Rus Willis and grandson Michael
with 500 year old Yew tree
TREE AND ENVIRONMENT
Taxus brevifolia is
native only to northwestern North America. It is commonly
referred to as the Pacific Yew, Western Yew or Montana Yew.
Varietals exist within its growing region. Very few trees
match the longevity of the Yew with some specimens aged at
500 to 1000 years old. It is slow growing, but long lived.
The Montana Yew is a
varietal, indigenous to northwestern Montana and
Its typical growth habit is a bushy, shrub-type tree
generally reaching 10-15 feet in height with an almost equal
spread. It grows best on northerly slopes at elevations of
3000-7000 feet, preferring a canopy of mature timber.
The leaves consist of linear, flat, slightly sickle-shaped
needles forming two comb-like ranks along the stem. Leaves
have a distinct, short petiole at the base. The undersides
are marked with two yellowish to grayish-green lengthwise
Species of this genus differ from other
gymnosperms in having a single, dark bluish seed surrounded
by a red, fleshy, cup-shaped covering. The seed with the
covering is about the size of a pea (approximately 1/3”
diameter). The bark is thin (about 1/8”) and reddish-brown
CONCERNS FOR THE SPECIES AND RESOURCE MANAGEMENT
Taxus brevifolia is not
currently an endangered or threatened species.
Before its pharmaceutical value was
discovered, the Yew was routinely slashed and burned during
logging operations. However, with prolonged manufacture of
the chemotherapeutic drug, Taxol, survival of the
species was threatened by long-term harvesting. (Bark
harvesting totally destroys the tree.) The only natural
source of Taxol, approved by the FDA, was the bark of
Taxus brevifolia for initial supplies. Subsequently,
the manufacturer of Taxol developed the
semi-synthetic Paclitaxel, eliminating the need for
great amounts of Taxus brevifolia bark. Paclitaxel
is now manufactured from the bough tips of nursery grown
cultivars of European yews and is approved by FDA.