華盛頓椰子

California palm
California fan palm
Washington palm
California Washington-palm
desert palm

More info for the terms: drupe, fruit, seed

California palm is a native evergreen monocot from 30 to 50 feet (9-15
m) in height and 1 to 2 feet (0.3-0.6 m) in diameter. The crown is a
rosette of large leaves. It is supported by a columnar trunk. Unburned
trunks are covered by a mass of pendent dead leaves called a shag or
skirt. Outer trunk tissue consists of a thick, barklike rind. The
inflorescence is a spadix. The fruit is a drupe containing a single
large seed [28,32,33]. California palm is a phreatophtye [40]. Roots
are variously described in the literature as shallow [1] or deep [28].
Presumably, root depth varies with depth of the water table, with palms
growing near seeps and springs having the more shallow root systems.
Determining the exact age of palms is difficult because tree-ring counts
cannot be made on monocots. The maximum age attained by this species is
estimated to be 200 years. Mature trees typically live about 150 years
[40]. California palm can withstand about 22 hours of subfreezing
temperature [9].

California palm occurs in disjunct groves from the Turtle and Cottonwood
Mountains and the Twenty-nine Palms region of the Mojave Desert,
California south to the Sierra de Juarez, the Sierra San Pedro Martir,
and Sierra Pinnate Mountains, Baja California [27,39]. Four groves are
located in Clark County, Nevada [7], and five others are in La Paz and
Yavapi Counties, Arizona [23]. Most United States populations occur
within the Colorado Desert along the San Andreas Fault. Due to
California palm's value as an indicator species (see Site
Characteristics), all known California palm communities have been mapped
[7]. It is extensively planted as an ornamental in semiarid and
subtropical regions of the world [9], and has naturalized in some places
[24].

More info for the terms: crown fire, fire frequency, fire management, fire regime, frequency, fruit, litter, natural, seed

Man-caused and natural fires are important factors affecting California
palm and the oases in which they grow. A survey of oases along the San
Andreas Fault revealed fire effects on palms at all sites. Prior to the
nineteenth century, Native Americans practiced fire management in oases,
burning them at intervals of about 4 years [40]. Burning increased the
yield of fruit crops, removed the dead shag from trunks for easier
access to crops, and removed understory phreatophytes competing for
water resources. Spring flows increased, which temporarily reduced the
high alkalinity of soils and favored California palm seed germination
and seedling growth. The oases were thusly maintained at pioneer or
early seral conditions [25,40].

Naturally-occurring oases fires are usually ignited by lightning
strikes; natural average fire frequency is undocumented. Oases fire
records show that fire can occur at any time of year. Oases fuels are
usually so prodigious and desiccated that lightning readily produces
fire even when occurring in winter during heavy rain [40]. Other
possible causes of natural fire have been suggested, including ignition
from sparks given off by falling rock in canyon sites, and spontaneous
combustion. Hydric portions of oases support dense growth with heavy
accumulations of litter [39]. Spontaneous combustion occurs naturally
in Louisiana marshes [38], and hydric portions of oases are similar in
composition and environment [40].

California palms are fire resistant. They are rarely killed by either
the initial burning of their shag or by subsequent burnings. Burning
experiments show that their fibrous trunks are difficult to ignite and
almost impossible to flame. Each successive burning kills some outer
vascular bundles and burns off some of the trunk, causing a reduction of
trunk diameter. Crown fire, a common occurrence, reduces crown size.
Repeated burnings sometimes results in fire-dwarfed trees. Reduction in
trunk and crown reduces the evapotranspiration rate, making more
effective use of limited water supplies and allowing for a greater
number of palms per oasis. Wind-blown, advancing crown fire does not
inflict as much damage or kill as many palms as a slow-moving fire
burning in still air [40].

FIRE REGIMES :
Find fire regime information for the plant communities in which this
species may occur by entering the species name in the FEIS home page under
"Find FIRE REGIMES".

More info for the terms: fire suppression, fuel, fuel loading, litter, natural, prescribed fire

Fire is an essential element of California palm regeneration and oasis
maintenance. Fire suppression, practiced in many oases for over 60
years, has resulted in dense understories of brush and young palms. The
Thousand Palms Oasis, for example, located in the Colorado Desert,
California, developed very little understory for 10 to 15 years
following its last fire. Saltgrass was the understory pioneer. It was
displaced by a dense growth of mesquite (Prosopis glandulosa; P.
pubescens) and goldenbush. After 35 years of fire suppression the oasis
supported a dense, tall undergrowth with a humid microclimate. Litter
accumulations were "massive" [40]. California palm's ability to resist
fire under such highly flammable conditions is unknown. Managers are
concerned that current fuel loading in many oases constitutes a severe
fire hazard to palms, and that the next fire will kill substantial
numbers of mature trees [1,40]. Manually removing portions of the
understory, followed by natural prescribed and/or prescribed fire is
recommended [1].

