Syn: Cupressus lawsoniana A. Murray 1855 (Michener 1993).
Trees to 50 m tall and 300 cm dbh. Bark reddish brown, stringy, 10-20(25) cm thick on old trees (1-2 cm thick on trees less than c. 100 years old), divided into broad, rounded ridges. Branchlet sprays predominantly pinnate. Leaves of branchlets mostly 2-3 mm, apex acute to acuminate, facial leaves frequently separated by paired bases of lateral leaves; glands usually present, linear. Pollen cones 2-4 mm, red to purple; pollen sacs red. Seed cones maturing and opening in 6-7 months, 8-12 mm broad, glaucous, purplish to reddish brown, not notably resinous; scales (6)8-10, the apical pair fused. Seeds 2-4 per scale, 2-5 mm, wing equal to or broader than body. Cotyledons 2. 2n = 22 (Michener 1993, Frankis 1999).
USA: From Coos Bay in SW Oregon to the Klamath River in NW California near the coast and locally to 1700 m in the Siskiyou Mountains and Mt. Shasta area. Prefers sandy and clay loams and rocky ridges. Usually in mixed, but sometimes pure stands. Climate cool Mediterreanean with summer fog (Little 1980, Michener 1993, Oregon Trees website). Hardy to Zone 6 (cold hardiness limit between -23.2°C and -17.8°C) (Bannister and Neuner 2001). See also Thompson et al. (1999).
The current largest living tree has a 365 cm dbh, height 69.8 m, crown spread 12 m, located in Siskiyou National Forest, OR (Van Pelt 1998). The tallest known is 81.08 m and 280.4 cm dbh, in Jed Smith State Park, California. This tree, measured in May 2009, had live foliage up to a height of 77.42 m with a spike top above that (Steve Sillett e-mail 2009.05.21). The next-tallest known tree is 72.8 m tall, located in the Coquille Falls Research Natural Area, Siskiyou National Forest, Oregon (tree measured by R. Van Pelt and C.J. Earle, 1999.05.13).
Much larger trees have been logged, a fate that befell the vast majority of trees within the native range of this species. Frank Callahan (email, 2009.06.23) reports that "In 1965, Eric Rutquist (Coos Bay, Bureau of Land Management timber cruiser) and I measured a stump averaging 17 feet [5.18 m] in diameter at 12 feet [3.66 m] above the averaged base (the tree was on a slope). The above ground footprint of the tree was ca. 24 feet [7.32 m] in diameter as the tree exhibited extreme buttressing below the 12 foot cut. At the stump-cut, Eric and I counted 1755 rings after scraping off the moss and noted that this was a single tree as the ringcounts matched from two different radius points. The bole (from previous cruise reports) was branch free for 180 feet [54.86 m] and the total height was 245 feet [74.68 m] taken by clinometer and actual length of felled log (upper Coquille River, Coos County, Oregon). The tree was alive and in good condition when it was felled (from older photographs)." Frank also reports that the BLM has since discarded all photographs and records documenting this tree.
Few data are available. Frank Callahan (email 2011.01.07) reports a stump that he counted in 1965 as having 1,755 rings, verified on two different radii; see above quote.
The white, aromatic wood is highly valued by the Japanese for shrines, temples and arrow shafts (Little 1980). Originally used for uses as diverse as shipbuilding and match sticks, it is now the most valuable wood harvested in western North America, thanks to past overexploitation. Many cultivars are used as ornamentals (Little 1980); it is the most important ornamental conifer species in the U.K., seen mostly as semi-dwarf cultivars in parks and gardens, and planted to the exclusion of many far more interesting species. Welch and Haddow (1993) list 559 cultivar names (many of them illegitimate), of which only about 30 to 40 account for nearly all of the trade (Frankis 1999).
An old growth stand is preserved in the Coquille River Falls Research Natural Area, Coos County, Oregon, and in general the species reaches its best development in the Coquille River Valley.
The species is also well represented at Adorni Research Natural Area just west of Aikens Creek Campground on highway 96 in Six Rivers National Forest, California. The area is at 41° 13' N, 123° 41' W. Parts of the site were logged in the 1960's, but it is generally a good example of the species at a low elevation site. In this stand, it is codominant with Douglas-fir (Pseudotsuga menziesii subsp. menziesii) above a subcanopy of tanoak (Lithocarpus densiflorus) and madrone (Arbutus menziesii); all of these species are regenerating on the site as well. The stand also contains incense-cedar (Calocedrus decurrens) and sugar pine (Pinus lambertiana) (Keeler-Wolf 1990).
The highest known stands are found in the Cedar Basin Research Natural Area, around Cedar Lake, Cliff Lake, Upper Cliff Lake, and Terrace Lake at the end of Forest Road 26 in Shasta-Trinity National Forest, California. The area is at 41° 12' N, 122° 27' W. Some of the trees are remarkably large, approximately 120 cm dbh and 400-500 years old, and the forest is highly productive, with basal areas of up to 226 m2/ha. The trees grow in pure stands, but neighboring forest types on mountain slopes are also of some interest because they grow on very poor serpentine soils. They include mixed conifer forests containing Jeffrey pine (Pinus jeffreyi), white fir (Abies concolor), Douglas-fir (Pseudotsuga menziesii subsp. menziesii), incense-cedar (Calocedrus decurrens), western white pine(Pinus monticola), and, at higher elevations, red fir (Abies magnifica), lodgepole pine (Pinus contorta) and mountain hemlock (Tsuga mertensiana) (Keeler-Wolf 1990).
Named for Peter Lawson, Scots nurseryman who introduced this species to the horticultural world (Little 1980).
"A [introduced] pathogenic root rot (Phytophthora lateralis) has spread through much of the range of Port Orford cedar (Chamaecyparis lawsoniana), resulting in the elimination of stands from some habitats and threatening the commercial status of the species throughout its range. The root rot has spread from the northern portions of the species range into remote areas, killing trees of all ages. No known genetic resistance or chemical control has been identified. The spores are spread via water or are transported by people, machinery, and animals, and through root grafts (Zobel et al. 1985). Therefore, it is critical for the conservation of this species to close roads and restrict further road construction in watersheds that contain uninfected stands (e.g, inland California populations)" (FEMAT 1993).
Of all major forest trees found in western North America, this species has suffered most from human activity. Nearly all old-growth forests have been logged, and the surviving trees are steadily dying from an introduced disease.
American Lumberman. 1911.11.11. "The Realization of a Great Commercial Dream." American Lumberman n.v. (November 11, 1911):43-142.
Last Modified 2014-12-05