When students returned to the District’s Capital City Public Charter School in September, they encountered old friends, new teachers and a one-of-a-kind classroom. Rather than walls and books, it bursts with plum and cherry trees, blueberry and aronia bushes, milkweeds and vegetables, and lots and lots of insects.

This lush, multilayered ecosystem of plants and animals both familiar and obscure, growing behind the three-story brick schoolhouse in Northwest Washington, is what’s known as a food forest. It is the first at a D.C. school and one of a handful at K-12 institutions anywhere. School leaders intend for this edible forest garden to yield a bumper crop of benefits: educational, nutritional, environmental, even vocational.

On a sunny September day, it also provided fun. A group of rambunctious third-grade boys competed at grabbing tiny moths off zinnia flowers. An 8-year-old named Liyah walked up. Ryoko Yamamoto, the school’s garden coordinator, spotted her and handed her a plastic bowl.

“Want to pick tomatoes?” Yamamoto asked. “Let’s try to fill the whole bowl.”

Liyah maneuvered among plants that loomed over her to grab ripe fruits, handling each one carefully and deliberately. Before long, she had filled half the bowl with bright orange Sungold cherry tomatoes. Does she like picking tomatoes? “Sometimes,” she said. “Not when it’s super-duper hot.”

Other students soon joined and plunked tomatoes into additional bowls. Later that afternoon, those same tomatoes were sold by 10th- and 11th-graders at Capital City’s weekly garden market. (And, yes, a few of the juicy tomatoes made their way into students’ mouths.)

Overlooked in the hunt for bugs and fruit were dozens of small trees and shrubs mixed in with the vegetables, herbs and flowers — some little more than twigs in the ground. But over the next few years, if all goes as planned, they will grow to dominate this space and produce foods rarely eaten in today’s fast-paced, grocery-store-dominated world.

School vegetable gardens are common nowadays. Food forests — biodiverse, edible landscapes anchored by fruit- and nut-bearing trees and shrubs — not so much. They require expertise to design and maintain, and years to grow before producing much of anything — a combination not often found at schools where teachers and administrators are already stretched thin and turnover can be high.

But Capital City has Yamamoto. She recalls picking plums and using bamboo poles to knock ripe persimmons from trees in her family’s yard while growing up in Japan. When she came to the United States, she encountered vast ecological and nutritional deserts known as American lawns. “It seemed like a waste of space,” she said.

When Capital City moved to its current home in 2012, Yamamoto, whose children attend the school, saw mostly barren grounds there, too: “It was nothing. It was not well taken care of, just some trees and plantings.”

She was soon hired and began converting the edge of a sun-soaked sports field behind the school into a vegetable garden. She planted a few pawpaws, figs and pear trees, which now tower so high she needs a ladder to harvest the fruit.

But Yamamoto wanted something closer to the bounty of her youth — and to the fruit- and nut-filled forests that are the native ecosystem of the D.C. region.

She found common cause with the city’s Urban Forestry Division, which is on a mission to increase the city’s tree canopy to 40 percent. It has planted trees in thousands of roadside tree boxes and in city-owned parks and green spaces but remains a few percentage points short of its goal.

Schools such as Capital City are among the few places in the District left with large expanses of open space, said Earl Eutsler, the associate director of the District Department of Transportation’s Urban Forestry Division.

“Schools are crucial to our goal of reaching 40 percent,” he said.

And those spaces are often neglected, said Karen Dresden, head of school at Capital City.

“Folks who design schools design the interior spaces. There’s often not as much intentionality with the exterior space,” she said. “That’s a missed opportunity in terms of what the outside can offer as a classroom.”

Eutsler had already been looking for a place to plant the District’s first food forest. He and Jack Chapman, a D.C. forester whose children attend Capital City, got a $30,000 grant from the U.S. Forest Service’s Chesapeake Watershed Forestry Program and matched it with $30,000 of District money. They hired Lincoln Smith, a Bowie, Md., landscaper who specializes in native edibles.

