An Unusual Sight from Above
High in the mountains of Nichinan, Miyazaki Prefecture, an aerial view reveals an extraordinary pattern — concentric circles of tall Obi cedar trees forming a spiral-like design.
While the arrangement has inspired curiosity and speculation, its origin is entirely documented and the result of a long-running forestry study.
Planting for Science
In 1973, the local forestry agency initiated a controlled experiment to measure the effects of tree spacing on growth. The chosen species was Obi cedar, a regional variety valued for its timber.
Foresters planted 720 trees in ten concentric rings, beginning with a tight cluster in the center and gradually increasing the distance between each ring. This design allowed different planting densities to be compared in a single location, providing decades of consistent data.
From Research to Recognition
The project was intended to run for many years, with the trees scheduled to be harvested in 2011. However, when aerial and drone images revealed the striking geometric formation, the site drew public attention.
The planned felling was postponed, and the experiment was extended through 2023 to allow further study and continued monitoring of growth differences between the inner and outer rings.
A Living Experiment
Today, the Spiral Forest remains both a functional research site and an object of visual fascination. The inner rings, planted more densely, show variations in height and trunk width compared to the more widely spaced trees in the outer rings.
Although it was never designed as a tourist attraction, it now draws interest from photographers, drone operators, and forestry experts. The formation provides not only a unique aerial view but also valuable insights into how planting density influences the long-term development of commercial timber species.
Aerial views above Nichinan, Miyazaki, Japan reveal concentric rings of trees on a mountainside.
The pattern is a documented forestry experiment begun in 1973.
It tested Obi cedar growth in controlled circles and remained in place for decades…🧵👇 pic.twitter.com/rNNiHNkwyT
— Fascinating True Stories (@FascinatingTrue) August 9, 2025