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Hidakasanmyaku Erimo Tokachi NP, Hokkaido
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Mount Apoi is built from peridotite, rock from Earth’s mantle that normally lies tens of kilometres below us. A plate collision about 13 million years ago pushed this rare deep-Earth material to the surface here.
At just 810 m, Apoi supports about 80 alpine plant species, including nearly 20 endemic species, subspecies, varieties and forms. Thin, nutrient-poor peridotite soil, sea fog and scant winter snow help create this unusual habitat.
Apoi’s flower season stretches for months: little winter snow usually melts by mid-April, and alpine flowers begin blooming around early May. Different species take their turn, with blooms continuing into October.
The rare Hidakaso, one of Apoi’s signature flowers, was once called Tsushima-sō after its discoverer. It was later given a name celebrating the wider Hidaka region, though the plant itself grows only in the Apoi Mountains.
The Hime-chamadara skipper is found in Japan only around Mount Apoi. Adults can be seen for just a short time around May, and its caterpillars feed on Kinkobai, a plant growing in the area.
At Apoi’s foothills, Ezo pikas have been recorded as low as 50 m above sea level—the lowest confirmed elevation for the species in Hokkaido. These small, cold-adapted mammals are usually associated with rocky mountain terrain.
A Samani Ainu legend says that when deer were scarce, people climbed the mountain, lit a fire and prayed to the kamuy; afterward, deer became plentiful. The name Apoi is linked to ape-o-i, “a place with many fires.”
In local Ainu tradition, Apoi was called Matne-shir, or “female mountain,” and paired with nearby Pinneshiri, the “male mountain.” The names give the neighboring peaks the story of a mountain couple.
Samani’s Apoi Fire Festival began in 1971, inspired by the mountain’s Ainu deer-prayer legend. Its opening includes a prayer ceremony at Apoi’s foot, and the festival fire is carried from there to the celebration.
Apoi’s alpine plant community became a Natural Monument in 1939 and a Special Natural Monument in 1952. That rare national designation recognizes not just individual flowers, but the mountain’s distinctive plant community.
After large-scale flower theft in the 1990s, local residents formed the Apoi Fan Club in 1997. Members patrol for plant theft, teach children about conservation and help maintain trails; a restoration committee followed in 2005.
Even though illegal digging has almost stopped, Apoi’s alpine plant communities continue to decline. Dwarf pines and Kitagoyo pines are spreading into flower fields, but the reasons for the wider change have not been pinned down.
Apoi’s summit is covered by a forest of Japanese birch, even though the trail reaches a forest limit lower down. The local Geopark describes this unexpected treeline reversal as one of the mountain’s puzzles.