Smith drew up a plan to cover more than a third of an acre of the school grounds with 74 varieties of food-bearing trees, shrubs and perennial plants. Some, such as pecan trees, could someday tower as tall as an oak. Others, such as apples and serviceberries, will keep their fruit within reach — at least of taller high-schoolers.

Between April and June, with Yamamoto supervising, D.C. contractors installed the trees. School staff, teachers, students and volunteers planted the rest of the food forest, filling one edge of the field and even spilling outside the school’s fence into an area that abuts the sidewalk.

The hope is that community members as well as students and parents benefit from the harvest.

For Smith, who has designed food forests for Maryland cities such as Hyattsville and Greenbelt, a school is an ideal setting. “If you don’t have people in the food forest using it and learning from it, then obviously it’s failing,” he said. “At a school, you have that baked in.”

Forest gardens at schools can also help urban children and adults regain once-common knowledge about food and nutrition. “I’ve been to locations where kids are around fruit, but they don’t even know it’s edible,” Smith said.

Integrating the forest garden into the school is Yamamoto’s next job. She is working with teachers to design lessons around ecology, cooking and food justice for the school’s students.

How that looks, of course, varies by grade. Morgan Grubbs, who teaches first grade, looks to imbue her students with a “sense of magic,” while also reinforcing science lessons.

“Right now, they’re often scared of bees and will see them and run. But when spring comes, after they’ve spent all semester learning about pollinators and how bees are important, they’ll see bees and run up to them,” she says.

“Now that there’s more food out here, they can eat things that were pollinated by honey bees, which is awesome,” Grubbs adds.

Ellen Royse, who teaches high school environmental science and urban ecology at Capital City, started using the forest pedagogically even before it existed: Last year, after learning of Yamamoto’s plans, she had her urban ecology students survey the plants and insects in the site selected for the forest. They found mostly crabgrass and English ivy, and a few insect species. This year’s class will return and resurvey. As the trees and shrubs grow, so will the students’ ability to see connections between a place’s flora and broader metrics of environmental quality.

Royse sees a second benefit: exposing students who will soon enter the work world to lesser-known career possibilities. When Smith came to speak to her class, “kids were like, ‘This is his job? He goes around and plants things and harvests food?’ ” she said.

Career preparation is the primary appeal of the garden for Nuri Cortez, an 11th-grader taking Royse’s class. She and her peers run a weekly farmers market selling vegetables and herbs from the garden alongside produce from local farms. Once the food forest starts producing berries and nuts, those will be added to the mix. Cortez hopes the marketing and people skills she learns will help her start a food store in her parents’ native Bolivia.

The forest garden also helps her see relationships between her local environment and larger issues she learns about in school or hears about on the news, she said. “Right now, the environment’s in crisis, with the forest fires in the Amazon,” she said in September. “That concerns me.”

The forest garden is already meeting some of its goals. Third-graders point out evidence of deer grazing on plants with the expertise of naturalists. One girl makes her way to the Asian pear tree almost hidden against the schoolyard’s back fence and drops the fruit into her backpack.

But it will take time for some of Yamamoto’s plans to fully ripen. Hazelnut trees planted in the spring are waist-high twigs with a few wrinkled, brown-edged leaves; edible nuts are still years away.

The school setting also presents challenges. High-energy elementary students can trample plants and cause soil erosion. They sometimes pick fruit when it’s not ripe. Yamamoto sets rules but allows students to bend them — to a point — if it keeps them in the garden. She estimates maintaining the garden will require $500 to $1,000 a year, which will come from market proceeds; D.C. staff will prune and mulch trees.

Capital City’s food forest might be the only school-based food forest in the District and maybe even the Mid-Atlantic, but it won’t hold that title for long. Smith is already designing a second one at the District’s Langley Elementary School for next year. And leaders at Horace Mann Elementary School have approved their own food forest. The grant and matching funds will cover both projects, D.C. forester Chapman says.

“If we can make spaces where trees can thrive, then people can probably do well there as well,” said Eutsler of the Urban Forestry Division. “It’s poised to be replicated many times.”