Tree shading, Solar radiation, and GIS Examining the effect of tree shading on sidewalk heat reduction

The Urban Heat Island (UHI) effect increases thermal stress in dense urban environments and is associated with elevated public health risks. Street-tree shading is a key passive strategy for reducing pedestrian-level heat exposure. This study quantifies the cooling effects of street trees on sidewalk microclimates in Los Angeles using a GIS-based framework that integrates spatial modeling, microclimate simulation, and field measurements. Field measurements were conducted on representative tree species to evaluate shading performance. Tree shading reduced pedestrian-level solar radiation by 50-70% during peak hours. A quantitative relationship between solar radiation and air temperature was derived, indicating that a reduction of 100 W/m2 corresponds to an approximate decrease of 0.5-0.75 °C in near-ground air temperature. Thermal comfort analysis using the CBE model indicates improved comfort conditions under shaded environments. scenario-based simulations were used to assess tree-planting strategies for a representative urban block. Increasing canopy width was associated with greater overall shading coverage, while increasing tree height primarily affected shading during peak radiation periods. Combined tree-building configurations resulted in more spatially continuous reductions in solar radiation compared to single-factor conditions.