Deng et al. (2026) Legacy effects of extreme precipitation sustain carbon sink of a subtropical forest

Identification

• Journal: Agricultural and Forest Meteorology
• Year: 2026
• Date: 2026-03-30
• Authors: Jinling Deng, Liuqian Yu, Jinshu Chi
• DOI: 10.1016/j.agrformet.2026.111142

Research Groups

Earth, Ocean and Atmospheric Sciences Thrust, The Hong Kong University of Science and Technology (Guangzhou), Guangzhou, China

Short Summary

This study investigates the seasonal to interannual effects of extreme precipitation on net ecosystem productivity (NEP) in subtropical forests using a land model, revealing that while extreme events immediately reduce NEP, legacy effects from deep soil water recharge sustain the carbon sink in subsequent years.

Objective

• To investigate the seasonal to interannual effects of increasing extreme precipitation events on net ecosystem productivity (NEP) in humid subtropical forests.

Study Configuration

• Spatial Scale: Subtropical forest in Dinghu Mountain, China (site-specific, regional context).
• Temporal Scale: Seasonal to interannual (event year and subsequent years, multi-year legacy effects).

Methodology and Data

• Models used: Community Land Model Version 5 (CLM5), the land component of the Community Earth System Model (CESM).
• Data sources: Site observations from Dinghu Mountain, China (eddy covariance CO2 fluxes, soil moisture, and soil temperature) for model validation; controlled precipitation manipulation experiments (simulated).

Main Results

• Extreme precipitation immediately reduces net ecosystem productivity (NEP) within the event year.
• This immediate reduction is due to pulse increases in heterotrophic respiration (Rh) and ecosystem respiration (Reco) under elevated soil moisture, while gross primary production (GPP) remains stable.
• Legacy effects enhance subsequent-year NEP by 9–39 g C m⁻² yr⁻¹, ultimately preserving the subtropical forest’s annual carbon sink strength (simulated NEP range: 242–264 g C m⁻² yr⁻¹).
• Prolonged legacy effects result from deep soil water recharge after extreme precipitation, sustained by hydraulic redistribution during subsequent dry periods.
• Event characteristics (intensity, frequency, and timing) are more critical than total precipitation amount in driving carbon flux responses.
• Frequent, intense, and late-season extreme precipitation events generate particularly pronounced legacies that persist across seasons and years, impacting carbon fluxes more strongly than their immediate effects.

Contributions

• Reveals the differential responses of underlying carbon flux components (GPP, Rh, Reco) to extreme rainfall in humid subtropical regions.
• Highlights the critical role of multi-year legacy effects, driven by deep soil water recharge and hydraulic redistribution, in sustaining the carbon sink of subtropical forests despite immediate negative impacts of extreme precipitation.
• Emphasizes that event characteristics (intensity, frequency, timing) are more important than total precipitation amount for projecting terrestrial carbon cycling under increasing precipitation extremes.
• Underscores the necessity of integrating both event-scale dynamics and multi-year legacy effects for accurate projections of terrestrial carbon cycling in future climate scenarios.

Funding

Not specified in the provided text.

Citation

@article{Deng2026Legacy,
  author = {Deng, Jinling and Yu, Liuqian and Chi, Jinshu},
  title = {Legacy effects of extreme precipitation sustain carbon sink of a subtropical forest},
  journal = {Agricultural and Forest Meteorology},
  year = {2026},
  doi = {10.1016/j.agrformet.2026.111142},
  url = {https://doi.org/10.1016/j.agrformet.2026.111142}
}