Forest thinning effects on soil carbon stocks and dynamics: Perspective of soil organic carbon sequestration rates

• Published in: Catena (Giessen) 2025-03, Vol.250, p.108759, Article 108759
• Main Authors: Qu, Qing, Xu, Hongwei, Xu, Lin, You, Chengming, Tan, Bo, Li, Han, Zhang, Li, Wang, Lixia, Liu, Sining, Xu, Zhenfeng, Xue, Sha, Wang, Minggang
• Format: Article
• Language: English
• Subjects: Forest management; Global forest; Plant community structure; Planted forests; Soil carbon cycling
• ISSN: 0341-8162
• DOI: 10.1016/j.catena.2025.108759

•Thinning promotes soil C accumulation.•Heavy thinning intensity weakens the soil carbon accumulation rate (RCC).•Long recovery time weakens the RCC.•The RCC in coniferous forests was higher than that in mixed forests.•Soil pH and soil C:N were important factors affecting the RCC. Forest thinning has significantly changed the forest community composition and structure and affected soil microbial activity and carbon (C) cycling. However, how thinning affects the soil C stocks and dynamics, especially the accumulation rate of soil C (RCC) and the driving mechanism of thinning affecting RCC globally, has not yet been revealed. Here, we analyze the effects of forest type (coniferous, broadleaf, and mixed), thinning intensity (light: 66.6 %), and recovery time (0–5, 6–10, and > 10 years) on the RCC by the 1056 data points. Our results showed that thinning increased soil C accumulation; in particular, thinning significantly increased soil C stocks (average value) in the 0–30 and 0–60 cm layers from 70.5 to 76.5 Mg/ha, and from 115.6 to 125.8 Mg/ha, respectively, compared to the un-thinning treatments (control). Furthermore, the RCC in coniferous forests (2.3 Mg/ha yr−1) was higher than that in mixed forests (1.3 Mg/ha yr−1) in 0–60 cm layer. Additionally, the RCC decreased with thinning intensity and recovery time. Finally, the RCC had significant positive relationships with soil pH, whereas initial soil C stock, thinning intensity, and average annual temperature were important factors affecting the RCC. In conclusion, thinning increased the accumulation of soil C in global forest ecosystems, but RCC decreased with increasing thinning intensity and recovery time at the global scale. The results enhance our understanding of the carbon cycle in forest ecosystems during thinning processes.