A young man who had fallen in love with the ancient redwood forests of Northern California was crushed and killed there by a falling tree cut down by a lumberjack during a protest against logging on private land.

David Chain, 24, a member of the radical environmental group Earth First!, died Thursday in the Grizzly Creek forest 300 miles north of San Francisco. He was attempting to slow down or stop loggers by playing what the activists call "cat-and-mouse" in the woods.

Cat-and-mouse means that the protesters put themselves directly in the path of chain saws and trees marked to be felled, in this case by a crew from a company called Pacific Lumber. Normally, the Earth Firsters would shout to the loggers that they should not cut a tree because it would fall on them.

The Earth Firsters said they have a videotape of Thursday's confrontation that will show the logger knew they were in the path of the trees.

But the Pacific Lumber president, John Campbell, said the logging crew, which was working two miles from the nearest public road, "had no knowledge that this individual was nearby." The feller, according to a company spokeswoman, "had not seen the protesters in the area for at least an hour."

Campbell added that sheriff's investigators said Chain's death was "an unfortunate accident" and that the company will conduct its own investigation of the incident.

The Humboldt County Sheriff's office said it also is investigating.

According to members of Earth First who were trespassing in the woods, Chain and eight others were taking part in "an intense direct action" against the loggers employed by Pacific Lumber, a family company that was taken over by corporate raider Charles Hurwitz in 1986 and has been the center of an environmental storm ever since because of its large holdings and its accelerated cutting of trees.

The protesters said they first argued with loggers, telling them that they were violating agreements over the protection of a seabird known as the marbled murrelet, and when this failed to stop the loggers, they played "cat and mouse."

"There were people all over the woods," said Jennifer Garner, one of the Earth Firsters based in Arcata, Calif., who came out to the redwoods a week ago with her friend Chain from Austin.

Environmentalists have been battling for over a decade in the great coastal forests of California, home to cathedral groves of redwood trees as much as 1,000 years old and towering as tall as a 30-story building. Some of the environmentalists belong to mainstream groups such as the Sierra Club and others use the courts to try to stop the logging. But the Earth Firsters believe in direct action.

They are often young, idealistic outsiders who live in group houses and have been trying to stop timber companies from harvesting lumber on private land. They argue that the ancient trees are too precious to cut and that the companies are disturbing habitat that belongs to endangered species like the coho salmon or the marbled murrelet.

But the outsiders are not liked by many of those who make their living in the saw mills. At Pacific Lumber's company town of Scotia, the muddy pickup trucks sport bumper stickers that read: "Support Earth First: Get them a job."

The Earth First activists often climb the trees and build temporary platforms in the high branches attempting to thwart the loggers. Activist Julia Hill, known as "Butterfly," has been sitting in a tree on Pacific Lumber land since last December, a record.

Earlier this month, the state of the California and the federal government completed a historic deal to purchase nearly 10,000 acres of mostly old-growth trees for $495 million, making it one of the most expensive such transactions in history. In addition to the land deal, the government is negotiating a Habitat Conservation Plan that would allow the company to harvest its trees for the next 50 years within certain guidelines that would permit some endangered species to be killed.

Some environmentalists called it a deal with the devil and vowed to continue to fight Pacific Lumber's logging efforts. CAPTION: Old-growth redwoods like this one -- felled by a state crew Tuesday because it was leaning precariously across a road near Redcrest, Calif. -- can be as tall as a 30-story building. CAPTION: A group of distraught Earth First! activists console each other after a fellow logging protester was killed.