How Japanese ‘tiny forests’ are sweeping Scotland

Grown using the Miyawaki method, fast-growing miniature forests in the middle of cities can bring surprisingly big benefits for people and the environment.

“It’s like going on a bear hunt!”

Not quite, perhaps, but these kids are definitely excited. They are on a visit to a miniscule patch of forest in the grounds of Queen Margaret University on the outskirts of Edinburgh, Scotland, and are about to head out armed with a bucket of water, a jug and a stopwatch.

They are measuring how fast patches of soil inside and outside the forest absorb water, so we leave the small circular howff (a traditionally-built shelter with a wildflower roof) in the middle of the vegetation. The child in charge of the stopwatch does a couple of test runs and the pouring begins.

“I want you to decide when it’s all gone,” says Elly Kinross, the woodland and greenspace officer at Edinburgh and Lothians Greenspace Trust who is running this session for the kids. “The grass can be wet, but basically the water needs to be gone… Yeh I think that’s gone. OK, good, give it a stop.”

This class of eight- and nine-year-olds is spending the day in a tiny forest (known, in Scotland, as a wee forest): small tennis court-sized patches of land, usually in urban areas, rigorously prepared and planted with the makings of a fast-growing, dense native forest.

These petite patches of greenery have been springing up across the world for decades now. Japan has planted thousands; India, where the tiny forest concept was developed, hundreds. The Netherlands is a hotspot for them too, and they are also now beginning to spring up across the US. But it is the UK that has most recently seen an enormous push towards these miniature urban forests, with hundreds planted since 2020.

As I visit the site alongside these schoolchildren on a beautifully sunny spring day, I’m also on a kind of hunt. I’m trying to work out how big the benefits of foresting such tiny areas really are. As it turns out, I’ve stumbled onto a thorny, decades-long debate.

A tiny revolution 

In many countries, including my home country of Scotland, there is now a huge effort to try to reforest large areas of land. This tends to concentrate on large, unbroken patches of land, and with good reason: such forests are critical for protecting wildlife and human health and have enormous benefits for carbon storage and water cycling.

But while smaller patches of forest have historically been somewhat dismissed as useful nature reserves, they do have benefits. One big plus is that they are easier to fit into an urban area – and thus be nearer to where most people live. And emerging evidence is showing we might have underestimated their benefits for nature too.

At around 200 sq m (2,200 sq ft), though, tiny forests are seriously small even compared to many urban forests. They involve around 600 trees being densely planted all at the same time in a heavily prepared soil. Ross Woodside, head of operations at Edinburgh and Lothians Greenspace Trust, the local delivery partner for this wee forest, points out to me some of the 18 different species planted here, from broom bushes to wild cherry and oak trees. As he does so, I wonder, how small a forest is too small?

This wee forest was planted just three years ago, so it’s got a long way to go before its Scots pines and hazel trees become what looks like a forest. For now, though, butterflies and bees skit around the yellow gorse bushes and tree saplings.

This wee Scottish forest is grown according to the Miyawaki method to grow them. Developed by Japanese botanist and ecologist Akira Miyawaki in the 1970s, it’s a way of speedily restoring native woodland on areas of degraded land. It’s a key aspect of what makes these areas “tiny forests”, not just small patches of trees.

The method involves randomly planting a mix of native species in a soil intensively restored with organic nutrients. All layers of a forest are planted together, with species based on an established native woodland nearby. In Scotland, for example, this might mean planting a canopy layer of tall oak and Scots Pine, a sub-canopy of smaller trees like silver birch and rowan and a scrub layer of broom and blackthorn all at once. The densely planted young trees fight for sunlight and grow faster. The result, its proponents say, is a mature, native forest in 10 years rather than 100.

Widespread in Japan, Miyawaki’s restoration methods have spread across the world, from the Amazon to India. It has its critics, though, with concerns around their cost and fears they are being used to compensate for virgin forest loss, despite not really being primary forest. Others argue they create an undue emphasis on dense forest creation at the expense of other types of ecosystems like open woodland or wildflower meadows, which may be just as important ecologically.

Still, the method, which works particularly well on derelict land, has found a natural home in urban areas, where fast-growing greenery can be a welcome relief. And there is some evidence that Miyawaki plots are an especially effective way of planting small forests. A 2023 report by the Tree Council, a UK non-profit, found they are better at surviving droughts, have higher biodiversity and are lower cost than similar small forests planted using more conventional methods. A recent council project in Kent, England, concluded that while the cost to plant a plot using the Miyawaki method was higher than standard tree planting methods, it actually cost far less per surviving tree, since trees had much higher survival rates.

