Thermal mitigation effects of building and tree shade in a high-rise and park-dense urban area

This study quantified the spatial and temporal characteristics of tree and building shade and evaluated their effects on air temperature (AT), land surface temperature (LST), and physiological equivalent temperature (PET) using ENVI-met simulations and ArcGIS Pro shadow analysis in a high-density commercial district in Daegu, South Korea. Both shade types mitigated urban heat, reducing AT by 0.03–0.38 °C (mean 0.20 °C), LST by 0.94–9.01 °C (mean 5.99 °C), and PET by 0.52–10.13 °C (mean 5.55 °C), with PET reductions sufficient to lower thermal stress by at least one category during morning and evening hours. Shading duration showed a linear relationship with cooling intensity, with combined tree–building shade providing the strongest effect. Building shade was more effective in densely built areas, whereas tree shade resulted in more stable thermal conditions near parks. Cooling benefits were most pronounced over asphalt, which exhibited the highest baseline heat load. Strategies should integrate continuous tree plantings with building shade, prioritize impervious surfaces, and strengthen green corridors to maximize cooling benefits.