HUDDLESTON, Va. — It was time for school, but Malachi Reilly hesitated at the edge of a steep, tree-clotted hill.

In the forest below, his nine classmates were getting ready for morning yoga. Malachi clung to his mom, who brushed her hair behind her ears and bent to make one last plea.

“Go ahead,” she whispered. “You’re going to have a wonderful day.”

“Malachi, I grabbed your swim shoes,” teacher Catherine Eubank called from halfway down the hill, “so when we get to the creek, you can play.”

With that, the 6-year-old slipped his thumb from his mouth and tumbled down a dirt path for his first week at the Organic Nature Experience (ONE) Forest School, a year-round, outdoor preschool and before-and-after-school program in rural Huddleston. Founded in the tradition of forest schools that dates to 1950s-era Scandinavia, the school teaches things such as the six ways to get a fire started, the difference between frogs and toads, and how to weigh the risks involved in swinging on a vine.

More than 250 nature-based preschools and kindergartens have sprouted across the country over the past decade or so, appearing in at least 43 states and serving approximately 10,000 children annually as of 2017, according to a national survey sponsored by several environmental education groups. Now, with traditional schools closed and more summer camps being canceled every day, the schools are “having a moment,” said Eubank, 53. “I think that’s the phrase?”

Other forest schools have closed because of the pandemic, including a once-a-week program in the nation’s capital. But Eubank’s Forest School was never required to close, because Virginia Gov. Ralph Northam (D) in late March issued an order classifying child-care centers as “essential businesses” that are allowed to continue operations. In line with federal guidance, Eubank has made adaptations — including asking families to attest that their children have not been sick or in contact with sick people — but not many.

Demand for enrollment at her school has risen 75 percent since the virus forced Virginia’s schools to close, Eubank said, and she is scrambling to find more summer staffers. She has also formed a school-board committee to explore how Forest School can launch a school for kindergartners to sixth-graders in the fall.

“More and more parents are screaming for alternatives,” Eubank said.

Social distancing is not difficult, given that classes typically max out at 12 students (with one adult teacher for every four kids) and children can roam throughout an eight-acre plot owned by Eubank and her husband. Although because the area has seen relatively few cases, distancing is not strictly enforced, she said.

And there’s no need for disinfectant, staffers figure. “We just don’t have surfaces,” Eubank said.

Heidi Sutherland is a summer staffer who teaches eighth-grade history at a middle school during the year. “It feels so much safer here than in a classroom,” she said.

The school, a nonprofit, costs $200 a week, though Eubank offers need-based and other discounts, and only one family currently pays full price, she said.

For stressed Bedford County families, the program has proved a godsend. Malachi’s mom, Bethany Reilly, 27, was still mourning the loss of her husband, who died of a drug overdose in August, when the virus hit. She quickly grew desperate to get her children out of the house, to distract them from their grief and allow her to attend therapy.

Reilly figured ONE Forest School was closed. But in mid-May, she texted Eubank anyway — and swiped open the reply to find a thrilling surprise.

“It would be so much harder without this,” Reilly said as she watched Malachi pick his way down the hill Friday morning. “If they offer it, I’d send my kids here for normal school in the fall, with all the virus craziness going on.”

The “craziness,” compounded by his father’s death, has made life especially difficult for Malachi. He is struggling more than his younger siblings, who are 5 and 4, and things got worse when the pandemic forced the cancellation of his counseling sessions.

Shortly after yoga that morning, Malachi stood staring across the water at the other children, who had decided the first lesson of the day would involve building a dam.

This is where the water should be flowing,” said a boy with a floppy mop of dark hair.

“We need more mud,” replied a girl in a black baseball cap.

Whooping and splashing, the others scrambled to comply, but Malachi held back. He looked at his swim shoes. He sucked his thumb.

Forest School students vote each morning to determine the day’s curriculum. The vote often takes place at “Base Camp,” a clearing in the woods that boasts three hammocks, a stone-lined fire pit and a tarpaulin shelter. No matter the weather — the school has canceled only once, for “extremely high winds,” Eubank said — students gather by six wooden seats, fashioned from tree trunks, to ponder their options: Whittling lessons? Den-building? Collecting microinvertebrates from the river, then examining them in the “wet lab,” an aquarium balanced on a picnic table?

Or should they tackle the rope course, a perennial favorite meant to teach balance and dexterity?

That course, like most everything else — Base Camp, the school kitchen — was hammered together by Eubank’s husband, Danny Eubank, 67, a retired builder.

“She draws a picture of what she wants,” he said, “and I do it for her.”

Catherine Eubank got the idea for Forest School about three years ago, after spotting an ad for forest schools on Facebook. She had just finished a 30-year career in the restaurant industry and was looking for something to do beyond playing with her 14 grandchildren. She was also concerned about rates of violence in schools and about spiking drug use in Bedford County, which has been hit hard by opioid abuse.

Plus, research suggested forest schools are effective: One 2018 study found that elementary school children who attended forest school once a week demonstrated improved writing, reading and math skills over a three-year period, compared with peers who did not.

It took about two years to get everything ready: She paid for online courses and got certified as a forest school teacher. Her husband set to work slicing logs on the eight-acre plot, which has been in his family for three decades. The Eubanks’ home is on the land. They launched a website and started advertising, on Facebook and through word of mouth. In total, the preparations cost less than $5,000, Catherine Eubank said, most of which came from their own pockets.

They started with nine students and eventually attracted a total of 50 over the past year — a number they expect to spike in coming months. They also hope to offer paid positions in the fall. Currently, all of Forest School’s five teachers are volunteers.

Danny Eubank is continuing to tinker with the campus, including grand plans for an arts-and-crafts pavilion. But he is pretty happy with the theater, a wooden structure with turquoise curtains that hosted its first, chaotic production of the summer Friday.

“Theater Director” Angus Sutherland, 12 — who had scrawled his title across the back of his orange T-shirt in black Sharpie — had done his best. Five minutes before showtime, he gathered his classmates backstage and, his speech garbled by the lollipop stick in his mouth, exhorted them to follow instructions.

The three-act play was supposed to take place in the deep, dark woods, where one of the main characters would get dramatically lost. But when Angus twitched the curtains back, three actors immediately ran offstage.

A 10-year-old flung his arms wide in an irrelevant imitation of Superman. A 4-year-old girl popped her head from behind the curtains to yell “Peek-a-boo!” at the audience. An 11-year-old in a camouflage T-shirt proclaimed he didn’t want to get lost.

As Angus shook his head, Catherine Eubank ended the madness the only way she could think of: “All right,” she called out, “who wants to eat a bug?”

The children scrambled up a hill to munch on dried insects, which Eubank distributed one by one from a large plastic bag.

Bright-eyed and grinning, Malachi raced to get there first.