The debate over logging the ancient forests of the Pacific Northwest has led to deliberate killing of spotted owls and has spawned such bumper-sticker sentiment as "I like spotted owls FRIED."

But though the logging industry has predicted economic troubles in the Northwest and blames the spotted owl, the endangered bird is only part of a complex problem, an environmental expert said Monday night.The larger issue, said Elliott A. Norse, is the need to protect biological diversity - the number of species that exist in a given area and how each contributes to the healthy environmental whole.

The spotted owl, placed on the federal endangered species list in June, is but one life form that depends on the unique environment of the ancient forests. Destroying the forests would cause irrevocable loss to the United States and the world, said Norse, chief scientist at the Center for Marine Conservation in Washington, D.C., and author of two books on the ancient forests of the Pacific Northwest.

Norse's lecture, "The Last Great Forests in the United States: Bringing It All Back Home," given at East High School, was the fifth and final installment of the Utah Museum of Natural History's series, "End of Nature?"

Logging companies have already cut 87 percent of the ancient forests of the Pacific Northwest, Norse said. Less than half of what is left is protected in national parks.

It is over the remaining forest, which Norse said is about 7 percent of the original virgin forest, that the owl vs. jobs controversy currently rages.

But many more animal and plant species depend on the virgin forests for their lives. Each contributes to the web of existence in the forest that in turn connects to the global environment, Norse said.

The forests contribute to a healthy climate, especially during droughts, he said. Citing a U.S. Forest Service study, Norse said that hydrologists have measured 8 inches more precipitation per year in ancient forests than in clear-cut areas. This is because the trees' needles catch fog, which precipitates and "rains" from the tree branches.

The forests also combat air pollution, because their location near the Pacific Ocean has forced them to adapt in such a way that they capture and filter airborne particles for the nutrients in them.

And, Norse said, the ancient forests they store more carbon than any other ecosystem on earth - including tropical rain forests - and are thereby a major counter to global warming.

While Norse didn't speak in detail on the relationship between a healthy environment and a strong economy, he did note that Japan, a nation roughly the size of California but with four times its population, has managed to create a vital economy while also preserving its forests.

Japan has been able to do this because the populace is hardworking and resourceful, and also because they would rather buy Pacific Northwest timber than log their own mountainsides, Norse said.

The United States could direct its considerable ingenuity in the same way, Norse said.

World attention has recently focused on the destruction of the tropical rain forests of Brazil, where forests covering land area the size of West Virginia - and thousands of different animal and plant species - are destroyed each year.

But Norse said the threat to the virgin forests west of the Cascade Range is equally serious and its loss would be devastating to the global environment.