The Biogeography of  the California Bay (Umbellularia californica)
 

by Nicole Hicks, student in Geography 316  Spring 2005

Thank you for visiting our site. This web pages was written by a student in Geography 316: Biogeography and edited by the instructor, Barbara Holzman, PhD.  All photos and maps are posted with specific copyright permission for the express use of education on these web pages. The students have tried to be as accurate as possible with the information provided and sources and references are cited at the end of each page.

Species Name: Umbellularia californica (California Bay)

 

Kingdom: Plantae Phylum:Magnoliophyta Class: Magnoliopsida Order: Laurales Family: Lauracea Genus: Umbellularia Species: Umbellularia californica
	photo by author

Description:

This evergreen tree stands about 40-50 feet (12-24 meters) in height and has a diameter at breast height of about 1 ½ - 2 ½ feet (.5-.8 meters). The tree has a short trunk of thin, reddish-brown bark with a dichotomously branched crown of heavily aromatic foliage. The leaves are about 2-5 inches (5-13 centimeters) in length and ½ - 1 ½ inches (1.2-4 centimeters) wide at the leaves widest point. The lance shaped leaves are shiny, dark green above and a duller, pale green underneath with prominent veins and release a strong scent of camphor when crushed (Little 1980). They tend to be leathery, with a thick cuticle. Soon into each leaves second year, they will turn yellow and be replaced by new growth.

 

photo by author

Natural History:

Late into winter through early spring, clusters of small (.25 of an inch long), pale yellow flowers can be seen clustering on the stalks at leaf bases. Generally there are six hermaphroditic flowers per cluster, each with one pistil and nine stamens. Pollinated by small insects such as bees, the small, pale yellow flowers of the Bay tree bloom between November and May, often before new leaves even appear and while the current fruits are just about to reach maturation. Trees as young as one year can develop buds (Stein 1990).

These flowers give rise to small (about 1 inch in diameter) purplish, round berries which reach maturation in the fall (Little 1980). Each fruit is about the size of an olive and contains a single, large seed (Beidleman 1994).  The fruits are distributed by mammals and the seeds by birds, though by no species in particular (Keator 2002). The fruits fall in winter and may stay viable through out the season. However, if conditions are harsh, seeds may only stay viable for a few weeks (USDA 2002).

photo by The Mildred E. Mathias Botanical Garden, UCLA

 These flowers give rise to small (about 1 inch in diameter) purplish, round berries which reach maturation in the fall (Little 1980). Each fruit is about the size of an olive and contains a single, large seed (Beidleman 1994).  The fruits are distributed by mammals and the seeds by birds, though by no species in particular (Keator 2002). The fruits fall in winter and may stay viable through out the season. However, if conditions are harsh, seeds may only stay viable for a few weeks (USDA 2002).

 Germination can occur soon after seed fall in the late winter or the following spring but usually takes about three months after the fruit has fallen. Seedlings establish themselves best when covered and undisturbed. They easily invade grasslands and woodlands such as the East Bay Hills in Oakland California. It is rare to see seedlings developing in the dryer parts of California but is not unheard of.  The seedlings retain their cotyledons until the plant is about 6-8 inches tall which usually is around June or July. When they are about 2-3 years old, the seedlings loose their terminal bud and begin to branch. These trees can then later reproduce by pollination, clippings, or by sprouting suckers whenever there is an opportunity out of the root, trunk or stump of an existing tree. The tree usually grows between 1-2 feet per year (Stein 1990).

 If you were to walk through most parts of California and some areas of Oregon, if adequate moisture was available, you would probably come across the Bay tree. The tree can be found in most woodland, chaparral, or mixed coniferous ecosystems, often accompanied by Coast redwood (Sequoia sempervirens), Giant sequoia (Sequoiadendron giganteum), and Douglas fir (Pseudotsuga menziesii) (USDA 2002). In our own Oakland Hills here in California, Bay can be found growing amongst Blue gum eucalyptus (Eucalyptus globulus), oak (Quercus agrifolia), redwood, and a multitude of trees found in the pine family (Stein 1990).

Evolution:

Although the genus Umbellularia is monophyletic (that is being comprised of only one species), the order Laurales consists of seven families with a total of 2,600 species in 87 genera. Lauralean fossils have been dated back as early as the Early Cretaceous and is part of the sister group to the Magnoliales, the order responsible for the earliest radiation of angiosperms (Renner 1997). The Lauraceae family is the largest of all the families making up the Laurales order. The family consists of 2,200-2,500 species in 55 genera (Rohwer, 1993). Lauracea fossils have been found from the early Cretaceous through to the Late Tertiary, going back 120 Ma (Eklund 2000). Other families sharing a derived common ancestor with Lauraceae include Monimiaceae, Hernandiaceae, Atherospermataceae, Gomortegaceae, Siparunaceae, and Calycanthaceae. Molecular data has exposed these relationships, although Laurales is not morphologically distinct from the others (Renner 1997). One explanation for this is that Laurales might have lost their ancestral morphological characteristics soon after diverging from their sister group, the Magnoliales, during the Lower Cretaceous. Another explanation is that the plant was not and has not been studied in that great of detail (Renner 1997).

