admin | May 23, 2025
News Brief
As African cities grow into concrete jungles, Nairobi is restoring green spaces using the Miyawaki method—a dense, native tree planting technique developed in Japan in the 1970s. Kenya has planted over 236,000 seedlings since 2007 in sites like Karura and Ngong Road forests. Though costly due to high seedling density, the method promotes rapid growth and biodiversity. Samuel Kiboi is a researcher at the University of Nairobi. He says, “We study undisturbed nearby forests to determine the area’s natural vegetation.” The project also boosts local livelihoods through seedling supply and forest maintenance jobs.
Many African cities are now characterized by deafening traffic and suffocating emissions, becoming concrete jungles as urbanization squeezes out natural forests. In Nairobi, however, a unique restoration technique—the Miyawaki method—is helping reclaim lost ecosystems by creating dense, fast-growing forest islands in urban spaces.
Developed in the 1970s by Japanese botanist Akira Miyawaki, the method involves planting native tree species closely together on small plots of degraded land. The trees grow rapidly, forming dense canopies that mimic natural forests. Nairobi’s forest cover, for instance, declined from 14% to 3% between 1976 and 2000, while bushland dropped from 22% to 13%.
Since 2007, Kenya’s Miyawaki project has established mini forests at sites including the University of Nairobi, Ngong Road Forest, and Karura Forest, planting over 236,000 seedlings. These forests serve as carbon sinks, support biodiversity, and enhance water retention and biomass creation.
Samuel Kiboi, a researcher at the University of Nairobi, explains that while the method accelerates ecological restoration and requires less long-term maintenance, it also presents challenges. These include identifying appropriate native species, sourcing seeds, and managing high upfront costs. He says, “We study undisturbed nearby forests to determine the area’s potential natural vegetation,” and notes that this baseline data guides species selection.
Seedling availability can be limited since nurseries prioritize commercially popular species. High-density planting—up to 10,000 seedlings per hectare—also makes the method expensive, but Mr. Kiboi emphasizes that long-term benefits outweigh initial costs. Once mature, the dense canopy suppresses invasive species, reducing the need for maintenance.
Simon Kage, director of Integrated Forest Consultancy and Management Services, confirms that while Miyawaki requires more seedlings than typical reforestation (1,000–1,100 vs. 8,000–10,000 per hectare), maintenance costs drop dramatically over time.
The method also boosts local livelihoods. Joseph Kamau Machina, a Karura resident, shares: “I’ve supplied over 30,000 seedlings and now work maintaining the forest, including watering and replacing trees.”
This story is based on an article written by Dann Okoth for Mongabay, titled “Kenya’s cities adopt Miyawaki method to restore lost ecological glory.” To read the full story, go to: https://news.mongabay.com/2025/03/kenyas-cities-adopt-miyawaki-method-to-restore-lost-ecological-glory/
Photo: Loita forest in Kenya. Image by Rhett A. Butler / Mongabay.