Impact of vegetation on the methane budget of a temperate forest

• Published in: The New phytologist Vol. 221; no. 3; pp. 1447 - 1456
• Main Authors: Plain, Caroline, Ndiaye, Fatou-Kiné, Bonnaud, Pascal, Ranger, Jacques, Epron, Daniel
• Format: Journal Article
• Language: English
• Published: England Wiley 01.02.2019; Wiley Subscription Services, Inc
• Subjects: Agriculture; Budgeting; Budgets; Climate; Emissions; Environmental Sciences; Fluxes; Forest ecosystems; forest soil; Forest soils; Forests; Global Changes; Glyceria striata; greenhouse gas; Herbivores; Juncus effusus; Lasers; Methane; Methane - metabolism; methanotrophy; Plant Stems - metabolism; Plantations; Plants - metabolism; Quercus - metabolism; Quercus petraea; Seasons; Soil; Stems; Temperate forests; Terrestrial ecosystems; Trees; Uptake; Vegetation; methanotrophy; Glyceria striata; methane; Quercus petraea; forest soil; Juncus effusus; greenhouse gas
• ISSN: 0028-646X; 1469-8137
• DOI: 10.1111/nph.15452

• Upland forest soils are known to be the main biological sink for methane, but studies have shown that net methane uptake of a forest ecosystem can be reduced when methane emissions by vegetation are considered. We estimated the methane budget of a young oak plantation by considering tree stems but also the understorey vegetation. • Automated chambers connected to a laser-based gas analyser, on tree stems, bare soil and soil covered with understorey vegetation, recorded CH₄ fluxes for 7 months at 3 h intervals. • Tree stem emissions were low and equated to only 0.1% of the soil sink. Conversely, the presence of understorey vegetation increased soil methane uptake. This plant-driven enhancement of CH₄ uptake occurred when the soil was consuming methane. At the stand level, the methane budget shifted from −1.4 ± 0.4 kg C ha−1 when we upscaled data obtained only on bare soil, to −2.9 ± 0.6 kg C ha−1 when we considered soil area that was covered with understorey vegetation. • These results indicate that aerenchymatous plant species, which are known to reduce the methane sink in wetlands, actually increase soil methane uptake two-fold in an upland forest by enhancing methane and oxygen transport and/or by promoting growth of methanotrophic populations.