In the 1990s, it was discovered that taxol, a chemical found in the bark of Pacific yew trees in the Pacific Northwest, was effective in treating ovarian cancer, which afflicts 10,000 women each year. It takes the bark of about 150,000 yew trees per year to extract enough taxol to treat these women, many of whom would otherwise die. The problem is that yew trees are slow growing and are mostly in old-growth forests that have taken hundreds of years to develop. Taxol has recently been found to be effective on a number of other cancers, such as lung cancer. This has increased the demand for it, meaning more trees are required. Even the development of a semisynthetic version of taxol does not completely solve the problem and complete synthesis is not yet feasible. Environmentalists point out that heavy logging of old-growth forests can damage other trees and the environment. Until scientists develop new sources of taxol, there will continue to be a trade-off: Saving women with ovarian cancer and persons with other types of cancer or saving Pacific yew trees.

What is the opportunity cost of saving yew trees? What is the opportunity cost of saving the lives of the women suffering from ovarian cancer who could be treated with taxol?