World Botanical Associates Web Page
Prepared by Richard W. Spjut
August 2006, Jan 2013, Dec 2013
Kern Co., Greenhorn Range along
Calocedrus decurrens (Libocedrus decurrens Torrey 1853) Florin 1956. Incense cedar. Old bark reddish brown, fibrous, longitudinally furrowed; leaves aromatic, scaly, overlapping, braid-like, opposite, with a long linear base, abruptly expanded to a short triangular tip; seed cones Aug–Nov, cone scales like “duck bills,” spreading apart at maturity and dispersing from the tree like whirly birds (but only with two of the four propellers spreading), containing 1–4 seeds (anisopterospermal valvular-cone, Stuppy & Spjut in prep). Montane coniferous forests, California to Sierra San Pedro Mártir in Baja California, western Nevada, and Oregon. “Incense cedar forest” (alliance) recognized in MCV2 when >30% relative cover in tree canopy in which ponderosa and Jeffrey pines are not dominant. Type from upper waters of Sacramento River. Kern Co.: Common in the Greenhorn Range where dominant in association with ponderosa pine, Jeffrey pine, white fir and/or sugar pine, and also in the Tehachapi Mountains, absent from Breckenridge Mountain (Twisselmann). Native Americans used twigs in a sweat bath, decoction of leaves for stomach troubles, or infusion inhaled as steam for colds (Moerman). Twig-leaf samples showed antitumor activity in the KB assay; 3’methylpodophyllotoxin was isolated (Hartwell).
The absence of incense cedar on Breckenridge Mt. is surprising in view of the extensive white fir forest there. Its occurrence is often related to fire history (MCV2), thus, its absence on Breckenridge Mt. may relate to a past fire. An example is a Piute cypress grove that once occurred on Breckenridge Mt. that was completely destroyed by fire (Twisselmann) in 1970, and although the species supposedly depends on fire for regeneration, it did not regenerate on Breckenridge Mt. (Nature Alley, http://natureali.org/SQF/cypress.html).