That the oldest tree in the world may have stood for centuries when the first boulders were erected at Stonehenge, new research suggests.
The old giant, an alarm (Fitzroya cupressoides), known as “Gran Abuelo” (or great-grandfather in Spanish), perched above a canyon in the Chilean Andes, could be around 5,400 years old, a new computer model suggests. If this date can be confirmed, the Gran Abuelo would be almost 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 (Pinus longaeva) known as “Methuselah” in California.
The exact age of the Alerce is still somewhat controversial, however, as it requires analysis of tree rings – a method known as dendrochronology, which is the gold standard for determining a tree’s age – and these dates are currently incomplete. The underlying data for the model has not yet been published or submitted to a peer-reviewed journal.
Regardless of its age, the tree is in danger and needs protection, said Jonathan Barichivich, a climate and global ecology scientist at the Laboratory for Climate and Environmental Sciences in Paris and the researcher who created the model.
“It’s really in bad shape because of tourism,” and the tree has been affected as well climate changeBarichivich told Live Science.
Related: What is the tallest tree in the world?
How old is Gran Abuelo?
The Gran Abuelo, a conifer towering 60 meters above the misty forest floor in Chile’s Alerce Costero National Park, was originally estimated to be around 3,500 years old. But scientists have never systematically analyzed his age, Barichivich said.
“We wanted to tell the story of the tree with the sole aim of enhancing and protecting it,” Barichivich said.
In 2020, Barichivich and colleague Antonio Lara, a professor of forestry and natural resources at the Austral University of Chile, used a non-destructive technique to drill a tiny core out of the tree, capturing tree rings dating back 2,465 years. However, the borer could not reach the center of the tree’s diameter of 4 m, meaning that many of the Alerce tree’s annual rings could not be counted.
To account for the remaining years of growth, the team developed a mathematical model that accounts for how F. cupressoides grows at different speeds, from a sapling to a mature tree. The model also accounted for growth rate variations due to competition and variations 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 resulted in a range of predicted ages for the Gran Abuelo.
The model estimated that the tree was most likely around 5,400 years old, Barichivich explained. The absolute oldest the tree could be was 6,000 years; the probability that the tree was older than 5,000 years was about 80%; and all simulated growth paths predicted it to be at least 4,100 years old, he said.
“Even if the tree grew very quickly, despite its size, it can’t be younger,” he said.
Another factor suggests that the tree is very old: a biological law known as compromise between growth and lifespan (opens in new tab), added Barichivich. This trade-off suggests that slow-growing species tend to live longer. And Alerce trees grow incredibly slowly – even slower than other long-lived species like giant sequoias (Sequoiadendron giganteum) or Great Basin Bristlecones , he said.
However, some tree dating experts said science magazine (opens in new tab) that they were cautious about using model data to estimate a tree’s age.
“The ONLY way to truly determine the age of a tree is to count the rings dendrochronologically, and that requires ALL the rings to be present or accounted for,” says Ed Cook, founding director of the Tree Ring Laboratory at Lamont-Doherty Earth Observatory at Columbia University New York, Science Magazine said in an email.
Although the tree has survived for thousands of years, its future is in doubt, Barichivich said.
The ancient tree has been surrounded by a narrow platform walkway that crushes its last living roots, he said, and the countless tourists who come to see the tree each year do further damage when they walk on it.
Climate change and the associated 10-year drought have also harmed the majestic Alerce; A second tree growing from the top of the towering giant is now dying, he said.
To protect the Gran Abuelo from further damage, Barichivich and his colleagues have proposed placing a 10-foot (3 m) net 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.