BOTANICAL AND ECOLOGICAL CHARACTERISTICS
SPECIES: Umbellularia californica | California Bay 



GENERAL BOTANICAL CHARACTERISTICS : 
California bay is a highly-branched native evergreen tree that grows
from 40 to 80 feet (12-24 m) in height.  Trees in Oregon generally grow
taller than those in California [31].  The largest recorded tree is in
Oregon, measuring 13.3 feet (4 m) in diameter and 88 feet (25 m) in
height [9].  On poor sites the tree grows in scrub form [7,31].  The
fruit is a drupe containing one large seed with a thin seedcoat [42].
The bark is thin and smooth on young trees, while older trees have thin,
scaly bark that is continually shed.  Authorities disagree on the
rooting habit of California bay.  Roots are described as either shallow
or as deep and wide-spreading.  Rootwads of windthrown trees in southern
Oregon were found to be limited in extent with no taproot, and 100
percent of California bay trees excavated in the Berkeley Hills of
California had their roots confined to the top 36 inches (90 cm) of soil
[9].


RAUNKIAER LIFE FORM : 
   Phanerophyte


REGENERATION PROCESSES : 
Sexual:  California bay begins reproducing by seed at 30 to 40 years of
age [7,9,31].  Seed crops are abundant in most years.  Seed is
disseminated by animals, water, and gravity.  Limited research suggests
that seed viability is retained over winter but diminishes rapidly after
that time [42].  Some fresh seed will slowly germinate over a 3-month
period without stratification or scarification.  Germination rates
improve, however, after a 2- to 3-month cold stratification at 40
degrees Fahrenheit (4 deg C).  Scarified seed has a slightly higher
germination rate than unscarified seed [9,42].  Germination is hypogeal.
Germination and seedling establishment are favored in riparian areas
where seed is buried by silt deposition or high water [27].  Seedling
establishment is poor in drier environments unless the ground is
disturbed [9].  Seedlings are good competitors against other species and
grow under moderately dense canopies.  Seedling recruitment is poor
under other California bay trees, however [9].

Vegetative:  California bay sprouts from the root crown, bole, or stump
[9,34].  Sprouts arise wherever surviving meristematic tissue receives
strong light [9].  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 [34].  Sprouts have been observed growing from
fallen California bay trees in Muir Woods National Monument, California
[25].


SITE CHARACTERISTICS : 

California bay grows on a variety of sites.  It occurs on xeric
chaparral, where the tree often grows in scrub form.  Scrub trees are
particularly common in serpentine chaparral [16].  California bay also
occurs on exposed ridges, steep mountain slopes, coastal bluffs, or
rocky outcrops.  Best development occurs on mesic sites:  deep,
well-drained alluvial benches, valley bottoms subjected to occasional
inundation, well-watered coastal slopes, or along foothill streams [9].

Soil:  California bay grows in loam, sandy-loam, or clay soils.  Soil
pH ranges from 5.7 to 7.4 [9].

Climate:  California bay grows in the cool, humid maritime climate of
dense coastal forests and the mediterranean climate of California
hardwood forests and chaparral [9].

Elevation:  California bay is found from sea level to 4,000 feet
(1,219 m) in northern California and Oregon and from 2,000 to 5,000
feet (610-1,524 m) in southern California [42].

Plant associates:  Overstory associates include bigcone Douglas-fir
(Psuedotsuga macrocarpa), grand fir (Abies grandis), white fir (A.
concolor), Colter pine (Pinus coulteri), sugar pine (P.  lambertiana),
western white pine (P. monticola), eucalyptus (Eucalyptus globus; E.
camaldulensis), valley oak (Quercus lobata), and black cottonwood
(Populus trichocarpa) [9,11,34].  (also see SAF cover types)

Subcanopy and understory associates include California sycamore
(Plantanus racemosa), bigleaf maple (Acer macrophyllum), boxelder (A.
negundo), interior live oak (Q. wislizenii), coast live oak (Q.
agrifolia), canyon live oak (Q. chrysolepsis), blue oak (Q. douglasii),
California scrub oak (Q. dumosa), Sadler oak (Q. sadleriana), Pacific
dogwood (Cornus nuttalii), California buckeye (Aesculus californica),
chamise (Adenostoma fasciculatum), various manzanitas (Arctostaphylos
nevadensis; A. mariposa; A. viscida), yerba santa (Eriodictyon
californicum), California rhododendron (Rhododendron californicum),
Pacific rhododendron (R. macrophyllum), and evergreen huckleberry
(Vaccinium ovatum) [9,11,34].


SUCCESSIONAL STATUS : 
Facultative Seral Species

California bay is seral in mixed evergreen forests, and climax in
California hardwood forests, riparian communities, and chaparral
[3,26,37].  In mixed-evergreen forest it is replaced by various conifers
(see SAF cover types and Site Characteristics: Overstory associates).  A
sun- and shade-tolerant species, California bay occurs in all seral
stages of mixed evergreen forest.  Pioneer seedlings or residual
sprouters appear in the initial community, and the species frequently
persists as a subcanopy dominant in the late seral community [3,25].  In
California hardwood forests, it is dominant or codominant with other
hardwood species [1,18].  In chaparral, it replaces brush species in the
absence of fire.  California bay seedlings were found growing in a
mature chamise (Adenostoma fasciculatum) chaparral community in the San
Gabriel Mountains of southern California 40 years following fire [33].
Such seedlings occasionally grow to maturity and outcompete existing
shrubs before the next fire cycle.  In riparian communities, California
bay codominates with red alder (Alnus ruba), bigleaf maple, boxelder,
and California buckeye [26,42].


SEASONAL DEVELOPMENT : 
The seasonal development of California bay varies with latitude and
elevation.  The general development is as follows [9]:

                                  Northern Ca     Southern Ca
     flowers out:                 April-Sept      year-round
     new leaves out:              May-June        Dec-April
     seeds ripe:                  Sept-Nov        Sept-Nov
     flora primordia develop:     Sept-Nov        Sept-Nov
     seed disseminated:           Nov-Jan         Nov-Jan                  

Related categories for Species: Umbellularia californica | California Bay