Scientists rush to save 1,000-year-old trees on the brink of death

No organism on Earth is known to live as long as the Great Basin bristlecone pine. The oldest documented tree, a well-hidden specimen nicknamed “Methuselah,” after the long-lived biblical patriarch, was a sapling when the ancient Egyptians built their pyramids more than 4,500 years ago. Even the relatively youthful trees in Death Valley are older than gunpowder, paper money and the English language.

The secret to their survival is their ability to withstand what others cannot. They produce a thick resin that traps insect invaders and quickly patches wounds. Their genomes, which are nine times as long as a human’s, contain a multitude of mutations that give them a better chance of adapting to changing conditions.

In 2018 when Constance Millar ascended the trail to Telescope Peak — the highest point in Death Valley National Park — she discovered hundreds of dead and dying bristlecones extending as far as she could see.

The trees’ needles glowed a flaming orange; their bark was a ghostly gray. Millar estimated that the damage encompassed 60 to 70% of the bristlecones on Telescope Peak.

“It’s like coming across a murder scene,” said Millar, an emerita research ecologist with the U.S. Forest Service who has studied bristlecone pines for the better part of 40 years.

In a study published this spring, she and fellow researchers showed that the West’s worst drought in at least 1,200 years had critically weakened the trees. Voracious bark beetles — a threat to which bristlecones were previously thought immune — delivered the death blow.

After outlasting millennia of disruptions and disaster, human-caused climate change is proving too much for the ancient trees to bear. Rising temperatures have caused an explosion in the populations of insects that threaten the trees and undermined their capacity to defend themselves, scientists say. Although Great Basin bristlecone pines are not considered at risk of extinction, cherished specimens and distinctive populations are struggling to survive.

And bristlecones are not the only victims. At this very moment, a fast-moving fire is scorching through the iconic giant sequoia grove in Yosemite National Park. Cedars are choking on saltwater as rising seas engulf shorelines on the East Coast. A rare oak species clings to life as the Texas desert grows hotter and drier.

A new study, published Wednesday in the journal Nature, found that climate change has pushed almost a quarter of Earth’s best-protected forests to a “critical threshold” for lost resilience — the point at which even a minor drought or heat wave could tip them into catastrophic decline.

23% of untouched forests are approaching the point at which they could be pushed into an abrupt and irreversible transition, the scientists said. Rainforest could turn into grassland. Thick stands of pine might give way to shrubs and desert.

“It’s a strong warning, I think, for society,” said Giovanni Forzieri, a professor of sustainable development and climate change at the University of Florence and lead author of the Nature study.

To Murphy Westwood, the vice president for science and conservation at the Morton Arboretum in Illinois, each loss feels like a moral failing.

“It’s overwhelming and almost crushing,” she said, “the stark reality of the biodiversity crisis that’s on our hands.”

Last year, Westwood helped publish a sweeping assessment of 58,497 tree species worldwide that found that nearly 30% are at risk of being wiped out. At least 142 species have gone extinct in the wild.

It’s not just trees. With global temperatures already more than 1˚C (1.8˚F) higher than in the preindustrial era, the Earth is losing species at a rate hundreds to thousands of times faster than normal.

If the world remains on its current warming track, as much as 29% of all creatures on land will face very high risk of extinction. In the ocean, the destruction will be even greater.

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