The ancient giants among us carry with them not only knowledge of the past, but also clues to the future. From the snowy plateaus of northwestern China to the Balkan Peninsula and the riverine swamps of Mexico, some of the oldest trees – more than thousands of years old – are still alive and thriving today.
How do they navigate life in a constantly changing world? A new book, In the Circle of Ancient Trees (2025; Greystone Books/Unipress), edited by Valerie Trouet, a dendroclimatologist at the University of Arizona’s Tree-Ring Research Laboratory, describes ten such iconic tree species through essays by 11 scientists.
Over time, everything from the giant European Bosnian pines to the resilient dwarf junipers of China have evolved different adaptations to survive in changing environments. Elsewhere, some have had swollen knees, while others have taken off their skin as protection.
Read on to see what they teach us.
Giant Sequoia: 3,300 years old, California
The giant sequoia’s reddish bark reaches 65 feet tall, even before its first branches appear. To understand the scale of the world’s largest tree by volume, imagine a trunk taller than the Statue of Liberty, with a circumference three times its size. Having survived more than a hundred wildfires in its lifetime, the “fire-resistant king of the forest” has adapted in spectacular ways.
For one, they are serotonous, learning to use fire to their advantage. The heat of a wildfire causes cones that have been sealed for more than 20 years to dry out, split open, and disintegrate the seeds. Its thick, often fibrous bark can also serve as an insulator, producing tannins that resist pests and diseases.
The indigenous people of North America may have been the first humans to interact with this species. The Miwok called them wo-wo-nau, meant to imitate the call of an owl, considered the guardian spirit of the tree. They were the first to use controlled fires as a way to clear debris to prevent larger outbreaks, shaping the response to tree fires along the way. The tree also self-prunes by dropping lower branches so that surface fires do not spread to the top.
Qilian Juniper: 2,868 years old, Qinghai-Tibet Plateau
For most of its life, the long-lived Qilian juniper has endured brutal conditions in China’s northeastern Qinghai-Tibet Plateau. Tolerating frequent periods of drought, nutrient-poor soils, cold temperatures and intense periods of high UV radiation.
They rarely exceed 26 feet in height and are only three feet wide, earning them the name Galao Han, which is Chinese for “dwarf old man.”
With a pointed, twisted stem and a hat-like crown, it is perhaps the most important species for tree-ring studies in China. Its long lifespan and strong climate sensitivity make it valuable for reconstructing past environmental conditions. Now also growing in the arid and semi-arid provinces of Qinghai, Gansu and Sichuan, they are able to survive in areas where rainfall is less than 250 mm per year, such as the Zongwulong Mountains in northwestern China.
Tree-ring studies show that about 18,000 years ago, there was a rapid transition from temperate forests to grasslands in the northeastern Qinghai-Tibet Plateau. “This has led to the rapid decline of Qilian juniper forests, leaving many isolated groups on the edge of the plateau,” writes Bao Yang, a paleoclimatology researcher at the Chinese Academy of Sciences, Lanzhou, in the book.
This beloved tree weaves its way through Tibetan folk tales and songs, its longevity a symbol of undying love and resilience. One folktale tells of a young girl who pleads with a tree to save her village from a drought monster. The Killian juniper responds by offering its twigs, which when burned release a sweet aroma, driving the demon away.
Bosnian Pine: 1,075 years old, Southeastern Europe
With curved, scaly bark and long, dark green needles, the Bosnian pine only grows to 70 feet tall, yet commands an impressive presence. The oldest known tree, Adonis, is a 1,075-year-old specimen that was discovered in the Pindus Mountains of northern Greece in 2016 and is believed to be the oldest living organism in Europe. The species was discovered on Mount Olympus in Greece, where they grew in the harshest conditions, at high altitudes exposed to chalky rocks, nutrient-poor soils and strong winds and heavy snow.