A recent planting frenzy means the wider UK now has hundreds of young tiny forests. The non-profit Earthwatch has planted almost 300 of them in the past few years and aims for a further 200 by 2030. These are often financially backed by companies whose staff plant the forest as a corporate day out.

In 2020, the Miyawaki method caught the attention of Rosanna Cunningham, Scotland’s environment minister, says Karen Morrison, the project officer at government agency NatureScot who supports the rollout of wee forests in Scotland. Cunningham decided to give tiny forests a go in Scotland.

Of course, there’s been the odd hiccup, says Morrison. In one tiny forest in Dundee, Scotland, a straw mulch layer (put down to seal in moisture and repress weeds) was set alight. “I think it was a sort of big beacon, you know, ‘come and set fire to me’,” she says. “So, we’re learning. We’re learning along the way.” Fortunately, she adds, the fire flashed through the straw quickly and the saplings actually survived.

Local benefits 

Tree planting as a way of stunting climate change is complex and at times unreliable. Still, many cities across the world aim to vastly increase the number of trees they have, often citing carbon absorption as well as improved resilience to extreme weather and other benefits to local people. Edinburgh, for instance, is trying to become a million-tree city by 2030.

There’s one very good reason to plant tree patches in urban areas: people who live near them benefit.

Around the world, many people are interacting with nature less and less. That’s also the case for children: one 2017 survey in the US found by the time they were 12, children on average spent over three times as many hours on computers and watching TV as they did playing outside.

At the same time, research shows urban nature can improve physical, psychological and social well-being. A 2024 Canadian study, for instance, found the diversity of birds and trees in urban areas was linked to good self-reported mental health. Children who spend more time in natural environments have significantly better mental health, according to a 2024 study led by Fiona Caryl, a public health data scientist at the University of Glasgow.

Creating new urban forests is one way of making this happen. And they can also provide resilience benefits for locals in the form of everything from cooler microclimates to flood protection. In one study looking at Madison, Wisconsin, researchers found city blocks with more canopy cover had lower daytime temperatures than those without, especially when cover reached over 40%.

Earthwatch, meanwhile, monitors the impacts of the UK’s tiny forests using measurements taken by locals – just as the schoolchildren were measuring during my visit. Its latest report found that tiny forests have cooler daytime air temperatures and faster water infiltration rates (by 32% on average) than surrounding areas.

Scotland’s wee forests have a particular focus on school and community engagement. Its 34 sites are all planted near schools, with a particular effort to have them in areas of deprivation. Children and other locals are involved in planting and long term citizen science data collection, with some harnessed as “tree keepers” to help to monitor and maintain the forest in the long term.

Other wee forests in Scotland are connected with local health services, with two in the Dundee area on the land of medical practices which take part in green prescribing, which connects patients with free nature-based activities.

Patrick Boxall, a lecturer in teacher education at Queen Margaret University who was involved in planting the wee forest now uses it for outdoor learning with schools and his students. “We’ve got a lovely group of active primary school kids, all engaged, happy as Larry, and there’s a rich experience,” he says, pointing to the kids. “We’re trying to build that into our curriculum.”

NatureScot has a long-term vision to plant a wee forest within a short walking distance of every school in urban Scotland, says Morrison, with an initial focus on one per school cluster (there are around 250-300 of these in Scotland).

But for now, funds for further wee forests is limited, she says. “At the moment, it’s being rather more opportunistic than strategic, just depending on that land, money, expertise and people coming together,” she says. “So there hasn’t been big jumps forward of swathes of new wee forests. It’s more incremental.” NatureScot’s focus is on restoring far larger landscapes, she adds. “Wee forests scattered throughout an urban landscape are not quite that landscape-scale objective.” The agency is exploring other routes for wee forests, though, she says.

A forest patchwork

Even nature-focused governments across the world face these types of tricky questions on how best to spend limited restoration funds. And it’s complicated to unravel just how big a part urban and other smaller patches of forest can really play in tackling the dual climate and biodiversity crises.

In the 1970s, it was influentially argued that smaller fragments of land tended to be less valuable for conservation, since the probability of extinction of species in each was higher than for larger patches of land. Small nature reserves surrounded by altered habitat (such as urban environments) were compared to small, isolated islands. Despite other scientists disagreeing at the time, the idea became embedded in conservation strategies, says Federico Riva, a scientist at the Instituut voor Milieuvraagstukken in the Netherlands.

