Using data from Toronto, a team of researchers has found that having 10 more trees on your street has self-reported health benefits akin to a $10,000 salary raise or moving to a neighbourhood with a $10,000 higher median income or being seven years younger.
By comparing satellite imagery of Toronto, an inventory of trees on public land and general health surveys, the team, led by University of Chicago psychologist Marc Berman, found that people who live on a tree-lined street are less likely to report conditions such as high blood pressure, obesity, heart disease or diabetes.
Their findings appeared last week in the open-access journal Scientific Reports.
The study suggests “pretty strongly” that planting 4 per cent more trees would have significant health benefits, Berman said.
Researchers don’t know why, exactly, trees seem to be good for people’s health.
“Is it that the trees are cleaning the air? Is it that the trees are encouraging people to go outside and exercise more? Or is it their esthetic beauty? We need to understand that,” he said.
The researchers surveyed more than 500,000 trees across the city, focusing on those flanking streets. The study excluded shrubbery and parks.
Faisal Moola, a director at the David Suzuki Foundation and a forest ecology professor at the University of Toronto who was part of the research team, said the results show there are other ways to address some social issues.
“It’s a lot easier to invest in programs to plant trees than it is to raise the median income of everybody in the city,” said Moola.
“This is not to distract that we do have to address systemic issues of poverty and access to health,” he said. “But it does suggest that environmental factors are really important when it comes to the health of local residents as well.”
Toronto is relatively green compared to other Canadian centres, covering 26 to 28 per cent of the city. But they aren’t evenly spread out.
Source: The Star