The species of Taxus are more geographically than morphologically separable; and they were all treated by Pilger (1903) as subspecies of Taxus baccata. All species are poisonous; most contain the anti-cancer agent taxol; and a study of heartwood constituents of Taxus baccata, Taxus brevifolia, Taxus cuspidata and Taxus floridana found them to be chemically almost identical. However, the vast ecological amplitude displayed by the various described species (over 60° of latitude and an impressive temperature and precipitation range) suggests that they are, in a meaningful sense, true species. Detailed study of the genus (not neglecting the cultivated representatives), including extensive fieldwork, is much needed and long overdue[].

Common Name: Pacific Yew

General Information

Taxus brevifolia is an evergreen shrub or small tree with an open, conical crown; it usually grows around 6 - 15 metres tall, occasionally reaching 25 metres, though in drier forests it can be a shrub.forming broad mats that may be several times wider than tall. The bole is straight to contorted, often fluted; it can be up to 60cm in diameter[, , ].
The tree is harvested from the wild for local use as a food, medicine and source of materials. The leaves and bark are a source of the anticancer drug 'taxol' and are harvested from the wild on a commercial scale. The plant is sometimes grown as an ornamental.
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. A second cause for the decline relates to habitat destruction from logging activities. This is continuing but at a lower rate. The plant is classified as 'Near Threatened' in the IUCN Red List of Threatened Species(2013)[].

Known Hazards

All parts of the plant, except the flesh of the fruit (actually an aril), are potentially highly poisonous. They contain the alkaloid taxine and , if ingested, can cause nervousness, trembling, slow pulse, pupil dilation, difficult breathing, abdominal pain, vomiting, diarrhoea, weakness and convulsions - in larger doses it can be fatal, having a paralyzing affect on the heart[, , , , , , ].
Another report says that the toxic alkaloid found in other yews, known as taxine, is not found in this species and that the toxicity of this species has not been conclusively proven[].

Botanical References

, ,

Range

Western N. America - southern Alaska, British Colombia, Washington, Idaho, Montana, Oregon, California.

Habitat

Growing singly or in small clumps on the banks of mountain streams, in deep gorges and ravines, open or dense forests, especially under large coniferous trees; at elevations from sea level to 2,200 metres[, ].

Properties

Conservation Status	Near Threatened
Edibility Rating
Medicinal Rating
Other Uses Rating
Habit	Evergreen Tree
Height	10.00 m
Growth Rate	Slow
Pollinators	Wind
Self-fertile	No
Cultivation Status	Ornamental, Wild

Cultivation Details

Taxus brevifolia is very cold-hardy when dormant, tolerating temperatures that can fall to between between -23.2°c and -17.8°c[]. The young growth in spring, however, is much more sensitive and can be damaged by late frosts[].
Plants are very shade tolerant[], though they can also succeed in full sun. They thrive in almost any soil, acid or alkaline, as long as it is well-drained[, ]. Succeeds in dry soils. Plants grow best in a position sheltered from cold, dry winds[].
In most of its range Taxus brevifolia grows as a tree beneath a closed forest canopy in late-successional forests dominated by large conifers such as Pseudotsuga menziesii and Tsuga heterophylla. In drier open forests of the eastern Cascade Range in Washington (and perhaps elsewhere) it adopts a shrub habit similar to Juniperus communis, forming broad mats of growth that may be several times wider than tall[].
A slow-growing but apparently long-lived tree[].
Plants produce very little fibrous root and should be planted in their final positions when still small[].
Plants are very susceptible to damage by fire[].
Because of its useful wood, large trees are unscrupulously poached from the wild and, in some areas, the species has been nearly extirpated. Exploitation of the species for medicinal purposes is further threatening it in the wild[]..
Plants in this genus are notably resistant to honey fungus[].
A dioecious species, both male and female forms must be grown if fruit and seed are required.

Edible Uses

Fruit - raw[, , ]. Very sweet and gelatinous, most people find it delicious though some find it sickly[]. The fruit is a fleshy berry about 8mm in diameter and containing a single seed[]. Trees usually produce good crops every year[]. All other parts of this plant, including the seed, are highly poisonous. When eating the fruit you should spit out the large seed found in the fruit's centre. Should you swallow the whole seed it will just pass straight through you without harm, if the seed has been bitten into, however, it could cause some problems.

Medicinal

The Pacific yew is a highly toxic plant but it was employed medicinally by several native North American Indian tribes who used it to treat a variety of complaints[]. This remedy is very toxic and, even when used externally, should only be used under the supervision of a qualified practitioner[]. See also the notes above on toxicity.
Modern research has shown that it contains the substance 'taxol' in its shoots and bark. Taxol has shown exciting potential as an anti-cancer drug, particularly in the treatment of ovarian cancers[]. Unfortunately, the concentrations of taxol are rather low and the bark of 6 trees is required to provide enough taxol to treat one patient[].

All parts of the plant, except the fleshy fruit, are diaphoretic and pectoral[].

A decoction of the branches and leaves has been used in the treatment of lung problems[].

An infusion of the crushed leaves has been used externally as a wash to cause perspiration and effect a general improvement in the health[]. A poultice of the crushed leaves has been applied to wounds[].

A decoction of small woody pieces has been used in the treatment of internal complaints including stomach pains and blood in the urine[].

The leaves are harvested in early autumn or spring, the bark from autumn to spring, for commercial extraction of taxol[].

Other Uses

The bark of most, if not all species of taxus is a moderate source of tannins[, ]. It is used in several species to produce a red dye[].

A red paint was made by mixing the woodchips with oil[].

The roots have been used as the weft in twined basketry[]. The root is very strong and is particularly good for hopper mortar baskets[].

The wood is fine-grained, dense, strong, hard, heavy, durable and resilient, taking a very fine polish. Though hard, the wood is easy to carve[]. Highly prized by west coast Native Americans who have used it for making bows, paddles etc. It is currently used for purposes such as tools and implements, musical instruments, boat decking, fence posts etc, and also for carving[, , , , , , , , ].

Propagation

Seed - can be very slow to germinate, often taking 2 or more years[, ]. It is best sown as soon as it is ripe in the autumn when it should germinate 18 months later. Stored seed may take 2 years or more to germinate. 4 months warm followed by 4 months cold stratification may help reduce the germination time[]. Harvesting the seed 'green' (when fully developed but before it has dried on the plant) and then sowing it immediately has not been found to reduce the germination time because the inhibiting factors develop too early[]. Prick out the seedlings into individual pots once they are large enough to handle and grow them on in pots in a cold frame. The seedlings are very slow-growing and will probably require at least 2 years of pot cultivation before being large enough to plant out. Any planting out is best done in late spring or early summer, after the last expected frosts[].
Cuttings of half-ripe terminal shoots, 5 - 8cm long, July/August in a shaded frame. Should root by late September but leave them in the frame over winter and plant out in late spring[]. High percentage[].
Cuttings of ripe terminal shoots, taken in winter after a hard frost, in a shaded frame[].
Layering the stems. Plants often self-layer in the wild[].