Resilient Cities in a Changing World AMPS | City, University of London Page 49 INFLUENCE OF STREET TREE DYNAMIC GROWTH ON PEDESTRIAN THERMAL COMFORT: A CASE STUDY OF HARBIN, A FRIGID CITY Author: YIMENG FENG1, JINGYI MI1*, GUANGHAO LI2, CHENGZHANG1 Affiliation: 1. SCHOOL OF ARCHITECTURE AND DESIGN, HARBIN INSTITUTE OF TECHNOLOGY, KEY LABORATORY OF COLD REGION URBAN AND RURAL HUMAN SETTLEMENT ENVIRONMENT SCIENCE AND TECHNOLOGY, MINISTRY OF INDUSTRY AND INFORMATION TECHNOLOGY, CHINA, 2 SCHOOL OF ARCHITECTURE AND PLANNING, SHENYANG JIANZHU UNIVERSITY, CHINA. INTRODUCTION As global temperatures rise, urban areas are experiencing more frequent and severe summer heat waves. These extreme conditions expose pedestrians to dangerously high temperatures, posing significant health risks. In addition to increasing the likelihood of heat stroke and fainting, these conditions may also elevate the risk of heart disease and exacerbate respiratory problems. Urban street morphology influences the thermal comfort of streets by altering the duration of direct sunlight. In response to the impact of street morphology on climate, Oke et al. proposed a theory to modify the regional microclimate by adjusting block layouts and controlling the block canyon layer.1 Currently, the primary method for studying how urban streets affect thermal comfort involves the use of street geometry indicators. Among these, the sky view factor (SVF),2 street aspect ratio, and street orientation were initially employed and remain widely utilized.3 Research on the role of vegetation in enhancing the thermal comfort of urban street spaces suggests that the impact of vegetation primarily depends on plant morphological characteristics and planting patterns.4 Studies examining the correlation between vegetation morphology and the urban thermal comfort focus on factors such as plant species, trunk height,5 tree height-to-width ratio,6 crown morphology,7 leaf area density (LAD) ,8 leaf area index (LAI) ,9 and other plant-related indices. Additionally, research on the correlation between planting patterns and the urban thermal comfort highlights the significance of plant number,10 arrangement,11 spacing,12 configuration, and other plant-to-plant indices.13 Vegetation influences the thermal environment of streets primarily through cooling and humidification mechanisms. The cooling effect is mainly derived from tree shading,14 while humidification occurs through water release via plant transpiration. Vegetation reduces the energy reaching the ground by blocking shortwave solar radiation,15 thereby lowering the air temperature in the street and increasing the relative humidity of the surrounding environment through transpiration. As water evaporates, the surrounding air temperature decreases. For built urban blocks, vegetation is the most effective measure for regulating thermal comfort in street canyons. Vegetation reduces thermal radiation and increases humidity through shading and
