Soil organic carbon is a key determinant of CH4 sink in global forest soils

Jaehyun Lee; Youmi Oh; Sang Tae Lee; Yeon Ok Seo; Jeongeun Yun; Yerang Yang; Jinhyun Kim; Qianlai Zhuang; Hojeong Kang

doi:10.1038/s41467-023-38905-8

Soil organic carbon is a key determinant of CH₄ sink in global forest soils

Nat Commun. 2023 May 30;14(1):3110. doi: 10.1038/s41467-023-38905-8.

Authors

Jaehyun Lee¹, Youmi Oh^{2

3}, Sang Tae Lee⁴, Yeon Ok Seo⁵, Jeongeun Yun¹, Yerang Yang¹, Jinhyun Kim^{1

6}, Qianlai Zhuang⁷, Hojeong Kang⁸

Affiliations

¹ School of Civil and Environmental Engineering, Yonsei University, Seoul, 03722, Korea.
² Global Monitoring Laboratory, National Oceanic and Atmospheric Administration, Boulder, CO, USA.
³ Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO, USA.
⁴ Forest Technology and Management Research Center, National Institute of Forest Science, Gyeonggi, Korea.
⁵ Warm Temperate and Subtropical Forest Research Center, National Institute of Forest Science, Jeju, Korea.
⁶ Division of Life Sciences, Korea Polar Research Institute, Incheon, 21990, Korea.
⁷ Department of Earth, Atmospheric, and Planetary Sciences, Purdue University, West Lafayette, IN, USA.
⁸ School of Civil and Environmental Engineering, Yonsei University, Seoul, 03722, Korea. hj_kang@yonsei.ac.kr.

Abstract

Soil organic carbon (SOC) is a primary regulator of the forest-climate feedback. However, its indicative capability for the soil CH₄ sink is poorly understood due to the incomplete knowledge of the underlying mechanisms. Therefore, SOC is not explicitly included in the current model estimation of the global forest CH₄ sink. Here, using in-situ observations, global meta-analysis, and process-based modeling, we provide evidence that SOC constitutes an important variable that governs the forest CH₄ sink. We find that a CH₄ sink is enhanced with increasing SOC content on regional and global scales. The revised model with SOC function better reproduces the field observation and estimates a 39% larger global forest CH₄ sink (24.27 Tg CH₄ yr^-1) than the model without considering SOC effects (17.46 Tg CH₄ yr^-1). This study highlights the role of SOC in the forest CH₄ sink, which shall be factored into future global CH₄ budget quantification.