Yakushima, Japan's fertile fantasy island

A hiking trail through Yakushima island’s dense rainforests "In ancient times, a land lay covered in forest, where from ages long past dwelt the spirits of the gods. Back then, man and beast lived in harmony, but as time went by, most of the great forests were destroyed. Those that remained were guarded by gigantic beasts who owed their allegiance to the great forest spirits, for those were the days of gods and of demons ..."
So boom the opening lines of Princess Mononoke, Studio Ghibli's classic 1997 anime. It's a strange romantic tale, but moreover a clash of man and nature, of technology versus tradition. It's a work of high fantasy and magic, and yet bizarrely for a hand-painted animation, some of its origins come from our real, comparatively dull world. Specifically the ancient, smothering forest is based on that which Ghibli founder Hayao Miyazaki saw when holidaying in Yakushima, a small verdant island in the Pacific Ocean 60km off the coast of Kyushu.
Japan is made up of almost 7,000 islands, but none is like Yakushima. Situated on the edge of the palaearctic and oriental biogeographic zones, it has a unique climate that fuels a huge range of flora. Despite being just 24km in diameter with a predominantly rainforest climate, Yakushima's highest peaks are above 1,800m and regularly receive snow in winter.
Those peaks also act like a beacon for rain clouds, which are attracted like fat moths to flames before they snag and burst, making Yakushima the wettest place in Japan. Because it lies farther south than Marrakech, Morocco, when the summer sun roars through the whole island swelters - the average humidity never drops below 65 per cent.
The heavy rain, tropical heat and steep slopes combine to make it an incredibly fertile place. As the island rises cone-like from the ocean, the rainwater runs from the hills, often gathering in plump waterfalls. Yakushima is a living island, and though there aren't any demonic boars, it's little wonder Miyazaki found inspiration here.
There are no boars but, as I discover on a drive around the south of the island, plenty of other fauna. The macaques and siki deer found here are very similar to those found in the rest of Japan, but grow smaller and are considerably more skittish. Back on the main island of Honshu, in places like Nara, deer are regarded as sacred and endlessly fed by tourists; similarly, Nagano's monkeys famously enjoy a hot spring and pose lazily for the cameras. Not so on Yakushima, where the subspecies are much more wary, much more wild. However, thanks to the whisper-quiet engine of our Toyota Prius, my driver Tomoyuki Umeki is able to sneak up on some of the timid deer. Ironically, their numbers are said to be rising so fast that they are damaging the forest at an unsustainable rate. Devastation is rarely wrought by anything so cute.
"Unfortunately, it's the wrong time of year to see the turtles," says Tomo, as he insists I call him, of the loggerhead turtle population that comes to Yakushima to breed. Around 4,000 adults start arriving in May, making it the biggest concentration of the endangered population in the North Pacific. Then, between July and September, the hatchlings begin their fraught, clumsy dash for the sea.
Tomo is a chief butler at the spectacular Sankara resort. Built on the fringes of Mugio, one of the few towns on Yakushima, it is the most luxurious hotel on the island. Importantly, there is a spa with a long massage menu - trekking is the primary reason people visit the island, but such is the topography that even a moderate hike is punishing to the untrained. Worse, as the peaks are deep in the heart of the island, most hikes require a dawn start.