The Lowly Yew Yields Riches

For a prickly, slow-growing runt that only a few short years ago was burned as refuse, the Pacific yew sure has come up in the world. Out in the rapidly vanishing ancient forests of the Pacific northwest, some 500 laid-off lumber-mill workers, college students and single mothers are trying to make a living by stripping this evergreen's bark. It contains taxol, which has shown promise in the battle against ovarian and breast cancers. Hauser Chemical Research, Inc., in Colorado is the sole supplier of taxol to pharmaceutical giant Bristol-Myers Squibb; Hauser pays its harvesters, who must have permits from the Forest Service, $2.25 a pound. That's good money in the economically strapped timberlands. Very good. A federal grand jury in Eugene, Ore., just indicted five men for harvesting yew bark without permits. Federal agents have pulled off an elaborate sting that netted a major yew-bark poacher. And the secretary of agriculture has offered up to $10,000 to anyone who helps convict yew bandits.

It's gold-rush time in the forest, and fingers are pointing every which way about who's to blame. Last January the federal government awarded Bristol-Myers the sole right to produce taxol from trees on public lands. Bristol-Myers contracted with Hauser to round up and process the bark. "It's a de facto monopoly," charges Jerry Rust, Lane County, Ore., commissioner. With no competitors to bid up the price of yew bark, critics contend, Bristol-Myers and Hauser have no incentive to conserve it by squeezing the most taxol from each tree. Instead, bark prospectors can just partly strip the bark from several trees, killing them all, rather than skin a single yew completely. As a result, says Wendell Wood of the Oregon Natural Resources Council, the species is imperiled: "Hauser only wants the bark that is easy to collect," says Wood. "They refuse to collect from the limb stock, twigs and needles." It's not for want of technology (NaPro of Boulder, Colo., has reportedly developed a way to extract taxol from needles). But the only approved source of taxol is bark.

Will the yew survive its popularity? To test taxol on 12,000 cancer patients (taxol is only experimental thus far), the National Cancer Institute requested 750,000 pounds of bark this year. That's at least 38,000 yews killed. Although no one knows how many remain, "this level can't be sustained," says Wood. Indeed, Bristol-Myers has contracted with forestry giant Weyerhaeuser Co. to develop yews that yield more taxol; they've already planted half a million test trees. Plantation yews won't yield much taxol for at least five years, but having them in reserve may decrease the incentive to preserve yews in the forest. Hauser's Neil Jans isn't worried, however. "We're going to have very little impact on the species," he says, since he expects alternative sources to turn up.

Other sources of taxol may be the only hope for Taxus brevifolia. Bark from three eight-inch trees is required to treat one patient with ovarian cancer, which kills 34 Americans a day. But the loaded question--Which is more important, lives or trees?--might be sidestepped if the yews hold out until taxol can be harvested from laboratories. Already, Phyton Catalytic, Inc., of Ithaca, N.Y., is just two to five years away from making limitless quantities of taxol by cultivating yew cells in bioreactors. "Tissue culture lets us use valuable genetic resources without depleting them," says Phyton president Rustin Howard. Some 30 research groups are hot on the trail of synthetic taxol. Robert Holton of Florida State University is exploring ways to extract precursors of taxol from yew needles; the precursors would then be chemically converted to taxol itself. Not long ago a man broke into Holton's lab in search of taxol for his mother, who was dying of breast cancer. Tree huggers aren't the only ones cheering on the chemists.

The Lowly Yew Yields Riches | News