Study: More Trees Improve Health

Trees clean the air, provide shade, and reduce climate changing emissions. And, says environmental neuroscientist Marc Berman, they also improve the health of people who live near them.

«I’m very interested in how the physical environment affects the brain and behavior,” says Berman, an associate professor of psychology at the University of Chicago.

His study of the effect of urban trees, published in the journal Nature, merged tree data and health surveys from 31,000 residents of Toronto, Canada.

“We found that, controlling for income and age and education, neighborhoods that had more trees on the street … that was related to improved health in those neighborhoods.”

Monetary trees

Specifically, the study found that ten more street trees per city block was related to a one percent increase in people’s health, as self-reported in the surveys. Berman says people in those blocks suffered less from hypertension and obesity compared with other neighborhoods with fewer trees.

“And that one percent increase in health perception seems pretty modest, but at least in our study to get that equivalent increase with money, you’d have to give every household in that city block $10,000 and have them move to a neighborhood that is $10,000 wealthier or make people seven years younger.”

Just plant them

Sounds pretty good, but could what works in Toronto work elsewhere? Berman says yes, it would, if you increase the number of trees on the street by ten.

While the study doesn’t identify which mechanism triggers those benefits, it finds that initiatives to plant more trees can improve air quality, relieve stress and promote physical activity — all contributing factors to overall better health.