We have known for a long time that people are happier around trees; only yesterday Megan wrote that "just being in nature helps to calm us, helps us to focus and is just plain essential to happiness. Now a new study demonstrates that trees do a whole lot more than just make us feel good. A team from the University of Chicago and various Toronto organizations claims that:
...people who live in neighborhoods with a higher density of trees on their streets report significantly higher health perception and significantly less cardio-metabolic conditions (controlling for socio-economic and demographic factors). We find that having 10 more trees in a city block, on average, improves health perception in ways comparable to an increase in annual personal income of $10,000 and moving to a neighborhood with $10,000 higher median income or being 7 years younger.
The study looked at Toronto, which has a lot of tree cover in its residential areas and good health data from the Province's universal health plan and found that "people who live on a tree-lined block are less likely to report conditions such as high blood pressure, obesity, heart disease or diabetes."
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 aesthetic beauty? We need to understand that,” he said.
City councillor Sarah Doucette is thrilled, noting that trees are the lungs of the city. We certainly can agree with her sentiment: “Yes, I’m a tree hugger — and I love it.”
Now being a proud Torontonian and TreeHugger, I do not want to complain, but have to note that one can read the data another way. That people are not thinner richer and younger because they are around trees, but they are around trees because, well, they are richer. A few years back, Brian wrote How to Spot Income Inequality from Space: Look for the Trees He quotes Tim deChant, who found a tight correlation between wealth and tree cover:
For every 1 percent increase in per capita income, demand for forest cover increased by 1.76 percent. But when income dropped by the same amount, demand decreased by 1.26 percent. That’s a pretty tight correlation. The researchers reason that wealthier cities can afford more trees, both on private and public property. The well-to-do can afford larger lots, which in turn can support more trees. On the public side, cities with larger tax bases can afford to plant and maintain more trees.
So which came first, the trees or the money? The fact is, it is easier to have urban trees on bigger lots in richer areas than it is on small lots. It's easier in older areas with back lanes than it is on streets where there is so much pressure for front yard parking. It's more likely in areas where people complain about tree maintenance instead of more basic things like personal safety. But whether it's chicken or egg, the conclusions are the same, either what Faisal Moola of the David Suzuki Foundation said in the Star regarding poorer areas with fewer trees:
I would love for the city to look at these results and say, in addition to dealing with all the other systemic issues that have to be looked at, what if we start thinking about reforesting these neighbourhoods.
Or as Brian Merchant concluded in TreeHugger:
The absurd thing here is that even trees themselves can come to reinforce socioeconomic standards; in this case, one that helps the rich get richer. An abundance of trees improves air quality, provides shade, reduces allergies, and even helps improve the mental health of nearby residents. People in tree-lined neighborhoods are likely to be fitter, happier, more productive.
It all makes a pretty powerful argument in favor of tree-planting initiatives in lower income neighborhoods.