EUGENE, ORE. -- Fear of corporate raiders has added a strange new twist to the bitter battle here over saving the last stands of ancient forests from the logger's snarling chain saws.

This fear is forcing private timber owners to cut their trees at a record rate, say environmentalists and economists, to avoid becoming leveraged buyout targets. And if they are swallowed by raiders, they say, there will be an orgy of tree-cutting to pay the junk bond debt.

To a raider, any tree standing is an unclaimed financial asset that could be cut and sold to maximize profits. Some timber companies have been taken over, and the new owners have accelerated harvests. In California, a backlash against the phenomenon got an initiative on the November ballot calling for a $710 million bond issue to buy and protect old forests.

Private logging companies under this kind of pressure are as much in danger of extinction as the forest's northern spotted owl, say environmentalists.

So, at least on this issue, some environmentalists have put aside their longstanding, sometimes violent feud with the timber industry and instead want to help private loggers.

''We have to take away the fear of private landowners of hostile takeovers,'' said Tim Hermach, executive director of the Native Forest Council in Eugene. About 70 percent of the nation's forests are owned privately and the rest by the federal government.

Once this threat is lifted, said Hermach, private forest owners ''could afford to manage lands for the long-term investment. They wouldn't have to liquidate in the quick term.''

That sort of long-term outlook would result in a sustained harvest on private lands, allowing the preservation of old forests held by the U.S. Forest Service, environmentalists believe.

The timber industry, however, has not changed its longstanding position that the old forests are a waste of wood. Timber allowed to die off and rot is neither economical nor beautiful to a logger.

''A young stand of trees is much better than old rotten trees,'' said R.L. ''Dick'' Ford, a regeneration forester for Weyerhaeuser Co. ''A 10-year-old stand of trees is the most beautiful thing there is.''

The debate has intensified with the recent U.S.-Japanese agreement to encourage exports of American wood products to Japan, a move that some timber company officials say will triple their sales. The timber industry, which fought for the relaxed import restrictions by Japan, estimates the agreement could provide tens of thousands of additional jobs.

Environmentalists contend that 95 percent of America's virgin forests have been cut down, the pace of destruction quickened by mechanization and automation. Though private foresters say they replant trees, activists say that creates a uniform ''tree farm'' with none of the biological diversity of a real forest.

The timber industry disagrees.

''It doesn't exist,'' said Weyerhaeuser's Ford, speaking of the tree-activist's view of the forest as a place of extraordinary biological diversity.

Because private foresters cut down their tall timber long ago, most of the remaining centuries-old forests are on federal land. Some trees are a thousand years and more old, making them the oldest living things on Earth. The old trees are vanishing at the rate of 170 acres a day, it has been estimated, and could be gone in decades.

Activists call further cutting of the old, or virgin, forests, ''the last great buffalo hunt,'' comparing it to the near-extinction of buffalo by commercial hunters in the last century.

Even logging people are breaking ranks. Ric Bailey of Joseph, Ore., was a logger in the 1970s and 1980s. Then he quit.

''There was no dignity in cutting down 700-year-old trees,'' he said.

''I didn't feel good about what I was doing.'' Now he's a truck driver.

The battle over virgin forests took a new turn in 1988, when the Sierra Club sued to protect the northern spotted owl, which lives in old growth forests in the Northwest. A federal court ordered the U.S. Fish and Wildlife Service to decide whether to list the bird as an endangered species.

If the bird achieves that designation, the Forest Service will be forced to protect it by making some of its habitat off limits to loggers. A decision is expected June 23.

Next came the corporate raiders.

Brian Gerber, assistant professor of forest economics at Oregon State University, said 90 percent of industry foresters are ''prudent land managers,'' who cut down and replace trees at roughly equal rates, a practice known as sustainable yield.

''There are concerns in the forestry community over purchase of forest lands by nontraditional forest owners, and whether they have the same goals and philosophy that traditional forestry landowners have toward the land,'' he said.

Gerber said takeovers by out-of-state investors in Oregon is ''a slowly growing trend'' that ''could become a rapidly growing trend,'' depending on the price of lumber.

Notable examples include Britain's Sir James Goldsmith's purchase of Crown Zellerbach Corp. and the leveraged buyout of California's Pacific Lumber Co. by Maxxam Corp. of Houston, with the help of junk bond underwriter Drexel Burnham Lambert Inc.

Californians were incensed. An ecology group known as Forests Forever got 800,000 signatures for a forest initiative in the state's November elections, calling for a $710 million bond issue to buy unprotected ancient forests in the state.

''The trigger to it was the change in corporate management of ... forest resources in California,'' said Leo McElroy, Forests Forever campaign manager.

Until the Pacific Lumber incident, said McElroy, ''most California lumber companies were owned by California firms that tended to take a long-term view of timber harvest practices.

''It's more like locusts now," he said. "They come in, take everything they want and leave bare countryside.''

John Campbell, Pacific Lumber Co. president, said the Scotia, Calif., firm doubled its timber harvest after Maxxam took over.

But he said the decision was made only after an inventory showed the company had 30 percent more timber than it realized.

Campbell said the takeover was healthy for the company, which added a sawmill to cut more timber.

''We've added over 300 full-time jobs,'' he said. He also pointed to a 121-year record of responsible management in which it sold 20,000 acres of redwood trees now in the Humboldt Redwood State Park.

''The management hasn't changed, the philosophy hasn't changed and we're still the same responsible company we were previously,'' he said.