Yakushima is one of those places that just wows you as you even get close to it. It's so amazingly green for one, and the mountains seem to stretch forever even though the island is quite small. Most visitors seem to do a 2 day trip, with the first day of arrival making a visit to Shitatani Unsuikyo (ravine) which inspired the movie Princess Mononoke. This part is great and a 3h hike through mostly roots, rocks, rivers and steps prepares you well for the rest of the hikes on the island. The ravine is NOT inside the UNESCO protected area but I do recommend it for a half-day trip after landing on the island assuming the water levels are low as the river crossings aren't easy.

Yakushima was inscribed for 2 reasons. The "natural beauty" is a little odd-ball because those opinion-related inscriptions are all in the eye of the beholder. The second one is for the vertical distribution that changes with altitude and can be easily observed inside the protected area. There is a great illustration of this inside the World Heritage Center up at the Yakusugi Land museum (free entrance for the center and lots of info on world heritage, Ramsa and other stuff around the island). Basically they make an example that the height of the island has similar climate as up north in Hokkaido but the island is located very south, and the vegetation has EVERYTHING of Japan in one tiny spot, i.e. from subtropical to cool.

Day 2 is that grueling ~10 hour hike to Jomon, the oldest tree on the island, or in Japan? It is the oldest cedar tree in the world apparently. The reason the cedar trees grow older than the usual 1,000 year life span is that the soil is not very rich and they need to grow thicker rings to survive, thus these tough buggers outlive us all. This all-day hike starts with a bus to the museum early morning before sunrise and even in October, Japan's Sports Day of all days, there were many people in line for the shuttle bus to the trailhead. Speaking of the national holiday, I was expecting a lot of people with families but in fact the school kids only arrived in large groups the day I was leaving and only 4 kids did the long hike. The hike only takes you into the world heritage area for the last 30 minutes or so. The Jomon tree is naturally inside this area. There are many hikes that go across the mountains that are less popular and one has to arrange staying in the huts on the mountains. One could, for example, hike from Shitatani Unsuikyo towards Jomon and even continue further west through the world heritage area. Was the hike worth it? Probably yes, but I found the 2.5h trek along the train lines merely interesting for one way and the return was a little pain in the butt even if you get lucky to see deer, yakushimazaru, weasel, (poisonous) snakes, mushrooms. Birds were kind of scarce although you can hear the chirp far up in the trees I didn't see a single one. The tough sections for the last 2h has amazing forestry and several stops on the way. Many Japanese hikers went in groups and the tour guide stopped a lot of times to point out growth behavior, flora and fauna, photo shoots at the big trees, the rest I couldn't guess. There is ample supply of fresh water flowing down the mountain to never worry about carrying too little and the fresh crisp mountain water will boost your energy. In fact since the hike is always in the shade I broke very little sweat. The next morning the legs were rubber though.

If you don't do the hike, the world heritage site stretches all the way to the west coast where buses aren't allowed to go through. Some people in the tourist information center inquired about what to do and they were suggested to seek out a waterfall. I don't find that worthy of coming all the way to Yakushima but so be it. If it is possible to see the vertical distribution of the vegetation there I am not sure. The bus system is a little slow around the island and it might be worth having an IDP to drive either a scooter or car. The "Kei" electric cars are very popular.

If you come in summer you can also observe the loggerhead turtles.

One of my favorite WHS and it happened to be my 500th so I'm very proud of this achievement.