In what is sure to be greeted nationwide with a resounding, “Well, duh,” researchers have concluded that urban neighborhoods with more trees contain healthier inhabitants.
On its face, the “duh” seems merited. After all, trees are green, and the more green things involved in one’s life, the healthier it is generally accepted to be. But a scientific study is necessary to put the stamp of fact on common sense. If, for instance, I told you that pumping heat-trapping gases into the atmosphere causes the planet to heat up, you may very well answer, “Well, duh.” But dedicated research into the subject is necessary so that we don’t have the logically-impaired crawling onto the Senate floor and lobbing snowballs at Congressional aides in weak attempts at subverting common sense and decency.
The study, “Neighborhood greenspace and health in a large urban center,” was published on Thursday in the open access journal Scientific Reports. Its authors build on prior studies that have shown how natural environments enhance human health by “examining the association between comprehensive greenspace metrics and health.”
In other words, it attempts to quantify what the greenery-to-health ratio is.
Using Toronto, Canada as their laboratory, the researchers cross-indexed over 30,000 health records of residents with some 530,000 trees, as well as satellite data of green and non-green areas. Surprisingly, the researchers found that the number of trees on an urban street had a greater impact on the area’s general health than whether residents had access to trees in their backyards.
“Controlling for income, age and education, we found a significant independent effect of trees on the street on health,” Marc Berman, a psychologist at the University of Chicago and co-author of the study, told the Washington Post. “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.”
Yet while neighborhoods with more trees were notably healthier, this study, like many before it, can’t exactly say why.
Berman told the Post that there is a neglected psychological component to simply living near more trees, which may influence the data. Other theories point to trees’ ability to suck pollutants out of the air.
According to the study, more trees on a block result in better health perception and “significantly less cardio-metabolic conditions” among residents. Basically, the more trees planted on a block, the less stressed out residents were. Researchers quantified it thusly: 10 more trees per block improved health perception “in ways comparable to an increase in annual personal income of $10,000…or being seven years younger.” Eleven more trees on a block, on average, decreased cardio-metabolic conditions “in ways comparable to an increase in annual persona income of $20,000.”