UN 
The Miyawaki method, a popular approach to urban reforestation that involves planting dense clusters of native tree species to create rapidly growing “mini-forests,” has come under scientific scrutiny. A recent study highlights the lack of empirical evidence supporting many of the method’s claimed ecological benefits, raising important questions about its scalability and long-term impact. Widely promoted as a way to enhance biodiversity and sequester carbon quickly in cities, the Miyawaki technique involves preparing soil and planting saplings at high densities, which proponents say leads to accelerated growth.
However, researchers caution that the dense planting may cause intense competition among young trees for sunlight, potentially undermining growth rates and forest health over time. The study, which analyzed multiple Miyawaki reforestation projects, found insufficient data to conclusively demonstrate the method’s superiority over conventional afforestation techniques. Soil preparation is also not standardized, which could affect outcomes and reproducibility.
Experts emphasize the importance of rigorous monitoring and long-term ecological assessments to verify claims about rapid biomass accumulation and biodiversity gains. While Miyawaki forests have become a popular tool for urban greening initiatives worldwide, especially in space-constrained environments, this new evidence suggests that policymakers and practitioners should temper expectations and consider integrating multiple approaches tailored to local ecological conditions.
The findings underscore the broader challenge of balancing innovative nature-based solutions with scientific validation in efforts to meet Sustainable Development Goals related to climate action, sustainable cities, and life on land. As urban areas continue to seek effective reforestation strategies to mitigate environmental degradation and enhance human well-being, transparent evaluation frameworks will be critical to identifying best practices that deliver measurable benefits.
