Beneath the red tile roofs of the Catalina Foothills, an affluent area north of Tucson, Arizona, lies a blanket of desert greenery: spiky cacti, sword-shaped yucca leaves, and the spindly limbs of palo verde and mesquite trees. Go south into the city, and the vegetation thins out. Trees are especially rare on the south side of town, where shops and schools and housing complexes spread across land covered in concrete.
On hot summer days you not only see but bird the difference. Tucson’s shadowy neighborhoods, which are predominantly low-income and Latino, are soaking up the heat. They swell at summer temperatures which eclipse the city averages 8 degrees Fahrenheit and the Catalina foothills 12 degrees. That disparity can be deadly in a city that has experienced 40 consecutive days above 100 degrees last year — heat that is sure to get worse with climate change.
The good news is there is a simple way to cool things down: plant trees. “You’re easily 10 degrees cooler when you step under the shade of a tree,” said Brad Lancaster, an urban forester in Tucson. “It’s dramatically cooler.”
A movement is underway to populate the city’s street corners and vacant lots with trees. Tucson’s city government, which has committed to planting one million trees by 2030recently received $5 million from the Biden administration to spur the effort — part of the $1 billion the US Forest Service committed last fall to urban and small-scale forestry projects across the United States, aimed at making communities more making them resilient against climate change and extreme heat.
But in Tucson and many other cities, tree planting initiatives can tackle much more than scorching temperatures. What if Tucson’s million new trees—and the rest of the country’s—didn’t just keep sidewalks cool? What if they also helped feed people?
That’s what Brandon Merchant hopes will happen on the shady south side of Tucson, a city where approx one fifth of the population live more than a mile from a grocery store. He is working on a project to plant velvet mesquite trees that thrive in the dry Sonoran desert and have been used as a food source for centuries. The mesquite trees’ seed pods can be ground into a sweet, protein-rich flour used to make bread, cookies and pancakes. Merchant, who works at the Community Food Bank of Southern Arizona, sees growing mesquite around the city and surrounding areas as an opportunity to alleviate heat and hunger. The outcome could be a network of “food forests,” community spaces where volunteers tend fruit trees and other edible plants for neighbors to eat.
“When we think about the root causes of hunger and the root causes of health issues, there are all these things that go together: lack of green spaces, lack of biodiversity,” Merchant said. (The food bank received half a million dollars from the Biden administration through the Inflation Reduction Act.)
City of Tucson
Merchant’s initiative fits a national trend to combine forestry — and Forest Service funding — with efforts to feed people. Volunteers, school teachers and urban farmers in cities across the country plant fruit and nut trees, berry bushes and other edible plants in public spaces to create shade, provide access to green space and provide neighbors with free and healthy food. These food forests, forest gardens, and edible parks have sprung up at churches, schools, vacant lots, and street corners in numerous cities, including Boston, Philadelphia, Atlanta, Seattle, and Miami.
“It’s definitely growing in popularity,” said Cara Rockwell, who researches agroforestry and sustainable food systems at Florida International University. “Food security is one of the big advantages.”
There are also numerous environmental benefits: Trees improve air quality, absorb carbon from the atmosphere and create habitat for wildlife, said Mikaela Schmitt-Harsh, an urban forester at James Madison University in Virginia. “I think food forests are becoming popular along with other urban green space efforts, community gardens, green roofs,” she added. “I think all those efforts are moving us in a positive direction.”
Researchers say food forests are unlikely to produce enough food to feed everyone who needs it. But Schmitt-Harsh said they can help supplement diets, especially in neighborhoods far from grocery stores. “A lot has to go into the planning of where the food forest is, when the fruits are harvestable and whether the harvestable fruits are fairly distributed.”
She pointed to the Philadelphia Orchard Project as an emblem of success. This nonprofit has partnered with schools, churches, public recreation centers and urban farms to oversee some 68 community gardens across the city. Their network of orchards and food forests generated more than 11,000 pounds of fresh produce last year, according to Phil Forsyth, co-executive director of the nonprofit.
Some of the sites in Philadelphia have only three or four trees. Others have more than 100, said Kim Jordan, the organization’s other executive director. “We do a variety of fruit and nut trees, berry bushes and vines, pollinator plants, ground cover, perennial vegetables — a whole range of things,” Jordan said.
The community food bank in Tucson started its project in 2021 when it bought six shelters to shelter saplings. Each hut can house dozens of baby trees, which are grown in bags and watered until they become sturdy enough to be planted in the ground. Over the past three years, Merchant has partnered with a high school, a community farm and the Tohono O’odham Tribal Nation to nurse, plant and maintain the trees. So far, they’ve only planted a few dozen saplings in the ground, and Merchant intends to ramp up efforts this year with a few hundred more plantings. His initial goal, which he described as “lofty and ambitious”, is to plant 20,000 trees by 2030.
The food bank also organizes workshops on growing, pruning and harvesting, as well as courses on cooking with mesquite flour. And they’ve hosted community events, where people bring seed pods to pound into flour — a process that requires a large hammer mill that’s not easy to use on your own, Merchant said. Those events include a mesquite pancake cookout, with the fresh flour.
Merchant signs on a model of tree plant that Lancaster, the urban forester, has been pioneering a downtown neighborhood called Dunbar Spring for 30 years. This area was once as bare as south Tucson, but a group of volunteers led by Lancaster – who began planting velvet mesquite and other native trees in 1996 – built up an impressive canopy. Over three decades, neighborhood foresters transformed Dunbar Spring’s bare curb into lush forests of mesquite, hackberry, cholla and prickly pear cactus, and more—all plants that have edible parts.
“There are over 400 native food plants in the Sonoran Desert, so we tapped into that,” Lancaster said. “That’s what we focused our plantings on.”
The Dunbar Spring Food Forest is now what Lancaster calls a “living pantry.” He told Grist that up to a quarter of the food he eats – and half of what he feeds his Nigerian dwarf goats – is harvested from plants in the neighborhood’s forest. “Those percentages could be much higher if I spent more time in the harvests.” The more than 1,700 trees and shrubs planted by Lancaster’s group also stored a ton of water—a precious commodity in the Sonoran Desert—by soaking up an estimated 1 million gallons of rainwater that would otherwise run off the pavement. would have flowed down storm drains.
Another well-established food forest is next to the Old West Church in Boston, where volunteers spent a decade transforming a city lawn into a grove of apple, pear and cherry trees that hang over vegetable, pollinator and herb gardens. Their produce — ranging from tomatoes and eggplants to winter melons — is donated to Women’s Lunch Place, a local shelter for women without permanent housing, according to Karen Spiller, a professor of sustainable food systems at the University of New Hampshire and a member of Old West Church helping with the project.
“It’s open for harvest anytime,” Spiller said. “It’s not ‘Drop a dollar and pick an apple.’ You can pick your apple and eat your apple.”
Merchant wants to apply the same ethic in Tucson: mesquite pods for everyone to pick — and free pancakes after a day staying cool in the shade.
