Wang et al. (2025) Water balance of three plantations in hilly areas of South China

Identification

• Journal: Agricultural Water Management
• Year: 2025
• Date: 2025-11-20
• Authors: Qian Wang, Ping Zhao, Ying Xiong, Teemu Hölttä, Xia Chen, Xiuhua Zhao, Liwei Zhu, Leena Järvi
• DOI: 10.1016/j.agwat.2025.109981

Research Groups

• School of Architecture, Changsha University of Science and Technology, Changsha, China
• South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, China
• Institute for Atmospheric and Earth System Research (INAR)/Forest Sciences, Faculty of Agriculture and Forestry, University of Helsinki, Helsinki, Finland
• School of Forestry and Biotechnology, Zhejiang A&F University, Hangzhou, China
• Institute for Atmospheric and Earth System Research (INAR)/Physics, Faculty of Science, University of Helsinki, Helsinki, Finland

Short Summary

This study assessed the water balance of three plantations (exotic Acacia mangium, native Schima wallichii, and native Cunninghamia lanceolata) in hilly South China to inform tree species selection for vegetation restoration. It found that native S. wallichii exhibited hydrological advantages, while exotic A. mangium was more water-limited in dry seasons and native conifer C. lanceolata posed risks due to high surface runoff and inefficient water use.

Objective

• To assess the water balance of three plantation species (Acacia mangium, Schima wallichii, Cunninghamia lanceolata) based on 2017–2018 field measurements in hilly areas of South China to inform tree species selection for vegetation restoration.
• To determine how these species differ in their contributions to key water balance components (canopy interception, stand-scale transpiration, litter interception, soil evaporation, soil water storage, surface runoff, and drainage).
• To evaluate the implications of the observed species-specific water balance responses for the long-term sustainability of these plantations and regional water resources.

Study Configuration

• Spatial Scale: Three adjacent monoculture plantation plots (1600 m² for A. mangium, 900 m² for S. wallichii, 800 m² for C. lanceolata) located at Heshan National Field Research Station of Forest Ecosystem catchment (112°54′E, 22°41′N) in Guangdong Province, South China. Plots shared similar elevation (80 m), slope (20%–30%), and soil characteristics (brick red soil). Soil water content was monitored down to 1.5 m depth.
• Temporal Scale: Field measurements were conducted from January 2017 to December 2018 (two full years). Data logging intervals were 10 or 30 minutes. Analysis focused on annual, wet season (April–September), and dry season (October–March) periods.

Methodology and Data

• Models used:
  • Granier’s thermal dissipation probe (TDP) method for sap flow measurement, scaled to stand-scale transpiration using a biomass-based extrapolation approach with species-specific allometric equations.
  • FAO-56 dual crop coefficient approach for estimating soil evaporation (ETo computed using the Penman–Monteith equation).
  • Water balance equation: P = ETc act + R + ΔS + D.
• Data sources:
  • Meteorological data (Precipitation, PAR, Air Temperature, Relative Humidity, Wind Speed): VAISALA MAWS301 weather station and tipping-bucket rain gauge (30-minute intervals).
  • Leaf Area Index (LAI): LAI-2000 plant canopy analyzer.
  • Soil Water Content (SWC): Soil moisture sensors (5TE, Decagon Devices) at 10 depths (0-150 cm) (30-minute intervals).
  • Canopy Interception (I), Throughfall (TF), Stemflow (SF): Custom-built rain gauges (1 m² collection area) and plastic tubes wrapped around tree trunks.
  • Stand-scale Transpiration (Ec): Granier’s thermal dissipation probes (TDP) in 15 representative trees per plantation (10-minute intervals).
  • Litter Interception (L): Six self-made litter interception rainfall devices (20 cm diameter).
  • Surface Runoff (R): Automatic water level meters with flow-measuring weirs.
  • Soil Physical Properties (bulk density, porosity, water holding capacity): Ring knife method from undisturbed soil samples.

Main Results

• No clear evidence indicated any tree species exhibited excessive deep water source extraction throughout the two study years. However, drainage (D) decreased in most months of 2018 despite 114.5 mm more rainfall than in 2017, largely due to increased frequency of heavy rain events leading to higher surface runoff rather than increased soil water storage.
• Exotic Acacia mangium consistently showed evapotranspiration-to-precipitation (ETc act/P) ratios above 1 and dry-season drainage deficits in both years, suggesting it was more water-limited and may pose greater risks to catchment water balance in the dry season. It also exhibited the highest litter interception and pronounced changes in soil water storage.
• Native broadleaf Schima wallichii demonstrated the greatest canopy interception during extreme rainfall in 2018, the lowest wet-season surface runoff, and the highest drainage in 2018 and the wet season of 2017 (excluding April), indicating its relative hydrological advantage for afforestation, especially under increasingly extreme rainfall.
• Native conifer Cunninghamia lanceolata showed significantly lower stand-scale transpiration (Ec), significantly higher soil evaporation (Es), and the highest surface runoff (R). After 30 years of growth, this species may pose risks to water balance sustainability due to inefficient water use and increased flood risks (R accounted for 20% of annual rainfall in 2018). Its lower LAI and downward-oriented branches contributed to less effective rainfall interception and higher soil evaporation.
• Stand-scale transpiration-to-precipitation (Ec/P) ratios were relatively low for all plantations (around 20% for A. mangium and S. wallichii, 6-8% for C. lanceolata). Soil evaporation was a significant component of ETc act, particularly in C. lanceolata (approximately 50%).

Contributions

• Provides one of the first comprehensive, species-specific evaluations of all major water balance components in adjacent plantations in subtropical southern China, addressing a significant research gap.
• Offers critical, process-level insights into the hydrological impacts of exotic versus native broadleaf and conifer species, directly informing tree species selection for large-scale vegetation restoration efforts.
• Identifies Schima wallichii as a hydrologically advantageous species for afforestation in southern China, particularly in the context of increasing extreme rainfall events.
• Highlights potential hydrological risks associated with widespread planting of Acacia mangium (dry season water limitation) and Cunninghamia lanceolata (high surface runoff, inefficient water use), guiding more sustainable land management decisions.

Funding

• Excellent Youth Project of the Hunan Provincial Department of Education (Grant Nos. 23B0316)
• China Scholarship Council Overseas Research and Training Program for Young Excellent Teachers (Grant No. 202100800002)

Citation

@article{Wang2025Water,
  author = {Wang, Qian and Zhao, Ping and Xiong, Ying and Hölttä, Teemu and Chen, Xia and Zhao, Xiuhua and Zhu, Liwei and Järvi, Leena},
  title = {Water balance of three plantations in hilly areas of South China},
  journal = {Agricultural Water Management},
  year = {2025},
  doi = {10.1016/j.agwat.2025.109981},
  url = {https://doi.org/10.1016/j.agwat.2025.109981}
}