Juniperus occidentalis

Scientific name: Juniperus occidentalis J.Hooker 1838

Synonyms: Chamaecyparis boursieri Decne., Cupressus bacciformis Knight ex Gordon, Juniperus andina Nutt., Juniperus californica var. siskiyouensis L.F.Hend., Juniperus dealbata Knight, Juniperus pseudocupressus Dieck, Sabina occidentalis (Hook.) Antoine

Common names:Western juniper

Description

Tree to 20(-30) m tall, unbranched for up to 1.5 m, with trunk to 1.5(-3.9) m in diameter. Bark brown or reddish brown, to 25 mm thick, fibrous, furrowed, peeling in longitudinal strips. Crown irregular and open, with spreading or rising branches. Branchlets three- or four-angled, stiff, 1-2 mm thick. Adult leaves in alternating pairs or trios, scalelike, 1-3 mm long, pale green, with a prominent resin gland often bearing dried white resin, the edges minutely toothed, the tip triangular, bent forward tightly against the stem. Pollen and seed cones on the same or separate plants. Pollen cones single at the tips of branchlets, plumply egg-shaped, 3-4 mm long, with four to six trios of pollen scales. Seed cones solitary at the tips of straight branchlets, slightly elongate, (5-)6-9(-10) mm long, bluish black with a thick waxy coating, maturing in 2 years. Seeds (one or) two or three, (2-)4-6.5 mm long, brown, the paler attachment scar extending up to a fourth of the length.

Western United States (hence the scientific name, Latin for “western”) from southeastern Washington and southwestern Idaho to southern California. Open woodlands of dry foothills and mountain slopes; (200-)1,000-3,000 m.

Conservation Status

Red List Category & Criteria: Least Concern

(Juniperus occidentalis is presently increasing in abundance, spread and numbers of mature individuals. The southern subpopulations are stable, but lack of recruitment locally could pose problems following destructive events. The overall assessment of Least Concern is driven by the larger subpopulations in the north, which are all increasing)

References

Farjon, A. (2010). A Handbook of the World's Conifers. Koninklijke Brill, Leiden.

Eckenwalder, J.E. (2009) Conifers of the World: The Complete Reference. Timber Press, Portland.

IUCN Red List of Threatened Species, International Union for Conservation of Nature and Natural Resources. Cambridge, UK /Gland, Switzerland

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