When the pyramids of Egypt and the megalithic monument of Stonehenge had not yet been erected, a seed of Patagonian larch germinated in a steep and humid place located near the chilean coastabout two and a half hours from where the city of Valdivia. The tree grew vigorously and after a few centuries it became an admirable giant with a trunk greater than ten meters in circumference, an unusual size for the species. However, what makes him a truly unique individual is that He is still alive.
It is true that its trunk has cavities, that a large part of the crown has fallen off and that lichens have colonized its ancient bark, all of which are obvious signs of decrepitude, but neither inclement weather, nor forest fires, nor logging nor diseases have been with him during… 5,484 years.
Chilean researchers have just arrived at this surprising figure, so precise that it could seem like a joke. Jonathan Barichovich Y Anthony Lara with a mixed method (half direct measurement, half extrapolation) that surely will not convince everyone. The matter is tricky because if the tree, popularly known as Millennial Larch or Great Grandfather, is actually over five millennia old, would out-age the famous long-lived pines (‘Pinus longaeva’) of the Inyo National Forest, in California (USA), and would become the oldest specimen on Earth. So far, the oldest tree confirmed by trunk ring counts is a long-lived pine called Methuselah (Methuselah), in Inyo, which is 4,853 years old and whose exact location is kept secret to preserve its integrity.
The magazine ‘Science’ has echoed the new dating in Chile in an informative article, but the authors have not yet shown their work in a peer-reviewed publication, the usual path followed by all scientific research. So we will have to wait to see if the international community takes it for granted, although Barichivich advances that his study has followed the usual standards in this field of dendrochronology. Barichivich is currently a researcher at the Paris Climate and Environment Laboratory (LSCE).
The Patagonian larchlahuán or cahuén (‘Fitzroya cupressoides’) is a species of the family of Cupressaceae, such as cypresses, sequoias, junipers, cryptomerias and yours, which grows exclusively in a small enclave in central Chile that extends to Argentina. Its habitat is included in the ecoregion known as jungle or Valdivian forest, characterized by dense evergreen forests in an environment of mild temperatures and abundant rainfall, over 2,000 mm. annuals, sometimes with boggy soils. The Spanish called it ‘alerce’ because of its supposed similarities to European larch trees, but they do not belong to the same family.
El Alerce Milenario is located in the heart of the Coastal Alerce National Parkon the winding road that connects the small town of The Unioncapital of the Ranco provincewith the beach Hueicollaalready in the Pacific. “It grows in a cold and very humid ravine that faces south, so it receives less sun, and surprisingly there is no other larch tree for at least a kilometer around,” Barichivich told this newspaper. It is surrounded by broadleaf trees.
Barichivich, a forest engineer and researcher in global ecology and climate, has been linked to the tree for decades since his grandfather, who worked as a ranger in the area, was the one who discovered it in 1972. And he himself suspects that he was one of the first children to see it. .
The dating, continues the Chilean researcher, is part of a larger investigation aimed at measuring the functioning of the larch forests. “We obtained permits to be able to work with the Alerce Milenario and obtain a sample very carefully and without damaging it.” The works were carried out in 2020, just before the coronavirus pandemic was declared.
The main tool to calculate the age of trees is to obtain a complete section of the trunk in which the rings, the imprint left on the wood by the annual cycle of growth, and then count them carefully one by one. This option, of course, is only possible when the tree has fallen due to felling, wind or lightning, for example.
For live specimens, what is normally done is to pierce the trunk with a drill that extracts a fine witness in which the rings can be seen and counted. However, says Barichivich, there are no augers big enough for trees as thick as the Alerce Milenario, which has about two meter radius. “The one we have is 90 centimeters and there is no longer one.” In addition, he adds, very old trees are rotten in the center, making it difficult to calculate the total age.
What Barichivich and Lara did was to develop a statistical method to simulate growth in the part that could not be analyzed. “In 90 centimeters, which is 43% of the radius of the tree, we count 2,400 years,” says the first. “The method we designed takes into consideration their entire growth history and how larch trees grow in all the populations we’ve sampled.”
Thus, the method yielded an overall age estimate of 5,484 years, with an 80% probability that the tree lived for more than 5,000 years. “It was amazing,” says Lara. “I expected the tree to have about 4,000.”
The dangers of tourism
The Alerce Milenario is marked as a tourist attraction and has an observation point so that visitors do not approach its base, but this does not prevent people from walking around it, which damages the roots and compacts the surrounding soil, laments Barichovich. “The main threat at the moment is tourists. People are killing it,” he adds. “It urgently requires our protection.”
The second danger is the weather, Barichivich continues. “The climate is becoming drier, which makes it difficult for the roots to absorb water and stresses the tree. Chile is experiencing an unusually long dry spell that has lasted 13 years now. And this will continue in the future because this region of the temperate rain forest of South America is a terrestrial ‘hotspot’ of rainfall reduction in climate change projections. It is even stronger than what the Mediterranean basin in Europe will experience.”
Despite the surprise of the latest dating, the enormous longevity of Patagonian larches is nothing new. In 1993, for example, Antonio Lara (Universidad Austral, in Valdivia) and Ricardo Villalba (University of Colorado, in the USA) published an article in the journal ‘Science’ in which they reported a dead tree stump in the Andean zone which had 3,622 annual growth rings. This dating placed the species as the second longest on the planet, ahead of the sequoias.
“In this region of the Cordillera de la Costa de Chile, which is called Cordillera Pelada, there are trunks (stumps) of large larch trees that testify that there were other large and ancient trees in the past, with diameters of up to 3, 8 meters”, concludes Barichivich. But Millennium Larch is the eldest.