A study recently carried out by two Chilean scientists has made it possible to establish that the tree specimen known as ‘Alerce Milenario’ or the ‘Gran Abuelo’, which lives inside the Alerce Costero National Park in the commune of La Unión (Chile), would have one age of 5,484 years. In light of this finding, the Chilean alerce is now considered a the oldest living tree in the worldthus surpassing the conical bristle pine known as ‘Methuselah’ (in the United States), whose age stands at 4,853 years.
The result of this analysis far exceeded the expectations of Jonathan Barichivich and Antonio Lara, co-authors of the research, carried out in collaboration with institutions such as the Alerce Corporation, the Universidad Austral de Chile and Conaf.
Jonathan Barichivich, forestry engineer and researcher in global ecology and climate, and who is also part of the entity known as the “guardians of the ancient larch”, explained that the study of ‘Great Grandfather’ is part of a broader investigation aimed at studying the functioning of the forests of this species.
“Within that frame, we obtained permits to be able to work with the ancient alerce tree and obtain a sample very carefully and without damaging it. To study the age of the trees there are the growth rings, which are annual and one can count them and know the age of the tree, having a sample up to the center”, he said in statements collected by Diario Austral Los Ríos.
Nevertheless, “in such giant and ancient trees, not all the rings that exist can be counted, first because the hole (tool to obtain the sample) that we have is 90 centimeters and there is no longer one to reach the center of the tree. The ancient larch is more than four meters in diameter, so to reach the center we would need a hole of more than two meters. But also, in general, very old trees are rotten in the center, so the rings are no longer there and that is a complication to be able to estimate the total age of these trees”, continued the expert.
A Statistical Method
So how did they manage to date the tree? Barichivich explained that to overcome this obstacle they developed “a statistical method to simulate the growth in that part that we could not sample. In 90 centimeters we count 2,400 years of age and it is only 43% of the radius of the tree. The method we designed takes into account their entire growth history and how the alerces grow in all the populations that we have sampled with my colleague Antonio Lara.”
And he continued: “We are sure of our method; Whether it is the oldest in the world or not, it matters little to us, what matters to us is to show that it is a unique specimen. The method allows us to estimate the distribution of the probabilities of the ages and in a range of 3,500 to 6,000 years, there is an 80% probability that this tree is older than 5,000 years. The peak of the probability is 5,484 years, so the most likely age is that. We expected the age to be over 4,000 years, but the figure of 5,000 really surprised us.”
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