After more than a year of lockdowns, with limited access to nature, Magdalena Begh was delighted when her six-year-old daughter came home from forest school and informed her she had found three rat skeletons. One of them, Alia told her, was “pretty fresh”. “These little observations are very crucial to their learning – it’s amazing,” says Begh.

Since Alia and her sister Hana, nine, started going to the Urban Outdoors Adventures in Nature after-school club in north London in June, they have used clay, learned about insects and made campfires, marmalade and bows and arrows.

They are part of a wave of children across the UK who have joined forest schools since the start of the pandemic, many since September.

Of more than 200 forest schools surveyed by the Forest School Association (FSA), about two-thirds said demand for their services had increased since March 2020. Among the reasons cited were increased awareness of the benefits of the outdoors, especially in relation to stress and anxiety, Covid safety, and dissatisfaction with the school syllabus after months of pandemic homeschooling.

“I don’t think it’s ever been more popular,” says Gareth Wyn Davies, chief executive of the FSA, who expects demand to keep increasing. But it’s still got some way to go. “It’s a fairly young sector, just over 20 years old. And it’s a grassroots moment – it doesn’t have that top-down government attention yet.”

Forest schools, which centre around unstructured play, exploration and intrinsic motivation, arrived in the UK in 1993. Inspired by the outdoors culture – or friluftsliv – of Scandinavia, sessions are usually held either entirely or mostly outdoors and are intended to supplement, rather than replace, traditional education.

State schools are increasingly putting on forest school sessions for pupils within the school day because they are considered to be beneficial to mental and physical health, behaviour and academic attainment – as well as being relatively “Covid-proof”.

Begh says that, having grown up in a village amid nature, she was always keen on signing her daughters up to forest school. So when she heard about one nearby, she put their names down straight away. “After the first session they were very excited – I’ve never seen them so happy after doing any after-school club like that.”

Abby Sutcliffe, director of Urban Outdoors Adventures in Nature forest school, which works with 100 children a week in after-school clubs, and 60 pupils in schools, says there has been a “massive uptake” in the last year. “It’s a combination of the lockdowns and people realising that being outdoors is actually quite good for your mental health.”

During the first lockdown, they ran free sessions for local children, and they have just finished a year-long youth programme including bushcraft, blacksmithing and herbalism. While some forest schools are held on National Trust land or private woodland, as an urban forest school, Sutcliffe’s is run in public spaces including a nature reserve and a canal-side park. The mental health and wellbeing benefits are “palpable”, she says.

Schools are turning to forest school to teach children social, emotional and physical skills that have become rusty during lockdown, says Vicki Stewart, who is director of Brightwood Training near Swindon. She says forest school is also being used to meet the needs of children, which have been changing since the 1990s but have been particularly accelerated by the pandemic.

“Children are indoors using technology to talk to their friends rather than going outdoors, and they have relied more and more on technology – since Covid that has happened even more.”

She teaches children old-fashioned group games such as hide-and-seek, tag and grandmother’s footsteps because they don’t know how to play them – in part, she says, due to Covid but also because of safety fears about playing outside, and pressure to achieve academically.

But while forest schools take children away from technology, it still “creeps in” via their imaginations, says Kent-based forest-school leader Anna Bell. “When a child now makes a camp, not always, but a lot of the time, there’ll be a flatscreen TV which is a piece of wood, there’ll be a remote control, there’ll be an Xbox or something.”

Lockdowns were “a chance to get off the treadmill” for families, says Lewis Ames, co-director of Devon-based forest school Children of the Forest. They’ve seen a rise in applications since the start of the pandemic, with about 150 families on their toddler-group waiting list, and 50-60 children on the waiting list for their forest school for home-educated children.

“That pause gave a lot of families time to think and go, ‘actually is this working? Or are we just surviving and getting through?'” Ames says. “Which then prompted a lot of the families that started with us to go ‘actually no, it isn’t quite right’.”