ENVIRONMENT / MEDICAL TWIST : Yew Tree Use in Anti-Cancer Drug Adds to Logging Debate

While the highly publicized tug-of-war over logging the ancient forests of the Pacific Northwest has been focused on the northern spotted owl, another controversy has slowly been brewing over the same issue--this one with a medical twist.

The biomedical research community, in an unusual alliance with environmentalists, has become increasingly worried about the fate of the Pacific yew--a rare and slow-growing tree whose bark is the only source of an experimental drug that has shown promise in the treatment of cancers.

LUJAN PETITIONED: Recently, 10 environmental organizations backed by cancer researchers and the American Cancer Society petitioned Interior Secretary Manuel Lujan Jr. to list the Pacific yew as a threatened species, which would require action to protect the tree.

The bark is the only source of a drug called taxol, which has reduced tumors in some patients with ovarian cancer, a malignancy resistant to other forms of chemotherapy. This year, an estimated 20,500 women are expected to be diagnosed as having ovarian cancer, and about 12,400 women are expected to die of the disease.

Taxol was discovered almost by accident in the 1960s during a large-scale program by the National Cancer Institute to screen plants for possible anti-cancer effects.

SCARCE SUPPLY: Dr. Sam Broder, director of the cancer institute, said at a recent meeting that his agency has enough taxol to treat about 200 to 300 people. Moreover, only 2.4 kilograms of taxol--enough to treat 2,500 patients--has been produced since 1975.

Finding a way to increase the supply of taxol is “an emergency priority” of the institute, Broder said. “We need to find either a renewable resource for taxol, or we need to find a completely synthetic method for making it.”

While efforts continue in the laboratory to find ways to increase the supply, the save-the-tree coalition is pressing its case.

“The debate over the future of the ancient forests involves more than a choice between spotted owls and logging jobs,” said Bruce S. Manheim, an attorney and scientist with the Environmental Defense Fund. “Our ability to assure an adequate supply of this novel anti-cancer compound is at stake as well.”

The irony implicit in their efforts is that harvesting the bark to obtain the drug kills the tree. Thus, environmentalists say they must strike a balance between needless destruction--which they say happens during logging--and the need to keep enough trees alive to preserve the future of the species. The trees require at least a century or more to reach a size at which they are useful for extracting the drug.

“People who are interested in taxol are interested in the large trees, but when the loggers come in, they knock down everything from large trees to seedlings,” said Elliott A. Norse, chief scientist for the Center for Marine Conservation.

INDUSTRY EFFORTS: Jackie Lang, a spokeswoman for the Oregon Lands Coalition, which represents the timber industry, said the efforts of the environmental/research groups was “just another attempt to lock up the forests.” She said there is an identification system in place for the yew that requires loggers to leave the trees alone. “A logger is in big trouble if he knocks down a yew tree,” she said.

Environmentalists say that even if yew trees are left standing while others around them are cut, the tree becomes endangered by increased exposure to heat and light.

Further, said William Murray, attorney for the American Forest Council, which represents the timber industry, several companies have begun to notify researchers and others when they plan to cut in an area of yews “so they can come in and get them. It’s not as if industry has ignored the need for the yew in terms of research.”

Also, he said, the Weyerhaeuser Co. has begun a research program to grow the tree in nurseries.