A Wild Maple That Survived the Ice Ages
In a spring-fed wetland at the foot of Mount Chausu, in the mountain village of Toyone in northeastern Aichi Prefecture, a small grove of maples turns red twice a year. For a week or two at winter's end, the bare branches fill with tiny crimson flowers before a single leaf has opened. By late autumn the same trees burn deep scarlet again, this time with their foliage. These are hananoki, the Japanese red maple, and the Kawaure colony is the only place in Aichi where they grow in the wild.
The grove sits within the precincts of Kawaure Shrine. Cold groundwater seeps across the gentle slope and keeps the soil saturated, so sphagnum moss and other bog plants cover the ground between the trunks. About a dozen mature trees grow here, mixed in with ordinary woodland species. The largest measures roughly 3.5 meters around at chest height and rises some 25 meters, and several others exceed 2 meters in girth. The site was placed under national protection on 12 October 1922.
One of Three Survivors
The hananoki (Acer pycnanthum) grows nowhere on Earth except Japan. It belongs to a small lineage of maples, the section Rubra, that once spread across the high latitudes of the Northern Hemisphere during the warm Tertiary period. Repeated ice ages erased most of that group. Three members came through: the red maple and silver maple of eastern North America, and the hananoki of Japan. Its two American cousins are common trees across a whole continent. The Japanese species clings on in a handful of relict bogs, a living link to a forest world that has otherwise disappeared.
Within Japan its range is tiny. Most wild trees grow inside a radius of about 50 kilometers around Mount Ena, on the Gifu and Nagano border, with scattered colonies reaching into northeastern Aichi. Botanists count it among the "Tokai hilly-land elements," relict plants confined to spring-fed lowland bogs in this corner of central Japan. The grove was designated under two of the criteria in Japan's natural-monument system: it marks a striking edge of a plant's distribution, and it shelters a rare and threatened species. The hananoki now appears as Vulnerable on the national Red List, its wetlands shrinking as land is drained and developed.
Two Seasons of Red
The flowering is brief and easy to miss. For a fortnight at the close of winter, before the surrounding forest shows any green, the crowns of the hananoki glow red from a distance. The species is dioecious: male and female flowers grow on separate trees. Both are small and crimson, the male flowers held upright on short stalks, the female ones hanging from longer threads that later carry winged seeds. Those seeds ripen and fall in late May, an oddity among maples, which usually scatter their seeds in autumn.
The autumn display is the better known of the two. From late October the leaves shift through yellow into a fierce scarlet that local people say outdoes even the spring bloom. Walk the shrine grounds slowly and look up. The same trees that flowered on bare wood in March now stand fully clothed in red.
A story clings to the grove. The shrine once honored Prince Yukiyoshi, a grandson of Emperor Go-Daigo who, by tradition, took refuge in these mountains during the wars between the Northern and Southern Courts in the fourteenth century. Local legend holds that a chopstick he planted after a meal took root and grew into the first hananoki. The prince survives in tradition rather than in the official imperial record, and a statue of him still stands beside the trees.
Around the Grove
The grove lies at the foot of Mount Chausu, which at 1,415 meters is the highest peak in Aichi and sits on the boundary with Nagano. The highland resort on its upper slopes draws visitors for carpets of moss phlox in early summer and for skiing in winter. Toyone itself is one of the least populous villages in Japan, ringed by clear streams and deep forest.
The site is remote. Public transport is sparse this close to the Nagano border, so a car is the practical way to reach it. There is no ticket gate; the trees grow on open shrine ground and can be seen at any time, though the rewarding moments are the brief spring flowering and the long autumn color.
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Q&A
- When is the best time to visit?
- There are two windows. Late March to early April brings red flowers on the bare branches, and late October to mid-November brings the autumn color. The autumn display is generally considered the more striking of the two.
- Where exactly is the grove?
- It lies within the precincts of Kawaure Shrine in Toyone Village, at the foot of Mount Chausu. There is no admission gate; the trees grow on open shrine ground.
- How do I get there?
- A car is essentially required. The village sits in remote northeastern Aichi near the Nagano border, with very limited public transport.
- What makes the hananoki different from other maples?
- It is endemic to Japan, has male and female flowers on separate trees, flowers before its leaves open, and drops its seeds in early summer rather than autumn. It is one of only three surviving species in its maple lineage worldwide.
- Can I see hananoki anywhere else?
- Yes. Other protected colonies survive in Gifu, Nagano and Shiga, and the tree is widely planted in parks and gardens as Aichi's official prefectural tree. Kawaure, though, is the only wild stand in Aichi.
Basic Information
| Name | Kawaure Hananoki Natural Habitat (Kawaure Hananoki Jiseichi) |
|---|---|
| Location | Kawaure Shrine precincts, Toyone Village, Kitashitara District, Aichi Prefecture (at the foot of Mount Chausu) |
| Designation | National Natural Monument |
| Date designated | 12 October 1922 (Taisho 11) |
| Criteria | Notable limit of a plant's distribution; habitat of a rare or threatened species |
| Species | Hananoki, the Japanese red maple (Acer pycnanthum), genus Acer |
| Scale | About a dozen mature trees; the largest roughly 3.5 m in girth at chest height and about 25 m tall |
| Managing body | Toyone Village |
| Viewing | Open shrine ground, accessible year-round; best in the spring flowering and the autumn color |
References
- National Database of Designated Cultural Properties, Agency for Cultural Affairs
- https://kunishitei.bunka.go.jp/bsys/maindetails/401/1406
- Aichi Prefecture Cultural Property Navigator
- https://www.pref.aichi.jp/kyoiku/bunka/bunkazainavi/kinenbutu/tennen/kunisitei/0935.html
- Toyone Village Official Site (Hananoki Habitat)
- https://www.vill.toyone.aichi.jp/soshiki/kyoiku/31.html
- Forestry and Forest Products Research Institute, Conservation of Acer pycnanthum
- https://www.ffpri.go.jp/labs/raretree/12_APindex.html
- Okumikawa Tourism Navi (Prince Yukiyoshi and Kawaure Shrine)
- https://www.okuminavi.jp/search/detail.php?id=128
Last verified: 2026.06.14