Lushootseed Name: c̓əx̌bidac (pronounced tch-uch-bih-dotz)

Location: This native yew specimen is located on the southwest corner of the Winkenwerder Forestry lab. It is planted beside a much larger but similar looking Coast Redwood.

Summary: You may have noticed over the course of this tour that even though Washington State is home to some of the most impressively tall forests on the planet, there are many types of trees from the region which are an understory species. Understory species are plants that have adapted to a life living beneath the uppermost canopy, often shaded by their taller cousins above. The Pacific Yew is yet another of these understory species. However, most understory species in the state are angiosperms (flowering plants), while the Pacific Yew is a gymnosperm (a non-flowering group of plants that includes all conifer trees). A relative of the massive conifers of our state, Pacific Yew likewise has needle-like leaves, but the obvious similarities end there. This tree, a denizen of older forests, grows incredibly slowly and seldom achieves a height of more than 50’ in height or diameters of greater than three feet. Pacific Yew does not produce the “cone” structures we might expect to protect its seeds. Instead, this tree has what are referred to as arils, fleshy outgrowths from the seeds which partially cover them. It is important to note that Pacific Yew seeds, bark, and needles are very toxic, and therefore these arils should not be consumed even if they look snackable. The species will sometimes form a dense spreading thicket, spreading out to access the limited light available in the shadows of Douglas-fir, Fir, and Hemlock forest. As with many slow growers, the Pacific Yew can live for hundreds of years in absence of disturbance, thus the removal of one of these small trees in logging operations can represent a far greater destruction of life than the size of the specimen might imply.

Aside from the Pacific Yew exhibiting great longevity, it is also the source of an incredible medicine. Native Americans of the Salish Sea region have long known the value of Pacific Yew as a source of a cancer-suppressing compound known as paclitaxel (marketed as Taxol). This is also the source of the species’ toxicity mentioned above. The compound was adopted into western medicinal practices for use in chemotherapy during the 20th century, and as a result this species was overexploited throughout its range by harvesters selling the bark to pharmaceutical companies. It is very fortunate, therefore, that this life-saving toxic compound found within the tree is actually created by a type of fungus that lives in symbiosis with the Pacific Yew. This means that since the early 2000s, companies have been able to synthesize the drug or grow it by inoculating other more hearty Yew species with the fungus, thus slowing the over-harvesting of our slow-growing native species. The Pacific Yew also is a traditional source of bows, arrows, canoe paddles, fish hooks, digging sticks, and clubs for various Indigenous Nations in the species home range.

Identifying Features light: Pacific Yew is a beautiful and distinctive species within our Pacific Northwest Ecosystems. Its needlelike leaves grow on a plane horizontally our of each twig, dark green and glossy on the top, with far lighter green underside. The bark is a vibrant reddish hue to dull gray, often flaking off in papery sheets. Note that this specimen grows nearby an extremely similar looking coast redwood, however, the redwoods needles do not exhibit quite the contrast in upper and lower need hues and the bark of the larger tree is far more spongy.

Identifying Features In Depth:

1. Form: A small understory tree, often with an angled or twisted trunk and broad crown. It is not uncommon for this species to be found fallen to the ground with new leaders emerging upwards off the downed trunk. When standing tall the branches are often horizontal. It can achieve heights of 50 ft (15m) and above but is usually much smaller, sometimes shrubby. In diameter it can achieve about 2 ft (0.6m).

2. Leaves: The leaves of the Yew are needlelike and evergreen, spreading at 180 degrees off either side of the twig. They are between 12 and 19mm in length and flat, with pointed ends and a short petiole (stalk). The top is a glossy yellowish green, the buttons far lighter in color, which may help distinguish them from the similar looking western hemlock.

3. Bark: The bark is a purplish brown to deep red hue, quite thin, with brown to gray papery scales which flake off to reveal smooth bark beneath. The fresh twigs are green, turning light brown and slightly drooping.

4. Reproductive Bodies: These trees are dioecious (some bearing male pollen cones and others bearing seeds rather than carrying both on a single tree). The elliptical seeds are ¼ of an inch (6mm) in length and blunt pointed, with two to 4 enclosed in soft juicy scarlet berry-like cup. These seeds are extremely toxic, and consuming even just one can cause death. They are scattered throughout the tree. Male pollen cones are pale yellow and 3mm in diameter, appearing at leaf bases on a short stalk.

Historical Background: The strong wood of this tree has been used for centuries by native peoples for archers bows and arrows, poles, tool handles and canoe paddles. In modern times, the lumber industry does not favor this tree as its small size does not endear it to great value. Birds consume the berry-like cups containing the toxic seeds, scattering the seeds in the process. Seeds and foliage are both poisonous, yet, in spite of this, moose are known to feed heavily on the foliage in the winter in some Rocky mountain Forests and some squirrels will eat the seeds and even cache them away (sometimes leading to new patches of saplings at a forgotten cache). The toxic nature of this tree has also been utilized in the production of Taxol (paclitaxol), a cancer fighting drug used in modern medicine but also known to indigenous peoples of the region for centuries. This substance is effective in the fight against ovarian and breast cancer. The harvest of Yew bark for this purpose in the 1990s caused considerable damage to populations in the northwest, but fortunately by the early 2000s other sources had been identified and synthesized. In western Washington in the most favorable conditions it has been known to reach 75ft (22.8m) in height, all the more impressive because this is an incredibly slow growing tree. A trunk 12 to 20in in diameter is likely 140-245 years old. In Europe, the Irish Yew has been known to live for over 2000 years. While no specimens denoting such age have been documented in the case of the Pacific Yew it is suspected that they may grow to be over 1000 years old. Of course to achieve such age they require stable unharmed old growth forest of a kind growing more and more rare in the Pacific Northwest. Modern logging methods are quite destructive to these trees, even if they are not specifically targeted they are not spared in the clearcut methods so often used.

Native Range: The Pacific Yew favors moist soils, particularly stream banks and canyons, most often in the understory of old coniferous forests. It grows from the islands of southeast Alaska down along western British Columbia as well as in the Rocky Mountains from Montana to Idaho. It grows south in the Cascades and Coast Ranges to the Santa Cruz and Sierra Nevada mountains of California. In Alaska it appears at sea level but tolerates up to 8000 ft (2438m) in Tulare County California at the southern end of its range.