“You can’t just go and cut concrete and put a tree in the ground,” says Rose Tileston, who is 32 and works on urban tree-planting projects across the country as part of her job at American Forests, a nonprofit based in Washington, D.C. To plant a tree in a public place, you need permission from the city first. Many will be eager to grant it. Trees make cities more resilient to climate change by sequestering carbon, absorbing storm-water runoff, decreasing temperatures, purifying air and reducing the costs and emissions from air-conditioning.
Plant the right tree in the right place. “Are there power lines above?” Tileston says. “Are there water pipes below?” You have to plan for the tree at full maturity, even if that growth will take decades. Many municipalities provide lists of approved tree varieties to choose from. If possible, pick a species native to the area. For a better chance of survival, plant a larger tree, with a trunk that is three inches in diameter when measured four and a half feet off the ground.
A tree of that size is heavy; it helps to have three people working together when planting. Dig a hole one to two feet wider than the diameter of the tree’s root ball. Make it as deep as the root ball but no deeper; you don’t want to cover the part of the trunk where the roots begin to flare out. Gently roll the root ball into the hole and cut away any wire or burlap. Stand back and make sure the tree is upright. Fill the dirt back in, tamping it as you go. Pound two wooden stakes into the ground and tie the tree in place. Water thoroughly; young trees need three years of regular watering.
The urban population in the continental United States is projected to increase by 91 million people over the next 40 years. To keep up with that growth and a changing climate, researchers say, we’ll need to plant some 31 million trees per year in urban areas. In most American cities, wealthier neighborhoods have more trees than lower-income areas do. “Some neighborhoods don’t have any trees at all,” says Tileston, whose organization works with community groups to address tree equity. If you’re planting outside your own neighborhood, make sure you have support first. “Don’t go into a community and say, ‘You need this,’” Tileston says. “Listen for the community to say, ‘We want this.’”