Fire kills desert palm borer beetle larvae near the trunk exterior
[8].

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More info for the term: phanerophyte

Phanerophyte

Topography and soils: California palm occurs at elevations below 3,500
feet (1,067 m) [24]. It serves as an indicator species, denoting
sources of year-round surface water in desert [22,33]; it is found near
seeps, springs, and streams [33]. It also occurs in canyons where water
is channeled from nearby mountains, in alluvial fan edges where
groundwater is trapped by bedrock, and where water percolates through
rock fractures caused by earthquake faulting [32]. Soils are generally
undeveloped and low in organic matter except in densely vegetated oases.
Hillside oases soils consist of lacustrine sediments of mud and rock,
while wash oases soils also contain sand. Seep oases have fine,
flocculent soils and are frequently covered by a thin crust of salts,
which tends to minimize soil erosion. If such soils are thickly
crusted, undergrowth is sparse or absent. Most soils supporting
California palm are high in pH (average pH 9.2) [40]. Soils in its root
zone, however, are generally less alkaline than topsoils [33].

Climate: California palm grows in a semiarid climate. Temperatures are
typically hot in summer (average 107 degrees Fahrenheit [42 deg C]) and
below freezing in winter. Temperature extremes recorded near one
Colorado Desert oasis are 13 and 125 degrees Fahrenheit (-17 and 52 deg
C). Oases temperatures are generally more moderate than the open
desert, being cooler in summer and warmer in winter. Average annual
precipitation ranges from 3 inches (8 cm) at the lowest to 8 inches (20
cm) at the highest elevations of California palm's range. Most
precipitation falls from December to March, but locally beneficial rains
occur from July through September. Lightning is common during such
storms [40].

Plant associates: Overstory associates not listed under Distribution
and Occurrence include Fremont cottonwood (Populus fremontii),
saltcedar, paloverde (Cercidium floridum), and California sycamore
(Plantus racemosa) [7,30,40]. Understory associates include cattail
(Typha spp.), reed (Phragmites australis), cane (Arundinaria spp.),
Olney bulrush (Scirpus olneyi), Torrey seepweed (Suaeda torreyana),
desert willow (Salix gooddingii), arrowweed (Pluchea sericea), saltgrass
(Distichlis spp), mesquite, alkali sacaton (Sporobolus airoides), alkali
goldenbush (Haplopappus acradenius), desert holly (Atriplex
hymenelytra), and allscale saltbush (A. polycarpa) [1,7,24,30,40].

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This species is known to occur in association with the following cover types (as classified by the Society of American Foresters):

242 Mesquite

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This species is known to occur in the following ecosystem types (as named by the U.S. Forest Service in their Forest and Range Ecosystem [FRES] Type classification):

FRES30 Desert shrub

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This species is known to occur in association with the following plant community types (as classified by Küchler 1964):

More info for the term: cactus

K027 Mesquite bosque
K040 Saltbush - greasewood
K041 Creosotebush
K042 Creosotebush - bursage
K043 Paloverde - cactus shrub

More info for the terms: association, cover, fruit, tree

Many animals live in close association with California palm. Amphibians
such as the canyon tree frog and Pacific tree frog frequent the hydric
zone and nearby boulders beneath palms. Various rodents use the palm's
shag for cover. A species of rat snake (Elaphe rosalica) depends upon
the shag for shelter and food (rodents). Oases attract numerous species
of birds because of the relative abundance of food, shelter, and nesting
sites as compared to open desert. Hooded orioles use fibers from older
palm leaves as nesting material [32], often constructing nests within
the palms [11]. Gray fox and various birds and rodents eat the fruit,
and the fruit is the main component in the fall diet of coyote
[6,32,40,].

California palm oases were used as cattle rangeland from 1911 to 1913,
and were grazed by sheep in the late 1940's [40].

More info for the terms: cover, forest, natural, xeric

California palm forms open to dense groves in moist areas, often
providing 100 percent of overstory cover [34]. Understory species are
sparse in dense groves and more alkaline areas; they may be abundant in
open groves or favorable sites [15]. California palm communities
separate into three distinct zones: the hydric zone, the oasis-proper,
and the oasis-desert ecotone. Oases located at wash or stream sites
gradually intergrade into open desert, while oases in seep areas
generally have abrupt ecotones, grading sharply into xeric desert
communities such as mesquite (Prosopis spp.) [40]. Publications naming
California palm as a dominant species are as follows:

Sonora Desert [5].
Natural terrestrial communities of California [15].
Riparian forest and scrubland community types of Arizona and New Mexico [34].
The vascular plant communities of California [35].

