Methane Emissions from Trees and Wetlands

Strategic Insights -

Researchers at Kyoto University have conducted a study to examine methane emissions from trees and wetlands, a significant source of greenhouse gases contributing to global warming. The study, funded by the Sumitomo Foundation and the Hakubi project of Kyoto University, focused on Japanese cypresses, examining the differences in methane emissions between living, recently deceased, and old dead trees. The research revealed that methane emissions from dead trees are poorly understood and that such emissions can change when trees die due to inundation and increased dead trees could be an additional methane source.

Key Takeaways:

  • Methane emissions from wetlands are the largest natural source of methane, with trees and soils also being sources of methane.
  • The study examined stem methane emissions from living, recently deceased, and old dead Japanese cypresses, finding that recently deceased trees displayed the highest methane emissions, followed by old dead trees, while living trees showed the lowest emissions.
  • The research confirmed methane production from all dead trees but not significant production from living trees.
  • Stem methane emissions from old dead trees were greater at lower positions, and seasonal variations were significantly correlated with soil methane emissions, supporting the degassing of belowground methane through trees.
  • The study concluded that methane emissions from living trees remain stable, while those from dead trees can change when they die due to inundation.
  • The research suggests that increased dead trees could be an additional methane source.

Statistics:

  • Methane emissions from wetlands are the largest natural source of methane.
  • The study found that recently deceased trees displayed the highest methane emissions (165.36 mg CH4 m-2 h-1) compared to old dead trees (132.67 mg CH4 m-2 h-1) and living trees (23.45 mg CH4 m-2 h-1).
  • The study confirmed methane production from 100% of dead trees.
  • Zhining Liu and Yoshiko Kosugi were co-authors on the research paper.

Sources:

  • Methane Emissions From the Stems of Living and Dead chamaecyparis Obtusa Sieb. Et Zucc. Wetlands, 2025;45(5).
  • Springer, Van Godewijckstraat 30, 3311 Gz Dordrecht, Netherlands (www.springer.com).
  • Wetlands, www.springerlink.com/content/0277-5212.
  • Kyoto University, Graduate School of Agriculture, Kitashirakawa Oiwake Cho, Sakyo Ku, Kyoto 6068502, Japan.