Standing proud in Chile’s Alerce Costero national park, an ancient Patagonian cypress may have just swiped the record for the world’s oldest tree.

A preliminary age estimation of the colossal tree – the Alerce Milenario, affectionately known as “Great-Grandpa” – suggests it could be around 5,400 years old.

If true, it would take the crown of “the world’s oldest tree” from the current record holder, an eastern Californian bristlecone pine known as Methuselah that’s an estimated 4,853 years old.

The species is a Patagonian cypress (Fitzroya cupressoides), a conifer native to Chile and Argentina nicknamed the “redwood of the south” because of its vast size and reputation for resisting the forces of time. Capable of growing 70 meters (229 feet) tall and up to 5 meters (16 feet) in trunk diameter, the species is thought to be the largest type of tree in South America. Unfortunately, it’s now considered Chile’s most threatened conifer due to rampant logging and tourism in the area.

Dr Jonathan Barichivich from the Climate and Environmental Sciences Laboratory in Paris is the scientist who recently carried out the age estimation of the colossal Patagonian cypress living in the depths of Alerce Costero national park. He reached this estimation through a core sample taken from Alerce Milenario in early 2020 using a special t-shaped drill that doesn’t harm the trunk

It's often possible to estimate a tree’s age by counting the number of rings in a cross-sectioned trunk, with a one-year cycle being shown through light pale wood that grew at the start of the year and a dark wood that grew at the end of the year. 

However, due to the tree's enormous size, he wasn't able to drill a core throughout the whole trunk meaning the rest of the rings had to be "filled in" through statistical modeling based on the growth rate of the trees, environmental factors, and random variation.

"The problem is that traditional-age determination by simply counting the annual rings of such a big tree is not possible. There is no tool long enough to extract a sample reaching the centre of the tree and even if we have one the inner part of the trunk might be rotten. The scientific problem to tackle then is how to estimate the age of the tree despite these methodological limitations," Barichivich told IFLScience.

From this inventive method, Barichivich concluded that the tree has an estimated age of 5,484 years old.

"The result was that there is 80 percent of statistical confidence that the tree is older than 5,000 years, with a most likely age around 5,484 years," added Barichivich.

Dr Barichivich has presented his findings at scientific conferences (video above) but is yet to publish a peer-reviewed study on the research. While he hopes to submit a paper to a journal in the coming months, many scientists will likely want to wait until the full study is out before ringing up the Guinness World Records hotline.

Barichivich appears to be confident he has covered all bases and argues that his study will stand up to the scrutiny. However, for him, the title of the "world's oldest tree" is not the important bit. 

Barichivich's grandfather said he discovered the tree in the 1970s and numerous members of his family have worked as rangers in the Alerce Costero national park. Over these few decades, they've seen how human activity is drastically meddling with this once-pristine ecosystem. Through this ongoing work, he hopes to emphasize the desperate need to protect this unique, but rapidly changing, environment. 

"The tree is a member of my family. Our family story as 'Guardians of the Alerces' is tight to this tree and the forest where it lives," continued Dr Barichivich.

"To me, this research is not about breaking age records but to raise awareness to protect the tree from uncontrolled tourism with extreme urgency."

[H/T Science]