 

phylogenetic tree by Peter Stevens

Distribution::

California bay can grow in a wide variety of soil types, developing into a bush in dry, sunny areas and growing into a full tree in valley bottoms where there is plenty of moisture and filtered shade. The tree can grow on canyon walls, shaded slopes and in remnants of alluvial fans (Moore 1993). Bay follows deep moisture, running water, and gravely creek deposits which is why it is common to find the tree in the semi-shady watershed areas in canyons and valleys where the soils are moist.

In California, the tree can be found in the Coast Ranges and in the Sierra Nevada up to 4,000 feet and into Southern California between 2,000-6,000 feet elevation.  In the north, the temperatures drop too low for this Mediterranean plant to survive the winter above the 4,000 feet limit. In the warmer southern part of the state, precipitation is the limiting factor on the Bay tree’s range. This California native can be found within 11 degrees of latitude spanning from the Umpqua River Valley, Oregon at the 44th parallel to San Diego, California at the 33rd parallel. From west to east, Bay can be found from the coast to the western slopes of the Sierra (Stein 1990). The rain shadow that exists over the Sierra Nevada creates enough precipitation for Umbellularia californica to exist on the western slope, but the arid region to the east is much too dry.

map by author

 

Although the tree can endure in a temperature range from -25 °  to  48°  C   (-13° to 118° F), the average annual temperatures of the plants habitats usually fall between 8° to 48°  C (46°  to 64°  F) (Stein 1990). Average annual precipitation ranges anywhere from 338 mm (13.3 in) up to 2,118 mm (83.4in), though it can survive both above and below each extreme (Stein 1990).
	climatogram by NOAA National Geographic Center

Other interesting issues:  

Umbellularia californica has had a history of multipurpose for human use. The aromatic oil in the leaves of the tree contains camphene, pinene, domesticine, nordomesticine, isoboldine and bufotenine. These oils were (and are) extracted and sniffed as a cure for headaches and sinus infections. The oil also has antifungal and antimicrobial properties and can been uses topically as an antifungal for athlete’s foot or other “moisture induced” conditions (Moore 1993). The leaves can also be used for culinary purposes, but are much stronger then the Mediterranean types sold in most grocery stores. If cooking with U. californica, the amount of Bay called for should be cut in half.

 The hardwood of California bay is a heavy, hard, fine grained, and rich in color. The wood is a light brown with darker streaks and is prized and used in the manufacturing of fine furniture, interior trim, paneling, and other woodenware. “Myrtalwood” is often used for making carvings and other novelties, all of which take on a beautiful finish. Roughly 19,950 to 22,800 m² (3.5 to 4 million f.b.m.) are used annually in the wood industry (Stein 1990).

Although not eaten by any species in particular, California bay provides shelter and habitat for a variety of rodents including the silver-gray squirrel, dusky-footed wood rat, and California mice. Steller Jays feed on the seeds and grazers such as deer and goats forage on the young sprouts before the oils in the leaves concentrate (Stein 1990).

Bibliography
Books
Beidleman, Linda and Eugene N. Kozloff. 1994. Plants of the San Francisco Bay Region: Mendocino to Monterey. Pacific Grove, CA. Sagen Press.

Keator, Glenn. 2002. Introduction to Trees of the San Francisco Bay Region.          Berkeley, CA. University of California Press.

Little, Elbert L. 1980. National Audubon Society Field Guide to North American Trees, Western Region. New York, NY. Alfred A. Knopf,    Inc.

Moore, Michael. 1993. Medicinal Plants of the Pacific West. Santa Fe, NM.   Red Crane Books, Inc.

Web
Gibson, Arthur C. (Fall 2000). The Mildred E. Mathias Botanical Garden Newsletter Volume 3(4) UCLA. [Online]. Available:           http://www.botgard.ucla.edu/html/MEMBGNewsletter/Volume3number4/a0801tx.html April, 2005].

NOAA National Geophysical Data Center-Boulder, Colorado. (1997). Interpreting Data on Climate Graphs. [Online]. Available: http://www.csc.gallaudet.edu/soarhigh/climatographs.html  [24 April,           2005].

Reener, Susanne S. (November 1997). Laurales, Angiosperms, Plant Classification by the University of Missouri. [Online]. Available:           http://www.umsl.edu/wbioren/Laurales.ELS.pdf#search=’evolution%20Lauraceae%20family.html [24 April, 2005].

Stein, William L. (December 1990). Silvics  of  North  America,  Volume  2: Hardwoods, United  States Department  of  Agriculture,  National Forest Service. [Online]. Available:           http://www.na.fs.fed.us/Spfu/pubs/sivics_manual/volume_2/umbellula  ria/californica.htm  [19 April, 2005].

Stevens, Peter. (2005, April, 19). Laurales. [Online]. Available:           http://www.mobot.org/MOBOT/Research/APweb/orders/lauralesweb. htm#Laurales [19 April, 2005].

University of Connecticut Ecology & Evolutionary Biology Conservatory.     (April 5, 2005). Umbellularia californica. [Online]. Available:          http://www.florawww.eeb.uconn.edu/acc_num/198501310.html [24April, 2005].

USDA-United States Department of Agriculture. (4 April, 2002). Plant Profiles: Umbellularia californica. [Online]. Available: http://www.plants.usda.gov [19 April, 2005].

Journals
 Rohwer, J. 1993. “Lauraceae.” The Families and Genera of Vascular Plants. Volume 2: 936-965.

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