Zuecco et al. (2025) Trees use predominantly summer water in a pre-Alpine catchment

Identification

• Journal: Journal of Hydrology
• Year: 2025
• Date: 2025-10-17
• Authors: Giulia Zuecco, Diego Todini‐Zicavo, Chiara Marchina, Stefano Brighenti, Daniele Penna, Marco Borga
• DOI: 10.1016/j.jhydrol.2025.134430

Research Groups

• Department of Land, Environment, Agriculture and Forestry, University of Padova, Legnaro, Italy
• Department of Chemical Sciences, University of Padova, Padua, Italy
• University School for Advanced Studies (IUSS), Pavia, Italy
• Faculty of Agricultural, Environmental and Food Sciences, Free University of Bozen/Bolzano, Bolzano, Italy
• Eco Research, Bolzano, Italy
• Department of Agriculture, Food, Environment and Forestry, University of Florence, Florence, Italy
• Forest Engineering Resources and Management Department, Oregon State University, Corvallis, USA

Short Summary

This study utilized a 6-year isotopic dataset in a pre-Alpine catchment to investigate the seasonal origin of water sources for soil and plants, revealing that beech and chestnut trees predominantly use summer precipitation with rapid water turnover, even during dry years.

Objective

• To investigate the seasonal origin of water sources in a small headwater catchment in the Italian pre-Alps.
• To assess how the seasonal origin of soil and plant water varies under different wetness conditions (based on soil moisture data).
• To determine the role of topography (riparian zone vs. hillslope) and wetness conditions on water uptake by beech and chestnut trees.

Study Configuration

• Spatial Scale: Small headwater catchment in the Italian pre-Alps.
• Temporal Scale: 6-year isotopic dataset.

Methodology and Data

• Models used: Seasonal Origin Index (SOI) for analysis.
• Data sources: Stable water isotopes (hydrogen-2 and oxygen-18) from precipitation, soil water, plant water, and groundwater; soil moisture data.

Main Results

• All water sources, except groundwater, exhibited distinct temporal variability.
• A quick turnover of waters in the catchment indicates that precipitation rapidly replenishes the soil, becomes available for plant water uptake, and contributes to stream runoff.
• Beech and chestnut trees predominantly use water derived from summer precipitation.
• Negligible differences were observed in water uptake between riparian and hillslope trees.
• Seasonality in water fluxes and isotopes in precipitation played a major role in Seasonal Origin Index (SOI) values of soil water and plant water compared to soil moisture.
• During the growing season, trees and the stream primarily use young waters, even during dry years.

Contributions

• Provides insights into the role of local factors (wetness conditions and topography) on the temporal origin of soil and plant waters using a long-term isotopic dataset.
• Highlights that pre-Alpine trees primarily rely on summer precipitation, challenging assumptions about water source usage.
• Demonstrates the dominant influence of seasonality in water fluxes and precipitation isotopes over soil moisture on the seasonal origin of soil and plant water.

Funding

• Not specified in the provided text.

Citation

@article{Zuecco2025Trees,
  author = {Zuecco, Giulia and Todini‐Zicavo, Diego and Marchina, Chiara and Brighenti, Stefano and Penna, Daniele and Borga, Marco},
  title = {Trees use predominantly summer water in a pre-Alpine catchment},
  journal = {Journal of Hydrology},
  year = {2025},
  doi = {10.1016/j.jhydrol.2025.134430},
  url = {https://doi.org/10.1016/j.jhydrol.2025.134430}
}