Tree diversity–soil organic carbon relationships strengthen under colder and more arid conditions

Soil organic carbon (SOC) plays an essential role in carbon sequestration and climate change mitigation in forest ecosystems. While experimental studies have shown that plant diversity usually increases SOC, it remains unclear whether this positive relationship holds in natural ecosystems across varying climatic conditions. Using a global dataset of 15 large and long-term monitored natural forest sites spanning a wide latitudinal range, we assess the relationship between tree diversity and SOC within and across sites in temperate, subtropical, and tropical regions. We found an overall positive relationship between tree taxonomic diversity and SOC. The relationships between tree taxonomic or functional diversity and SOC became stronger under colder and more arid conditions. Additionally, tree functional composition was linked to SOC only within a subset of sites in more arid climates. These findings suggest that warmer and more humid conditions increase decomposition, offsetting diversity-driven carbon inputs, while colder and more arid conditions enhance SOC through low decomposition and increased inputs through abiotic facilitation and biotic interactions in high-diversity communities. Our findings indicate that conserving plant diversity is critical for enhancing carbon sequestration and mitigating the effects of climatic conditions, particularly in cold climates and regions facing an increase in arid conditions.

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Publication Details

Journal
New Phytologist
Published
2026-05-08
DOI
https://doi.org/10.1111/nph.71242
Primary Topic
Soil Carbon and Nitrogen Dynamics
Type
article
Field-Weighted Citation Impact
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article

Tree diversity–soil organic carbon relationships strengthen under colder and more arid conditions

Daniel J. Johnson, Yankun Liu, Glen Reynolds, Norman A. Bourg et al.
New Phytologist
Soil Carbon and Nitrogen Dynamics
article

Tree diversity–soil organic carbon relationships strengthen under colder and more arid conditions

Daniel J. Johnson, Yankun Liu, Glen Reynolds, Norman A. Bourg, Nathaly R. Guerrero‐Ramírez, Haoru Yan, Sabine Both, X H Liu, Marko J. Spasojevic, Keith Clay, Jie Yang, Yi Li, Hongxin Su, Xuehong Xu, Yan Enrong, Jinyao Nie, Yan Zhu, Chengjin Chu, Richard P. Phillips, Yann Hautier, Xiujuan Qiao, Xiaodong Yang, Michael J. O'Brien, Hu Du, Luxiang Lin, Guangze Jin, Hua Huang, Jonathan A. Myers, Shangwen Xia, Bernhard Schmid, Guochun Shen, David F. R. P. Burslem, Feng Liu, Kristina J. Anderson‐Teixeira, Xiangcheng Mi, Keping Ma, William J. McShea
article en

Abstract

Soil organic carbon (SOC) plays an essential role in carbon sequestration and climate change mitigation in forest ecosystems. While experimental studies have shown that plant diversity usually increases SOC, it remains unclear whether this positive relationship holds in natural ecosystems across varying climatic conditions. Using a global dataset of 15 large and long-term monitored natural forest sites spanning a wide latitudinal range, we assess the relationship between tree diversity and SOC within and across sites in temperate, subtropical, and tropical regions. We found an overall positive relationship between tree taxonomic diversity and SOC. The relationships between tree taxonomic or functional diversity and SOC became stronger under colder and more arid conditions. Additionally, tree functional composition was linked to SOC only within a subset of sites in more arid climates. These findings suggest that warmer and more humid conditions increase decomposition, offsetting diversity-driven carbon inputs, while colder and more arid conditions enhance SOC through low decomposition and increased inputs through abiotic facilitation and biotic interactions in high-diversity communities. Our findings indicate that conserving plant diversity is critical for enhancing carbon sequestration and mitigating the effects of climatic conditions, particularly in cold climates and regions facing an increase in arid conditions.

New Phytologist
University of California, Riverside (US), Tulane University (US), Smithsonian Tropical Research Institute (PA), Rainforest Alliance (US), Kunming Institute of Botany (CN), Sun Yat-sen University (CN), Utrecht University (NL), University of Aberdeen (GB), Chinese Academy of Sciences (CN), University of Zurich (CH), Washington University in St. Louis (US), Ministry of Ecology and Environment (CN), Smithsonian Conservation Biology Institute (US), Beijing Botanical Garden (CN), Xishuangbanna Tropical Botanical Garden (CN), University of Florida (US), Heilongjiang Vocational Institute of Ecological Engineering (CN), Estacion Experimental de Zonas Aridas (ES), Institute of Subtropical Agriculture (CN), Indiana University Bloomington (US), Wuhan Botanical Garden (CN), National Biodiversity Institute (CR), Nanning Normal University (CN), Rocky Mountain Research (United States) (US), Yunnan Academy of Forestry (CN), University of Chinese Academy of Sciences (CN), ZheJiang East Crystal Electronic (China) (CN), Shanghai Institute of Pollution Control and Ecological Security, China National Botanical Garden, Northeast Forestry University (CN), East China Normal University (CN), University of Göttingen (DE), University of New England (AU)
Climate action
Openalex Percentile: Top 7%
Soil Carbon and Nitrogen Dynamics
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