Calocedrus decurrens / California incense-cedar

Calocedrus decurrens, as described in 1956 by John Torrey (1796–1873), Carl Rudolf Florin (1894-1965), in Taxon, vol.5:192, is commonly known as California incense-cedar, or California post-cedar; as well as cedro incienso in the Spanish language. In the Latin language, "decurrens" translates into, "hanging down the stem," which describes how seed cones are produced in this species.

Ethnobotany. The tree is widely grown as a valuable ornamental landscape tree. Formerly it was also an important timber species, much preferred for the manufacture of pencils 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.

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Description. California incense-cedar is a large, resinous, aromatic, coniferous species of tree, typically growing to mature heights of 125 to 200 feet (40 – 60 m); with a tapering, irregularly angled trunk of up to 10 feet (3 m) in diameter measuring at breast height; and a broad conic crown of spreading branches.

  • Bark is orange-brown, weathering grayish, smooth at first, becoming fissured and exfoliating in long strips on the lower trunks of old trees.
  • Foliage is produced in flattened sprays of scale-like leaves 0.08 to 0.6 inch (2 – 15 mm) long. They are arranged in opposing decussate pairs, with the successive pairs closely then distantly spaced, so forming apparent whorls of four; the facial pairs are flat, with the lateral pairs folded over their bases. The leaves are bright green on both sides of the shoots with only inconspicuous stomata.
  • Pollen cones are 0.24 to 0.32 inch (6 – 8 mm) long. colored red-brown to light brown.
  • Seed cones are 0.8 to 1.4 inches (20 – 35 mm) long, pale green to yellow in color, with four (rarely six) scales arranged in opposite decussate pairs; the outer pair of scales each bears two winged seeds, the inner pair(s) usually being sterile and fused together in a flat plate. The cones turn orange to yellow-brown when mature about 8 months after pollination.
<em>Calocedrus decurrens </em>— Species Range Map
Calocedrus decurrens — Species Range Map

Distribution. This species is native to western North America, with the bulk of the range in the United States, from central western Oregon through most of California and the extreme west of Nevada, and also a short distance into northwest Mexico in northern Baja California. It grows at elevations of 165 to 9,200 feet (50 – 2,900 m) above sea level.

Within its native range, the climate is characterized by dry summers, usually with less than 1 inch (25 mm) precipitation per month; annual temperature extremes are from -30° to 118°F (-34° - 48°C). Annual precipitation, part of which is snow, varies from 15 to 80 inches (380 - 2,030 mm), with the driest conditions found near the specie's 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.

Hardy to USDA Zone 7, cold hardiness limit between 0° and 10°F (-17.7° and -12.2°C).

This tree is the preferred host of a wood wasp, Syntexis libocedrii a living fossil species which lays its eggs in the smoldering wood immediately after a forest fire. The tree is also host to incense-cedar mistletoe (Phoradendron libocedri), a parasitic plant which can often be found hanging from its branches.

Calocedrus decurrens — mature tree in Stanley Park, Vancouver, B.C., Canada
Photo by Blake Willson – TreeLib.ca
Calocedrus decurrens in in the Rose and Fragrance Garden of The Arboretum at Penn State in State College, Pennsylvania. Insert shows tree on planting in 2012, main photo taken 2018.
Photo by Patrick Williams
Incense-cedar (Calocedrus decurrens) foliage and pollen cones detail; photographed at the north end of Manzanita Safety Rest Area, north of Grants Pass, Oregon.
Photo by Walter Siegmund via Wikipedia
Calocedrus decurrens — the Tanner Lake Giant. Oregon's State Champion California incense cedar.
Photo by Jason Romandell Brown
A Calocedrus decurrens tree, located in the San Jacinto Mountains in Southern California, of the Peninsular Ranges System
Photo by Geographer via Wikipedia
Calocedrus decurrens — trunk of a mature tree
Photo by Blake Willson – TreeLib.ca
Calocedrus decurrens — foliage in early summer
Photo by Blake Willson – TreeLib.ca
Incense-cedar, Calocedrus decurrens), foliage and mature seed cones detail; photographed at Manzanita Safety Rest Area, north of Grants Pass, Oregon.
Photo by Walter Siegmund via Wikipedia
Calocedrus decurrens — seed cones reaching maturity
Photo by Blake Willson – TreeLib.ca
Calocedrus decurrens — seed cones that have opened and dispersed their seeds
Photo by Blake Willson – TreeLib.ca
Calocedrus decurrens — profile of a flat spray of foliage
Photo by Blake Willson – TreeLib.ca
Calocedrus decurrens — closeup of foliage detail; tree at Greenhorn Summit Guard Station, Kern Co., California.
Photo by D. Nickrent
Calocedrus decurrens — close-up of foliage
Photo by Blake Willson – TreeLib.ca

Comments

Austin Morris

Hello, what a pleasure to find your site.

Can you direct me to distinctions between California incense-cedar and why it would not be called a California incense-Juniper ?

David Olszyk

Hello Austin ... distinctions between California incense-cedar and "what?" ... although Calocedrus decurrens is probably more closely related to juniper or cypress than to cedar, only plants in the Juniperus genus can rightly be called "junipers." I suspect that early botanical pioneers called everything they encountered with aromatic wood "cedars."

Common names can be a pain.

Austin Morris

Thank you David for your reply yesterday (sorry I was away for the day).

What a pleasure to make the connection with you via the American Conifer Society. I look forward to reviewing the material / site, which surely holds a wealth of information for education and inspirational fellowship.

My first 'look see' was of your Conifer Quarterly, Summer 2018. Therein a most intimidating garden of Jack Christiansen >>> holy cow !! Then I progressed to your introductory letter to the Society, well done. Might I be correct in suspecting the photo was taken at Sequoia National Park ? Anyway all the best to you and your continued success with the ACS.

Regards, Austin

David Olszyk

Thank you so much for your words of kindness, sir. Yes, my profile picture was taken during a recent adventure in Sequoia National Park. Big trees are awesome. I wish you the best and if you ever have any questions or concerns, by all means, fire away.