Chen et al. (2026) Divergent transpiration regulation among 20 urban tree species under extreme heat revealed by UAV multisource remote sensing

Identification

• Journal: Remote Sensing of Environment
• Year: 2026
• Date: 2026-10-13
• Authors: Tuqiang Chen, Jinhui Jeanne Huang
• DOI: 10.1016/j.rse.2026.115712

Research Groups

College of Environmental Science and Engineering, Sino-Canada Joint R&D Centre for Water and Environmental Safety, Nankai University, Tianjin, China; Shenzhen Research Institute of Nankai University, Shenzhen, China.

Short Summary

This study used UAV multisource remote sensing to investigate the transpiration regulation among 20 urban tree species under extreme heat. The research revealed divergent responses among species and identified key regulatory factors and tipping points for crown-scale transpiration.

Objective

• Investigate how different urban tree species respond to extreme heat in terms of transpiration regulation.
• Identify the dominant controls of crown-scale transpiration and their tipping points.

Study Configuration

• Spatial Scale: Urban landscape with 20 tree species across multiple locations.
• Temporal Scale: Diurnal and extreme heat events (normal day vs. extreme-heat day).

Methodology and Data

• Models used: UAV-based single-source energy balance model.
• Data sources: Multispectral, thermal infrared, and LiDAR observations from UAVs; eddy covariance measurements; sap-flow-derived transpiration; leaf area index (LAI)-upscaled portable-photosynthesis-system transpiration estimates.

Main Results

• Divergent responses among 20 urban tree species under extreme heat: enhanced, neutral, or suppressed transpiration.
• Random forest analysis identified temperature vegetation dryness index (TVDI) and leaf-to-air vapor pressure deficit (VPDL) as dominant controls of crown-scale transpiration.
• SHAP-derived tipping points for TVDI (0.23–0.34) and VPDL (5.34–5.84 kPa) suggested transition toward soil-water limitation and atmospheric-demand regulation.

Contributions

• This study provides a framework for spatially explicit assessment of urban tree water use and identifies species-specific heat responses, key regulatory factors, and tipping points for crown-scale transpiration.
• The findings have implications for species selection and irrigation management during extreme heat events.

Funding

• Sino-Canada Joint R&D Centre for Water and Environmental Safety; National Natural Science Foundation of China (Grant No. 52177003).

Citation

@article{Chen2026Divergent,
  author = {Chen, Tuqiang and Huang, Jinhui Jeanne},
  title = {Divergent transpiration regulation among 20 urban tree species under extreme heat revealed by UAV multisource remote sensing},
  journal = {Remote Sensing of Environment},
  year = {2026},
  doi = {10.1016/j.rse.2026.115712},
  url = {https://doi.org/10.1016/j.rse.2026.115712}
}