Shade for pedestrians: A novel approach to calculate the spatio-temporal shade benefits of street trees considering pedestrian flow

Accurately quantifying the site-specific shade benefits of trees is crucial for enhancing pedestrian thermal comfort through urban tree planting. Neglecting pedestrians’ actual exposure to shade could result in a gap between actual and expected benefits. To address this, a novel approach is proposed that integrates a tree shade simulation module and a pedestrian flow simulation module, along with a new indicator, namely spatio-temporal tree shade benefit (STTSB), to calculate the site-specific shade benefits of street trees considering pedestrian flow. The approach was applied to a study area in Munich, Germany. The results indicate that the method accurately simulates each tree's STTSB, revealing variations in benefits among trees across locations and periods of the day. The site-specific characteristics of the STTSB highlight the challenges of linking shade benefits directly to canopy shape or tree location due to the dynamic changes in shade patterns of both trees and buildings, and variations in pedestrian flow. The proposed approach can support urban designers in making human-centered urban tree-planting decisions to improve streetscape quality.