CHLA

Chamaecyparis lawsoniana

port orford cedar

Cupressaceae

The Basics

Flora of North America

Silvics Manual

Port-Orford-cedar (Chamaecyparis lawsoniana), also called Lawson cypress and Port Orford white-cedar, is known for its grace in ornamental plantings and for its versatile wood. As logs, mostly exported to Japan, it brings higher prices than almost any other conifer in the United States. This valuable tree, however, has a very limited range and an uncertain future. Management of Port-Orford-cedar has become impossible in much of its range since the introduction of a fatal root rot that is still spreading. Old-growth forests are being depleted rapidly, and the use of second-growth forests is complicated because early growth is relatively slow.

Port-Orford-cedar is tolerant of shade and of competition in natural stands. Its slow growth beyond the sapling stage results in its being overtopped, but it continues to grow and retains into old age the ability to respond after the dominants die. Port-Orford-cedar can reproduce effectively from seed after clearcutting and partial cutting (where a sufficient seed source is present) and under almost all natural forests, and it can be used for under-planting established forest or scrub. Some old-growth forest structures resulted from repeated waves of invasion, almost certainly after fires.

Port-Orford-cedar is extremely variable morphologically. Most horticultural cultivars originated as seedling mutations, produced by descendants of apparently only a few introductions to Great Britain. Some cultivars are notably more resistant to winter damage and spring frosts than are most, and some root more easily than others. (Silvics Manual)

Identification

Trees to 50 m; trunk to 3 m diam. Bark reddish brown, l0--20(--25) cm thick, 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, dark brown; pollen sacs red. Seed cones maturing and opening first year, 8--12 mm broad, glaucous, purplish to reddish brown, not notably resinous; scales 5--9. Seeds 2--4 per scale, 2--5 mm, wing equal to or broader than body. 2n = 22. (Flora of North America)

Threats

The major causes of damage to Port-Orford-cedar are fungi of the genus Phytophthora. An exotic root rot caused by P. lateralis was introduced into Coos County about 1952 and has decimated many stands in the area where Port-Orford-cedar grows best. Neither resistance to the rot nor effective treatment of it has been identified. Spores of the fungus are carried by water, so one introduction of the disease may spread to all stands in the watershed below.

Although young trees are easily killed by fire, older trees develop thick bark and survive large, deep fire scars. In old stands, Port-Orford-cedar seems as tolerant of fire as Douglas-fir.

Reproduction

Flowering and Fruiting - Pollen and seed cones develop on the same branches of this monoecious species. Reproductive organs are initiated in late spring or summer... Each fertile scale of the 7 to 10 scales in the globose cone usually bears 2 to 4 seeds. Cones contain about 20 percent of their weight in seeds.

Seed Production and Dissemination - Seed production starts when the tree is 5 to 20 years old The seeds are small, averaging about 463 000/kg, with a range of 176 to 1323/g. Despite having small wings along both sides, the seeds apparently fall more rapidly than many larger conifer seeds. The seed wings appear to aid their flotation on water... Seeds may be stored frozen at less than 10 percent moisture in a sealed container for more than 10 years and retain considerable viability.

Vegetative Reproduction - Cuttings may be rooted with relative ease. A recommended practice is to use cuttings from tips of major branches from the lower crown of young trees, taken from December to February. Auxin treatments sometimes aid rooting. Natural layering of Port-Orford-cedar occurs occasionally. Several vertical limbs of windthrown trees in open stands may develop into separate trunks attached to the horizontal "parent" trunk. (Silvics Manual)

Species Distribution

Port-Orford-cedar grows in a small area near the Pacific coast, from about latitude 40° 50' to 43° 35' N. in southern Oregon and northern California (13). It is most important on uplifted marine terraces and in the Coast Ranges of southern Coos County and northern Curry County, OR. A secondary concentration is found at high elevations in the upper reaches of the Illinois and Klamath River drainages near the Oregon State boundary. Throughout the rest of its range, Port-Orford-cedar is found as small, scattered populations, most common in the drainages of the middle Rogue, upper Illinois, Smith, lower Klamath, and lower Trinity Rivers. A major inland disjunction includes small populations of the upper Trinity and Sacramento River drainages southwest of Mount Shasta, CA. (Silvics Manual)

Citation

USDA Plant Database http://plants.usda.gov/characteristics.html USDA, NRCS. 2016. The PLANTS Database (http://plants.usda.gov, 4 February 2016). National Plant Data Team, Greensboro, NC 27401-4901 USA.

Flora of North America http://www.efloras.org/flora_page.aspx?flora_id=1 Flora of North America Editorial Committee, eds. 1993+. Flora of North America North of Mexico. 19+ vols. New York and Oxford.

Silvics of North America Burns, R.M., and B.H. Honkala. 1990. Silvics of North America (Volume 1: Conifers, Volume 2: Hardwoods). USDA Forest Service Agricultural Handbook 654.

Intermountain Herbarium http://intermountainbiota.org/portal/collections/harvestparams.php Consortium of Intermountain Herbaria. 2016. http//:intermountainbiota.org/portal/index.php. Accessed on February 04.

Burke Museum Plant Image Collection The plant image collection at the Burke Museum, University of Washington.

Jepson Manual http://ucjeps.berkeley.edu/eflora/ The Jepson Manual: Vascular Plants of California. B.G. Baldwin, D.H. Goldman, D.J. Keil, R. Patterson, T.J. Rosatti, and D.H. Wilken [editors]. 2012. 2nd edition, thoroughly revised and expanded. University of California Press, Berkeley, CA., hardcover; 1600 pages. ISBN-13: 978-0520253124.

USGS Plant Species Range Maps http://esp.cr.usgs.gov/data/little/ Critchfield, W.B., and Little, E.L., Jr., 1966, Geographic distribution of the pines of the world: U.S. Department of Agriculture Miscellaneous Publication 991, p. 1-97. Little, E.L., Jr., 1971-1978, Atlas of United States trees, volume 1,3,13,17, conifers and important hardwoods: U.S. Department of Agriculture Miscellaneous Publications.