Belgian forester and researcher Momchil Panayotov described his first impression of the tree, writing, “It is neither tall nor very thick, but it looks as if an ancient prophet is peacefully looking down on the valley below.” Their stems are gnarled and have irregular crowns – some spreading far apart, and others intertwined as if they were deliberately planted together.
And, in a way, they were. When the birds gathered their food for the winter, the seeds from the forgotten reserves took root and turned into pine trees.
In Bulgaria’s steep Pirin Mountains, researchers now know that pines have suffered from both fires and avalanches. Avalanches will leave scars, break the trunk (from where the tree will regrow) or bend or nearly uproot, forcing the stem to grow horizontally and produce what is called reaction wood – an excellent clue used by researchers everywhere.
Fire, on the other hand, was both killer and helpful. Panayotov writes, “Not only did they kill off young trees with thin bark, but they also killed off larger, thin-barked trees of faster-growing species than Bosnian pine, such as Norway spruce, silver fir, and Scots pine, essentially eliminating competition.”
Bald cypress: over 2,600 years old, North Carolina
A huge tree, 100 feet high with a diameter of 12 feet, stands on the banks of the Black River in North Carolina, which is more than 2,646 years old. Characterized by its “swollen knees” or buttresses that can grow up to 10 feet tall, they produce wood that is resistant to decay in a light brown, reddish color.
Matthew Therrell, a geography professor at the University of Alabama, writes, “Bald cypress tree-ring records have been used to link the failure of early English settlements on the East Coast, such as the lost colony of Roanoke and the famine of Jamestown, to some of the region’s worst droughts in the past millennium.”
Therrell’s team found that climate change and other environmental factors may have led to severe drought conditions, which contradicts the historical theory that poor management by Jamestown’s early settlers in 1607 may have been the sole cause of their conflict.
One can imagine that a tree growing in water would be indifferent to heavy rainfall or drought. Yet bald cypress is extremely sensitive to even minor reductions in its water supply. By increasing “swollen knees”, they are able to adapt. These act as storage sacks for nutrients and carbohydrates in addition to providing air access to submerged root systems.
In Mexico, the bald cypress (which was even declared its national tree at the beginning of the 20th century) occupies an honorable place due to its antiquity. Their presence in swamps and waterways sets a terrifying stage for local folklore, as in the enduring legend of La Llorona (the Weeping Woman). Spanish conquistador Hernán Cortés is said to have cried in the shade of the tree at Popotla, after his defeat by the Aztecs in 1851.
Kauri: over 2,000 years, Te Ika-a-Maui, New Zealand
With an imposing presence that invokes awe, kauris are strong and enduring, held in place with deep, taproots. Found naturally only in Te Ika-a-Maui (upper North Island), they are the southernmost members of the Agathis family and the largest trees by volume in Aotearoa, New Zealand.
The most notable of these, Tane Mahuta, is more than 16 feet in diameter and nearly 150 feet tall. In Māori mythology, the tree is considered a descendant of the supreme being, Io Matua Kore, and the embodiment of Tāne, the god of the forest, birds, and people.
Kauri forests were once fertile playgrounds for birds, bats, reptiles, frogs and invertebrates such as fish and eels in their waterways. This changed with the arrival and settlement of Māori from Polynesia around 1250 AD. “Forest gave way to gardens for growing kumara (sweet potatoes),” writes archaeologist Gretel Boswijk of the University of Auckland.
The bark looks hammer-like and peels off in large pieces, revealing a soft reddish surface. The flaky barks help protect against insects, parasites or epiphytes such as lichen or hanging fork fern, while their extensive root systems prevent erosion, and contribute to soil stability, especially in mountainous areas.
Research conducted in 2019 by scientists at Auckland University of Technology revealed that kauri trees, through a grafted root system, exchange water and resources with each other to keep them alive.
Left to their own devices, these giant trees could outwit us all. However, their greatest threat is the water-sucking pathogen that causes root damage in a disease called kauri dieback. Hiking boots, shoes, and tires often spread pathogens, which is why it is the most frequented analog hiking trails on the island.
