Mount Apoi was added to Your Favorites!
Hidakasanmyaku Erimo Tokachi NP, Hokkaido
Claim this place to tell your story your way.
Mount Apoi is built from peridotite, rock usually hidden deep beneath Earth’s crust. A tectonic collision about 13 million years ago pushed this mantle material upward, creating a rare window into Earth’s interior.
At only 810 m, Mount Apoi supports about 80 alpine plant species, including nearly 20 endemic forms. Its remarkable plant community became a Special Natural Monument in 1952.
Peridotite makes challenging soil: it is thin, dry, and poor in nutrients, with abundant magnesium and nickel. These conditions discourage conifer forest and leave room for Apoi’s specialist plants.
Snow usually fades by mid-April, and flowers begin opening in early May. Different species take turns blooming into October, giving Mount Apoi an alpine-flower season of almost 6 months.
Apoi-kanba grows only on this mountain and reaches just about 1 m. DNA research traces this unusual dwarf birch to a cross between wetland and mountain birches as the climate warmed 8,000–10,000 years ago.
Found on Apoi by university students in 1973, this skipper is Japan’s only population; elsewhere it ranges across Europe, Siberia, and northeast China. Adults appear around May; it became a Natural Monument in 1975.
Apoi-maimai, a snail about 1 cm across, lives in crevices among the peridotite rocks of the Apoi massif and nearby Horoman River. It was described as a new species in 1970.
In the Horoman River valley beside the Apoi massif, pika have been recorded at just 50 m above sea level—the lowest known habitat for them in Hokkaido, despite their usual association with rocky mountain slopes.
A Samani Ainu legend links Apoi’s name to a summit fire lit while praying for deer. Since 1971, the town’s Apoi Fire Festival has echoed the story with a fire-lighting ceremony at the mountain’s foot.
One Ainu tradition called Apoi Mattne-shiri, the “female mountain,” paired as wife with nearby Pinneshiri, the “male mountain.” The names preserve a local way of seeing the two peaks as a couple.
Heavy plant poaching in the 1990s badly damaged Apoi’s meadows. Local residents formed the Apoi-dake Fan Club in 1997; its work includes patrols and experiments to help restore the rare alpine plant community.
The rare white flower Hidaka-sō bears the name of the broader Hidaka region, not just Mount Apoi. It was once called Tsushima-sō after its discoverer, Masao Tsushima.
