Ueno Narahara Shioji Forest is a nationally designated Natural Conservation Area in Narahara, Ueno Village, Tano District, Gunma Prefecture. Located along the Kitazawa Stream, a tributary in the upper reaches of the Kanna River, the forest preserves a remarkably natural stand of shioji ash trees. It is considered one of Japan’s most valuable remaining examples of this type of forest ecosystem.
Natural Conservation Areas are a special category among Japan’s nationally designated natural monuments. They are designated as representative areas containing particularly valuable natural features that require protection. Only 23 such areas have been designated throughout Japan. Ueno Narahara Shioji Forest was designated on July 25, 1969, and is one of the few Natural Conservation Areas remaining in the inland part of Honshu.
Of Japan’s 23 Natural Conservation Areas, only four are located in the Kanto region. Two are on islands belonging to Tokyo, while on the main island of Honshu, only Oze and Ueno Narahara Shioji Forest have this designation.
The survival of such an extensive, relatively undisturbed forest deep in the Kanto Mountains is therefore particularly significant. The area provides an exceptional opportunity to experience a natural mountain environment that has remained largely unchanged for centuries.
Shioji ash (Fraxinus platypoda) is a deciduous broadleaf tree belonging to the ash family. It is mainly found along mountain streams on the Pacific side of Honshu, Shikoku, and Kyushu, generally at elevations of around 400 to 1,700 meters.
It is a characteristic tree of riparian forests, which develop along waterways in mountainous areas. Shioji ash trees have tall, straight trunks and attractive wood grain, making the timber valuable for furniture, interior fittings, and other woodworking applications. It has also traditionally been regarded as a high-quality material for doors.
Because of its usefulness as a timber tree, many shioji forests throughout Japan were harvested, and almost all extensive pure stands disappeared. In contrast, the forest at Ueno Narahara is said to have remained uncut since the Hōreki era in the mid-18th century, allowing its natural character to survive.
The Natural Conservation Area extends from approximately 920 to 1,680 meters above sea level. Around Hosoozawa in the upper reaches of the Kitazawa Stream, a particularly rare pure stand of shioji ash can be found.
Some trees reach heights of more than 35 to 40 meters, forming an impressive canopy over the valley. Alongside the shioji ash are other deciduous broadleaf trees, including Japanese wingnut, Japanese horse chestnut, painted maple, and katsura.
The forest floor is home to plants such as deep-mountain nettle, Deinanthe bifida, and various ferns. The combination of clear mountain water, rocky streambeds, towering trees, and abundant vegetation creates an atmosphere of profound tranquility.
The surrounding ecosystem is also home to Japanese serow and a wide variety of wild birds, demonstrating the richness of both the plant and animal life preserved within the forest.
There is no road leading directly into the Shioji Forest. Visitors must walk along a mountain trail following the Kitazawa Stream. The trail begins near Shioji-no-Yu, a village-operated hot spring facility in Ueno Village.
The distance is approximately 5 km one way, making the round trip more than 10 km. Allow around six hours for the round trip. This is a demanding hiking route rather than a casual sightseeing trail, so appropriate footwear, clothing, food, water, and preparation are essential.
The trail follows the clear mountain stream, allowing hikers to experience the changing scenery of the forest throughout the seasons. In spring and early summer, fresh green foliage covers the valley, while autumn brings brilliant colors to the surrounding mountains.
In recent years, increasing numbers of Japanese deer have been observed around Ueno Village, and damage caused by deer feeding on young shioji trees has become a concern. In particular, the decline of young trees that will form the next generation of the forest is an important conservation issue.
The decline of vegetation on the forest floor has also been reported. To preserve this valuable ecosystem for future generations, local authorities and related organizations have been considering and implementing measures such as deer population management and protective fencing.
Narahara, Ueno Village, Tano District, Gunma Prefecture, Japan
From Shimonita Station on the Joshin Electric Railway Joshin Line, take the Ueno Village shared taxi service to the final stop, Ueno-mura Fureai-kan. The journey takes approximately 65 minutes.
From the Shimonita IC on the Joshinetsu Expressway, take Gunma Prefectural Route 45 toward Ueno Village via the Yunosawa Tunnel. The journey is approximately 30 km and takes around 35 minutes by car. From the parking area at Shioji-no-Yu, enter the mountain trail leading toward the forest.
Ueno Narahara Shioji Forest is an ancient mountain forest preserved deep within a quiet valley. Towering trees that have grown for hundreds of years in an environment largely untouched by human development offer visitors a powerful reminder of the scale, resilience, and value of Japan’s natural heritage.
The forest is not an easy place to reach, but the effort is part of the experience. For hikers and nature enthusiasts seeking a deeper encounter with the mountains of Gunma, the journey offers an opportunity to walk beside a pristine mountain stream and experience one of the region’s most precious protected forests.