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Shady practices: New mapping tool shows inequity of tree coverage in the metro

While ideal canopy cover is around 45 percent, according to the Metropolitan Council, different parts of the Twin Cities fall far above or below that, with neighborhoods that are whiter and wealthier tending to have more trees.

Lisa Burke and Chris Stevens tending to the Canopy Connectors gravel bed at Unity Church in St. Paul.
Lisa Burke and Chris Stevens tending to the Canopy Connectors gravel bed at Unity Church in St. Paul.
MinnPost photo by Greta Kaul

There’s a simple pleasure to walking through a neighborhood lined with big-leafy trees that shade the sidewalk, rustle gently in the wind and provide habitat for animals.

But trees are far more than just a pretty landscape feature. Among other benefits, they also block wind, provide cooling, and help to clean the air we breathe.

The advantages trees provide are not distributed evenly across neighborhoods in the Twin Cities metro area, according to a new tool from the Metropolitan Council that maps tree cover by Census block group, city, and Minneapolis and St. Paul neighborhoods.

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Mapping shade

Called Growing Shade, and built as a collaboration between the Met Council, Tree Trust and the Nature Conservancy, the mapping tool allows users — whether city planners, foresters, neighborhood groups or regular people — to see tree canopy cover across the seven-county Twin Cities metro area.

While ideal canopy cover is around 45 percent, according to the Metropolitan Council, different parts of the Twin Cities fall far above or below that, with neighborhoods that are whiter and wealthier tending to have more trees.

In addition to showing tree cover, Growing Shade helps users understand how climate change, conservation, environmental justice and public health intersect with tree coverage, and where planting and maintaining trees could have the most benefits.

“This is what Growing Shade is trying to promote,” said Eric Wojchik, a planning analyst with the Met Council. “The interconnection of the issues around public health, biodiversity, climate change [and] environmental justice. All of these are interconnected and the tree canopy is an avenue by which we can actually address some of the emerging threats that we’re facing.”

The benefits of trees

Trees have many benefits to people — direct and indirect, said Karen Zumach, director of community forestry at Tree Trust. 

Trees conserve energy by shading homes in the summer and blocking wind in the winter. They suck up carbon and store it, reducing greenhouse gasses in the atmosphere. They slow stormwater runoff and reduce the pollution it causes by collecting rain. Trees increase property values. And there’s plenty of research that finds trees improve people’s mental and emotional health.

“We like to call them super heroes. There’s really not too much they can’t do,” Zumach said.

That means neighborhoods that have lots of trees reap the benefits of them, while neighborhoods that don’t miss out.

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The city of St. Louis Park has been using the Growing Shade tool to understand where to prioritize putting in trees — particularly on private property.

St. Louis Park is among the first cities to use the Growing Shade tool in its efforts to build out tree canopy equitably within its borders. Overall, the Growing Shade tool shows St. Louis Park has 34.6 percent canopy coverage — higher than the metro area city average, 27.8 percent. But Census block groups within St. Louis Park range between 12 percent canopy cover and 54 percent.

The tool helps the city identify not only where more trees are needed, but  areas where the city can focus its efforts to help residents plant trees, said Michael Bahe, natural resources manager for the city.

One of those neighborhoods is St. Louis Park’s Aquila neighborhood, east of Highway 169 and north of Highway 7, which includes many big box retailers as well as homes.

Neighborhood differences

Tree diseases, like Dutch elm disease, wiped out a huge share of the tree canopy in all sorts of neighborhoods across the Twin Cities in the second half of the past century, and emerald ash borer, which has more recently killed many of the region’s ash trees.

But many neighborhoods had fewer trees in the first place, Zumach said.

Historic land use is part of the issue: Industrial areas don’t tend to have many trees. So is historic disinvestment in communities: areas that were redlined tend to have less tree cover than areas that were not.

In North Minneapolis, a devastating tornado wiped out a large portion of neighborhoods’ tree canopy in May of 2011.

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The lack of trees in neighborhoods like Camden, north of Lowry Avenue in North Minneapolis, exacerbates other underlying economic inequalities. For instance, Camden has 16 percent tree canopy coverage, according to the Met Council. Its median household income is about $46,500 and 59 percent of residents are Black, Indigenous or people of color.

Across town, St. Paul’s Summit Hill neighborhood northwest of downtown, has 42 percent tree canopy cover. Median household incomes are about $118,600 and 9 percent of residents are Black, Indigenous or people of color.

During one summer heat wave, Camden averaged 97 degrees, while Summit Hill averaged 94 degrees — temperature differences that push higher air conditioning costs in neighborhoods where the average person is living within a tighter household budget.

When you map temperatures during a heat wave, the difference in temperatures can be significant, Wojchik said, between places with more and fewer trees. “That’s a huge difference in terms of human health and how we’re feeling,” he said.

With climate change, temperatures are expected to rise, making the inequalities across neighborhoods like Camden and Summit Hill worse. According to the Met Council, the Twin Cities could see an additional 40 days above 90 degrees per year by 2050 (currently, we average 13 days). 

Greening Frogtown

Another neighborhood in the Twin Cities with lower tree cover is St. Paul’s Frogtown, at 22.7 percent 

There are reasons Frogtown has less tree canopy than other neighborhoods, said Patricia Ohmans, the director of Frogtown Green, which has a free trees program that aims to increase tree canopy in the neighborhood.

The majority of St. Paul residents are renters, and that’s even more true in Frogtown, she said. Trees can be expensive — both to buy and to maintain, and they require space, Ohmans said.

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“Homeowners are more likely to plant a tree and care for a tree and even have a backyard to plant a tree in,” she said. Frogtown Green has done lots of outreach to homeowners and is now trying to reach more landlords to get trees onto rental properties in order to increase canopy coverage.

Map showing tree canopy cover in St. Paul. Frogtown is highlighted.
Metropolitan Council
Map showing tree canopy cover in St. Paul. Frogtown is highlighted.
Frogtown Green grows bare root trees — little more than sticks when it gets them — by planting them in boxes full of gravel and irrigating them over the summer. 

“By the end of the summer you have taken these very inexpensive bare root trees and they’ve developed a really nice root ball and you can take them around to your neighbors and plant them in their yards,” Ohmans said.

Other neighborhoods have gotten in on the program, including Hamline-Midway and Summit-University.

Lisa Burke first heard about what Frogtown Green was doing at a Wednesday evening talk — over Zoom, during the pandemic — at Unity Church-Unitarian in St. Paul, in Summit-University.

She and others in the church’s Stop Climate Change group decided to bring the free tree concept to their church’s neighborhood. Last year, they constructed a box and filled it with gravel. By fall, they had their first free trees.

The Canopy Connectors, as they call themselves, gave out 25 free trees last year to people in the Summit-University and Rondo-University neighborhoods. This year, they expect to increase the number to 75.