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Elevated methane concentrations in trees of an upland forest
Author(s) -
Covey Kristofer R.,
Wood Stephen A.,
Warren Robert J.,
Lee Xuhui,
Bradford Mark A.
Publication year - 2012
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2012gl052361
Subject(s) - methane , environmental science , atmospheric methane , sink (geography) , methanogenesis , abiotic component , temperate climate , soil water , anaerobic oxidation of methane , temperate forest , carbon cycle , greenhouse gas , ecology , temperate rainforest , environmental chemistry , biology , chemistry , soil science , ecosystem , cartography , geography
There is intense debate about whether terrestrial vegetation contributes substantially to global methane emissions. Although trees may act as a conduit for methane release from soils to atmosphere, the debate centers on whether vegetation directly produces methane by an uncharacterized, abiotic mechanism. A second mechanism of direct methane production in plants occurs when methanogens – microorganisms in the domain Archaea – colonize the wood of living trees. In the debate this biotic mechanism has largely been ignored, yet conditions that promote anaerobic activity in living wood, and hence potentially methane production, are prevalent across forests. We find average, growing season, trunk‐gas methane concentrations >15,000 μ L·L −1 in common, temperate‐forest species. In upland habitat (where soils are not a significant methane source), concentrations are 2.3‐times greater than in lowland areas, and wood cores produce methane in anaerobic, lab‐assays. Emission rate estimates from our upland site are 52 ± 9.5 ng CH 4 m −2 s −1 ; rates that are of a similar magnitude to the soil methane sink in temperate forest, and equivalent in global warming potential to ∼18% of the carbon likely sequestered by this forest. Microbial infection of one of the largest, biogenic sinks for carbon dioxide, living trees, might result in substantial, biogenic production of methane.