EGU21-4706
https://doi.org/10.5194/egusphere-egu21-4706
EGU General Assembly 2021
© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.

Methane exchange in forests

Ruochan Ma1, James Stockdale2, Niall P. McNamara3, James Morison4, Sirwan Yamulki4, and Sylvia Toet1
Ruochan Ma et al.
  • 1Department of Environment and Geography, University of York, York, United Kingdom
  • 2Department of Biology, University of York, York, United Kingdom
  • 3Centre for Ecology & Hydrology (CEH), Lancaster, United Kingdom
  • 4Forest research, Surrey, United Kingdom

Methane (CH4) is the second most important anthropogenic greenhouse gas (GHG) after carbon dioxide (CO2), globally responsible for more than 20% of the additional radiative forcing since 1750. Well-drained forest soils are considered as one of the most important biological CH4 sinks. Net CH4 exchange in forest soils depends on the balance of two contrasting microbial processes, i.e. CH4 production and CH4 oxidation, which are controlled by the population and activity of methanogens and methanotrophs, respectively. Additionally, recent reports have shown that living stems and shoots of trees in forests may produce and emit substantial quantities of CH4, which can offset CH4 consumption by soils; potentially switching the forest from a net CH4 sink to a net source.

Tree-emitted CH4 in forests may result from biological production in soils which is subsequently absorbed by roots and then transported in stems and emitted from stems and leaves. However, there is also evidence that CH4 emissions from living tree stems may be biologically produced in situ within tree stems themselves. Long-term and high-frequency measurements of stem CH4 flux in various individuals, tree species and forest ecosystems are needed to unravel the potential underlying mechanisms and pathways of stem CH4 exchange.

This research compares CH4 exchange from tree stem fluxes and soil in forest stands of English oak (Quercus robur) and Japanese larch (Larix kaempferi) and tries to understand the underlying mechanism of stem CH4 exchange in temperate forests. High-frequency measurements of tree stem CH4 exchange across various individuals were carried out in 2020 and the results will be presented from this study to help inform forest management and how to promote this globally important forest CH4 sink under climate change.

How to cite: Ma, R., Stockdale, J., P. McNamara, N., Morison, J., Yamulki, S., and Toet, S.: Methane exchange in forests, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-4706, https://doi.org/10.5194/egusphere-egu21-4706, 2021.

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