of herbaceous wetland vegetation is known to be the dominant pathway for methane moving from belowground soils to the atmosphere (Nisbet et al., 2009). Woody vegetation such as trees have only been recognized recently to move substantial amounts of methane to the atmosphere in forest ecosystems and we understand little about the mechanisms by which gases move through the complex anatomy of woody tissues. Although the literature on methane emissions from trees is small, there are enough studies on rates of tree stem methane fluxes to understand the broad outlines of how emissions vary with factors like climate, hydrologic setting, and major taxonomic class (Fig. 1). Largely missing are mechanistic studies on the regulatory role of wood anatomy on methane transport. Jeffrey et al. (000-000) help to fill this gap in an article recently published in New Phytologist by demonstrating, for the first time, that bark characteristics can play a major role in mediating methane transport from soils through tree stems, emphasizing the influence of stem anatomy on gas transport.