Wang et al. (2025) Vegetation cover change as a growing driver of global leaf area index dynamics

Identification

• Journal: Nature Communications
• Year: 2025
• Date: 2025-10-20
• Authors: Dashan Wang, Alan D. Ziegler, Joseph Holden, Dominick V. Spracklen, Philippe Ciais, Liqing Peng, Zhenzhong Zeng
• DOI: 10.1038/s41467-025-64305-1

Research Groups

• State Key Laboratory of Soil Pollution Control and Safety, Southern University of Science and Technology, Shenzhen, China
• School of Geography and Planning, Sun Yat-sen University, Guangzhou, China
• School of Environmental Science and Engineering, Southern University of Science and Technology, Shenzhen, China
• Andaman Coastal Station for Research and Development, Kasetart University, Ranong, Thailand
• School of Geography, University of Leeds, Leeds, UK
• School of Earth and Environment, University of Leeds, Leeds, UK
• Laboratoire des Sciences du Climat et de l’Environnement, CEA/CNRS/UVSQ/Université Paris Saclay, Gif-sur-Yvette, France
• Department of Geography, The University of Hong Kong, Hong Kong, China
• Institute for Climate and Carbon Neutrality, The University of Hong Kong, Hong Kong, China

Short Summary

This study quantifies the contribution of vegetation cover change (VCC) to global leaf area index (LAI) dynamics over the past four decades using a data-driven framework. It finds that VCC explains 18.1 ± 5.9% of the observed global LAI increase, driven by afforestation in the Northern Hemisphere and partially offset by deforestation in the Southern Hemisphere.

Objective

• To quantify the specific contributions of vegetation cover change (VCC) to the observed global leaf area index (LAI) dynamics across space and time since the 1980s.

Study Configuration

• Spatial Scale: Global, with analysis conducted at 3° × 3° grid spacing using 0.1° × 0.1° aggregated cells from original 0.05° × 0.05° or 1/12° resolution satellite data.
• Temporal Scale: Four decades, specifically from 1982 to 2015.

Methodology and Data

• Models used: Data-driven framework based on statistical models, including an improved Bounded-Variable Least Squares (BVLS) approach to disentangle greenness parameters (βTC, βSV, βBG) for tree cover, short vegetation, and bare ground. Linear regression was used to derive long-term trends.
• Data sources:
  • Satellite-based observations:
    • Vegetation Continuous Fields (VCF) version 1 product (VCF5KYR): 0.05° × 0.05° spatial resolution, yearly (1982-2016), providing percentage of tree cover, short vegetation, and bare ground.
    • Advanced Very High-Resolution Radiometer (AVHRR) Global Inventory Monitoring and Modeling Studies (GIMMS) LAI3g dataset: 1/12° spatial resolution, bi-monthly (1982-2015), used as the primary LAI product.
    • Alternative LAI products for robustness analysis: NOAA Climate Data Record (CDR), Global Land Surface Satellite (GLASS) AVHRR LAI V50, and GLOBMAP LAI V3.
  • Ancillary data: Global cropland extent map (2003-2019) for estimating stable cropland effects.

Main Results

• The observed global maximum monthly LAI increased by 0.093 ± 0.011 m² m⁻² decade⁻¹ since the early 1980s, consistent with the model-reconstructed trend of 0.094 ± 0.012 m² m⁻² decade⁻¹.
• Vegetation cover change (VCC) contributed 18.1 ± 5.9% (0.017 ± 0.005 m² m⁻² decade⁻¹) of the global LAI increase.
• Increased tree cover was the main positive contributor (25.8%), partially offset by reduced short vegetation (−7.4%) and bare ground (−0.3%).
• VCC-induced LAI increases were pronounced in the Northern Hemisphere (33.8 ± 3.6%; 0.031 ± 0.003 m² m⁻² decade⁻¹), primarily due to afforestation in regions like China and Europe.
• LAI decreases due to forest loss were mainly observed in the Southern Hemisphere (−15.7 ± 3.1%; −0.014 ± 0.003 m² m⁻² decade⁻¹).
• The sensitivity of LAI to tree cover losses in South America (−0.306 ± 0.010 m² m⁻² decade⁻¹ per 10% tree cover loss) and Oceania (−0.360 ± 0.015 m² m⁻² decade⁻¹ per 10% tree cover loss) was notably higher than to gains in Asia (0.264 ± 0.008 m² m⁻² decade⁻¹ per 10% tree cover gain) and Europe (0.218 ± 0.009 m² m⁻² decade⁻¹ per 10% tree cover gain).
• The contribution of VCC to LAI trends progressively increased over time, showing a significant upward trend of 0.017 ± 0.001 m² m⁻² decade⁻² from the period 1982–1997 to 1982–2015.
• Cropland management without vegetation cover change accounted for no more than 14.2 ± 2.0% of LAI change.

Contributions

• Developed a novel data-driven framework to quantitatively disentangle and attribute the specific contribution of vegetation cover change (VCC) to observed global LAI dynamics, separating it from indirect factors.
• Provided robust observational evidence that VCC plays a significantly larger role (18.1 ± 5.9%) in global LAI increases than previously estimated by ecosystem models (e.g., 4%).
• Revealed the increasing importance of VCC over time in shaping global LAI trends, particularly in the 2000s, with distinct latitudinal and regional patterns.
• Highlighted the critical implications of VCC for future LAI trajectory projections, Earth system model development, and the effectiveness of nature-based climate mitigation policies.
• Emphasized the detrimental consequences of forest loss in tropical regions due to higher LAI sensitivity to tree cover declines compared to gains.

Funding

• National Natural Science Foundation of China (42371026, 42071022)
• Shenzhen Science and Technology Project for Sustainable Development in Special Innovation (KCXFZ20230731093403008)
• Guangdong Basic and Applied Basic Research Foundation (2022A1515240070)
• Shenzhen Key Laboratory of Precision Measurement and Early Warning Technology for Urban Environmental Health Risks (ZDSYS20220606100604008)
• High-level special funds provided by Southern University of Science and Technology (G03034K001; G030290001)
• Funding agencies of Zhejiang Province and Ningbo Municipality through the program "Novel Technologies for Joint Pollution Reduction and Carbon Sequestration"
• Otto Poon Research Institute for Climate-Resilient Infrastructure at the Hong Kong Polytechnic University (visiting fellowship for Z.Z.)

Citation

@article{Wang2025Vegetation,
  author = {Wang, Dashan and Ziegler, Alan D. and Holden, Joseph and Spracklen, Dominick V. and Ciais, Philippe and Peng, Liqing and Zeng, Zhenzhong},
  title = {Vegetation cover change as a growing driver of global leaf area index dynamics},
  journal = {Nature Communications},
  year = {2025},
  doi = {10.1038/s41467-025-64305-1},
  url = {https://doi.org/10.1038/s41467-025-64305-1}
}