What is the Miyawaki Method?
This method of afforestation was developed by botanist Doctor Akira Miyawaki. It emphasizes planting native climax species very densely together, resulting in diverse and healthy forests that differ from conventional monoculture plantations in several ways:
- Miyawaki forests grow 10x faster, becoming self-sufficient after only 2-3 years of maintenance.
- They are 30x denser, resulting in more carbon captured from the air, better filtration of water, decreased erosion, and improved protection from winds, storms, noise, and heat.
- They have high biodiversity and are therefore more resilient and provide better habitat for animals.
Miyawaki mini-forests are well suited to urban environments because they can be planted on sites as small as 3m2. They have been successfully planted all around the world, in a variety of climates.
How do I plant a Miyawaki mini-forest?
1. Species List
The first step to planting a mini-forest is to create a list of species to plant. The Miyawaki Method uses native plant species because they are the best adapted to the area. These are referred to as the “potential natural vegetation” (PNV) of the site.
The Miyawaki Method also emphasizes planting climax species. Climax species are generally larger, more shade-tolerant, longer-living, and slower-growing than the pioneer and early successional species that quickly grow on disturbed sites. By planting climax species, the Miyawaki Method bypasses the early stages of ecological succession, achieving a more mature and stable forest in a shorter amount of time.
A high variety of species should be selected, representing the four layers of the forest – canopy, subcanopy, shrubs, and mid-sized herb plants. The majority of the plants (70-80%) should be canopy and subcanopy species, leaving about 10% shrubs and the remainder mid-sized plants.
2. Amend the Soil
Climax species are adapted to crumbly soil that is rich in organic material. Soil on urban sites usually needs to be decompacted and amended before planting to increase its softness, fertility, and water retention.
The soil should be loosened to a depth of 30cm – 1m and mixed with the appropriate amendments. The soil should be tested to determine what types and amounts of amendments need to be added. A simple soil “ribbon” test can be performed by hand to determine the soil texture, though further lab testing may be necessary to determine the soil fertility.
In rainy areas, the soil is heaped into low planting mounds of about 100m2 to prevent water from pooling. Round planting mounds are ideal in windy locations because they maximize the amount of sheltered, interior area. About 1m of distance is left between the mounds to allow for maintenance.
Planting should generally take place in the spring or fall. Plants are densely clustered at about 3-5 per m2 and distributed so that species belonging to the same layer are not next to each other.
After planting, the area is heavily mulched to mimic the layer of fallen leaves on a forest floor. The mulch will increase the water retention of the soil and protect it from frost. Within each planting mound, a 1m strip of prepared soil is left unplanted but well mulched. This is planted 8-10 months later with “fringe” species that naturally occur on the edges of forests.
Consistent watering and weeding will improve the survival rate of seedlings. After 2-3 years of maintenance, the mini-forest will retain enough moisture on its own to be self-sufficient, and the canopy will have filled in enough that sunlight no longer reaches the forest floor and sustains weeds.
Planting a Miyawaki mini-forest in the Pacific Northwest
At our reforestation site, we are attempting to recreate a forest typical of the Coastal Western Hemlock Zone (CWH). The CWH is one of the zones described by the British Columbia Ministry of Forests’ biogeoclimatic ecosystem classification system, reaching from low to mid elevations along the B.C. coast and down through Washington and Oregon. The main species found in the CWH are western hemlock, Douglas-fir (particularly on drier sites and secondary growth sites), and western red cedar. Other common species include grand fir, red alder, bigleaf maple, oceanspray, salal, Pacific rhododendron, Oregon grape, and western sword fern.
The following resources were helpful in identifying the potential natural vegetation for our site:
- Natural Vegetation of OR and WA
- North Pacific Maritime Douglas-fir - Western Hemlock Rainforest
- Coastal Western Hemlock Zone - by J. Pojar, K. Klinka, and D.A. Demarchi
- Coastal Western Hemlock Zone - UBC
Miyawaki Method Resources
- Mini-Forest Revolution – this book provides an in-depth discussion of the methods and benefits of planting Miyawaki mini-forests, including case studies of mini-forest planting projects and a step-by-step walkthrough of how to plan, plant, and maintain a mini-forest
- The Miyawaki Method for Creating Forests
- SUGi’s network of “forest makers” has planted pocket forests in urban spaces all around the world. This site provides an overview of the principles, benefits, and basic stages of the Miyawaki Method; along with examples of Miyawaki mini-forests planted by SUGi’s partners.
- Afforestt is a company based out of India that plants mini-forests using the Miyawaki Method. They offer a series of free video tutorials with detailed instructions for planting mini-forests
- Forest Creation Tutorials
- TED Talk by Shubhendu Sharma, the founder and director of Afforestt.