Impacts of street tree canopy coverage on pedestrians' dynamic thermal perception and walking willingness

Abstract

During extreme heat conditions, street trees play a crucial role in improving the thermal environments on urban non-motorized roads. This study examined the effects of varying street tree canopy cover on pedestrians' thermal perception, walking willingness, and heat mitigation behaviors in Lin'an District, Hangzhou, by measuring meteorological parameters of four roads with different tree canopy coverage ratios and analyzing questionnaires of 51 subjects. Results show that there were significant differences in air temperature between different experimental roads (p < 0.01). The road with high tree canopy cover experienced a reduction in air temperature by approximately 2.8 °C compared to the treeless road, effectively improving the thermal environments of sidewalks. Analysis of subjective thermal perception votes and skin temperatures of the forehead also indicated greater thermal comfort on the high-coverage road. Its significant shading effect reduced pedestrians' thermal exposure and decreased the frequency of heat mitigation behaviors. Additionally, varying levels of tree canopy cover had a substantial impact on pedestrians' walking willingness. The high-coverage road attracted more pedestrians to walk outdoors, with an average walking distance 0.75 km longer than on the treeless road. Roads with medium and low tree canopy cover also provided some improvement, though less effectively than the high-coverage road.