Scientists Find East Asia's Tallest Tree After Decade-Long Quest

A Thousand-Year Giant Emerges

Deep in a secluded valley near Taiwan's Da'an River stands an 84.1-meter-tall Taiwania fir that researchers estimate is about 1,000 years old . The team named the massive fir tree "Heaven Sword of the Da'an River" — a nod to the legendary weapon from Jin Yong's martial arts novels . This tree, christened the 'Heaven Sword of the Da'an River,' was officially recorded as the tallest specimen in Taiwan and East Asia .

To the Indigenous Rukai people, these gargantuan firs are known by a much more poetic name, 'The tree that hits the moon' . The discovery represents the culmination of a group of Taiwan tree seekers — including professional tree climbers, ecologists, geologists and remote-sensing specialists — who have been working since 2014 to document the island's tallest trees .

High-Tech Hunt Meets Old-School Verification

As part of their project, the researchers first built a national canopy map using airborne laser scanning data, initially flagging 57,065 candidate trees . The technology had its limitations: steep cliffs caused rampant false positives: in one striking example, a tree barely 25 m tall registered as 90 m because it sat atop a sheer cliff face .

The team found an innovative solution by asking the public for help. Some 372 online volunteers examined laser-scan profile images of trees, winnowing the list down to 4,736 serious candidates, eliminating 92% of the manual verification work . Despite all the advanced technology, the team identified the Heaven Sword the old-fashioned way — by scaling the massive tree and dropping a tape measure from the top .

Reaching the Heaven Sword involved over 20 kilometers (12 miles) of swimming and rock climbing upstream, followed by two days of an arduous, uphill hike . When the tape measure read 84.1 meters, Hsu recalled feeling immense relief .

Taiwan's Secret Forest Giants

The final tally mapped 941 giant trees across the island, all taller than 65 m, clustered in montane cloud forests at elevations between 1,500 and 2,500 m . Near Mt. Benya, we found a single hectare of forest containing 11 trees that each exceed 65 meters . The researchers discovered what they call "a 'pure forest' of approximately 30 giant Taiwania firs growing in a dense, ancient cluster" .

This makes Taiwan's giant forests some of the most carbon-dense environments in the entire world, comparable to the most famous old-growth forests on Earth . A single giant tree can sequester an amount of carbon equivalent to an entire stand of mid-sized trees .

Racing Against Time and Climate

The discovery comes at a critical moment for Taiwan's ancient forests. Climate change is pushing cloud bases higher in Taiwan's mountains, threatening forests that giant trees depend on for moisture. Typhoon intensity hitting the island has risen 35% over the past four decades, and storm-driven floods and landslides pose an acute threat to trees that grow precisely in steep river valleys .

"We found that the previous equations from forest management institutions tend to underestimate their carbon density significantly," Hsu said . The team's next steps involve selecting several giant tree species for additional lidar observation to construct 3D models that will calculate their biomass . This research could revolutionize how we understand and protect these living monuments, ensuring that future generations might still glimpse trees that truly do seem to touch the moon.