The method involves planting two to four trees per square meter. Miyawaki's forests grow in two to three years and are self-sufficient. They help lower temperatures in concrete heat islands, reduce air pollution and noise, attract local birds and insects, and create carbon sinks. A Miyawaki forest planted by urban forests grows a minimum of 1 meter each year, without chemicals or synthetic fertilizers.
Miyawaki identified potential natural vegetation in the area and studied the forests surrounding two nearby tombs (Usa and Yusuhara). Miyawaki also contributed to massive reforestation in China by his government and Chinese citizens in Pudong, Qingdao, Ningbo and Ma'anshan. Akira Miyawaki (, Miyawaki Akira, January 29, 1928 - July 16, 2002) was a Japanese botanist and expert in plant ecology specializing in seeds and natural forests. There was also a distinct stratification in forest structure, with slow-growing canopy species, tree layer species, smaller subarboreal layer species, shrubs and grasses covering the ground.
Whether cultivated in public or private spaces, the establishment of Miyawaki forests could be part of this solution. In 1998, Miyawaki piloted a Quercus mongolica dominated reforestation program along the Great Wall of China, and gathered 4,000 people to plant 400,000 trees, with support from the Aeon Environment Foundation and the city of Beijing. Research by the University of Wageningen in the Netherlands, which found an increase in fungi, bacteria, pollinators and amphibians in two small forest sites planted in urban Zaanstad based on Sharma models, gives scientific credit to this claim. These forest fragments were composed of trees such as Japanese blue oak (Quercus glauca), Japanese chestnut (Castanea crenata) and sakaki (Cleyera japonica), rather than coniferous trees such as larch (Larix kaempferi) and Japanese cedar (Cryptomeria japonica), which had been introduced from other areas and dominated forests locals.
This creates a resilient and thriving forest ecosystem with species that complement each other, restoring “native forests” with native trees. From that manual, an aspiring forester learns how to determine soil type using the “tape test”; how to collaborate with a local nursery to find truly native species; how to prepare the planting site; and how to organize young trees, three to four per square meter, in a grid. Urban forests reduce local temperatures (-1.3°C in a study), improve air quality by reducing pollutants, sequestering carbon and improving residents' well-being, as well as creating a natural oasis for invertebrates and birds. Over a period of two to three years, the site is monitored, watered and weeded, to give the nascent forest a chance to settle.
As a young graduate student in the late 1950s, Akira Miyawaki learned about the emerging concept of potential natural vegetation (PNV). The Miyawaki Forest planting method, named after the botanist who developed it, encourages tree communities to grow upwards and share resources, while the dense structure deters humans.