Syn: Libocedrus decurrens Torrey 1853 (Thieret 1993).
Resinous, aromatic tree 18-46(57) m tall and 90-150(360) cm dbh. Tapering, irregularly angled trunk and narrow, columnar crown, becoming open and irregular. Bark light or reddish-brown, thick, fibrous, deeply and irregularly furrowed into shreddy ridges. Twigs much-branched and flattish, with wedge-shaped joints longer than broad; composed of scalelike leaves. Leaves evergreen, shiny, opposite in 4 rows, 3-14 mm long, scalelike, including long-decurrent base, rounded abaxially, apex acute (often abruptly), usually mucronate, the side pair keeled, long-pointed, overlapping the next pair, extending down twig; aromatic when crushed. Pollen cones red-brown to light brown. Seed cones cones red-brown to golden brown, 14-25 mm long (including wings), oblong-ovate when closed, pendant at end of slender, leafy stalk, proximal scales often reflexed at cone maturity, median scales then widely spreading to recurved, distal scales erect. Seeds 4 or fewer in cone, paired with 2 unequal wings. 2n= 22 (Little 1980, Thieret 1993).
Although the big "cedars" (actually, species of Calocedrus, Chamaecyparis, Cupressus, and Thuja) of western North America tend to look alike at first, the incense-cedar is easily distinguished by the fact that its foliage is held in flattened vertical sprays.
USA: W Oregon, Nevada (the Lake Tahoe area) and California; Mexico: Northern Baja California Norte; at elevations of 50-2010 m in the northern parts of its range, rising to 910-2960 in the south. The northern range limit is on the southern slopes of Mount Hood, while the southern limit is in the Sierra San Pedro Martír (Powers and Oliver 1990). See also Thompson et al. (1999).
Within its native range, the climate is characterized by dry summers, usually with less than 25 mm precipitation per month; annual temperature extremes are -34°C to 48°C. Annual precipitation, part of which is snow, varies from 380 to 2030 mm, with the driest conditions found near the species' northern limits in Oregon and northeast California. It grows on an exceptionally wide variety of soils, derived from silicate, serpentine, and carbonate parent materials, and textures ranging from coarse sand to clay (Powers and Oliver 1990). Hardy to Zone 7 (cold hardiness limit between -17.7°C and -12.2°C) (Bannister and Neuner 2001). Considering its superficial resemblance to the other large western cedars, Thuja plicata, Chamaecyparis lawsoniana and Cupressus nootkatensis, it shows a surprising tolerance of hot, dry sites with poor soils, growing in settings more typical of Cupressus or Juniperus, notwithstanding, the largest specimens tend to occur on sunny, well-watered sites such as riparian areas in canyons or near subalpine lakeshores.
Seldom found in pure stands, it is usually a subdominant or codominant component occurring in mixed forest with, in the northern part of its range, Chamaecyparis lawsoniana, Thuja plicata, Abies concolor var. lowiana, Abies grandis, Pinus jeffreyi, Pinus lambertiana, Pinus monticola, Pinus ponderosa, Pseudotsuga menziesii subsp. menziesii, Tsuga heterophylla, Quercus garryana, Quercus kelloggii, Lithocarpus densiflorus, Castanopsis chrysophylla, and Arbutus menziesii. In the central part, it grows with Sequoiadendron giganteum, Abies concolor var. lowiana, Abies magnifica, Pinus contorta subsp. murrayana, Pinus jeffreyi, Pinus lambertiana, Pinus ponderosa, Pseudotsuga menziesii subsp. menziesii, Quercus kelloggii, Lithocarpus densiflorus, Castanopsis chrysophylla, and Arbutus menziesii. In the southern part, common associates are Pinus coulteri, Pinus jeffreyi, Pinus ponderosa, Pinus lambertiana, Pseudotsuga macrocarpa, and Quercus kelloggii. Tree associates on ultramafic soils include Pinus attenuata, Pinus jeffreyi, Pinus lambertiana, Pinus monticola, and Pseudotsuga menziesii subsp. menziesii (Powers and Oliver 1990).
Calocedrus decurrens is tolerant of moderate intensity fire because of its thick bark (Little 1980).
This species is listed as threatened in Mexico under NOM-ECOL-059-94.
The Devil's Canyon Colossus: dbh 378 cm, height 50.3 m, stem volume 223 m3, located in Devil's Canyon near Sawyer's Bar, Marble Mountains Wilderness, California; also the Alex Hole Cedar, 456 cm dbh, on the north side of Condrey Mountain in Rogue River National Forest, Oregon; also the Tanner Lakes Titan, 391 cm dbh, 42.06 m tall, stem volume 123 m3, near East Tanner Lake in Red Buttes Wilderness, Oregon. The tallest known, diameter 175 cm, height 69.8 m, is near Tiller in Umpqua National Forest, Oregon (Van Pelt 2000, 2001; Tanner Lakes Titan ht/dbh data from 2011 remeasurement, email, J. Black, 2011.07.27).
There is a record of 933 years, but without supporting information (Carder 1995).
Has been used in quite a few fire history studies and a selection of other dendroecological studies, with a little bit of climate research.
The tree is widely grown as a handsome ornamental. Formerly it was also an important timber species, much preferred for the manufacture of pencil due to its softness and isotropy. Although timber harvests have been reduced by depletion of old growth stands, its wood, exceptionally resistant to decay and highly durable when exposed to weather, is still useful for woodworking applications including cedar chests and closets (Little 1980, Thieret 1993).
Have seen in many locales, including the Sierra San Pedro Martir, Mt. San Jacinto, many parts of the Sierra Nevada, and the South Cascades as far north as H.J. Andrews Experimental Forest. One of the more remarkable areas is Cedar Basin in Red Butte Wilderness, California, where it grows in an almost pure stand and some quite large trees are found.
Florin, C.R. 1956. Nomenclatural notes on genera of living gymnosperms. Taxon 5(8):188-192.
Powers, Robert F. and William W. Oliver. 1990. Incense-Cedar, in Burns and Honkala (1990).
Farjon (2005) provides a detailed account, with illustrations.
Last Modified 2012-11-25