O the oldest tree in the world it may have been standing for centuries when the first boulders were erected at Stonehenge, new research suggests.
The ancient giant, a warning (Fitzroya cupresoides) known as the “Gran Abuelo” (or great-grandfather in Spanish) that rises over a ravine in the Chilean Andes, may be around 5,400 years old, a new computer model suggests. If that date can be confirmed, it would make the Gran Abuelo nearly 600 years older than the current official record holder (opens in new tab) for the oldest tree in the world, a Great Basin bristlecone pine (pine longicornis) in California known as “Methuselah”.
However, the exact age of alerce is still somewhat disputed, because confirming this requires analyzing the tree’s rings — a method known as dendrochronology and the gold standard for determining a tree’s age — and this data is incomplete. The data underlying the model has not yet been publicly released or submitted to a peer-reviewed journal.
Whatever its age, the tree is in danger and needs to be protected, said Jonathan Barichivich, a climate scientist and global ecology at the Laboratory of Climate and Environmental Sciences in Paris and the researcher who created the model.
“It’s in really bad shape because of tourism,” and the tree was also affected by of Climate ChangeBarichivich told Live Science.
Related: What is the tallest tree in the world?
How old is Gran Abuelo?
The Gran Abuelo, a conifer that rises 60 meters above the misty forest floor in Chile’s Alerce Costero National Park, was initially thought to be around 3,500 years old. But scientists have never analyzed its age systematically, Barichivich said.
“We wanted to tell the story of the tree for the sole purpose of valuing and protecting it,” said Barichivich.
Then, in 2020, Barichivich and his colleague Antonio Lara, a professor of forestry and natural resources at the Universidad Austral de Chile, used a non-destructive technique to drill a small core of the tree, which captured 2,465 years of tree rings. The drill, however, was unable to reach the center of the tree’s 4 m diameter, meaning that many of the alerce tree’s growth rings could not be counted.
To account for the remaining years of growth, the team developed a mathematical model that took into account how f. cupresoids grows at different rates, from a seedling to a mature tree. The model also incorporated variations in growth rate based on competition and fluctuations in environment and climate.
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The team then used the model to simulate the tree’s growth trajectory 10,000 times, Barichivich said. These simulations provided a range of predicted ages for the Gran Abuelo.
The model estimated that the tree was likely to be around 5,400 years old, Barichivich explained. The absolute oldest the tree could be was 6,000 years old; there was about an 80% chance that the tree was over 5,000 years old; and all simulated growth trajectories predicted it to be at least 4,100 years old, he said.
“Even though the tree is growing very fast, for all that size it can’t be any younger than that,” he said.
Another factor suggests that the tree is very old: a biological law known as life-growth exchange (opens in new tab), added Barichivich. This tradeoff suggests that slow-growing species tend to live longer. And larch trees grow incredibly slowly – slower even than other long-lived species like giant sequoias (Sequoiadendron giganteum) or Great Basin bristlecone pines , he said.
However, some tree dating experts said Science Magazine (opens in new tab) that they were cautious when using modeling data to estimate the age of a tree.
“The ONLY way to really determine the age of a tree is to dendrochronologically count the rings and that requires ALL the rings to be present or accounted for,” Ed Cook, founding director of the Tree Ring Laboratory at Columbia University’s Lamont-Doherty Earth Observatory in New York York, told Science Magazine via email.
Although the tree has survived for thousands of years, its future is uncertain, Barichivich said.
The ancient tree was surrounded by a narrow platform walkway that is crushing its last living roots, he said, and the countless tourists who come to see the tree every year do more damage when they walk on it.
Climate change and the ensuing 10-year drought also undermined the majestic alert; a second tree growing on top of the giant is now dying, he said.
To protect the Gran Abuelo from further damage, Barichivich and his colleagues proposed placing a 3m high veil around the tree to prevent people from getting too close. They also recommend moving the walkway much further away from the tree’s old root system, he told Live Science.
Originally published on Live Science.