Wang et al. (2025) Hydrothermal integration and synergy regulate carbon exchange in forest ecosystems of eastern China

Identification

• Journal: Agricultural and Forest Meteorology
• Year: 2025
• Date: 2025-11-25
• Authors: Yin Wang, Xiaojuan Tong, Jinsong Zhang, Jun Li, Ping Meng, Weifeng Wang, Yating Wang, Mingxin Yang, Qingyuan Liu
• DOI: 10.1016/j.agrformet.2025.110888

Research Groups

• School of Ecology and Nature Conservation, Beijing Forestry University, Beijing 100083, China
• Key Laboratory of Tree Breeding and Cultivation of State Forestry Administration, Research Institute of Forestry, Chinese Academy of Forestry, Beijing 100091, China
• Henan Xiaolangdi Forest Ecosystem National Observation and Research Station, Jiyuan 454650, China
• Key Laboratory of Water Cycle and Related Land Surface Processes, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China
• College of Ecology and Environment, Nanjing Forestry University, Nanjing 210037, China

Short Summary

This study investigated the influence of hydrothermal integration and synergy on carbon exchange across 16 forest ecosystems in eastern China, developing novel indices (TP and D) that more effectively explain the variability in gross primary productivity, ecosystem respiration, and net ecosystem productivity, with soil water content and atmospheric hydrothermal synergy identified as primary drivers.

Objective

• To examine the divergence of carbon exchange (Gross Primary Productivity, Ecosystem Respiration, Net Ecosystem Productivity) over 16 forest ecosystems in eastern China.
• To explore the controls of hydrothermal change on carbon exchange by developing and evaluating two novel indices for hydrothermal integration (TP) and hydrothermal synergy (D) based on the copula function.
• To clarify how hydrothermal conditions impact carbon exchange in forest ecosystems and provide insights into assessing forest responses to climate change.

Study Configuration

• Spatial Scale: 16 forest ecosystems in eastern China.
• Temporal Scale: Seasonal and spatial variations.

Methodology and Data

• Models used: Copula function (for developing TP and D indices), Random forest analysis.
• Data sources: Observational data from 16 forest ecosystems in eastern China, including carbon fluxes (GPP, Re, NEP) and meteorological variables (e.g., temperature, precipitation, vapor pressure deficit, soil water content).

Main Results

• The newly developed indices, Hydrothermal Integration (TP) and Hydrothermal Synergy (D), demonstrated higher sensitivity and applicability in capturing seasonal and spatial variations in hydrothermal conditions compared to traditional indices (e.g., water and thermal product index K, aridity index AI, standardized precipitation evapotranspiration index SPEI).
• Vapor pressure deficit (VPD), soil water content (SWC), and aridity index (AI) exhibited nonlinear responses to TP and D, with coordinated hydrothermal conditions enhancing SWC and uncoordinated or scarce conditions increasing drought risk.
• TP and D collectively explained over 80% of the variability in Gross Primary Productivity (GPP), Ecosystem Respiration (Re), and Net Ecosystem Productivity (NEP), providing a better explanation of hydrothermal controls on carbon exchange than temperature and precipitation alone.
• Carbon fluxes peaked at a TP value of approximately 1 and a D value slightly above 0, indicating that moderately water-dominated hydrothermal synergy provides optimal conditions for photosynthesis and respiration.
• Random forest analysis revealed that soil water content (SWC) was the primary driver of GPP, Re, and NEP, followed by the hydrothermal synergy index (D) for GPP and NEP.
• Forest carbon exchange is primarily regulated by soil water availability and atmospheric hydrothermal synergy.

Contributions

• Developed and validated novel indices (Hydrothermal Integration, TP; Hydrothermal Synergy, D) that more accurately represent the complex interplay of hydrothermal conditions and their impact on forest carbon exchange compared to existing indices.
• Quantified the significant explanatory power of these new indices, demonstrating that they account for over 80% of the variability in GPP, Re, and NEP across diverse forest ecosystems.
• Identified soil water content and atmospheric hydrothermal synergy as the dominant drivers of carbon exchange in eastern Chinese forest ecosystems, providing a clearer mechanistic understanding.
• Offers improved tools and insights for assessing forest ecosystem responses to climate change and managing carbon sequestration under varying hydrothermal regimes.

Funding

Not explicitly mentioned in the provided text.

Citation

@article{Wang2025Hydrothermal,
  author = {Wang, Yin and Tong, Xiaojuan and Zhang, Jinsong and Li, Jun and Meng, Ping and Wang, Weifeng and Wang, Yating and Yang, Mingxin and Liu, Qingyuan},
  title = {Hydrothermal integration and synergy regulate carbon exchange in forest ecosystems of eastern China},
  journal = {Agricultural and Forest Meteorology},
  year = {2025},
  doi = {10.1016/j.agrformet.2025.110888},
  url = {https://doi.org/10.1016/j.agrformet.2025.110888}
}