Taxus brevifolia was the first Yew species to be exploited for the production of anti-cancer medicines. SInce the development of alternative sources the rate of decline has reduced.
Distribution
Widely distributed in the Pacific northwest of the United States and Canada from northern California to southern Alaska. The extent of occurrence is well in excess of 20,000 km2 and there are more than 10 locations. The area of occupancy is unknown but estimated to be more than 2,000 km2.
Taxus brevifolia is not uncommon within the main range of its distribution. Patterns of distribution vary from scattered to dense patches throughout its wide range. There has been an estimated population reduction of 10-30% within the last three generations as a result of logging and bark harvesting for Taxol production. One generation is estimated to be at least 30 years due to its slow growth rates
Habitat and Ecology
In coastal areas this very fire susceptible and slow growing species is usually found as a small tree; in montane and some inland areas it may be a decumbent shrub. It is most abundant in the shaded understorey of late seral or old growth coniferous forests (Busing et al. 1995). Common associates in more mesic situations (where most of the trees are found) include Abies grandis, Tsuga heterophylla, Thuja plicata, Berberis nervosa, Polystichum munitum and Acer circinatum.
In inland areas and in the drier parts of its range it is restricted to moist areas such as streamsides. Its generation length is likely to be in excess of 30 years. It is recorded from sea level up to 2,440 m
Human Uses
The strong, dense timber from this species is highly prized by west coast Native Americans for bows, tools and carving. In the 1980s and 1990s it was heavily exploited for its bark which was used for the production of anti-cancer drugs. Following the discovery of alternative sources and methods for Taxol production by the mid-1990s, the pressure on T. brevifolia populations has eased.
Conservation Status
Global Status
Near Threatened
Global Rationale
Taxus brevifolia has undergone a population decline within the last three generations that is estimated to be less than 30%. A significant part of that decline related to its overexploitation for the production of anti-cancer medicines. This exploitation has largely ceased following the development of alternative methods for Taxol production and the focus on exploiting Asian Yew species. The majority of the Asian species are now listed as threatened in the IUCN Red List and are also listed on Appendix II of CITES. A second cause for the decline in T. brevifolia relates to habitat destruction from logging activities. This is continuing but at a lower rate. On this basis an assessment of Near Threatened under the A2acd criterion is appropriate until the next assessment.
Conservation Actions
This species is recorded from numerous protected areas throughout its range. Guidelines for the management and harvesting of T. brevifolia were produced in response to its heavy exploitation
References and further reading
Busing, R.T., Halpern, C.B. and Spies, T.A. 1995. Ecology of Pacific Yew (Taxus brevifolia) in Western Oregon and Washington. Conservation Biology 9(5): 1199-1207
Frisvold, G. and Day-Rubenstein, K. 2008. Bioprospecting and biodiversity conservation: what happens when discoveries are made. Arizona Law Review 50: 545-576.
NatureServe. 2011. Taxus brevifolia in NatureServe Explorer: An online encyclopedia of life [web application]. Version 7.1. Arlington, Virginia Available at: http://www.natureserve.org/explorer.
Vance, N.C., Borsting, M., Pilz, D. and Freed. J. 2001. Special forest products: Species information guide for the Pacific Northwest. General Technical Report PNW-GTR-513. UDSA Forest Service, Pacific Northwest Research Station, Portland, Oregon