The Guardian Weekly

At 5,484 years old, could this be the oldest living tree?

By John Bartlett JOHN BARTLETT IS A JOURNALIST BASED IN CHILE

In a secluded valley in southern Chile, a lone alerce tree stands above the canopy of an ancient forest. Green shoots sprout from the crevices in its thick, dark trunks, huddled like the pipes of a great cathedral organ, and water streams down its lichen-streaked bark on to the forest floor from bulbous knots in the wood.

“It was like a waterfall of green, a great presence before me,” said the climate scientist Jonathan Barichivich, 41, of the first time he encountered the Gran Abuelo, or “great-grandfather”, tree as a child. Barichivich grew up in Alerce Costero national park, 800km south of the capital, Santiago. It is home to hundreds of alerces, Fitzroya cupressoides, slow-growing conifers native to the cold, wet valleys of the southern Andes.

“I never thought about how old the Gran Abuelo could be,” he said. “Records don’t really interest me.” However, Barichivich’s study has shown the 30-metre giant could be the world’s oldest living tree.

In January 2020, he visited the Gran Abuelo with his mentor and friend, the dendrochronologist Antonio Lara, to take a core sample from the trunk.

They were able to reach only 40% into the tree as its centre is likely to be rotten, making a complete core unattainable. Yet that sample yielded a finding of about 2,400 years. Undeterred, Barichivich set about devising a model that could estimate the Gran Abuelo’s age, producing an astounding estimate of 5,484 years old – but some colleagues assert that complete, countable tree ring cores are the only true way of determining age.

That would make it more than six centuries senior to Methuselah, a bristlecone pine in eastern California recognised as the world’s oldest nonclonal tree – a plant that does not share a common root system. Some clonal trees live longer, such as Norway’s Old Tjikko, thought to be 9,558 years old.

Barichivich believes ancient trees may help experts understand how forests interact with the climate.

“The Gran Abuelo isn’t just old, it’s a time capsule with a message about the future,” he said. “We have a 5,000-year record of life in this tree alone, and we can see the response of an ancient being to the changes we have made to the planet.”

In January, Barichivich, who works at the Climate and Environment Sciences Laboratory in Paris, won a €1.5m ($1.46m) European Research Council starting grant.

He has embarked on a five-year project to assess the future capacity of forests to capture carbon, hoping to add tree-ring data from thousands of sites around the world into climate simulations for the first time.

By adding data for xylogenesis, the formation of wood, Barichivich believes he could provide 100-year predictions for climate change – and revolutionise our ability to understand and mitigate its effects.

Barichivich’s mentor Antonio Lara, 66, has spent his career working to reconstruct temperature, precipitation and watershed levels throughout history. Lara, a professor at the Faculty of Forest Sciences and Natural Resources at Chile’s Austral University in the city of Valdivia, has been able to prove that alerces can absorb carbon from the atmosphere and trap it for between 1,500 and 2,000 years in standing dead trees. Buried alerce trunks can hold carbon for more than 4,000 years. He has also pinpointed exact climatic events by translating tree rings into numbers, which can then be read like a barcode. “The great-grandfather tree is a miracle for three reasons – that it grew, that it survived, and then that it was found by Jonathan’s grandfather,” Lara said.

In the mid-1940s, Barichivich’s grandfather, Aníbal Henríquez, arrived from the southern city of Lautaro to work for the forestry companies felling the lahuan, as the alerces are known in the Indigenous language Mapudungun, his native tongue.

Alerce shingle was used as currency by local populations throughout the 1700s and 1800s and the wood was commonly used in construction. The famous Unesco-protected wooden churches on the island of Chiloé are built from alerce trunks.

Henríquez happened upon Gran Abuelo while on a patrol in the early 1970s. Word got out and people began to arrive: now, more than 10,000 tourists trek down to the wooden viewing platform next to the tree each summer. Footfall around the base of the tree has damaged the thin layer of bark on its roots, affecting nutrient uptake.

While the scope of his research is far broader, Barichivich insists the national park is where he belongs. When he was eight years old, his grandfather disappeared on a patrol out in the snow. His body was found two days later. Another uncle, also a park ranger, later died in the park.

“The same fate probably awaits me, dying with my boots on out in the forest,” Barichivich said. “But first I want to unlock its secrets.”

Spotlight | Environment

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2022-09-30T07:00:00.0000000Z

2022-09-30T07:00:00.0000000Z

https://theguardianweekly.pressreader.com/article/282007561266330

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