Umbellularia californica

California laurel (bay)

Lauraceae

The Basics

Taxonomy: Kingdom - Plantae (plants). Subkingdom - Tracheobionta (vascular plants). Superdivision - Spermatophyta (seed plants). Division - Magnoliophyta (flowering plants). Class - Magnoliopsida (dicotyledons). Subclass - Magnoliidae. Order - Laurales. Family - Lauraceae (laurel family). Genus - Umbellularia (Nees) Nutt. (california laurel). Species - Umbellularia californica (Hook. & Arn.) Nutt. (california laurel).

Ecology: California laurel is a perennial, evergreen tree or shrub that is native to California and southern Oregon. The trees have many slender erect branches and a dense crown that can be rounded to pyramidal in shape. The height is variable depending on conditions and the plants can grow from 3 to 45 meters tall. The smallest forms are found under dry conditions and they reach their greatest size on deep alluvial soils near rivers. The greenish to reddish brown bark, which is thin and smooth on young trees, begins to peel and shed as the trees mature. The alternately arranged leaves are oblong to lance-shaped (2.5 to 11 cm long and 1.5 to 3 cm wide). Leaves are glossy dark yellow-green, thick, and leathery. When crushed, the leaves give off a strong peppery menthol-like odor, which is the reason the early European settlers gave the tree the name pepperwood.

Interesting Uses

All parts of the plant, but especially the leaves, contain an aromatic camphor-like volatile oil that has cooling, irritant, insecticidal and germicidal qualities. Laurel leaf tea was drunk to treat stomachaches, colds, sore throats, and to clear up mucus in the lungs. The leaves were steeped in hot water to make an infusion that was used to wash sores. Laurel leaves were steeped in baths for rheumatic patients. Infusions of the leaves were used to rid the head of lice. The Pomo and Yuki tribes of Mendocino County treated headaches by placing a single leaf in the nostril or bathing the head with a laurel leaf infusion. Leaves and branches were placed around the yard to discourage fleas.

The seeds were roasted until they were crisp and brown. The roasting removes much of the pungency and leaves just a hint of acridity and gives the roasted nuts a spicy or coffee-like flavor. The parched nuts are then shelled and either eaten whole or pounded into a meal. California laurel leaves are used as a more robust seasoning substitute for sweet bay leaves (Laurus nobilis) in cooking.

Threats

California laurel is relatively free of insect pests but can be affected by aphids, greedy scale, ivy scale, soft brown scale, thrups, white fly, laurel white fly, leaf blotch miner, and inconspicuous white fly. Heart rot, caused by the fungus Ganoderma applanatum can be controlled by cutting down infected trees to a height of 20cm and allowing them to stump sprout.

Fire effects: The thin bark of this tree provides little protection against fire. Moderate-severity fire kills California bay seedlings and top-kills saplings and mature trees. Severe fire kills the seed. Some studies indicate that germination of buried seed may slightly increase following light to moderate fire due to the cracking of the thin seed coat. California bay sprouts from the root crown or bole following fire. California bay increases fuel loading by the continual shedding of its bark.

Reproduction

Seed Production - California bay begins reproducing by seed at 30 to 40 years of age. Seed crops are abundant in most years. Seed is disseminated by animals, water, and gravity.

Seedling Development - Germination and seedling establishment are favored in riparian areas where seed is buried by silt deposition or high water. Seedling establishment is poor in drier environments unless the ground is disturbed. Seedlings are good competitors against other species and grow under moderately dense canopies. Seedling recruitment is poor under other California bay trees, however.

Vegetative Reproduction - California bay sprouts from the root crown, bole, or stump. Sprouts arise wherever surviving meristematic tissue receives strong light. Bole sprouts are more common on plants growing on south-facing slopes, while root collar sprouts usually appear on plants on north-facing slopes. Sixty sprouts have been reported growing on the trunk of one burned tree.

Species Distribution

Citation

USDA Plant Database
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
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 2: Hardwoods). USDA Forest Service Agricultural Handbook 654.

Intermountain Herbarium
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
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. $131.95, 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.