Yakushima, the Island That Invented Forest Bathing

It rains on Yakushima, the islanders say, thirty-five days a month. The joke is old and nobody laughs at it anymore, but it is not really a joke. Parts of the island receive close to ten metres of rain a year. The moss does not so much grow as accumulate. It lies on the rocks in pillows, climbs the trunks, drips from the branches, and softens every edge until the forest looks less like a place than a green weather system that happens to have trees in it.

This is the island where shinrin-yoku — forest bathing — was, in a sense, waiting to be named. The term was coined in 1982 by Japan's Forestry Agency, and its earliest promotional campaigns leaned heavily on Yakushima's photographs. If you want to understand what the word was trying to point at before it became a wellness product, this is the place to go and stand in the rain.

An island shaped like a stone dropped in the sea

Yakushima sits about sixty kilometres south of the southern tip of Kyushu, in Kagoshima Prefecture. It is almost circular, roughly thirty kilometres across, and it rises from the Pacific to nearly two thousand metres in the middle. Warm, wet air off the ocean hits those mountains and has nowhere to go but up, which is where the rain comes from. The island is a machine for making cloud.

That geography stacks climates on top of each other. The coast is subtropical, with banyans and hibiscus. Halfway up you are in a temperate rainforest. Near the summits there is snow in winter and alpine grass in summer. You can, in a single long day, walk from something like Okinawa into something like Hokkaido.

In 1993 the interior became one of Japan's first UNESCO natural World Heritage sites, alongside the beech forests of Shirakami-Sanchi. The citation was for the cedars.

The old ones

Yakusugi is the local word for a cedar more than a thousand years old. Younger trees — anything under a millennium — are called kosugi, "small cedar," which tells you what counts as old here.

The trees grow slowly because the granite bedrock gives them almost nothing to eat. Slow growth means dense, resinous wood, and dense resinous wood resists rot, which is why the oldest specimens have been standing since before the Heian court was writing poetry. The most famous is Jōmon Sugi, named for the prehistoric Jōmon period because someone once guessed it might be that old. More careful estimates put it somewhere between two and seven thousand years. It is a ten-hour round trip on foot, much of it along an old logging railway, and the tree is now viewed from a wooden platform because the roots were being trampled to death by admiration.

That logging railway is worth pausing on. Yakushima was not always a sanctuary. From the Edo period onward the cedars were cut for roof shingles, and after the war the felling accelerated. What saved the forest was partly its own inconvenience — the mountains are steep, the rain relentless — and partly a shift in what the trees were understood to be for. Stumps from those centuries of cutting are still everywhere in the forest, some of them wider than a car, many of them with new cedars growing straight out of the top. The island has a way of turning damage into shelter.

What the forest does to a body

Here is where the science and the sensation meet.

The research on forest bathing, much of it done in Japan by the physician Qing Li and colleagues in the 2000s, points to a few consistent effects: lower cortisol, lower blood pressure, a measurable rise in natural killer cell activity, and a shift from sympathetic to parasympathetic nervous activity — the body moving from alert to at rest. One proposed mechanism is the phytoncides, the volatile compounds conifers release to protect themselves from insects and rot. Cedars produce them in quantity. Yakushima, being mostly cedar and mostly humid, is a phytoncide bath with the tap left running.

But the studies describe a mechanism. They do not describe what it is like. What it is like is this: you walk into Shiratani Unsuikyō, the ravine north of the port town of Miyanoura, and after about twenty minutes the sound changes. Not the volume — the texture. The rain is still falling but the canopy has broken it into a thousand small sounds, drip and patter and the deeper note of water finding rock, and your own footsteps join that chorus rather than interrupting it. Your eyes stop looking for the path and start looking at the moss. Time gets wide.

That widening is, I think, the thing the Forestry Agency was reaching for in 1982. The word yoku (浴) means bathing, but the Japanese verb it comes from also means to be showered in something — light, praise, attention. To bathe in a forest is to be on the receiving end of it. You do not do anything. The forest does it to you.

The Ghibli question

You will hear, before you arrive and constantly after, that Shiratani is the forest that inspired Princess Mononoke. The film's director, Hayao Miyazaki, did visit Yakushima before making the film, and the studio's art staff sketched in the ravine. The forest spirits in the film — the small, head-clicking kodama — are widely believed to have been born here.

It is true enough to be worth knowing and slightly beside the point. Visitors who come looking for a film set tend to walk through the forest checking it against the movie, which is a way of not seeing it. The forest was here for several thousand years before anyone drew it. The more useful direction of influence runs the other way: the film gives Western visitors a ready-made vocabulary for the feeling that Japanese visitors already had a word for. Kodama means the echo of a tree. It is an old word. Miyazaki did not invent it; he just made it visible.

How to actually do it

A few practical notes, because the difference between a good day here and a miserable one is mostly preparation.

Go slow. The mistake almost everyone makes on their first visit is treating the island as a hiking destination and Jōmon Sugi as the summit to be bagged. If you have limited time, the Shiratani ravine and the Yakusugi Land trails offer more forest per hour than the long march to the famous tree. Choose a loop of two to four hours and walk it at half your normal pace.

Assume rain. Not "bring a jacket" — assume you will be wet from the knees down for the entire day, and buy proper rubber boots in Miyanoura if you did not bring any. Locals wear them. The boots are the difference between fighting the island and joining it.

Stay more than one night. The ferry from Kagoshima takes two to four hours depending on the boat, and a day trip leaves you with a few damp hours and no sense of the place. Three nights is enough to walk, rest, and walk again, and to sit in one of the small coastal onsen — Hirauchi Kaichū, on the south coast, is a set of rock pools in the tidal zone that can only be used at low tide, which is about as Yakushima as an experience gets.

Stop talking. This is the hardest instruction and the one that matters most. Groups on the trail tend to narrate the forest to each other, and the narration replaces the forest. Agree with your companions on twenty minutes of silence. Then extend it.

The part that stays

On my last morning there the rain lifted for an hour and the sun came sideways through the ravine, and every drop hanging from every strand of moss lit up at once. I did not photograph it. It would not have survived the photograph. What survived instead was the feeling, weeks later in an ordinary city, of standing at a crossing and noticing that the plane tree on the corner was also, in its way, breathing on me.

That is what forest bathing was named for. Not the island. The habit the island teaches you, which you can take home.