General: Pine Family (Pinaceae). White fir is a large coniferous tree, growing up to 55 m tall and having a dbh of up to 1 to 2 m, depending on location. The bark is smooth, whitish-gray, and occasionally blistered with resin vesicles, becoming thick, hard and irregularly furrowed with age. The crown tends to be symmetrical and dome-shaped, although the varieties of white fir may exhibit differences in crown shape. California white fir has a cylindrical crown while Rocky Mountain white fir has a broader crown. Branches are short and stout, arranged in whorls of 4 or 5. Buds are blunt. Leaves (needles) are 3-7 cm long, loosely 2-ranked, rounded at the ends, and curved upward. A waxy covering give the needles a bluish cast. Needles also have two white lines on their undersides. Cone production varies by site, tree size, and age. White fir trees begin cone production at about 40 years and bear cones at the upper third of the crown. Cones are 10-13 cm long, greenish-yellow becoming dark purple, produce about 185-295 seeds each, and shatter upon maturity. The seeds are released in the fall and germinate in the spring.
Key characteristics of white fir include the similar coloring on both upper and undersides of the needles, smooth bark with resin blisters, long needles (in comparison to other fir species), resinous buds, circular leaf scars, and a citrus odor that is released when the needle is broken.
Morphological and chemical characters, such as needle tip shape, stomatal arrangement, and terpene content, separate the two white fir varieties.
Distribution: White fir is native to the western United States, from Idaho, south through Colorado and New Mexico, and west through California and Oregon. The Great Basin creates the gap between the varieties. Rocky Mountain white fir occurs in the central portion of the white fir range, from southeastern California, Arizona, and New Mexico to southeastern Idaho and Colorado. It has also been planted in the New England states. California white fir occurs from central California into western portions of Nevada and southwest Oregon. It has been reported in southern California, although there is no confirmation that these plants are not the Rocky Mountain variety.
For current distribution, please consult the Plant Profile page for this species on the PLANTS Web site.
Habitat: In the mixed conifer forests of California and southern Oregon, white fir may form pure stands or share dominance with species such as incense-cedar, ponderosa pine, lodgepole pine, sugar pine, Jeffrey pine, and Douglas pine. It is also a secondary species in subalpine woodlands represented by whitebark pine, limber pine, mountain hemlock, lodgepole pine, western white pine and foxtail pine. California white fir is one of the coniferous dominants of the California hardwood forests. In the mixed-conifer forest of the Sierra Nevada Mountains, it may share dominance with incense cedar, ponderosa pine, sugar pine, and Douglas fir. The mesic sites at upper elevations of the Sierra Nevada Mountains are referred to as the white fir zone.
Within the Cascade Range of northern California and central Oregon, the white fir zone occurs at elevations above 1500 m. It is the dominant species, having 18 known associations with species like lodgepole pine, western serviceberry, mountain hemlock and Pacific rhododendron. It is also found within mixed conifer stands at mid-elevations.
White fir is an indicator species of the lower elevation limit of montane forest vegetation in the Klamath Mountains of California and Oregon. At higher elevations, white fir shares dominance with red fir. In the mountain ranges of southern California, white fir becomes the dominant species at higher elevations. It is associated with sugar pine, incense cedar, and western juniper.
The white fir series in the major mountain ranges in the southwest can have any mixture of white fir with Douglas fir, Engelmann spruce, blue spruce, subalpine fir, ponderosa pine, and southwestern white pine. It is a dominant or climax species of several habitat types and series in Arizona, New Mexico, Utah, and Colorado.
In Utah, white fir occurs throughout the higher mountain ranges of the northwestern region and increases in importance through southern Utah. It occurs in subalpine zones with Engelmann spruce and blue spruce in the Douglas fir series and ponderosa pine habitat types.
In southern Colorado and northern New Mexico, white fir is a co-climax species with Douglas fir and is associated with blue spruce, limber pine, ponderosa pine, Engelmann spruce, subalpine fir, quaking aspen, and Rocky Mountain juniper. The white fir-Douglas fir-pondersoa pine series is the most widespread and one of the most varied types in Arizona and New Mexico. In mixed conifer forests, dominated by the white fir-gambel oak habitat type, white fir shares climax status with Douglas fir. Other associates include Chihuahua pine, Rocky Mountain lodgepole pine, Mexican pinyon, and New Mexico locust.
White fir is widespread in riparian areas of Utah, Wyoming, Colorado, Arizona, and New Mexico. It is associated with boxelder and narrowleaf cottonwood in Utah, blue spruce and lodgepole pine in Wyoming, and with blue spruce, cottonwood species, and Rocky Mountain maple in Colorado, Arizona, and New Mexico. More detailed habitat descriptions can be found in Zouhar (2001).
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