García-Hernández et al. (2026) Assessing silvicultural treatment effects on catchment hydrology under current and future climate scenarios

Identification

• Journal: Agricultural and Forest Meteorology
• Year: 2026
• Date: 2026-10-16
• Authors: J. García-Hernández, N. Lana-Renault, J. Zabalza, D. Regüés, Estela Nadal‐Romero
• DOI: 10.1016/j.agrformet.2026.111523

Research Groups

• Pyrenean Institute of Ecology-Consejo Superior de Investigaciones Científicas (IPE-CSIC), Zaragoza, Spain
• Area of Physical Geography, Department of Human Sciences, University of La Rioja, Logroño, Spain

Short Summary

This study used eco-hydrological modeling to assess the impact of two forest thinning strategies (Uniform Shelterwood System and Group Selection System) on ecohydrological responses (Leaf Area Index, Evapotranspiration, and streamflow) in a Mediterranean mountain catchment under current and future climate scenarios, finding that the Group Selection System significantly increased water yield under milder scenarios, while extreme climate attenuated management effects.

Objective

• To assess the sensitivity of eco-hydrological responses (Leaf Area Index (LAI), evapotranspiration (ET), mean streamflow, and maximum streamflow (peakflow)) to two contrasting forest thinning strategies (Uniform Shelterwood System (USS) and Group Selection System (GSS)) and three climate change scenarios (SSP1–2.6, SSP2–4.5, and SSP5–8.5) in the San Salvador catchment.
• Hypothesis: The effects of forest thinning on hydrological response would vary depending on the specific thinning practices and climate change scenarios, but light thinning interventions were anticipated not to significantly alter water yield.

Study Configuration

• Spatial Scale: San Salvador catchment, Central Spanish Pyrenees, with a surface area of 0.92 square kilometers. The model uses patches as the smallest indivisible units.
• Temporal Scale:
  • Climate data reference baseline: 2001–2022.
  • Future climate series projection: 2023–2099.
  • Daily simulations: 2001–2100.
  • Model calibration period: 1 March 2018 to 29 February 2020.
  • Model validation period: 1 March 2020 to 29 January 2022.
  • Hydrometeorological data summary: 1999–2024.

Methodology and Data

• Models used: Regional Hydro-Ecologic Simulation System (RHESSys) eco-hydrological model. Climate change scenarios from CMIP6 (SSP1–2.6, SSP2–4.5, SSP5–8.5).
• Data sources:
  • Field observations for model calibration and validation, rainfall partitioning, and soil data.
  • Hydrometeorological monitoring from a gauging station, tipping-bucket rain gauges, ultrasonic sensor, pressure transducer, meteorological station, and piezometers.
  • Climate change coefficients derived from the multi-model mean of 33 CMIP6 simulations (KNMI Climate Explorer platform).
  • Digital Elevation Model (DEM) generated from 2021 LIDAR data (Spanish National Aerial Orthophotography Plan - PNOA) at 1 meter spatial resolution.
  • Fractional Canopy Cover (FCC) maps developed from PNOA LIDAR point cloud.
  • Vegetation species maps compiled from field surveys and manual digitization based on PNOA orthophotography.
  • Multispectral imagery (MSI) from Sentinel-2 satellite for species proportion estimation.
  • Soil data from previous catchment information and the Spanish National Geographic Institute (IGN).
  • Land use and land cover maps produced by digitizing PNOA orthophotography.
  • Daily atmospheric CO2 concentration data from the Global Monitoring Laboratory - Carbon Cycle Greenhouse Gases (noaa.gov).

Main Results

• Both Uniform Shelterwood System (USS) and Group Selection System (GSS) thinning strategies significantly reduced Leaf Area Index (LAI).
• The effects on Evapotranspiration (ET), mean streamflow, and maximum streamflow (peakflow) varied depending on the silvicultural system applied.
• USS did not produce statistically significant changes in ET, mean streamflow, or peakflow relative to the no-management (NM) scenario across any climate scenario, despite a 20% reduction in fractional canopy cover.
• GSS significantly reduced ET and increased mean and maximum streamflow under the milder climate scenarios (SSP1–2.6 and SSP2–4.5).
• Under the most extreme climate scenario (SSP5–8.5), the effects of thinning on ET and streamflow were attenuated or negligible for both USS and GSS strategies.
• The spatial configuration of thinning, rather than just its intensity, significantly conditions the catchment-scale ecohydrological response, with GSS showing a greater impact due to its spatially concentrated harvesting pattern.
• The RHESSys model provided a robust framework for evaluating coupled vegetation-hydrology dynamics under silvicultural interventions in data-scarce Mediterranean mountain environments.

Contributions

• Provides a comprehensive assessment of the combined effects of two contrasting forest thinning strategies and three future climate change scenarios on ecohydrological responses in humid Mediterranean mountain catchments, an area with limited existing research.
• Highlights that the spatial configuration of silvicultural treatments (e.g., uniform vs. group selection) is a critical factor influencing catchment-scale hydrological outcomes, beyond just the intensity of biomass removal.
• Demonstrates the limitations of forest management interventions in mitigating hydrological impacts under increasingly extreme climate forcing, suggesting that management effects may be overridden by severe climatic stressors.
• Validates the utility of the RHESSys eco-hydrological model as a valuable tool for simulating complex vegetation-hydrology dynamics in data-scarce Mediterranean mountain regions, aiding in scenario development and policy guidance.
• Offers key insights for forest managers to integrate hydrologically oriented practices into adaptive landscape planning, aiming to improve water provisioning services and strengthen resilience in Mediterranean mountain landscapes.

Funding

• FORWARD project (PID2024-1613140B-100) funded by MICIU/AEI /10.13039/501100011033 and FEDER (UE).
• MOUNTWATER project (TED2021-131982BeI00) funded by the MCIN/AEI/10.13039/501100011033 and NextGeneration EU/PRTR.

Citation

@article{GarcíaHernández2026Assessing,
  author = {García-Hernández, J. and Lana-Renault, N. and Zabalza, J. and Regüés, D. and Nadal‐Romero, Estela},
  title = {Assessing silvicultural treatment effects on catchment hydrology under current and future climate scenarios},
  journal = {Agricultural and Forest Meteorology},
  year = {2026},
  doi = {10.1016/j.agrformet.2026.111523},
  url = {https://doi.org/10.1016/j.agrformet.2026.111523}
}