On a sunny Friday morning in April, a group of preschool kids bang sticks against a downed tree. Others balance on a wobbly log or mix wood chips in a bowl or climb rocks. Their teacher, Teri Torchia, stands nearby. She answers questions and makes suggestions when needed, but mostly she watches her 11 kids explore their surroundings. For almost three hours, they scramble around the top of Hemlock Hill in the center of Boston’s 281-acre Arnold Arboretum. And they’ll be back again on Monday, rain or shine.

Torchia teaches one class in the growing Boston Outdoor Preschool Network (BOPN), a three-year-old nature-based preschool founded by Sarah Besse (’17), Shela Sinelien (’19), and Sara Murray. Their concept is simple: immerse kids in the outdoors and nature will provide the curriculum.

Nature immersion has grown popular in Europe over the past 70 years. Germany alone has more than 1,500 waldkitas, or forest kindergartens. While more traditional preschools may introduce kids to reading and arithmetic, it’s possible that just going outside to play is the best preparation of all for school. Studies have linked time spent outdoors to improved confidence, cognitive function, and academic performance and reductions in obesity and symptoms associated with attention deficit hyperactivity disorder. Even bullying decreases.

Nature-based education has been slower to catch on in the US, but that’s changing. According to the North American Association for Environmental Education, there were 585 nature preschools in the US in 2020—up from fewer than 50 a decade earlier—and anecdotal evidence suggests that the pandemic only increased interest. BOPN, which opened with a single nine-child class in 2019, now serves more than 100 at two sites, in Boston and Wellesley, with 15 teachers and about two dozen interns, fellows, and youth workers. And the founders have ambitious goals to expand even further.

Shela Sinelien (left) and Sarah Besse (right) started Boston Outdoor Preschool Network with kids’ curiosity about nature at the center. “Every time the children come to school, they discover something that wasn’t there the day before,” Sinelien says.


“We’re part of a trend now,” Sinelien says. “It’s just a matter of time before we see people really understanding that we should take our kids outdoors. Even at public schools, children can spend time outdoors every week. BOPN and other organizations are shaping that for families.”



Besse and Sinelien—who received Young Alumni Awards in 2021—met while studying at BU Wheelock, then taught together in a Cambridge public school in 2018. Sinelien was working with children with high needs and noticed a pattern: “Whenever they were outside, they were just happier and all of the behavior [problems] decreased,” she says. 

Besse had seen the same thing, but the two teachers had to follow the school’s rules and schedule, which included limited time outdoors. So the two friends began dreaming. “Why don’t we build our own school? Then no one would tell us not to take the children outside,” Sinelien recalls saying. 

“That’s how BOPN started.”

Midyear, Besse quit her job to look for a site. “A lot of people thought I was completely insane,” she says. But she knew of other programs doing what they wanted to do—Tiny Trees Preschool, based in Seattle-area parks, was a major inspiration—and believed there was demand in Boston. 

She spent time staring at Google Maps and driving to green spaces that might agree to host a class. 

“It was a lot of reaching out and getting ‘nos’,” she says. “It was so lonely.” 

Finally, in September 2019, BOPN opened its first class at Arnold Arboretum.



A class with no classroom still seems like a radical idea to many, but the questions are mainly logistical—What if it rains? What if it snows? The benefits and the learning opportunities of outdoor play are pretty intuitive.

BOPN classes meet rain or shine. A dangerous combination of temperature and windchill might lead to a canceled or shortened day—that’s a rarity. Thirteen degrees and sunny? They’re outside. Fifty and rainy? No problem. Teachers and kids dress accordingly, with BOPN providing gear for families who can’t afford it. Full-day classes also have an indoor base to return to in bad weather—and for naptime—but the half-day classes are always outside.

The seasons provide teachers with a constantly changing backdrop to inspire their classes. “Every time the children come to school, they discover something that wasn’t there the day before,” Sinelien says. Kids become curious about worms when they emerge after a rainstorm. They ask about leaves changing colors in the fall and flowers blooming in the spring. They can smell pine needles and touch tree sap.

Sinelien grew up in Haiti, where time outdoors was a given. “I grew up around a farm. I learned in nature,” she says. “If it was

a lesson relating to flowers, I didn’t want to learn that indoors—bring me out, show me the flowers. It’s a better way to teach children.”

The elimination of classrooms has other benefits. The kids don’t have to change clothes to go outside or move from room to room. And they can play with mud, rocks, and sticks as much as they want. Melissa Sinclair, the mother of four-year-old Marcus, watches her son play. She is tagging along with Torchia’s class today to help celebrate his birthday. “Inside, you hear ‘no’ so much. I love that he doesn’t hear ‘no’ all day.” 

Lu Agosti and Vanessa Niro teach at the Arboretum as well. Their class is playing on the side of Peter’s Hill, about a quarter mile from Torchia’s group. They pull their supplies in a three-wheeled wagon. It carries stuffed birds that sing when squeezed, nature guides, yoga cards, and Pantone color swatches in a spectrum of natural colors, as well as first aid supplies and extra clothes. 

They watch as kids invent their own games. One group sweeps pine needles into a mound, then takes turns running and leaping into it. Then they take a break to pretend that a tree is a rocket, about to launch. Agosti watches the activity and quotes one of her mentors: “Never rush a curious child.”



From one class the first year, BOPN expanded to eight classes at two sites—adding the Massachusetts Horticultural Society in Wellesley—in year two when the pandemic hit and interest really exploded. “We knew there was a need,” Sinelien says. “But I

don’t think parents knew there was a need until COVID. Then families realized, ‘There’s nowhere to go but outside.’”

BOPN now offers a mix of half- and full-day classes for kids as young as 15 months, and they plan to add an infant class in Wellesley soon. The founders are hoping momentum from the pandemic helps them reach more kids in more locations—and reach their goal of making nature-based education accessible to families regardless of their financial resources. 

“Now that we’ve established a reputation in the community, it’s time to focus on equity,” Besse says. Thus far, BOPN has been funded mostly by tuition, but they’ve filled out an administrative team that should now have the bandwidth to start writing grants. “Nature-based education is very upper class and white,” Besse says. “Here we are in Boston—we should be able to change that.”

Becoming a universal prekindergarten provider is one way to make that happen. Boston provides free preschool for every four-year-old in the city and BOPN wants to partner with the city in the future. 

Sinelien and Besse are also looking into ways to partner  directly with schools located near outdoor spaces. BOPN staff could help them facilitate weekly outings, a trend known as Forest Fridays. “We’d love to do what we do with every four-year-old classroom in the city of Boston,” Besse says, then pauses. “That’s a little ambitious.” But the teachers and principals she knows are excited by the idea, she says. “People get it. They just need logistical support.” 



Back on Hemlock Hill, Torchia asks her class to collect the large circle of orange cones that have marked the perimeter of today’s outdoor classroom. As the kids scatter, she packs books and musical instruments into a rolling suitcase. Then the kids slip on their backpacks and prepare for the short hike downhill to meet their parents. 

Besse focuses her attention on one boy, Theo. He wants to take a big stick with him and starts to get upset when he’s asked to put it down. Besse picks up her own stick and quickly defuses the situation. “Can I show you my routine?” she asks him. “I like to hide my stick in a special spot.” Theo is listening. Besse tucks her stick up against a tree, just off the trail, and Theo immediately copies her. 

Ten minutes later, the group arrives at the bottom of the hill for pickup. Parents, kids, and teachers mingle, talking about the day’s adventures before heading home. Theo, near tears just a few minutes earlier, looks up at a man there to pick him up, and says, “I went to Hemlock Hill and it was so fun. I want to go again!”