Overview
The Miyawaki method of reforestation, developed by Japanese botanist Akira Miyawaki in the 1970s, is gaining traction in the United States as a practical approach to creating dense, fast-growing forests on small urban and agricultural plots. The technique involves planting a diverse mix of native species in close proximity — typically 3 to 5 trees per square meter — on prepared soil, then mulching heavily. The resulting competition for light, water, and nutrients accelerates growth, producing a mature-looking forest in 20 to 30 years instead of the 50 to 100 years typical of conventional reforestation.
How it works
The method starts with identifying the "potential natural vegetation" — the tree, shrub, and herbaceous species that would naturally occupy a site without human intervention. Soil is decompacted and aerated, then amended with organic matter. Seedlings are planted densely, often 20 to 30 species per site, and covered with a thick layer of mulch (e.g., leaf litter). The dense planting ensures that some trees will die, but that mortality feeds the survivors. No chemical fertilizers or pesticides are used; the forest is designed to be self-sustaining after the first two to three years of watering and weeding.
Real-world examples
Horn Farm Center for Agricultural Education (York, Pennsylvania) planted what it believes was the first Miyawaki-style forest in the Eastern U.S. in 2019 — over 500 native trees in a 12-foot-wide, 100-foot-long strip along Route 30. Six years later, the overstory of oaks, hickories, and sycamores stands nearly 30 feet tall, with understory species including redbuds, dogwoods, elderberry, and viburnum. The forest now serves as a noise and pollution buffer, a biodiversity haven, and a flood-control sponge.
Ascot Hills Park (Los Angeles) features a 10,000-square-foot forest with 850 native plants, planted in 2021. Applied ecologist Demian Willette of Loyola Marymount University reports an 89 percent plant survival rate after two years, 51 percent more biodiversity than a control plot, and roughly one ton of carbon sequestered. He projects 55 tons of annual carbon sequestration in 20 years.
Griffith Park (Los Angeles) hosted a 1,000-square-foot pilot forest planted in 2021 by horticulturalist Katherine Pakradouni.
Costs and tradeoffs
An average micro forest costs around $25,000, according to Ethan Bryson of Natural Urban Forests, an Afforestt partner. The Ascot