Trees are crucial to the future of our cities

University of Wisconsin-Madison

2019-03-25

ScienceDaily

Keywords: Trees, Urban Temperature, Canopy Cover, Heat Island Effect, Climate Adaptation, City Blocks, Bike Sampling, Air Temperature Sensors, Urban Heat Archipelago, Low-Income Neighborhoods, Equitable Greening, Long-Term Ecological Research

"Tree canopy cover can actually do more than offset the effects of impervious surfaces," Ziter says. During the day, "an equivalent amount of canopy cover can cool the air down more than pavement will warm it up."

A study published in the Proceedings of the National Academy of Sciences highlights the significant role of trees in cooling urban areas. The research found that adequate tree cover can reduce summer daytime temperatures by up to 10 degrees Fahrenheit, with noticeable variations even between different city blocks. The study's authors, including Monica Turner from the University of Wisconsin-Madison, emphasize the importance of trees in mitigating the urban heat island effect, as they provide shade and release water through transpiration, cooling the air. The lead author, Carly Ziter, discovered that tree canopy cover must exceed 40 percent to maximize this cooling effect, which is crucial in the context of climate change and increasing heat waves. The study used innovative methods, such as temperature sensors attached to a bike, to collect detailed data on urban temperatures. The findings suggest that city planners should focus on increasing tree cover, especially in areas near the 40 percent threshold, to enhance the livability and resilience of cities. The research also underscores the need for a coordinated approach among different stakeholders to ensure equitable distribution of urban green spaces.

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Tags: Urban Cooling, Tree Canopy, Urban Heat Island, Climate Change, Heat Waves