The Sanbe Jomon Forest Museum, also known as the Sanbe Azukihara Buried Forest Park, is located in Sanbe Town, Oda City, Shimane Prefecture. It offers visitors a rare opportunity to experience a forest from the Jomon period, approximately 4,000 years ago, preserved underground almost exactly as it once stood.
The giant cedar trees were suddenly buried by an eruption of Mount Sanbe. Remarkably, many of the trees remain upright with their roots still firmly embedded in the ground. Their enormous trunks create a breathtaking sight and provide a vivid connection to Japan’s prehistoric natural environment.
The Sanbe Azukihara Buried Forest is designated as a Natural Monument of Japan and is also one of the cultural assets that make up the Japan Heritage story, “The Eternal History Told by the Volcanoes of Iwami.” It is a fascinating place where nature, geology, archaeology, and history come together.
The museum’s main attraction is its underground exhibition facility. The space makes use of a huge excavation pit approximately 30 meters in diameter and 13.5 meters deep, where the ancient forest remains preserved in the ground.
As you descend the stairs, it feels as though you are entering a forest from prehistoric Japan. Enormous trees stand before you with their roots still anchored in the ancient soil and their long trunks reaching upward.
Some of the giant cedars have root systems measuring nearly 10 meters around. Their remarkable scale offers a powerful sense of how large and rich the forests of the Jomon period could have been.
A buried forest is a prehistoric forest that was covered by geological deposits while still remaining close to the place where it originally grew. Such sites are sometimes described as “fossil forests.”
More than 30 buried forests have been identified in Japan, but in many cases only the bases or roots of trees remain. At Sanbe Azukihara, numerous giant trees have survived with their long trunks still standing upright, making the site exceptionally rare on a global scale.
The remarkable size and state of preservation of the trees also make the buried forest an important site for scientific research into the natural environment of prehistoric Japan.
The buried forest was created by volcanic activity at Mount Sanbe approximately 4,000 years ago. An eruption generated debris flows and pyroclastic flows that filled the valleys and rapidly covered the surrounding forest.
Normally, such powerful forces would knock down trees. At Azukihara, however, the flow weakened because of the local terrain, allowing many trees to remain standing as they were buried.
The trees were then covered by volcanic ash and sediment. Groundwater protected the buried wood from prolonged exposure to air, greatly slowing decomposition. The combination of these unusual geological conditions allowed the forest to survive for thousands of years.
The buried forest contains mainly cedars, which account for approximately 80 percent of the identified trees. Horse chestnuts, zelkova, and various oak species have also been found, revealing the diversity of the ancient forest.
Traces of fallen leaves and insects have also been discovered within the geological layers. These remains provide valuable clues about the ecosystem and climate of the Jomon period.
The site can therefore be viewed as a kind of time capsule of the ancient natural environment, preserving information that would otherwise have disappeared thousands of years ago.
The buried forest was discovered in 1983, when upright trees emerged from the ground during work to improve rice paddies. The discovery did not initially attract widespread attention, but later investigations by volcanologists revealed its remarkable scientific importance.
Full-scale excavation and research subsequently uncovered numerous buried trees. By 1998, research had confirmed that the forest dated to the Jomon period. In 2004, the Sanbe Azukihara Buried Forest was designated a Natural Monument of Japan.
The site was eventually developed as a museum where visitors can see these extraordinary remains while learning about the geological processes and history behind their preservation.
The museum offers guided tours by reservation, providing detailed explanations of how the buried forest was formed and how the excavation and research were carried out.
Exploring the site with a knowledgeable guide can make the enormous trees and surrounding geological layers even more meaningful, turning a sightseeing visit into an engaging learning experience.
The museum shop also sells wooden products made from excavated buried wood. These unique souvenirs offer a tangible reminder of a forest that has survived for thousands of years.
A separate Root Stock Exhibition Building provides another perspective on the buried forest. Here, visitors can closely examine enormous excavated tree root stocks.
After descending a spiral staircase, visitors encounter a massive root stock with distinctive shapes and visible growth rings. The rings provide a fascinating record of the tree’s growth and offer another way to appreciate the passage of time preserved within the forest.
The museum is approximately 70 minutes by car from JR Izumoshi Station and about 20 minutes from JR Oda-shi Station.
It is also approximately 20 minutes from the Ota Chuo-Sanbe Interchange on the San’in Expressway and about 35 minutes from the Nima-Iwami Ginzan Interchange.
From the nearest Chigobashi bus stop, the museum is approximately a 20-minute walk.
The Sanbe Jomon Forest Museum is much more than an ordinary tourist attraction. It is a place where visitors can experience the immense power of nature and the extraordinary passage of geological time.
Standing before giant cedar trees that once grew in Japan’s Jomon period creates a remarkable sense of connection with the distant past. The trees quietly reveal how nature can preserve traces of life for thousands of years under extraordinary circumstances.
Walking through the underground exhibition space feels almost like stepping beyond the boundaries of time and entering an ancient forest. For anyone interested in Japanese history, archaeology, geology, volcanoes, or nature, this remarkable site offers a memorable experience beneath the foothills of Mount Sanbe.