The large study builds on a body of prior research showing the cognitive and psychological benefits of nature scenery — but also goes farther in actually beginning to quantify just how much an addition of trees in a neighborhood enhances health outcomes. The researchers, led by psychologist Omid Kardan of the University of Chicago, were able to do so because they were working with a vast dataset of public, urban trees kept by the city of Toronto — some 530,000 of them, categorized by species, location, and tree diameter — supplemented by satellite measurements of non-public green space (for instance, trees in a person’s back yard).Share
They also had the health records for over 30,000 Toronto residents, reporting not only individual self-perceptions of health but also heart conditions, prevalence of cancer, diabetes, mental health problems and much more.
“Controlling for income, age and education, we found a significant independent effect of trees on the street on health,” said Marc Berman, a co-author of the study and also a psychologist at the University of Chicago. “It seemed like the effect was strongest for the public [trees]. Not to say the other trees don’t have an impact, but we found stronger effects for the trees on the street.” (Read more.)