Taiwan Confirms East Asia's Tallest Tree — an 84-Meter Giant Named the Heaven Sword

A joint research team from Taiwan's Forestry Research Institute and National Cheng Kung University has confirmed that a Taiwania tree along the upper Da'an River stands 84.1 meters tall — the highest known tree in Taiwan and, researchers say, in all of East Asia. Formally named the "Heaven Sword of the Da'an River (大安溪倚天劍)," the tree was identified through a decade-long search combining professional climbing, airborne laser mapping, and mass citizen participation. The findings, released Friday at a Science Media Center Taiwan briefing, were published in the international journal Frontiers in Forests and Global Change.

The hunt formally began in August 2014, when researchers from the Taiwan Forestry Research Institute launched their first major expedition into the Cilan conservation area to scientifically document a legendary cluster of giant Taiwania firs known as the "Chilan Three Sisters (棲蘭三姊妹)." The tallest of those trees measured 69.3 meters with a trunk nearly three meters in diameter. Subsequent expeditions pushed deeper into the island's remote interior, but researchers quickly realized that identifying the tallest trees by eye alone, beneath the dense layered canopy of old-growth forest, was unreliable. A more systematic approach was needed.

Taiwan's forests are expansive: roughly 60 percent of the island remains forested, sheltering an estimated 950 million trees. While intensive logging between 1912 and 1991 significantly reduced original primary forest cover, the island's exceptionally steep terrain served as an inadvertent safeguard, placing the most ancient stands beyond the reach of industrial operations.

The team turned to government-commissioned airborne LiDAR (light detection and ranging) data, using laser pulses capable of penetrating the forest canopy to measure the distance between the ground and the topmost point of each tree. That calculation produced a canopy height model — and even after setting a threshold of 65 meters, the data flagged more than 57,000 candidate sites across the island.

Taiwan's rugged topography, however, introduced a persistent source of error: cliffs can mimic tall trees in raw LiDAR data, with some readings showing trees over 100 meters that turned out to be 54-meter trees growing atop 50-meter escarpments. NCKU professor Chi-Kuei Wang (王驥魁), who led the spatial mapping component, noted that correcting for this required human operators to manually rotate point-cloud renderings to find angles that clearly showed the base of each tree — a task that two full-time staff working alone would have taken an estimated 15 years to complete. In the end, 93 percent of algorithmically flagged candidates proved to be mismeasurements.

To solve the problem at scale, the team recruited 372 citizen scientists who reviewed anonymized LiDAR cross-section images through an interactive website. Over roughly six weeks, that volunteer pool cut the candidate list from 57,000 to 4,736 sites. Professional verification then whittled it further, producing a final inventory of 941 trees confirmed at or above 65 meters. Representative specimens were subsequently climbed and measured directly by arborists using rope descent techniques. The full database is publicly accessible at no1tree.tw.

In January 2023, the team used the completed map to target its most promising candidate. The expedition required 20 kilometers of river tracing and two days of steep uphill hiking. When climbers finally reached the crown and dropped a measuring tape to the ground, the reading was 84.1 meters. The tree — christened the Heaven Sword of the Da'an River — was officially recorded as the tallest in Taiwan and East Asia. By early 2026, the team had climbed ten Taiwania trees exceeding 70 meters, two of which have broken the 80-meter barrier.

Why Taiwan Grows Giants

Forestry Research Institute associate researcher Rebecca Chia-Chun Hsu (徐嘉君) explained that conditions suitable for extreme tree height are rare globally. Such forests tend to concentrate in cloud forest zones, found mainly along the Pacific Northwest coast of North America, the Amazon basin, Borneo, the upper Yarlung Tsangpo gorge, and parts of Victoria and Tasmania in Australia. Taiwan's position on the Tropic of Cancer, where temperate and tropical biomes converge across a narrow but dramatically vertical landscape, creates the altitude gradients and persistent cloud cover that allow trees of this scale to develop. To the Indigenous Rukai people, these towering Taiwania firs carry a more poetic name: "the tree that hits the moon."

The research also quantified what these forests store. In August 2024, the team and 15 citizen scientists surveyed a four-hectare old-growth stand in Taoshan Sacred Tree Valley — home to Taiwan's third-tallest tree — and measured above-ground carbon stocks of approximately 1,384 tonnes per hectare. That figure approaches the benchmark set by Tasmania's celebrated giant forests, currently the world record holder at 1,867 tonnes per hectare. Hsu noted that about 80 percent of the carbon in the Taoshan stand is concentrated in trees with a trunk diameter exceeding one meter, underscoring the outsized climate value of individual giant trees.

Hsu added that the current figures likely understate the true carbon density by at least one-third, since the team used forestry agency formulas rather than the direct volumetric measurements employed by Tasmanian researchers. She called for sustained investment in the protection and long-term monitoring of Taiwan's giant tree forests, and pointed to a newly discovered cluster on Benyeshan — 11 trees over 65 meters packed into roughly one hectare — which the team has named the "Cathedral of Giants."

Wang said the probability of finding a tree taller than 84.1 meters is low but cannot be ruled out. A second round of national LiDAR mapping, of noticeably higher quality than the first, has already led the team to a spruce exceeding 70 meters in the Central Cross-Island Highway corridor. More sobering is another finding from the two data sets: comparing surveys taken roughly a decade apart, the team found that approximately five percent of the 941 confirmed giant trees had disappeared — a rate of loss that Wang said exceeded researchers' expectations.

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