When talking about urban cities and inequality, we tend to focus our conversations around income and housing. But what about trees? Yes, inequality can also come in the form of tree coverage in your neighborhood. Tree coverage can lead to more time spent outside, improved health due to better air quality, lower overall temperatures, reduced flooding and even lower stress.
Unfortunately, when looking at an urban city map from above, you can see specific disparities in tree coverage — often only growing lusher in wealthier neighborhoods. This data was shown by nonprofit American Forests, one of the oldest conservation organizations in the U.S.
For example, in socioeconomically disadvantaged neighborhoods, families tend to see more asthma in their children due to repeated exposure to environmental triggers, like poor air quality, smog and more. Trees around the country absorb 17.4 million tons (15.7 metric tons) of air pollutants, preventing nearly 700,00 cases of asthma annually. This is why tree equity matters.
What Is the Tree Equity Score?
Trees have become a commodity as they were often planted along race and class lines, often in wealthier, usually white neighborhoods, according to American Forests. Chronically ignored areas often house underserved people and people of color in high-density areas of the urban landscape. Neighborhoods with a majority of people of color have 33 percent less tree canopy on average than majority-white communities.
"Tree canopies have so many environmental and health benefits. Everything from air quality, which results in less asthma and other health issues to mental health and water quality," says Trees Atlanta co-Executive Director Greg Levine.
"Often lower economic areas don't have a good tree coverage and have more pavement around them from urban areas. They also don't see as many replanting efforts since they're not as high on the agenda of community needs."
According to American Forests, the Tree Equity Score indicates if a neighborhood has enough trees in the right places so that all residents enjoy the health, economic and other benefits from the trees.
Out of 100 points, the Tree Equity Score considers existing tree canopy, population density, income, employment, surface temperature, race, age and health. The score is only calculated in places with a population of 50,000 or more people.
For example, in Atlanta, areas such as downtown, surrounding neighborhoods, and former Atlanta Housing Authority developments have less than 5 percent tree cover, according to Trees Atlanta. In early 2020, the city of Atlanta purchased 13 acres (5 hectares) of green space to bring a tree-filled park to the Southwest Atlanta community, something the area has historically lacked.
In Southwest Atlanta, near Mercedes-Benz Stadium, the Tree Equity Score is 48 out of 100. The current tree canopy cover is only 10 percent. The health index, signaling poor mental and physical health, is 53 out of 100, with 99 percent of the residents being people of color.
Why Does Urban Tree Canopy Matter?
As climate change threatens the world with unpredictable weather patterns, including heat waves and poor air quality, these underserved neighborhoods with low Tree Equity Scores can experience the "urban heat island effect."
The effect forms small pockets of dangerously hot temperatures that bring up health issues, including heatstroke and heat-related deaths, to these low-income communities. The heat pocket can be up to 7 degrees Fahrenheit (-14 degrees Celsius) hotter than the rest of the city.
"Trees cool down the whole planet," Levine says. "But people don't often think about how it cools down their own neighborhood."
"We had a test on the Atlanta BeltLine — the center of the BeltLine was 22 degrees F (12 degrees C) higher than underneath a tree that was just about 15 yards (2.7 meters) away from the center of the path. This shows you how much places can heat up when you don't have shade."
Trees Atlanta is doing its part by working with various metro Atlanta municipalities to bring more shade trees to people's yards and sidewalks. Since its founding in 1985, Trees Atlanta has planted more than 140,000 trees. The urban tree canopy in Atlanta varies largely by zoning and land use, but neighborhoods can take charge of that. Through the nonprofit's front yard free tree program, for example, residents can receive up to three shade trees in their front yard by just submitting a request.
"In Atlanta, we're a little different than some other cities. It's more about where you're located versus necessarily your economic levels," Levine says. Often, mixed-income areas like Downtown, Midtown, Old Fourth Ward and Summerhill have low tree coverage. While to the Northwest, you start seeing higher tree coverage.
Unfortunately, that's not the case with other cities where the income gap is more glaring, Levine says. "We believe that everyone should be able to walk somewhere under the shade."
The Tree Equity Score alerts cities of tree inequality and can also function as a data point to enact policies and requirements within the city. They can pass laws that protect existing trees and require new ones to be planted.