Passage II

A Tree's Change in Status

[1]

[1] For almost two millennia, the yew an evergreen tree with a poisonous fruit and a twisted trunk, was scorned or feared by many people, particularly Europeans. [2] In the first century A. D, the Greek biographer Plutarch warned of sleeping in the shade of a yew was a deadly practice. [3] About the same time, the Roman author Pliny pronounced the yew “unpleasant and fearful to look upon." [4] The old British practice of planting yews in cemeteries did nothing in changing or altering that reputation. [5] Recently, however, the discovery of taxol, a substance found in the bark of the yew, has given the tree new status. (19)

[2]

In the 1960s, scientists discovered that it was a promising anticancer drug. (21) Although pharmaceutical companies that begun to produce the drug learned that taxol could be extracted from the bark of all species of yew, its attention was soon focused on the Pacific yew. (24)

[3]

To produce enough taxol to provide for the needs of all patients, chemists estimated that they would need the bark from about 40,000 Pacific yews each year. Since the yew is slow growing and sparsely distributed among other trees in the forest, it is scattered throughout the area. To save the trees and still provide for the patient's needs, scientists began to produce taxol synthetically in the laboratory from the tree's leaves. This process is more costly than harvesting the bark, growing the foliage in a nursery provides a renewable resource.

[4]

Recent studies have shown that Pacific yews can be successfully propagated at a minimal cost. Whether the young plants are kept under conditions with high humidity, their survival rate is about 70 percent. These studies indicate that chemists will be able to secure an adequate supply of taxol and also save the Pacific yew from possible extinction.

[5]

With the discovery of taxol, the tree that was once associated with death has now become a tree of life.