A Northwestern University study examining Chicago over an 11-year period finds that neighborhoods that lose more urban tree canopy experience higher mortality rates. Researchers track changes in tree canopy cover—areas covered by trees’ leafy crowns—and compare them with death rates across different parts of the city. The study reports that the association is strongest in Chicago’s hottest neighborhoods, where reductions in canopy coincide with higher mortality.
The findings suggest that the shrinking of urban tree cover may increase health risks in areas with elevated temperatures, potentially through reduced shade and cooling effects. The study’s results align with the view that tree canopy can be a public-health factor in cities, particularly during hot conditions. In response, the researchers and associated reporting point to strategies such as protecting existing mature trees and planting new ones to help maintain or restore canopy coverage. Both accounts describe a clear relationship between canopy loss and mortality, with heat-related vulnerability playing a key role.
