Study finds loss of city tree cover linked to higher death rates in Chicago

A new GeoHealth paper reports that Chicago census tracts with shrinking tree canopy from 2011 to 2021 saw a rise in mortality, particularly in hotter neighborhoods. Using yearly satellite imagery and more than 220,000 death certificates, the researchers built a model that accounted for other health influences and found that net gains in canopy were tied to fewer deaths across several disease categories. Senior author Daniel Horton noted that previous studies only captured a single snapshot of tree cover, while this work tracks changes over time.

Lead author Harrison Garcia recalled feeling the heat difference while walking through sparsely treed blocks, prompting the investigation. Co-author Raed Mansour urged the city to safeguard existing mature trees and supplement them with new plantings, estimating that adding about 14,000 trees each year could prevent roughly 105 deaths annually.