https://www.euronews.com/green/2024/12/29/the-japanese-micro-forest-method-is-transforming-cities
The Japanese ‘micro-forest’ method is transforming cities
"More than 420 million hectares of forest have been lost to other uses since 1990, according to the UN’s 2020 State of the World’s Forests Report.
With more than 85 per cent of the global population living in urban areas, micro-forests in cities offer an essential opportunity to combat deforestation.
The Miyawaki Forest Technique, invented by Japanese botanist and plant ecology expert Professor Akira Miyawaki in the 1970s, is the inspiration for micro-forests worldwide.
These diverse, organic small forests can be created on sites as small as nine square metres, and only use native species that would otherwise grow naturally in the planting area. They grow up to 10 times faster than monoculture forests, in just two to three decades.
Since Miyawaki’s work began, more than 280 micro-forests have been planted."
...
"In polluted urban areas, micro-forests can help to restore soil, water and air quality, according to the Woodland Trust.
Their small size allows plantation in relatively limited urban space, often taking advantage of unused spaces such as school playgrounds, cemeteries, and near metro stations. They can also help to reduce the impact of heavy rainfall, and to keep towns and cities cooler.
Micro-forests can create more habitats for wildlife in cities, such as blackbirds or hedgehogs. When planted in distinct layers, they can also develop plant communities of smaller shrubs and herbs, which allow the micro-forests to become self-sustaining after just three to five years of growth.
“Our pocket forests offer a myriad of benefits” says Elise Van Middelem, Founder and CEO of SUGi.
“Perhaps most importantly, they can support the positive well-being of communities. From a psychological perspective, interacting with nature reduces physical stress and can improve symptoms of mental ill health, including anxiety or depression.”
The link provided doesn't really go over the method, so I looked into it a bit more. The key is planting a bunch of native trees close together. Like, 2ft tall trees, 2 ft apart. The overall garden can be just 3ftx3ft, any is fine really. By planting the trees close together, they grow upwards faster (rather than out sideways). Additionally, they make sure to prepare/improve the soil in advance to hold lots of water, and to apply lots of mulch over the top. You water it tons and weed it in the first two years or so, then it goes on by itself without maintenance.
The more diversity in native trees you can plant, the better. I think this @jstor blog post on the jstor website has a nice overview and some info on how the technique is being utilized around the world: https://daily.jstor.org/the-miyawaki-method-a-better-way-to-build-forests/
