The study found that antidepressants were prescribed less frequently in areas in London which have more trees. To gain this information, researchers gathered data for antidepressant prescriptions across London in 2008-2010 and then compared that data with the numbers of street trees in the same area. They soon discovered that antidepressant prescriptions were significantly lower in areas which housed a higher concentration of trees.
How Do Tree’s Make Us Happier?
The idea that trees can have a positive influence over our mental state and wellbeing isn’t entirely new. As Nature&Health reports: “In Japan, people practise ‘forest bathing’, where they spend quiet time absorbing the wisdom of ancient forests, taking long walks among the trees to stimulate their immune system. In Taoism, students are encouraged to meditate among trees, and it is believed that the trees will absorb negative energies, replacing them with healthy ones. Trees are seen as a source of emotional and physical healing, and themselves as meditators, absorbing universal energies.”
To further study the reasoning behind these practices, Geoffrey Donovan looked at comparable death rates in areas where the emerald ash-borer decimated tree populations. He found that as more and more trees died, so too did deaths from cardiovascular and respiratory diseases increase. In other research, he discovered that areas with a higher density of trees actually had lower crime rates! While there could be other explanations behind these phenomena, of course, the suggestion that there is a correlation between our wellbeing and our interaction with trees is, nevertheless, quite interesting.
“Well my basic hypothesis was that trees improve people’s health. And if that’s true, then killing 100 million of them in 10 years should have an effect. So if we take away these 100 million trees, does the health of humans suffer? We found that it does,” says Geoffrey Donovan.
Furthermore, the USDA’s Forest Service has also compiled research that shows people who live around trees are physically healthier: “About 850 lives are saved each year, the number of acute respiratory symptoms is lower by about 675,000 incidents each year, and the total health care savings attributed to pollution removal by trees is around $7 billion a year.”
Wealthier Areas Have More Trees
What’s even more interesting is the difference in tree coverage depending on the socioeconomic status of a given area. This was found by Tim de Chant at Per Square Mile who used Google Earth to examine various areas:
They found that for every 1% increase in per capita income, demand for forest cover increased by 1.76%. But when income dropped by the same amount, demand decreased by 1.26%. 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.
Comparison of tree coverage in a lower income area (top) and a higher income area (bottom).
What Can We Take From This?
Trees are important! There’s no denying the therapeutic value that comes from spending time outside and enjoying nature. We’ve all experienced it at one time or another and don’t need a study to tell us that. Sure it helps to have these feelings grounded in hard science, but some things we just know and feel to be true. Sometimes it’s science that needs to do the catching up.
I believe this illustrates the importance of maintaining green areas in urban spaces as much as possible, and green does not mean grass and bushes – we need more! Larger pockets of trees and accessible areas where we can connect with nature, right inside the city, would do a world of good.
We need to challenge neighbourhoods and builders to maintain as much green space as possible when building new developments. We’ve come to accept the idea that we should cram as many houses into one area as possible, but this is only helping to degrade our quality of life.