SEQUOIA NATIONAL PARK, Calif. (AP) — High in the canopy of General Sherman's evergreen tree, the world's largest tree, researchers searched for evidence of bark beetles, a new threat to giant sequoias.
Climbers descended the towering 2,200-year-old tree on Tuesday with good news.
“The General Sherman tree is doing well right now,” said Anthony Ambrose, executive director of the Ancient Forest Society, which led the expedition. “It appears to be a very healthy tree that should be able to ward off any beetle attack.”
Sequoia National Park attracts visitors from all over the world, but this was the first time climbers had summited the park's iconic 275-foot (85-meter) sequoia trees.
The largest living organisms on Earth, giant sequoias have survived for thousands of years in the Sierra Nevada mountain range in western California, the only place their species grows naturally.
But as the climate becomes hotter and drier, giant sequoias, once thought to be virtually indestructible, are increasingly threatened by extreme heat, drought and wildfires.
Record wildfires in 2020 and 2021 killed 20% of the world's 75,000 mature sequoias, according to park officials.
“The most significant threat to giant sequoias is climate-driven wildfires,” says Ben Blom, director of management and restoration for Save the Redwoods League, “but we definitely don't want to be surprised by a new threat, which is why we're studying these beetles now.”
Researchers climbed General Sherman, the world's largest tree, in Sequoia National Park, California, Tuesday, May 21, 2024. They examined the 275-foot-tall tree for evidence of bark beetles, a new threat to giant sequoias. (AP Photo/Terry Chia)
Researchers climb General Sherman, the world's largest tree, in Sequoia National Park, California, on Tuesday, May 21, 2024. They inspect the tree for signs of bark beetles, a new threat to giant sequoias. (AP Photo/Terry Chia)
Tourists walk through a grove of giant sequoias near General Sherman, the world's largest tree, in Sequoia National Park, California, on May 21, 2024. Researchers surveyed the 275-foot-tall tree for signs of bark beetles, an emerging threat to giant sequoias. (AP Photo/Terry Chia)
But researchers are growing concerned about the beetles, which have not posed a serious threat in the past.
The beetles are native to California and have coexisted with sequoias for thousands of years, but only recently have they begun to kill the trees. Scientists say they have recently found about 40 dead sequoia trees killed by the beetles, mostly in national parks.
“The combination of drought and fire has left us documenting trees that are too weak and dying to defend themselves against beetle attack,” Ambrose said.
The beetles attack trees by drilling holes from the crown into the branches and down the trunk. If left unchecked, these tiny beetles can kill a tree within six months.
So park officials gave Ambrose and his colleagues permission to climb General Sherman. They inspected the tree's health while reporters and tourists watched as they made their own climbs on ropes dangling from the canopy. They examined the branches and trunks, looking for tiny holes that could indicate beetle activity.
Clay Jordan, superintendent of Sequoia and Kings Canyon National Parks, speaks in front of General Sherman, the world's largest tree, in Sequoia National Park, California, Tuesday, May 21, 2024. Researchers have been examining the 275-foot-tall tree for evidence of bark beetles, a new threat to giant sequoias. (AP Photo/Terry Chia)
Researchers climbed General Sherman, the world's largest tree, in Sequoia National Park, California, Tuesday, May 21, 2024. They examined the 275-foot-tall tree for evidence of bark beetles, a new threat to giant sequoias. (AP Photo/Terry Chia)
Researchers examine General Sherman, the world's largest tree, in Sequoia National Park, California, Tuesday, May 21, 2024. The team examined the 275-foot-tall tree for signs of bark beetles, a new threat to giant sequoias. (AP Photo/Terry Chia)
But because it's not possible to climb every sequoia tree and observe its canopy directly, the team is also testing whether they can use drones equipped with sensors and satellite imagery to monitor and detect beetle infestations in the forests on a larger scale.
Tuesday's health inspection of General Sherman was organized by the Giant Sequoia Lands Coalition, a coalition of government agencies, Native American tribes and environmental groups, which want to establish a program to monitor the health of the towering trees.
Officials said if they spot a beetle infestation, they may combat the attack by spraying water, pruning branches or using chemicals.
Bark beetles have ravaged pine and fir forests across the western United States in recent years but have never previously posed a threat to giant sequoias, which can live for up to 3,000 years.
“These trees have been surviving insect attacks for many years, so why are we seeing these changes now?” said Clay Jordan, manager of Sequoia and Kings Canyon National Parks. “We have a lot to learn about how to properly manage these trees over the long term.”
