European beech is a net annual source of methane (CH4)

0544693 - ÚVGZ 2022 DE eng A - Abstract
Macháčová, Kateřina - Warlo, Hannes - Svobodová, Kateřina - Agyei, Thomas - Uchytilová, Tereza - Horáček, Petr - Lang, F.
European beech is a net annual source of methane (CH4).
EGU General Assembly 2021 (vEGU21: Gather Online). Göttingen: European Geosciences Union, 2021.
[EGU General Assembly Conference 2021. 19.04.2021-30.04.2021, online]
R&D Projects: GA ČR(CZ) GJ17-18112Y; GA MŠMT(CZ) LO1415; GA MŠMT(CZ) EF16_019/0000797; GA MŠMT(CZ) LM2015061
Institutional support: RVO:86652079
Keywords : methane * fagus sylvatica * exchange * tree stem * forest floor * seasonal * annual * flux
OECD category: Plant sciences, botany
https://www.egu21.eu/

Trees are known to be sources of methane (CH4), an important greenhouse gas, into the atmosphere. However, still little is known about the seasonality of the tree stem CH4 fluxes, particularly for the dormant season, and about the impact of environmental parameters on this gas exchange. This makes the estimation of net annual ecosystem CH4 fluxes difficult. We determined seasonal dynamics of CH4 exchange of mature European beech stems (Fagus sylvatica) and of adjacent forest floor in a temperate montane forest of White Carpathians, Czech Republic, from November 2017 to December 2018. We used static chamber methods and gas chromatographic analyses. We aimed to understand the unknown role in seasonal changes of CH4 fluxes of these forests, and the spatiotemporal variability of the tree fluxes. The beech stems were net annual sources for atmospheric CH4, whereas the forest floor was a predominant sink for CH4. The stem CH4 emissions showed high inter-individual variability and clear seasonality following the stem CO2 efflux. The fluxes of CH4 peaked during the vegetation season, and remained low but significant to the annual totals during winter dormancy. By contrast, the forest floor CH4 uptake followed an opposite flux trend with low CH4 uptake detected in the winter dormant season and elevated CH4 uptake during the vegetation season. Based on our preliminary analyses, the detected high spatial variability in stem CH4 emissions can be explained neither by the CH4 exchange at the forest floor level, nor by soil CH4 concentrations, soil water content and soil temperature, all measured in vertical soil profiles close to the studied trees. European beech trees, native and widely spread species of Central Europe, seem to markedly contribute to the seasonal dynamics of the ecosystem CH4 exchange, and their CH4 fluxes should be included into forest greenhouse gas emission inventories.
Permanent Link: http://hdl.handle.net/11104/0321521