Click For Photo: https://www.sciencedaily.com/images/2019/03/190325173305_1_540x360.jpg
According to the study, the right amount of tree cover can lower summer daytime temperatures by as much as 10 degrees Fahrenheit. And the effect is quite noticeable from neighborhood to neighborhood, even down to the scale of a single city block.
"We knew that cities are warmer than the surrounding countryside, but we found that temperatures vary just as much within cities. Keeping temperatures more comfortable on hot summer days can make a big difference for those of us who live and work there," says Monica Turner, a University of Wisconsin-Madison professor in the department of Integrative Biology and a co-author of the study.
Change - Heat - Events - Summer - City
With climate change making extreme heat events more common each summer, city planners are working on how to prepare. Heat waves drive up energy demands and costs and can have big human health impacts. One potentially powerful tool, the study's authors say, are organisms that have been around long before human civilizations could appreciate their leafy benefits. And those trees may be the secret to keeping the places we live livable.
Essentially, says Turner, impervious surfaces -- like roads, sidewalks and buildings -- absorb heat from the sun during the day and slowly release that heat at night. Trees, on the other hand, not only shade those surfaces from the sun's rays, they also transpire, or release water into the air through their leaves, a process that cools things down.
Benefit - Cooling - Service - Study - Canopy
To get the maximum benefit of this cooling service, the study found that tree canopy cover must exceed 40 percent. In other words, an aerial picture of a single city block would need to be nearly half-way covered by a leafy green network of branches and leaves.
Traditionally, says Carly Ziter, lead author of the paper, studies like these have tended to focus on what's known as the "urban heat...
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