The Stratosphere Giant, the world's reigning tallest living tree, seems to have lost its title -- to not one but three contenders.

Like the 370-foot Giant, the three trees are coast redwoods. They were discovered this summer in Redwood National Park near Eureka by a team of California researchers who spend most of their free time bushwhacking through North Coast forests in search of taller and taller trees.

So far, the group has found about 135 redwoods that reach higher than 350 feet, said team member Chris Atkins, the man credited with finding the Stratosphere Giant in August 2000 in nearby Humboldt Redwoods State Park.

The tallest of the three new finds, a redwood named Hyperion, measures 378.1 feet. Next in line, Helios, stands at 376.3 feet; Icarus, the third, reaches 371.2 feet.

Redwood experts say the discovery is a bit surprising considering that so much of the state's redwood forests have been logged. Although officials decline to pinpoint the exact locations of the tall trees, the stand found by Atkins and fellow amateur naturalist Michael Taylor were protected less than 30 years ago by an expansion of the national park's boundary.

Atkins and Taylor discovered Helios and Icarus on July 1 and Hyperion on Aug. 25. They took initial measurements with hand-held lasers before returning with Steve Sillett, a Humboldt State University biologist known for his work on the ecosystems of ancient forest canopies, and Robert Van Pelt, a forest ecologist at the University of Washington. The foursome shot more measurements using a tripod-mounted laser fitted with a remote trigger designed to eliminate human-induced wobbles.

Atkins said Hyperion soon will be measured again with a tripod laser or with a "tape drop" -- in which someone climbs the tree and drops a measuring tape to the ground -- before its record-breaking status is confirmed. Tape drops can't be conducted for at least two weeks because of National Park Service restrictions to protect the marbled murrelet, a small seabird that nests in old-growth redwoods.

If and when the measurement on Hyperion is confirmed, it is likely to supplant the Stratosphere Giant in the Guinness Book of World Records.

To change the record, the tree's dimensions must be sent to Guinness, which will forward the information to its record verification department in the United Kingdom. It could take several weeks to confirm the new record, Guinness spokeswoman Kristen Opalach said.

George Koch, a biology professor at Northern Arizona University who specializes in plant ecophysiology, called the find incredibly exciting.

"With so much of the old-growth redwoods gone -- more than 90 percent -- you wouldn't necessarily expect a discovery like this," he said.

The find is all the more remarkable, Koch said, because the trees are in a tract added to the park belatedly, during President Jimmy Carter's administration.

"They aren't all that far from an old clear-cut," he said. "Basically, they were almost nuked. The fact that they weren't is amazing."

Koch said the trees are also noteworthy for their location. It had long been assumed, he said, that very tall redwoods favor creek bottoms where rich, alluvial soils and abundant water allow for extravagant growth. The newly discovered trees live on slopes.

"It seems that they were close to tributary stream courses, however, so they probably were able to keep their feet wet," he said.

Atkins confirmed that all three of the trees were adjacent to creeks or springs.

"Even though they're on steep slopes, they're growing in the finest redwood habitat on the planet," Atkins said. "They're right below a ridge, so they're protected from the wind. They're near abundant water, and they have plenty of fog, which keeps the local microclimate mild and moist. And they have great sun exposure."

The tree's precise location has not been revealed and probably won't be. The Stratosphere Giant's location is generally referred to as the Rockefeller Forest.

Rick Nolan, the acting superintendent of Redwood National Park, said it would be nearly impossible for visitors to find the trees. Unlike isolated giant sequoias, including one in Sequoia National Park that holds the record as the world's most massive tree, coast redwoods grow together.

"From the visitors' perspective, it's important to understand that if they come looking for the biggest tree, they're not going to find it," Nolan said. "They're consumed by the rest of the forest."

Reaching the backcountry is difficult. Atkins said he takes heavy gear, including the laser tripod, over steep slopes, over downed trees and through thick vegetation.

"Bushwhacking in that kind of country is kind of like climbing Everest at 28,000 feet," he said. Reaching the record-breaking trees "isn't a pleasure hike."

The difficult terrain isn't the only reason to keep the location a secret. Ruskin Hartley is the conservation director for the Save the Redwoods League, the country's oldest conservation group devoted to redwood ecosystem preservation. She said problems sometimes occur when superlatives are appended to specific trees.

One such case, he said, involved the Mendocino Tree, a redwood near Ukiah that at one time was considered the world's tallest tree. The rush of visitors created management problems. Similar problems, including root damage, have injured other giant trees.

"We need to remember that while redwoods are large robust trees, they are also delicate in some ways. They have very shallow root systems, and the landscapes they comprise are vulnerable to disturbance," Hartley said. "We need to draw attention to the forest as a whole, to the entire system, not the individual trees."

Record trees

Tallest living tree: Hyperion (coast redwood), 378.1 feet, Redwood National Park

Tallest recorded tree: Unnamed eucalyptus, 500-plus feet, recorded in 1872 in Australia

Most massive living tree: General Sherman (giant sequoia), estimated weight 4 million pounds, Sequoia National Park

Largest tree canopy: A great banyan in Calcutta's Indian Botanical Garden covers three acres.

Oldest living tree: Methuselah (Bristlecone pine), estimated 4,650 years old, California's White Mountains

Source: Guinness Book of World Records