The Miyawaki planting method developed in Japan in the 1970’s has finally found its way to the UK. Will this be the key to helping restore our woodlands?
Since 2020, research has been put into the value and effectiveness of The Miyawaki method across the UK. This Japanese woodland creation technique developed by Dr. Akira Miyawaki aims to rapidly restore poor land and create self-sustaining ecosystems and quickly. Until a week ago, when I came across a research paper and then a book in the studio, I had never heard of this method nor its wild success. Since then, I’ve taken a deep dive into what it is, how it works and how successful it really is.
Who was Dr Akira Miyawaki?
Dr. Akira Miyawaki was a renowned Japanese botanist and an expert in plant ecology. His true passion was for restoring natural forests and was an active worldwide specialist in natural vegetation restoration of degraded land. He began developing his unique planting method in the 1970’s and from that point instructed people on planting in over 1,700 areas around the world. In total, it’s estimated that he was involved in the planting of over 40 million native trees. His legacy continues to inspire environmental restoration efforts worldwide.
Big in Japan
By the year 2000, approximately 550 Miyawaki forests had been planted throughout Japan, ranging from schoolyards and roadsides to industrial sites and disaster-prone coastal areas. The previous decades had seen a large uptake of this method due to its initial success in the 70’s thanks to Nippon Steel.
The large-scale implementation within Japan with Nippon Steel is an absolute stand-out example of how well this method of planting can work. Starting in 1971, Nippon Steel’s ‘Creation of Hometown Forests’ project gave Miyawaki his first chance to show the country, and ultimately the world, the good work his prior research had led to. By 2022, the initiative had restored around 830 to 840 hectares of native forest. Forests on factory grounds and surrounding areas using the Miyawaki method not only reached impressive heights at a fast rate but also recreated multi-layered ecosystems typical of Japan’s natural vegetation.
In terms of growth performance, Miyawaki forests in Japan demonstrate extraordinarily fast development compared to conventional reforestation techniques. Saplings planted at around 30cm can grow to 7 metres in height within just 10 years and over 10 metres by year 15. Beyond growth, these forests also deliver significant biodiversity and ecological benefits. They’re composed entirely of native species, chosen based on region, and over time develop into self-sustaining ecosystems.
How it Works
Preparation: The site is prepared, often with enriched soil, which may involve adding compost and fertiliser.
Native Species Selection: A variety of tree and shrub species that are native to the area are selected. Observations are done within the nearby woodlands and shrublands and create an accurate selection of plants that would naturally grow.
Dense, Layered Planting: Saplings are planted densely – far denser than a normal planted woodland – with multiple layers of canopy plants included from the start, mimicking the structure of a natural forest. This close proximity of the plants encourages competition for light, water and nutrients, just as it would in a natural situation. This healthy competition is exactly what promotes faster and stronger growth throughout the saplings.
Maintenance: After planting, the site is mulched to retain moisture and improve soil fertility. The forest is maintained with watering and weeding for the first two or three years. After this, it is intended to become self-sustaining.
Natural England – a study
After decades of success in Japan and in other countries across the world, the UK has finally been looking towards the Miyawaki method. Natural England has been the frontrunners in creating trials, developing their Trees Outside Woodland programme to include new innovative and sustainable new ways to increase tree cover, addressing both climate and ecological emergencies. As part of the experimental process, 16 urban Miyawaki method plots were created. These were arranged adjacent to comparison plots, using standard local authority planting methods across four English local authorities. Interestingly, Natural England took a look at old data and chose sites with a record of planting failure.
It was ensured that both the Miyawaki and comparison plots were treated equally. Tree whips comprising of the same species mix from the same nurseries were used and they were maintained equally through the first three years.
Research findings
The past few years of growth of the Miyawaki method against standard planting has been monitored. It’s now clear that the Miyawaki method provides much higher survival rates, especially under adverse conditions such as poor soil quality or urban sites. One example from Natural England is 79% success of Miyawaki vs 47% standard planting. Not only is general success rate higher but this method creates faster growth. This is due to the dense planting and element of competition seen in natural ecosystems.
Creating new woodlands is a fairly expensive feat. Despite there being obvious ecological benefits, organisations of course want to know if the cost can be justified. The denser planting method of Miyawaki has a far greater upfront cost however the cost per surviving tree works out far lower as many more trees survive to maturity. The average median cost of the Miyawaki method was £10 per surviving tree, against £50 for standard practice planting methods.
In the UK, success isn’t just measured by tree survival, but the biodiversity and ecological benefits. The mix of native and regional trees and shrubs create a layered woodland and diverse ecosystem. This encourages early wildlife use and an ideal habitat for species which may otherwise be struggling.
In our own work
As someone fairly new to White Mosaic, I was unaware that a previous design project had used the Miyawaki method. Taking a look through the design archives, I’ve found an except from a document dating back to 2020. This was just when a number of the previously mentioned Miyawaki schemes started in the UK.
“Using the Miyawaki Method we can renature sections of the land using trees planted at close density 3 – 4 saplings per metre. Using acorns, seeds and cuttings collected from the existing woodland and grown on in our glasshouse we can renature the land in a site specific way. It will take 3 years for the woodland to mature and block out existing ground plant competition and will become relatively maintenance free and rich in wildlife. During this period dead and damaged trees from our woodland are kept onsite to further enhance biodiversity with larger branched deadwood being used to repair fences hedgerows and section the woodland from the restored hay meadow.”
Ecology is always at the forefront of our minds in any project. We are inspired by pioneers such as Dr Akira Miyawaki every day to strive for more sustainable and environment-kind methods.
The future is uncertain
Since the experimental plots within the UK are recent, the forest’s long‐term survival and ecological stability are still unproven. The Miyawaki method was originally developed in temperate climates such as Japan followed by trial sites in Oceania and Asia. Because of this, there have been some necessary adaptions for UK conditions. Adaptations in soil preparation, species and density may all affect the overall success of the projects within the UK. Although early signs are promising and studies show high success rates, only time will tell in this country. These projects may well prove revolutionary, and I’ll certainly be watching to find out.
Resources:
https://eprints.whiterose.ac.uk/id/eprint/218777
https://naturalengland.blog.gov.uk/2024/09/19/testing-the-miyawaki-method-in-our-urban-greenspaces/
https://www.chichester.gov.uk/article/39565/Unique-Miyawaki-style-tree-planting-project-completed-in-Chichester
https://www.bbc.co.uk/news/articles/cr426z3zw34o
https://www.norfolk.gov.uk/article/39511/Miyawaki-mini-forests
https://treecouncil.org.uk/the-tree-council-shares-insights-into-miyawaki-planting-in-partnership-with-kent-county-council/