A Thousand Years Old and 20 Stories High: Finding Taiwan's Tallest Trees

Scientists in Taiwan have found the country's tallest tree, a towering conifer that stands 84.1 meters high — taller than most 20-story buildings. The tree, which is probably 1,000 years old, was given the name "Heaven Sword of the Da'an River." A research team led by Dr. Rebecca Hsu spent more than ten years searching Taiwan's forests to find and measure these giant trees. Their findings were published this month in a science journal called Frontiers in Forests and Global Change.

Heaven Sword is a species called Taiwania cryptomerioides, a type of conifer with a tall, straight trunk. For the first 45 meters, the tree has no branches at all — just a smooth column of wood shooting upward. Higher up, the branches spread out, and rare plants, animals, and insects make their homes there. Standing near the top, climbers can hear a soft whooshing sound as the wind moves through the leaves far above the ground.

The tree is like a small city for wildlife. Ferns grow on the shaded forest floor below. Flying squirrels and owls sleep inside hollow trunks. Bright yellow rhododendron flowers bloom in the lower branches. Higher up, thick lichens coat the bark, and a rare orchid called Bulbophyllum ciliisepalum grows in the cloud-soaked branches near the top. Dr. Hsu says that every species in the tree has its own favorite spot, because the temperature, wind, and light change with every meter of height.

Reaching Heaven Sword was not easy. The research team had to hike for several days through rough wilderness and cross a river that was flooded from a recent snowstorm. To climb the tree itself, they used an air cannon to shoot a fishing line up into the branches. The line was then swapped for a rope, which the team climbed using special devices called ascenders that grip the rope and help climbers pull themselves up.

Steve Pearce, a naturalist from Australia who joined the team to climb and photograph Heaven Sword, says the tree grew so tall because of its environment. Long ago, it was surrounded by other tall trees and had to race upward to reach sunlight. As its lower branches got shaded out, they died and fell off, leaving that long bare trunk. Today, the top of the tree is still healthy and growing, even 80 meters in the air.

Taiwan's tallest tree joins a list of record-breaking giants around the world. The tallest known living tree on Earth is a coast redwood in California that measures 116 meters — taller than London's famous Big Ben clock tower. Chris Swanston, a scientist who works to protect redwood trees in California, says height is not just about breaking records. He explains that in a single ancient redwood, dozens of generations of animals and plants can live and grow within the branches.

Old, tall trees are also important fighters against climate change. They absorb large amounts of carbon dioxide, the gas that is warming the planet. But these giants are now in serious danger. Wildfires, droughts, and stronger storms are killing trees that have lived for thousands of years. In California, about 17.6% of all large giant sequoia trees have been burned since 1984, with most dying in 2020 and 2021.

In Taiwan, researchers found that tall trees are dying at a rate of 4% to 5% every ten years. Dr. Hsu said this number was "beyond our imagination." Typhoons — powerful tropical storms — have grown about 35% stronger over the past 40 years, bringing fiercer winds and heavier rain. Most of Taiwan's giant trees grow on steep hillsides near rivers, making them especially vulnerable to floods and landslides.

Scientists are using a technology called lidar to find tall trees more quickly. Lidar works by firing laser pulses and measuring how long the light takes to bounce back, creating a detailed 3D map of a forest. It is the same technology used to guide self-driving cars. However, lidar is not perfect — it can struggle on steep or uneven land, like the slopes where Taiwan's tallest trees grow. In Dr. Hsu's study, 93% of the tree measurements taken by lidar from the air had to be corrected.

For Dr. Hsu, the work is about more than setting records. She hopes her research will help people understand and care about these ancient trees before it is too late. She is already planning her next project, looking into why Taiwan's Taiwania seedlings tend to sprout in areas where landslides have recently occurred. Above all, she wants the public to see these trees and feel a sense of wonder. "To let people know how lucky we are to have these beautiful trees," she says.