Jōmon Sugi

Where it sits. Jōmon Sugi stands at about 1,300 metres on the northern flank of Miyanoura-dake, the highest mountain on Yakushima and in the whole Kyushu region, deep inside the island's World Heritage core zone in Kagoshima Prefecture. There is no road to it and no view of it from anywhere else. The tree grows on a slope of granite boulders and thin acidic soil among other ancient cedars, wrapped in the near-permanent humidity that gives the island its four to ten metres of annual rainfall. It is the largest and probably the oldest of the yakusugi, the Japanese cedars of Yakushima that have passed a thousand years of age, and reaching it is a full mountain day rather than a sightseeing stop.

The tree itself. The measurements are the reason for the reputation: 25.3 metres tall, a trunk circumference of 16.4 metres, and a timber volume of roughly 300 cubic metres, which makes it the largest conifer in Japan. It does not look like a tall tree; it looks like a piece of geology that happens to be alive. The bole is lumpy, fused, scarred and burled, the bark grey and stone-like, and the crown is broken and irregular where centuries of typhoons have removed limbs. Age estimates vary wildly because the heartwood is hollow and cannot be cored cleanly. Ring dating on branch material established a firm floor of at least 2,000 years; published estimates run from about 2,170 years to as much as 7,200, and the commonly repeated figure of "over 3,000" is a convention rather than a measurement. The name refers to the Jōmon period of Japanese prehistory, on the assumption that the tree was already growing then.

Why it survived. Satsuma-domain foresters logged Yakushima's cedar intensively from the seventeenth century, mostly for roofing shingles, and commercial felling on the island continued until the late 1960s. Trees this size and this gnarled were spared largely because their twisted grain made them commercially useless — the same deformity that makes them photogenic made them worthless as timber. Jōmon Sugi was brought to national attention in the late 1960s, and the publicity did two things at once: it accelerated the campaign that ended logging and led to the island's protection, and it created the tourism industry that now accounts for more than half of Yakushima's economy. After the World Heritage inscription of 1993, the crowding around the tree became a conservation problem in itself, and access was pulled back to a wooden observation deck set roughly 15 metres away. Nobody touches the tree now. In 2005 vandals cut a piece of bark about ten centimetres square from the trunk, which hardened attitudes further.

The walk. The standard route is the Arakawa trail, and it is long: about 22 kilometres round trip and eight to ten hours of walking for a reasonably fit person, with roughly 700 metres of ascent. The first eight kilometres follow the trackbed of an abandoned 762-millimetre-gauge forestry railway, walking sleeper to sleeper on a raised timber way through the gorge, past the ruins of Kosugidani, a logging village that once held a school and hundreds of residents and was abandoned in 1970. The rail section is nearly flat and deceptively easy on the legs. Where the rails end, the real climb begins on a rough boulder-and-root path, passing:

• Wilson's Stump, the hollow remains of a cedar felled around 1586, named for the botanist Ernest Henry Wilson who surveyed it in 1914 — standing inside it and looking up frames a heart-shaped opening of sky
• Daiō Sugi, "the great king cedar", the second-largest tree on the route
• Meoto Sugi, two trunks fused by a horizontal branch

The longer Kusugawa route from the north is an alternative for experienced walkers. Most people start in darkness at around four in the morning and return in the late afternoon.

Practicalities that matter. Private vehicles are barred from the Arakawa road during the main season, roughly March to November, so the trailhead is reached by a mandatory shuttle bus from the Yakusugi Museum near Anbō, booked in advance, typically leaving before dawn. A modest mountain-use contribution is collected. There is one toilet block and a set of portable toilet tents on the route; carry-out bags are issued and expected to be used. Water is drawn from streams. There is no shelter on the exposed section and no phone signal for most of the way. Guides are not compulsory but a large majority of visitors hire one, and in poor weather the guiding companies are the ones who decide whether a party turns back.

Timing and weather. May and June are the wettest months, September brings typhoons, and the trail can hold snow and ice from December to March, when the shuttle stops running and the route becomes a genuine winter mountaineering objective. April, late October and November give the best odds of a dry day. Full waterproofs, gripped boots and a head torch are the minimum kit, regardless of the forecast.