Those of us who enjoy a good park run understand that striding beneath the branches is a great way to receive some shade during an intense session, while at the same time improving our mental health through appreciating their beauty. Most know that trees play an important role in generating clean oxygen, but science is now doubling down on the importance of trees, and has even predicted the number of lives that might be saved thanks to our bark-built-buddies ability to keep a lid on temperatures.

In London, a densely populated location that reflects many of the world’s major cities, scientists estimate that trees have saved more than 150 lives in the course of eight years by reducing large patches of the city by up to 35°F (2°C)

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Why we should reduce the ‘Urban Heat Island Effect’

Unfortunately, developing global cities have long been uprooting trees in favor of concrete car parks and pedestrianized zones, forcing those who love to get outdoors and run or walk to head into urban areas for their exercise fix instead. The problem is that these concrete jungles are just not as healthy as natural ones, producing what is known as the “Urban Heat Island Effect.”

It is estimated that the city of Chicago is on the path to seeing more than 30 more days per year where the temperature hits more than 100 degrees Fahrenheit (37.8°C). The disadvantage of higher temperatures is that they can exacerbate existing health conditions such as cardio vascular diseases, respiratory problems, and even diabetes. To make matters worse, urban areas tend to have higher levels of air pollution and without trees, we are losing out on the potential filtering process that these plants provide.

“During the heatwave events of 2022, we estimate that the current tree coverage (in London) helped avoid around 16 heat attributable deaths,” says the ground-breaking study, published in IOP Science. “The cooling benefits from trees become even greater under hotter future climates. The results of this study support increasing tree canopy coverage to help mitigate high urban temperatures in the future, with urban greening (suggested as) part of a set of broader public health actions that can help reduce heat-related mortality in the future.”

So, next time you lace-up your sneakers for a scenic run, remember to thank your leafy friends.