- Researchers have confirmed Taiwan’s tallest known tree: an 84.1-meter (276-foot) Taiwania fir they named “the Heaven Sword of the Da’an River.”
- A team called the “Taiwan tree seekers” found it after a decade-long search using airborne laser scans of the island’s forests.
- A group of 372 citizen scientists helped sort through the data, producing a map of 941 giant trees across Taiwan.
- The giant trees store huge amounts of carbon but face growing threats from drought, lifting clouds, stronger typhoons, and illegal logging.
Deep in Taiwan’s misty mountains, researchers have confirmed the tallest tree in the country: a thousand-year-old fir tree higher than a 20-story building, which they’ve named “the heaven sword of the Da’an River.”
Climbers scaled the tree and dropped a measuring tape from the top to the forest floor during the Lunar New Year holiday in January 2023. The tree measured 84.1-meters (276-feet). The findings have been published in Frontiers in Forests and Global Change.
A team of ecologists, geologists, remote-sensing specialists, professional climbers and Indigenous people that calls itself the “Taiwan tree seekers” began the search in 2014.
“The common characteristics [of the team] are probably that we are all tree lovers and like adventures,” Rebecca Chia-Chun Hsu, lead author from Division of Forest Ecology, Institute of Taiwan Forestry Research, told CNN.
Taiwan is one of the few places on Earth where trees can grow this tall. The island sits where the tropics meet the subtropics, and its mountains host several giant conifer species. The species behind the new record, Taiwania cryptomerioides, is known to the Indigenous Rukai people as “the tree that hits the moon.”
Although nearly 60% of Taiwan is covered in forest, loggers cleared much of the island’s old-growth forest between 1912 and 1991. However, its steep slopes were too dangerous to reach, and pockets of ancient forest survived. Still, finding the tallest tree amid the rugged terrain was a task. Taiwan has 258 peaks above 3,000 meters (9,840 feet) and an estimated 950 million trees.
The team’s first expeditions were old-fashioned. In 2014, they hiked into the Cilan area to document a famous trio called the “Chilan Three Sisters.” The tallest measured 69.3 m (227 ft). A later trip near Mt. Benya, in an area near Great Ghost Lake considered sacred by Indigenous peoples, required four days of hiking to reach a 71.7-m (235-ft) tree.
“Within the dense, multi-layered canopy of an old-growth forest, your eyes can easily deceive you,” the co-authors wrote in an editorial about the study.
So, the tree seekers decided to seek help from above. Working with remote-sensing experts at National Cheng Kung University, the team used airborne lidar, laser pulses fired from an aircraft that build a 3D map of the forest below.
“Finding the tallest trees of a species or region is definitely made easier by use of airborne LiDAR,” Steve Sillett, a professor at California State Polytechnic University, Humboldt, in the U.S., who studies old-growth forest canopies and confirmed the world’s tallest tree, told Mongabay by email. “Back in the old days we had to find them on foot using handheld rangefinders.”
However, Taiwan’s steep cliffs confused the computer. A short tree on the edge of a cliff could look much higher in the data. In fact, 93% of the trees the algorithm flagged turned out to be wrong.
To sort through the mistakes, the team turned to citizen science. Starting in 2020, nearly 400 volunteers logged onto a website and clicked on the apparent top and base of each candidate tree in sliced-up profile images. They narrowed down more than 57,000 candidate trees to fewer than 5,000, which experts reviewed.
By late 2022, the team published the Taiwan Giant Tree Map, cataloging 941 confirmed trees taller than 65 m (213 ft). In January 2023, the team used the map to pick out their most promising candidate, a tree in the Sheshan range of northern Taiwan, near the Da’an River.
The Taiwan tree seekers set out on another expedition to measure the tallest tree by hand. The group again included professional climbers, researchers, and Indigenous guides.
“Indigenous people were involved [in the research] from the beginning, especially in every expedition we had,” Hsu told Mongabay in an email. “We survive because of their local knowledge in the mountains.”
The Heaven Sword expedition was difficult and required tracing a river for 20 kilometers (12 miles) along with two days of steep uphill hiking. When the climbers reached the tree’s crown and lowered the tape, the tree came in at 84.1 m, nearly 5 m (16.4 ft) taller than the lidar had predicted.
“The measurement moment was intense but we were very happy when verified, especially those members who guessed the tree’s real height correctly,” said Hsu.
Taller specimens have been confirmed elsewhere, including the Amazon’s tallest known tree, Dinizia excelsa, which measures 88 m (289 ft) and Cupressus austrotibetica in China (102 m, or 335 ft). The world’s tallest known living tree is a coast redwood (Sequoia sempervirens) in the U.S. state of California, measured at 115.6 m (379 ft).
But the giants are in trouble. Tall trees worldwide are more vulnerable to drought, and climate models suggest the cloud cover that montane forests depend on is lifting higher, drying out their habitat. This trend has already been observed in northeastern Taiwan’s Chilan cloud forest, according to a 2024 study co-authored by Hsu.
Storms striking Taiwan have grown about 35% stronger over the past four decades. Most of the mapped giants in Taiwan grow on steep slopes in the upper reaches of rivers, putting them at risk of landslides and floods when typhoons hit. In 2009, Typhoon Morakot triggered landslides that wiped out large stretches of old-growth forest.
And although more than 95% of the large trees mapped by the seekers grow within protected areas, the team said they found signs of illegal logging during their expeditions.
Large, old trees play an outsized role in their ecosystems, the paper notes. A single giant can store as much carbon as an entire stand of mid-sized trees. They also create habitats and microclimates that smaller trees can’t, supporting forest biodiversity in ways that can’t be replaced.
“These ‘trees that hit the moon’ are not just natural wonders,” the authors wrote. “They are essential guardians of the environment.”
Banner image of team climbing ‘The Heaven Sword’, Taiwan’s tallest tree. Credit: Steven Pearce.
Liz Kimbrough is a staff writer for Mongabay and holds a Ph.D. in ecology and evolutionary biology from Tulane University, where she studied the microbiomes of trees. View more of her reporting here.
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Citations:
Hsu, R. C.-C., Wang, C.-K., & Lee, C.-C. (2026). The journey of finding the tallest tree in Formosa Taiwan. Frontiers in Forests and Global Change, 9, 1746112. doi:10.3389/ffgc.2026.1746112
Pandey, R. S., & Liou, Y.-A. (2022). Typhoon strength rising in the past four decades. Weather and Climate Extremes, 36, 100446. doi:10.1016/j.wace.2022.100446
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