Could living near trees really improve your health? Researchers who set out to examine this very question say it might. A recent study found that residents in urban neighborhoods with more trees reported feeling healthier and had fewer cardio-metabolic conditions, such as heart disease and diabetes.
There have been some studies that suggest green space is better for your health, but few studies have analyzed the relationship between individual trees and health. So, the researchers decided to quantify just how much a tree on a street could improve health.
They collected the health records of 31,000 adult residents of Toronto, which included the residents' cardio-metabolic conditions, household income, years of education and their perception of their own health. Researchers combined this data with satellite imagery and public data on half a million trees in Toronto.
The study, published in Scientific Reports, found that planting 10 or more trees in a city block, on average, increased how someone rated their health and decreased cardio-metabolic conditions. These improvements in health were comparable to an “increase in annual income of $10,000, moving to a neighborhood with $10,000 higher median income or being 7 years younger,” according to the study.
Co-author Marc Berman told The Washington Post that after controlling for income, age and education, the study "found a significant independent effect of trees on the street on health".
Researchers chose Toronto to study as residents benefit from Canada’s universal health care, so access to doctors shouldn’t vary as much as places without universal health care, which reduces the health impact of trees. Though, universal health care doesn’t remove all disparities as “Canadians with lower incomes and fewer years of schooling visit specialists at a lower rate than those with moderate or high incomes and higher levels of education,” the study explains.
While the results of the study found a correlation between trees and health, it cannot show cause and effect. Researchers were unable to pinpoint why trees seemed to improve health, but suggest it might have something to do with an improvement in air quality, relieving stress, or promoting physical activity. The study was also limited by the data it used. Although researchers controlled for a number of factors, someone’s perception of their own health is subjective.
Researchers hope to test their current findings in a “more comprehensive manner that obviates the mentioned limitations.” For the time being, the study recommends that every block plants 10 more trees – about a 4% increase in street tree density – in Toronto, which they suggest is “logically feasible.”