'Green Inequity' Plagues U.S. Cities, Study Finds

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St. Louis is one of 10 cities analyzed in a new study that examines urban green space equity, or the lack thereof. (Photo: xiquinhosilva/Flickr)

In America, financial wealth can get you a lot of things: power, prestige, influence and even greater access to woody vegetation.

A newly released study conducted by forestry experts at the University of British Columbia (UBC) and published in the journal Landscape and Urban Planning uses census data and aerial imagery to explore the link between access to urban green space and socioeconomic indicators in 10 cities: Seattle, Chicago, Houston, Phoenix, Indianapolis, Jacksonville, St. Louis, Los Angeles, New York City and Portland, Oregon.

In these cities — and in North America's urban areas as a whole, where over 80 percent of the population of both the United States and Canada now live — residents who enjoy some degree of affluence and/or have advanced educations also enjoy more immediate access to parks, trees and other types of greenery-filled spaces than those less wealthy and educated.

The push to improve access to parks and greenery to all city dwellers, no matter their socioeconomic background, isn't new. Underserved urban areas are frequently starved of beautifying, mood-boosting natural elements. As the study elaborates, the very things these communities are lacking — parks, trees, grass, community gardens — are the things that can make the most dramatic difference in enhancing the well-being of those who would ultimately reap the greatest benefits from them. As urban areas grow and become more densely populated, the need for equitable and public health-benefitting green space grows in urgency.

"Vegetation keeps our cities cool, improves air quality, reduces storm water runoff and reduces stress — it makes a huge difference in citizens' well-being," says Lorien Nesbitt, a postdoctoral research and teaching fellow at UBC's Department of Forest Resources Management, in a press release. "The issue is that when access to greenery isn't equitable, those benefits aren't always fairly distributed, reducing access for our most marginalized citizens who need them most."

Nesbit stresses that everyone living in an urban area regardless of income, age, race or education should reside within a comfortable 10-minute walk of a park. Ideally, everyone should also have trees, shrubbery and other types of vegetation growing on their street or in outdoor area directly adjacent to their homes. This 10-minute walk factor is at the heart of a campaign launched in 2017 by the Trust for Public Land that aims to raise awareness of the importance of park accessibility. Per 2018 data, about 30 percent of Americans residing in urban areas live more than a 10-minute walk from the nearest park.

Despite the need for greater park accessibility in cities nationwide, Nesbitt and her colleagues found parks ultimately to be more "equitably distributed" than woody and mixed vegetation, which were generally located in closer proximity to residents with higher levels of income and education. But as the study points out, "inequities exist across all cities and vegetation types."

Jacksonville skyline and trees
Jacksonville, Florida, varies from other cities analyzed in the study in several key areas. (Photo: James Willamor/Flickr)

General themes emerge, but some cities have variations

Things get interesting when you dive deeper and examine how the study's findings play out on a city-by-city scale.

Jacksonville, the most populous city in Florida as well as the largest city in the continental U.S. by land area, is a notable outlier compared to the nine other urban areas selected as study sites.

For one, proximity to parks and vegetation aren't as strongly linked to Jacksonville residents' socioeconomic backgrounds as, for example, Chicago and Houston. What's more, racial and ethnic minorities as well as those with lower income and education levels have greater access to trees and parks than wealthier, more educated and white residents. But as the study's authors point out, Jacksonville is the smallest urban area included in the analysis in terms of population as well as the least dense, leading researchers to believe that low population density can lead to "somewhat more equitable urban vegetation distribution patterns." They do note, however, this is an observation open to further research.

Jacksonville was also one of three cities including Los Angeles and Phoenix where the spread of woody vegetation — this includes trees, large shrubs and hedges — was particularly narrow. What's more, Jacksonville, despite being home to the largest urban park system in the U.S., had a markedly narrow distribution of parks, which includes city and county parks, national parks, forest preserves, botanical gardens and community gardens. The distribution of parks was found to be notably wide in Chicago and Seattle while the spread of both woody vegetation and mixed vegetation — this includes all vegetation such as trees, grass, shrubs, gardens plants, etc. — was wider-than-the-norm in New York.

As for who had the strongest positive and negative correlations with vegetation cover, those identified as white on census data and those with higher incomes and advanced educations were largely on the positive end of things. Latino residents and those without high school diplomas had the strongest negative correlations with the exception of Jacksonville, where Latinos and residents lacking high school diplomas showed positive correlations with urban greenery. St. Louis also diverged from the other cities in some areas but not in as pronounced a manner as Jacksonville.

In New York, a city famous for its crowd-drawing parks, a post-secondary education played a stronger role than income in the realm of park access. Big Apple residents with advanced degrees were also more likely to live on tree-lined streets and have assorted greenery growing in their own backyards.

"In larger cities like Chicago and New York, racial and ethnic factors played an important role as well," elaborates Nesbitt. "People from Hispanic backgrounds had less access to vegetation in Chicago and Seattle, while people identifying as African-American had less access to green spaces in Chicago and St. Louis. Those identifying as Asian-American had less access in New York."

Vegetation lines Interstate 5 in downtown Seattle
Seattle has a notably wide distribution of parks compared to the other cities analyzed. (Photo: Maarten Brinkerink/Flickr)

A call for more urban green space

Nesbitt and her colleagues conclude that there's a growing need for a wider distribution of trees, pocket parks and shrubs as North America's urban areas. But as the study makes clear, "resolving the challenge of urban green inequity will require an in-depth understanding of the local issues that shape it." The researchers suggest that particular emphasis should be placed on the planting of more street-side trees as well as tree-planting efforts on private residential property.

"For many people, the trees in their neighbourhood are their first contact with nature — maybe even the only contact for those who have less opportunity to travel to natural spaces outside of the city," Nesbitt says. "As the effects of climate change intensify, we should plan for more urban green spaces and ensure that citizens from all backgrounds can access them readily and equitably."

While these new findings emphasize the relationship between access to urban green spaces and societal well-being, a similarly enlightening 2018 study conducted by the U.S. Forest Service's Northern Research Station zeroes in the economic benefits of urban vegetation, specifically trees.

Per the study, five states are particularly bankable when it comes to the economic perks associated with urban trees with Florida leading the way at roughly $2 billion in annual savings. California, Pennsylvania, New York and Ohio are each estimated to have roughly $1 billion in annual tree-related benefits including carbon sequestration, reduced emissions and improved energy efficiency in buildings.