A recent study by Chilean researchers identifies a remarkable specimen known as the Alenen Milenario or Gran Abuelo, located in the Alenen Costero National Park within the La Unión commune in Chile. The team concludes that this tree is about 5,484 years old, a finding that places it as the oldest living tree on record, surpassing Methuselah, a bristlecone pine in the United States aged at roughly 4,853 years.
The results exceeded the expectations of the study collaborators, which include researchers from the local institutions and collaborating organizations such as Alenen Corporation, Universidad Austral de Chile, and Conaf. The work is part of a broader program focused on understanding the growth, longevity, and ecological role of this species in its native forests.
Jonathan Barichivich, a forest engineer and ecologist involved in global climate research, who is associated with a group known for studying ancient larches, explained that the current project is part of a wider effort to explore how these forests function and persist over millennia. The emphasis is on how the Great Grandfather tree fits into its ecosystem and what its age reveals about historical climate patterns and forest dynamics.
“Researchers obtained permissions to study old alder trees and to take samples with care to avoid damage. Tree ages are determined by counting growth rings, which are annual, and a core sample can reveal the tree’s age from the center outward”, notes collected by Diario Austral Los Ríos. The team explains that samples were taken with precision to safeguard the living organism.
They also acknowledge a practical challenge: ancient larches can have trunks over four meters in diameter, and removing a sample large enough to reach the center requires a drilling hole much larger than standard equipment. Often, the internal rings have decayed, complicating exact age estimation. Still, the researchers pursued a robust approach to overcome this limitation by applying a statistical method to model growth where direct sampling could not reach the core.
A Statistical Method
The team sought to estimate age despite sampling constraints. Barichivich described the solution: a statistical method that simulates growth for portions of the tree that could not be sampled. At a 90-centimeter depth, the observed rings suggest about 2,400 years, which represents roughly 43% of the tree’s radius. The method integrates multiple growth histories from diverse populations studied by Barichivich and his colleague Antonio Lara to project the overall age distribution.
Barichivich emphasized that the exact ranking of age is not the sole objective. The method provides a probabilistic distribution of epochs, indicating that the range between 3,500 and 6,000 years contains a significant probability peak for this tree. In particular, the most likely age is 5,484 years, a figure that surprised the team and exceeded their initial expectations of being over 4,000 years old. The assessment points to a striking example of persistent growth in ancient forests and the value of statistical approaches when direct measurement is limited.
Further reflections highlight the importance of documenting and understanding these ancient trees as living records of environmental change and resilience. The study underscores that such specimens can offer unique insights into climate history, forest genetics, and conservation strategies for long-lived species in coastal ecosystems.
Notes from the environmental research team indicate the ongoing nature of the project and the importance of continued monitoring to refine age estimates and assess the health and longevity of the forest community in Alenen Costero National Park.
End of report.
End of study updates will be communicated through official channels and scientific publications.
[Citation: Diario Austral Los Ríos discussions and field notes referenced in this summary].