Soil organic carbon is a key determinant of CH<sub>4</sub> sink in global forest soils.

Lee, Jaehyun; Oh, Youmi; Lee, Sang Tae; Seo, Yeon Ok; Yun, Jeongeun; Yang, Yerang; Kim, Jinhyun; Zhuang, Qianlai et al. · Nat Commun · 2023

basic_science · Level V

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Abstract

Soil organic carbon (SOC) is a primary regulator of the forest-climate feedback. However, its indicative capability for the soil CH<sub>4</sub> 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 CH<sub>4</sub> 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 CH<sub>4</sub> sink. We find that a CH<sub>4</sub> 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 CH<sub>4</sub> sink (24.27 Tg CH<sub>4</sub> yr<sup>-1</sup>) than the model without considering SOC effects (17.46 Tg CH<sub>4</sub> yr<sup>-1</sup>). This study highlights the role of SOC in the forest CH<sub>4</sub> sink, which shall be factored into future global CH<sub>4</sub> budget quantification.