Effects of Different Urban-Vegetation Morphology on the Canopy-level Thermal Comfort and the Cooling Benefits of Shade Trees: Case-study in Philadelphia

Urban morphology directly influences heating or cooling rate in street canopies. This paper assessed cooling benefits of street-trees in Philadelphia city, PA considering morphological elements. We assessed summertime thermal comfort for humid subtropical climate (i.e. Philadelphia) by studying human-biometeorological parameters such as Mean-radiant temperature (T_mrt) and Physically Equivalent Temperature (PET) utilizing Rayman model. This paper will; 1. Quantify impacts of built environment with and without existing vegetation on pedestrian level temperature, 2. Observe impacts of T_mrt, surface temperature (T_s), PET and global radiation at road intersections in five different scenarios where urban canopies are characterized as: a) built environment without vegetation (BE), b) built environment with existing vegetation (BEEV), c) built environment with additional vegetation after 1-year (BEAV-1), d) built environment after 5-years (BEAV-5) and e) built environment after 10-years growth period (BEAV-10). Compared results with the BE scenario suggest that, planting trees in residential and mixed-use sites with higher Sky-view factor (SVF) can improve pedestrian comfort in the long-term by reducing Tmrt, and PET, compared to the commercial sites with lower SVF and T_s. Mixed-use sites were observed to provide highest thermal comfort and further benefit from tree plantation, while commercial sites receive lowest cooling benefit from street trees.