Yakushima

ForestsKagoshima,Japan

A Japanese island so wet its cedars grow at a crawl and live thousands of years, walked to along a logging railway through moss forest.

September·Edge of season

Aug–Sep

Hatchlings scramble to the sea from late July and the water is warmest, near 28°C for snorkelling. But this is the typhoon window, when a single storm can ground ferries and flights for days, and the heat and humidity peak.

Year-round The moss forest, the ancient cedars and the rain are here in every month; only the turtles and the summit snow keep a calendar.

Yakushima grows cedars that live for thousands of years, while the same species on the Japanese mainland seldom passes five hundred. The island is a granite dome south of Kyushu, its soil thin and poor, so the trees grow at a crawl: tight-grained, soaked in their own resin, all but rot-proof. Cedars past a thousand years old earn the name yakusugi. The greatest of them, Jomon Sugi, stands 25 metres tall and 16.4 metres around, and carbon dating has proved it at least 2,170 years old. Rain does the rest — 4,000 millimetres a year on the coast, up to 10,000 on the peaks, the wettest ground in Japan. Above the subtropical shore the land climbs to 1,936 metres at Miyanoura-dake, so one day's walk carries you from the plants of Okinawa to those of northern Japan. The place to feel it is Shiratani Unsuikyo, the mossy ravine Miyazaki's team scouted before making Princess Mononoke: mist between the trunks, cedar roots gripping wet granite, no sound but water. Boardwalks and the rails of an old logging line lead deeper in. From about 1640 islanders felled yakusugi and split them into roof shingles as tribute to the Satsuma domain. The walk to Jomon Sugi still follows that railway: 22 kilometres there and back, eight to ten hours, begun in the dark. Access is tightly held now: from March to November no private car may use the Arakawa forest road, so every hiker rides the shuttle and pays a conservation fee. On the north coast, Nagata Inakahama is the largest loggerhead nesting beach in the North Pacific, and on early-summer nights the turtles climb the sand to lay.

Worth knowing

Good to know

Private cars are barred from the Arakawa forest road from March to November — take the early shuttle from the Yakusugi Museum, buy the ticket a day ahead, and expect a mountain conservation fee.
Start the Jomon Sugi walk in the dark — it runs about 22 kilometres round trip and takes eight to ten hours, and the last shuttle down will not wait for slow walkers.
Assume rain on any day of the year and carry a real waterproof, because wet moss and cedar roots turn as slick as ice underfoot.
Turtle nights at Inakahama run on strict rules — join the local observation group rather than walking the beach alone, and leave the torch and the camera flash behind.
The rock pools at Hirauchi Kaichu Onsen only surface around low tide — check the tide table, bring your own towel, and know that the baths are open-air and clothing-free.

Things to do

1
Walk the old logging railway to Jomon Sugi
The trail to the island's greatest cedar begins on the rails that once carried its cut ancestors down to the coast, then leaves them for a hard climb through the mountain forest. Eight to ten hours of walking end at a viewing deck, where a trunk 16.4 metres around stands in front of you with a couple of thousand years behind it.
2
Find the moss ravine that became Princess Mononoke
Shiratani Unsuikyo is the valley Miyazaki's team came to study: granite boulders furred over with moss, stunted trunks leaning across the stream, mist filling the gaps between them. Come within an hour of rain, when the moss is soaked and the whole ravine glows a green that looks turned up too far.
3
Watch the cloud pour over the interior ridges
From the mountain road the island's green interior opens up, ridge behind ridge, with cloud sliding down over the tops almost continuously. This is the rain being made in front of you, and it is the closest most visitors come to seeing the shape of the whole island.
4
Wait on Inakahama for a loggerhead to come ashore
On early-summer nights the biggest loggerhead nesting beach in the North Pacific fills with turtles hauling up the dark sand to dig. Watching is done in small groups under red light, standing well back, listening to the sound of a half-metre of sand being thrown behind a heavy animal.
5
Step into the hollow of the Wilson Stump
A cedar felled more than four centuries ago left a stump big enough to walk into, with a spring running across its floor. Stand in the right corner, look up through the opening, and the sky comes through it in the shape of a heart.