About me
Johanna Arnet, Alain Paquette, Carly Ziter
Impact of spatial context and tree crown characteristics on the cooling capacity of urban tree canopy
Climate change is increasing the frequency, extent, and duration of extreme heat events. In urban areas, these extreme temperatures are exacerbated by the urban heat island (UHI) effect, due to the abundance of impervious surfaces and a corresponding lack of vegetation. This heat can lead to many negative effects on the physical and mental health of urban residents, including potentially deadly conditions such as heat stroke. Numerous studies support tree planting initiatives as a promising nature-based solution to mitigate the UHI effect, due to trees’ cooling effects through shading and evapotranspiration. However, cities are heterogeneous in their form, with variations in building density and building height, affecting the urban climate on a “micro” scale. In addition, the urban tree canopy can be variable depending on the tree-crown characteristics of the species that form the canopy. Given that the surrounding microclimate and tree crown metrics are both closely linked to the physiological processes underlying the cooling effects of tree, the magnitude of temperature reduction may vary not only as a function of total canopy cover but also as a function of space and tree canopy composition. To investigate the impact of urban form and canopy composition on the overall cooling potential of urban trees, my research uses an innovative bike-based mobile temperature sensor which allows for collection of high-resolution, fine-scale temperature measurements during both day and night. This knowledge will help cities around the world optimize both tree selection and tree placement to achieve a maximum cooling effect.
