A backyard in Tacoma, a healing forest on Yakama land, and a newly planted Miyawaki-style pocket forest in Attleboro, Massachusetts—show how a decades-old Japanese method has spread in the U.S. Yet researchers say many of the climate claims haven’t been backed
In Tacoma, Washington, Wendy Clapp has a small forest growing where Japanese knotweed once took over everything. For 25 years, she battled the aggressive, bamboo-like invasive plant that filled her yard. Then. in October 2024. she started planting native species close together—using the Miyawaki method—and watched her space change its story.
Her Miyawaki pocket forest is beginning in plain sight. A wooden gate leads to an understory of wild strawberries. ferns. and Pacific ninebark. while a big leaf maple stands not far from what Clapp calls her pride and joy: a paper birch. She says she kept imagining a different timeline—one where her Victorian home hadn’t been developed. and native plants would have surrounded it for centuries.
“What if Tacoma had never been developed?” she asked as she set out to build something closer to that earlier landscape.
The method is built for speed and density. Miyawaki-style planting involves putting native trees and vegetation close together so densely that. in some descriptions. 350 trees can fit in an area as small as six parking spaces. The plants compete for nutrients and sunlight, which proponents say forces quick growth. The pitch is that within 20 to 30 years a fully mature pocket forest can emerge.
That promise—of fast restoration, compact biodiversity, and resilient green space—has traveled far beyond individual backyards. Miyawaki forests now exist across the world, including India, Ireland, Brazil, and the United States.
In Washington’s Yakama Nation, that idea has taken on a different shape. The Yakama Nation planted a small forest at the Yakama Nation Corrections & Rehabilitation Facility six years ago. Marylee Jones. a gatherer and member of the Yakama Nation. described the meaning of learning from land that hasn’t been disturbed.
“We live in such a world right now, where we strive to learn about what [undisturbed land] looked like without knowing it,” Jones said. “When you do things like this, you’re setting up opportunities.”
Those opportunities include shade for visitors during hot summer months in the high desert. It is also a place to heal and to learn about traditional plants. Jones said time itself can feel different in a space like this.
“When you’re out here, you start to understand the value of sunshine, and you start to understand the value of not just the tick-tock of the clock, but of how many heartbeats you have in one day,” she said.
Farther east. in Attleboro. Massachusetts. the Miyawaki approach is being used with another goal: absorbing water where a hard-packed baseball field once stood. In May. 50-some volunteers gathered to plant a Miyawaki-style forest. turning the abandoned field into an area meant to absorb water during heavy rain.
The community is weighing what that means practically. Jamie Young, a junior at Clark University who helped plant the forest, said the effort could cool the area around it and act like a sponge for flooding water.
“This will cool the area that it surrounds and sponge the water that comes in from flooding,” Young said. “That’s a big deal in a place that has dealt with flooding, most recently in 2023.”
The method’s origins trace back to Japan. Akira Miyawaki, a late Japanese ecologist and botanist, developed the approach in the 1970s. He aimed to recreate lush native forests preserved in sacred areas near temples and shrines. He drew on what he called potential natural vegetation to select native species and then planted a variety of trees tightly together.
Miyawaki found that these forests competed for sunlight and nutrients in a way that could make them grow up to 10 times faster than if they had rooted on their own. Japanese law in the 1970s required industrial companies to have green areas on their sites to prevent pollution and disasters. Fumito Koike. a professor emeritus specializing in ecology at Yokohama National University. said Japanese companies asked Miyawaki to plant small. dense forests on their lands.
Miyawaki worked with companies. including Nippon Steel and Mitsubishi. and hosted workshops for employees on how to quickly turn barren land into rich. mature forests. His work spread quickly. Japanese multinational companies asked him to work on overseas sites. and Miyawaki—who died in 2021—led plantings in 15 different countries. including Malaysia and China. He claimed that restoring native forests is one of the best ways to prevent ecological disasters and improve carbon dioxide absorption.
Even so. the central question facing communities now is whether Miyawaki pocket forests can deliver on the climate promise—especially compared with less intensive options. Miyawaki wrote in his essay “A Call to Plant Trees” that creating indigenous. real forests and covering as much of the land as possible with forests is “the most certain and effective measure to reduce carbon dioxide.”.
But when researchers dig into the evidence, the picture is more complicated. Narkis Morales, who works at the Bioeconomy Science Institute in New Zealand, sifted through 51 published studies about the Miyawaki method. Morales found that many of the claims about the method haven’t been verified. He likened it to a placebo in a medical trial.
“Are you going to give someone a drug that perhaps is not going to have any effect on that person?” Morales asked.
Morales’ findings—published in the British Ecological Society’s Journal of Applied Ecology—suggest Miyawaki forests have not been as rigorously evaluated as other planting methods. The study concludes that most of the claimed benefits. including rapid growth. higher carbon sequestration. and increased tree density. don’t have enough research to back them up.
Cost is another issue communities can’t ignore. Morales, using available data, estimated that a Miyawaki project in the United Kingdom could cost $1.3 million per hectare. He contrasted that with a different method that supports existing natural vegetation rather than planting new trees. which costs. on average. $143 per hectare.
For cities trying to address climate issues, Morales said the math should push planners to look harder.
“Perhaps there are better options or ways to do it in a more efficient way,” he said.
At the same time, Morales did not dismiss the approach entirely. He said dense pocket forests can still bring positives, especially in hot urban environments.
“Any vegetational cover that you put in the city is going to have a positive effect, especially with heat,” Morales said. “People have a place to gather or sit or meditate, or kids can go there and play.”
Fazal Rashid. an ecological gardener working in India. also questioned the idea that Miyawaki-style planting can be treated as a universal solution. After trying it himself, Rashid said ecosystems vary and require different approaches. In an email to NPR. Rashid wrote that to effectively rewild a landscape. people need to test different planting tactics in small areas.
“Instead of reaching out for a supposedly universal one-size-fits-all insta-formula like the Miyawaki method. ” Rashid wrote. “we need to accept that rewilding is more about local people reconnecting with their local ecologies and beginning the slow process of restoring a relationship with each other and the land.”.
Those relationships—between plants, people, and ongoing care—are at the heart of why some communities keep going even as evidence debates continue.
In Attleboro. for example. high school and college students joined other community members to plant 550 native saplings in the once hard-packed soil of an old baseball field. John Rogan, a professor of geography at Clark University, helped plant the forest. He has studied how community engagement affects tree survivability.
“The best tree planting you could ever have is by people who are trained, who live in that street, and they have ownership of that tree,” Rogan said.
In other words, stewardship isn’t a side benefit. It’s part of whether trees make it.
That’s also what Clapp has been betting on in her Tacoma backyard. Community members showed up two years ago to help her plant her mini-forest. They gathered on her birthday for a planting party and celebrated later around a fire. Clapp continued adding more plants in recent years.
She says she’s seeing early results. The invasive Japanese knotweed that once dominated her yard is now getting crowded out by native plants.
“This is the first time I’ve seen real hope, where I see, like, we’re actually making a difference out here now,” Clapp said.
Backed by tradition, inspired by speed, and embraced by neighborhoods that want green relief, Miyawaki-style pocket forests are spreading. The tension is that while they can be transformative on the ground—cooling spaces. stabilizing soil. and building shared ownership—their role as a precise climate fix is still under debate.
Miyawaki method pocket forests climate solutions carbon sequestration Japanese knotweed native planting Yakama Nation Attleboro Tacoma urban heat ecological restoration