Most great mountains break free of the trees somewhere near the top. Choorechillum barely does. Rainforest cloaks it the whole way up, shifting in character as the air cools and thins. Down low, the lowland tropical forest is a riot of broad-leaved trees, palms, ferns, and vines tangled into a single living wall. Climb higher and the leaves shrink, the canopy lowers, and the forest grows quieter and stranger. Above 1,000 metres, mist rolls in almost daily, and the trees enter the realm of cloud forest - gnarled, stunted, and so thickly upholstered in moss and other plants that the bark all but disappears. Near the summit, one tree, Eucryphia wilkiei, grows nowhere else on Earth, its closest cousins clinging to the cool rainforests of Tasmania and Chile, half a world and an ice age away.

No rain gauge sits on the summit, but the numbers from nearby Mount Bellenden Ker tell the story. Estimated annual rainfall on these peaks runs to around 8,000 millimetres, with a potential maximum that could reach an astonishing 17,000 - among the heaviest on the planet. Even the so-called dry season here is wet by any normal standard. In 1911, calculations based on lowland data suggest a single day during a cyclone may have dumped as much as two metres of rain, which, if accurate, would rank among the greatest daily downpours ever recorded anywhere. This relentless water is the mountain's sculptor and its guardian, feeding the Russell River, leaching the granite soils, and keeping the cloud forest perpetually dripping.

Christie Palmerston was the first European recorded to reach the top, in October 1886; he blazed a tree with his initial and the date and left it at that. Today the standard route climbs roughly 15 kilometres return from the Josephine Falls car park, gaining around 1,500 vertical metres through slick roots, leech-rich undergrowth, and yellow markers spaced every kilometre. Ten to twelve hours is normal. The summit's promised reward - a sweep over the coastal lowlands one way and the Atherton Tablelands the other - is anything but guaranteed, because the peak so often sits inside the very clouds that feed its forest. Experienced walkers start before dawn in the dry months, from April to October, and accept that the view may never arrive.

The high country shelters life found almost nowhere else. The Bartle Frere skink, an endangered lizard, lives on these upper slopes and the peaks around them, adapted to the cool, wet, alpine-feeling world near the top. Two other lizard species carry the mountain in their scientific names. Among the granite boulders of the cloud forest grows Rhododendron lochiae, Australia's only native rhododendron, sometimes rooted in rock, sometimes perched high in the canopy as an epiphyte. BirdLife International recognises the mountain as part of the Wooroonooran Important Bird Area, a refuge for birds that exist only in Queensland's Wet Tropics. It is a small, vertical island of cool-climate species marooned in the tropics.

The peak holds a quieter, sadder distinction too. On 21 April 1942, an American B-25 Mitchell bomber slammed into the mountain in cloud, killing all seven men aboard. The aircraft had only recently come home from the Royce Raid, a daring strike against Japanese forces in the Philippines, and then met its end not in combat but on a fog-bound Australian peak. Decades on, the wreckage still lies on the slopes, the white US star insignia visible in photographs from the 1980s - a reminder that even in this remote rainforest, the reach of the Second World War left its mark, and that seven young crewmen rest somewhere in Choorechillum's enduring green.