Plants have definite personalities. Oak is considered mighty and unyielding; willow is a symbol of compliance, maybe sadness, and daisies are cheery.
Our ponderosa pine, scattered throughout the Rogue Valley and its nearby forests, is stately and bold. One of my favorite plants is the yew (Pacific yew, Taxus brevifolia). I think of it as shy and patient, but tough.
It is not at all showy. It almost never stands out in the forest. It is known as an "understory" tree (growing beneath the main tree canopy) and is one of the slowest growing trees in southwest Oregon.
Trees more than 20 feet tall are rare and the average diameter, according to local inventories, is less than 5 inches, although we measured one unusual specimen greater than 30 inches in diameter.
Yew ranges from Northern California into Canada mostly along the coast and the western edge of the Cascades (it thrives in high humidity), but there is a detached population scattered across the moist, windward side of the Idaho Rockies. Locally, humid areas near watercourses provide the wettest and safest habitat, since moderately intense fires easily kill yew.
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Not only that, but like its big brother, the coast redwood, it sprouts. Of 25 (or more) conifers here in southwest Oregon, they are the only two that can sprout.
Yew has been used for weapons (longbows), medicines and ceremonies (religious and funeral) in some parts of the world. Here it is predominantly known to deer and elk as a low-growing, nutritious winter meal.
Yew might have retained its local anonymity had it not been for the National Cancer Institute. In the mid-1960s yew was part of a massive screening of 35,000 plants. Taxol, a chemical named after the genus Taxus, found in the bark, showed promise as a treatment for ovarian and other cancers.
The potential for preventing more than 16,000 deaths a year is undoubtedly newsworthy. Since then the shy yew has had more than its allotted 15 minutes of fame.
Collection of yew bark for study and treatment increased in the 1980s to about 200,000 pounds in 1988. Approximately 60,000 pounds came from Southern Oregon alone.
When all this started we in the U.S. Forest Service didn't know how much yew bark would be needed, nor precisely how much was out there. We had census data, estimates and built predictive models, but to be sure, we specifically inventoried yew populations throughout its range.
I was particularly excited since my job was to analyze our data to help determine (a team was established to evaluate ecological concerns) harvest effects and the potential for Taxol production.
Cooperation was exceptional. The possibility of arresting particular types of cancer was exciting to everyone involved. Within two weeks after asking for sets of data, I received almost a dozen 31/2" floppy disks in the mail (the most efficient method of transferring data at that time). Not only were there quite a number of existing studies to draw from, research and university personnel quickly refocused. We all wanted assurance that the ecosystem could produce the needed Taxol while maintaining the Pacific yew's role in ecosystem processes.
Of course, we knew that taking all the bark from a section around the trunk, called girdling, would kill the tree. But we found yew could survive if 90 percent of the bark was removed leaving only a thin strip of bark connecting the crown to the trunk (our team recommend leaving 50 percent or the bark on the trees that were stripped and leaving half the trees in any group untouched).
We found that pollen mixing within a small riparian population was substantial. We determined common sex ratios and how trees interacted with each other. Within a short period, we learned a great deal about a tough little tree and we were heartened by how people came together and worked intensely for such a vital need.
As it turned out, it was not long before other sources and synthetic versions of Taxol were produced. Pacific yew is no longer the center of attention. It can again reside in the understory. And that is a good thing.
Tom Atzet is a retired Forest Service ecologist living in Merlin. He can be reached at P.O. Box 1226, Merlin, OR 97532.
