中国森林の窒素保持と炭素隔離を定量化(National Synthesis Quantifies Nitrogen Retention and Carbon Sequestration in China’s Forests)

2026-02-10 中国科学院(CAS)

中国科学院応用生態研究所の研究チームは、中国森林における大気由来窒素の保持量と炭素固定への寄与を初めて全国規模で定量化した。Global Change Biologyに発表された本研究は、18地点・4生態帯・3遷移段階の^15Nトレーサー実験を統合解析し、森林が沈着窒素の約65%を保持し、その約3分の2を土壌に蓄積すると報告。寒帯林では最大約90%と高い一方、亜熱帯・熱帯林では窒素飽和の影響で50~70%に低下した。一次林は鉱質土壌に、人工林は有機層に多く保持し、硝酸態は植物吸収、アンモニウム態は有機土壌に蓄積する傾向が示された。窒素沈着は年間約0.11Pgの炭素吸収を促進し、中国森林炭素吸収量の20~30%を占めると推定された。

中国森林の窒素保持と炭素隔離を定量化(National Synthesis Quantifies Nitrogen Retention and Carbon Sequestration in China’s Forests)
Nitrogen-induced forest carbon sequestration (C-N response) (a) and its decline with increasing nitrogen deposition (b) across Chinese forest ecosystems (Image by Geshere Abdisa Gurmesa)

<関連情報>

中国の森林における窒素沈着の要因と炭素隔離への貢献 Drivers of Deposited Nitrogen Retention and Its Contribution to Carbon Sequestration in Chinese Forests

Geshere Abdisa Gurmesa, Ang Wang, Shanlong Li, Feifei Zhu, Kai Huang, Yihang Duan, Qinggong Mao, Quan Zhi, Ronghua Kang, Per Gundersen, Weixing Zhu, Yunting Fang
Global Change Biology  Published: 30 January 2026
DOI:https://doi.org/10.1111/gcb.70724

ABSTRACT

Anthropogenic nitrogen (N) deposition alters forest functioning and their capacity to sequester carbon (C), yet its contribution to the forest C sink depends on N retention and allocation between plant biomass and soil pools. Despite high N deposition across China, the magnitude and drivers of N retention and contribution to forest C sequestration remain unclear due to a lack of systematic regional synthesis. Here, we synthesized data from decades of 15N tracer experiments spanning boreal to tropical regions of China to quantify the retention of deposited N, distribution among plant and soil pools, and contribution to forest C sequestration. On average, Chinese forests retained ~65% of the deposited N, with about two-thirds stored in the soil. Total retention and partitioning of N varied with climate, successional stage, and N forms. Soil organic layer retention declined, while mineral soil retention increased along a north–south gradient in mean annual temperature. Chronically N-saturated and disturbed forests exhibited low plant retention, whereas other forests showed substantial uptake across climate zones. Total ecosystem retention efficiency generally declined from boreal to tropical forests. Across successional stages, retention did not differ significantly; however, primary forests retained more deposited N in mineral soils, whereas plantations favored retention in the organic layer. Stoichiometric scaling indicates that CN response (kg C sequestered per kg deposited N) varies among forest types, ranging from ~7 to 40 kg C kg−1 N, with boreal forests and plantations exhibiting the strongest C response due to greater N limitation. This suggests that over the past decade, N deposition enhanced C sequestration by approximately 0.11 Pg C year−1, accounting for 20%–30% of China’s forest C sink. Overall, these findings advance understanding of the drivers of deposited N retention and its contribution to C sequestration, with implications for predicting forest N and C dynamics under global change.

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