Thermal Regulation of Urban Climate by Trees: Shading and Canopy Temperature

This review synthesizes twenty years of experimental and modelling research on the capacity of urban trees to regulate thermal climate. It details how tree architecture intercepts light to shade soil and buildings, while leaf-level transpiration lowers air temperature. Findings are presented at multiple scales—from individual trees on streets to extensive urban parks—linking physical shading effects to physiological processes such as stomatal conductance. The analysis emphasizes that sufficient water availability is essential to sustain transpiration and maximize cooling. Field observations and simulation examples illustrate the conditions needed for trees to mitigate urban heat island intensity.