The cooling effect of robust urban tree canopies is more pronounced in hotter, drier cities like Phoenix and Las Vegas.
New research from the U.S. Geological Survey shows that tree canopies in hot, dry cities have a bigger impact on local air temperature than those in cooler areas.
“The multi-year study was conducted in Baltimore, Los Angeles, Phoenix, Portland, Miami, Tucson, Denver and Las Vegas. Scientists placed 80-100 sensors on trees in each city and measured hourly air temperatures for three months during the summers of 2016-2019.” The researchers found a stronger cooling effect in the hotter and drier regions, where the trees served to counteract the heating effect of buildings.
The study also notes that “Trees reduce heat in all studied cities, but their effectiveness was contingent on local water availability. Irrigation is crucial for maintaining trees’ cooling effects in all studied areas.” Surfaces such as grass (which helps with cooling) and pavement (which increases heating) showed more consistent impacts across cities.
FULL STORY: Trees in cities are beyond shady
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Eagle County Government
Harvard University Graduate School of Design
Nashville Planning Department
The Architects Foundation
University of Cincinnati Online
The Pocatello Development Authority
The Urban Renewal Agency of the City of Pocatello
Journal of the American Planning Association