Role of vegetation placement for temperature moderation in an urban microclimate

Through optimal planning and site design, strategic selection and placement of vegetation is one approach to prevent warming in the urban core. To test this hypothesis, a paired sampling design using temperature loggers, was conducted in the City of Toronto to assess the overall effect that shading through vegetation had on moderating temperatures in the microclimate proximate to built structures. The role of vines, a single mature tree, and multiple trees growing at one site, was investigated to compare their temperature moderating benefits. Tree placement on the west facing aspect of built structures delivered the greatest overall benefits when compared to south and east facing building walls. Temperature differences between loggers reached a maximum of 11.7°C during the month of August. A mixed model evaluated the longitudinal study data and revealed that temperatures were significantly cooler (p < 0.05) in the shade of both trees and vines compared to those recorded in the sun for all aspects throughout peak solar access periods.