In Taiwan, biologists have found the tallest tree in East Asia: a thousand-year-old fir 84.1 meters high. The giant, hidden in a remote gorge by the Daan River, was named Heavenly Sword after legendary weapons in the Chinese wuxia novels of Jin Yong. Finding and measuring this living skyscraper took an international team of scientists, professional climbers, and volunteers ten years of hard searching, with aircraft, laser scanners, and tough expeditions along wild mountain rivers.
A ten-year hunt for the tree that strikes the Moon
The Taiwan fir (Taiwania cryptomerioides) is a sacred plant for local Indigenous peoples. The Rukai people of the islands southern mountains have long called this evergreen the "tree that strikes the Moon." Finding one record specimen in Taiwans dense, multi-layered forests, which cover 60% of the island, proved extremely hard.
From 2014, a group of enthusiasts including ecologists, geologists, and remote-sensing specialists surveyed the island from the air with lidar optical locators. Mountain terrain constantly fooled the automation: because of steep cliffs and sloping ground, the computer algorithm miscalculated tree height in 93% of cases.
Correcting the AIs mistakes had to be done by hand. Scientists enlisted thousands of online volunteers to analyze 3D maps, and by the end of 2022 they had a list of 941 giant trees taller than 65 meters. Early in 2023 they reached their main target.
Simply reaching the base of Heavenly Sword meant floating and scrambling more than 20 kilometers upstream along a wild river, then two more days climbing through jungle. The final measurement was old-school: climbers scaled the firs crown and dropped an ordinary builders tape measure. Study lead Dr. Rebecca Hsu of the Taiwan Forestry Research Institute recalls feeling huge relief: the exhausting trek into nowhere had paid off.
How steep cliffs saved the giants from axes
Heavy annual rainfall and a stable climate gave Taiwan ideal conditions for centuries of giant-tree growth. For comparison, the tallest living tree on Earth today is still Californias Hyperion sequoia at 116 meters, but for Asia an 84-meter fir is an absolute record.
That Heavenly Sword survived to our day is pure chance. During industrial logging on the island from 1912 to 1991, lumberjacks destroyed vast tracts of ancient forest. But the extremely steep, dangerous terrain of the Daan River gorge made hauling timber uneconomical, and the ax never reached the giant. Today the area is under strict state protection.