Riva, who researches the ecological value of smaller forest patches, thinks this was an oversight. He and other researchers argue we shouldn’t underestimate the wider ecological benefits of smaller patches of forest.

Along with his colleague Lenore Fahrig, a landscape ecologist at Carleton University in Canada who has spent decades researching the biodiversity of fragmented habitats, he investigated this in a 2022 study. After analysing dozens of land datasets, they concluded that small patches of land can actually have disproportionately large benefits for biodiversity. Sets of several small patches typically had more species per area of land than fewer larger patches in the same area, they found, including for species of conservation concern.

“Because every small patch is slightly different from the other, when you put them all together in a landscape, the entire landscape can have more biodiversity,” says Riva. “[So] we shouldn’t lose those fragments, because they have value as a whole.”

Other research also supports these findings. One analysis of the birds seen in around 500 parks in 21 US cities, for instance, found that collections of small parks actually had a higher number of different species, including rare species, than fewer, larger ones. And small patches of trees can add up to significant carbon intake. A study in New Zealand looking at tree patches smaller than a hectare (2.5 acres), for example, found they sequester the equivalent of 3-8% of the country’s agricultural emissions.

It’s an important debate, because globally it’s smaller patches of forest which are most at risk of suffering further habitat loss, according to a 2022 paper by Riva, Fahrig and several other researchers. “If you have a landscape with habitat being broken, it is more susceptible to deforestation,” says Riva.

Still, other researchers argue that restoring and preserving the largest areas of continuous, unbroken habitat should always be the priority. Another big concern is that when the focus turns to small patches of already degraded land, there’s a negative payoff for the old-growth forests harbouring the most threatened species.

Of course, no-one is arguing that biodiversity strongholds like the Amazon and Indonesian rainforests and the Congo Basin are not critical to protect. And it all depends on what is being weighed against what. A single isolated patch of dense forest in the middle of a sea of concrete and skyscrapers will be very different to a series of patches across a less sparsely populated area that also contains lots of gardens and parks.

Jocelyn Timperley

Still, in highly populated places like the UK, Riva argues, restoring a bunch of smaller forests does have advantages. “If you have a landscape that is very diverse, maybe you want to capture all these different habitat types.”

The areas of small land patches involved in Riva’s research are not necessarily as tiny as the wee forests I’m visiting in Scotland. Earthwatch has found, though, that the UK’s tiny forests are supporting a range of biodiversity, including less commonly observed urban species such as newts, solitary bees and slow worms. They also soak up a modest amount of carbon: based on tree growth measurements, the average four-year-old tiny forest already stores half a tonne of carbon, with sequestration expanding each year.

“They are wee, so it’s not the answer to everything,” says Morrison. “But locally, a well designed, well chosen site can be really good.”

And at a bigger scale, the benefits could add up. “If you create hundreds of tiny forests in a city, then you’re effectively establishing ecological corridors, in the form of ‘stepping stones’, for species to navigate the landscape,” says Riva. Which species will be able to capitalise on those corridors will depend on things like their mobility, he adds. “Regardless, you’re certainly providing people with space and opportunities to see biodiversity, from the tiniest things like flowers and butterflies to birds, trees, and mammals.”

Queen Margaret University’s wee forest has also seen an uptick in biodiversity since it was planted in 2020, says Boxall, noting that they are seeing more butterflies, amphibians and birds, as well as a bee colony now established on the green roof of the howff.

The fence currently around Queen Margaret University’s wee forest will eventually come down, and the forest might spread outside the borders, adds Boxall. There are plans for the vast grassy lawn to be turned into a wildflower meadow. Boxall is eyeing another patch to become a second wee forest. “Hopefully we’ll end up with half of Queen Margaret University feeling like a nature reserve,” he says.

Boxall sees wee forests as something that could be planted pretty much anywhere, observing the area involved is not dissimilar to the lawn area of some American houses. He says they help to show the importance of small patches of municipal woodland. “You know, a hedge matters, little bits of woodland at the end of schools and parks and community centres, they actually matter.”

As the morning comes to a close, Kinross gives the kids some free time. They cheer and head off to look at the ducks in the river. A couple of the students stay to tell me their thoughts about the day though.

“I liked getting mucky in the soil,” a boy named Jude tells me. “I learned that you have to measure the soil to see if it’s alright.”