If You Care About People, You Should Care About Trees. Here’s Why …

Cleveland’s News 5 recently found a terrific non-traffic-related use for its helicopter: showing dramatic differences in tree canopy cover between Cleveland’s neighborhoods and nearby suburbs like Shaker Heights. Shaker is well covered; most of its streets are lined with trees. But in the City of Cleveland, tree cover is sparse.

“We are for sure one of the worst cities [for tree canopy coverage] in the U.S.,” says Rich Cochrane, director of the Western Reserve Land Conservancy, in the News 5 report. Once known as the Forest City, Cleveland is now just 19 percent covered by trees. Pittsburgh and Cincinnati’s canopies are roughly double that size.

Cochrane has been promoting this issue for years. In a 2015 TED Talk, he explained that the value of trees in a city goes far beyond aesthetics: “We’ve looked at cities and urbanized areas all over the world … The common denominator of success happens to be a healthy tree canopy, and the common denominator of distress happens to be the lack of trees. It’s remarkably consistent all over the world.”

This image is from “Cleveland Tree Plan: Making Cleveland the Forest City Once Again,” by Sustainable Cleveland 2019 and The City of Cleveland.

Studies in Washington, D.C, Seattle and elsewhere have born this out. A report on a study of several American cities announced its findings right in the title: “Trees Grow on Money: Urban Tree Canopy Cover and Environmental Justice.”

This affects much more than property values. A heat mapping project in several U.S. cities found that “temperatures on a scorching summer day can vary as much as 20 degrees across different parts of the same city, with poor or minority neighborhoods often bearing the brunt of that heat,” according to a New York Times report. A study of Los Angeles by the National Bureau of Economic Research found compelling data to support anecdotal evidence that violent crime increases on hot days.

A 2013 study suggested a direct link between trees and human health by showing that deaths from cardiovascular and lower respiratory illnesses rose in areas where an invasive insect, the emerald ash borer, wiped out large numbers of ash trees in just a few years.

What’s the connection between all of these effects? Stress, and the role nature can play in helping us cope with it.

In 2018, researchers in Philadelphia added to the large body of evidence supporting Attention Restoration Theory, which asserts that access to nature is vital to mental and physical health. In an experiment, they cleaned and beautified some abandoned lots in the city, simply cleaned others by removing debris, and left other lots as they were, over-grown and trash-strewn, for a control group.

As NPR reported: “The team surveyed residents living near the lots before and after their trial to assess their mental health and wellbeing. … People living near the newly greened lots felt better.… The impact was strongest for residents of poorer neighborhoods—they showed at least a 27.5 percent reduction in the prevalence of depression.”

Ming Kuo, an associate professor at the University of Illinois’ Department of Natural Resources and Environmental Sciences, has found similar results in Chicago. She explained on the Hidden Brain podcast that in surveys of residents of public housing facilities with varying levels of greenery nearby, “we found social breakdown in buildings without trees and grass around them.” People living in those buildings were less likely to report knowing and sometimes relying on neighbors. Police reports also showed higher numbers of calls to the less-green sites.

“When people don’t have access to nature, they’re going to be more mentally fatigued,” Kuo explains. “When you’re mentally fatigued, you’re also less good at handling difficult social situations.”

To be very clear, trees are not a “solution” to poverty. But voluminous evidence suggests they can mitigate some of poverty’s effects, and that they contribute to economic growth. They even offer a high return on investment. According to Dan Burden, an urban designer and walkability expert, “For a planting cost of $250-$600 (including first three years of maintenance), a single street tree returns over $90,000 of direct benefits (not including aesthetic, social, and natural) in the lifetime of the tree.”

All that is lacking, it seems, is agreement that trees are not a luxury for the affluent but a priority for all.

“Maybe we ought to start talking about shade deserts, just as we talk about neighborhoods without grocery stores as food deserts,” writes journalist Sam Bloch in an essay for PlacesJournal.org about the lack of shade in L.A. neighborhoods. “It’s not actually that hard to come up with designs for creating urban shade. What’s hard is building the political support to fund programs and roll out designs at scale, given the complexity of ownership and regulations on city streets. What we need, first of all, is urbanists in and outside City Hall who conceptualize shade itself as a public good.”

We also need patience and persistence. Trees grow slowly. But Cleveland is moving in the right direction. The city released its Tree Plan in 2015, and in 2017, Mayor Frank Jackson committed to increasing the city’s tree canopy from 19 to 30 percent by 2040 (and eventually 40 percent). This year, he followed through with a promise of up to $1 million in funding per year for the next decade.

Jackson’s pledge came soon after Cuyahoga County announced its plans to invest $950,000 in its Urban Tree Canopy Program. The county planning commission’s assessment states that the county’s current 110,000 acres of tree canopy could be increased by hundreds of thousands of acres.

From Cuyahoga County Planning Commission’s Urban Tree Canopy Assessment web page.

To keep up with this issue, follow the Western Reserve Land Conservancy on Facebook, Twitter or Instagram. The Cleveland Tree Coalition, a collaborative group of public, private and community stakeholders, is also on Facebook.

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