More info for the term: tree

Tree

More info for the terms: seed, tree

Many California palm oases have been destroyed by agricultural and urban
development. Others have been eliminated due to loss of oases water
sources. California palm is sensitive to any change in water level;
either a lowering of water tables or the inundation of root systems may
kill plants [40]. Groundwater pumping by the town of Twenty-nine Palms,
California may be partially responsible for the 10-foot (3 m) drop in
the water table at some sites of nearby Joshua Tree National Monument
[1]. California palms in the Monument's Oasis of Mara are threatened by
the drying up of the spring feeding the oasis [1,41]. Other
phreatophytes competing for limited water resources can also greatly
effect how much water will be available to palms. Increases of mesquite
in the understory of the Oasis of Mara are probably an additional cause
of the water table drop [1]. Saltcedar (Tamarix spp.), a strongly
competitive exotic with an extremely high evapotranspiration rate, can
dry up or reduce the yield of oases seeps and springs [4]. Saltcedar is
displacing California palm in some areas [31,40]. (See the FEIS
write-up on Tamarix ramosissima for information regarding the control of
saltcedar.) Near the San Andreas Fault, palms receiving percolating
water through rock fractures sometimes perish when the fault shifts,
eliminating or relocating seeps [32].

Harmful agents: California palm is resistant to most fungal and
bacterial infections [26]. A crown rot (Penicillium vermoeseni)
sometimes infects trees that have been injured by lightning strikes or
fire. Lightning-injured trees may be difficult to detect because palms
do not generally show lightning disfigurement [18]. Palms, however, are
occasionally decapitated by lightning [39]. California palm is the
specific host of the giant palm borer beetle (Dynapate wrightii).
Larvae of this insect feed on the wood [26,32] and can weaken or kill
trees [8].

Outlying California palm oases are popular destinations for hikers,
four-wheel drive, and dune-buggy enthusiasts. Vegetation disturbance,
vandalism, and theft of Indian relics by unscrupulous recreationists are
of continuing management concern [32].

Cultivation: California palm is easily grown from seed. The seed is
abundant; it stores and germinates well, and seedlings transplant easily
[12,25]. Information on seed processing, storage, and germination
techniques and seedling care is available [19].

California palm fruits, including seeds, contain 348 calories per 100
grams. Percentages by weight of several nutrients in fruits (including
seeds) are as follows [8]:

protein 3.1
fat 2.8
carbohydrate 77.7
fiber 10.4
ash 5.4

Milligrams per 100 grams of several other nutrients in fruits (including
seeds) are as follows [8]:

calcium 110
phosphorus 89
iron 7.8
carotene 180
thiamine 0.06
vitamin C 0.13
niacin 1.0
riboflavin 0.13

AZ CA HI NV MEXICO

More info for the terms: fresh, fruit

California palm is greatly valued as a landscaping ornamental [12].

Kamia and Cahuilla Indians selected California palm oases for village
sites. The oases provided sources of water, food, and shade.
California palm vegetative buds, flowers, and fruits were utilized as
food. The fruits, resembling commercial dates in taste, were eaten
fresh or dried; some dried fruit was made into meal. Leaves were used
as thatching. Sandals, clothing, and baskets were fashioned from leaf
fibers. Spoons and hunting bows were made from the petioles. The wood
was used for kindling. Because of historical use by Indians, California
palm oases are important archeological sites [25,26,32].

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Flowering occurs in May and June [32]. The leaves die at the end of the
summer growing season, remaining attached to the trunk [33]. Fruits
ripen in September [23], and seeds ripen and drop from November to
January [19,6].

More info for the terms: root crown, secondary colonizer, seed

Tree without adventitious-bud root crown
Secondary colonizer - on-site seed
Secondary colonizer - off-site seed

More info for the terms: fruit, hypogeal, natural, pericarp, seed, tree

California palm regenerates from seed [12]; vegetative reproduction does
not occur (J. W. Cornett, in [22]). Cultivated trees have flowered at
age 19 [26], but the age at which trees growing under natural conditions
first flower is unreported. Pollination is predominantly
insect-mediated (J. W. Cornett, in [22]), but self-pollination may also
occur [22]. Natural populations of California palm are reseeding well
[23]. A heavy crop for an individual tree probably approaches 10,000
fruits. In the southern Anza-Borrego region of California, 11 percent
of trees fruited 1 year, followed by 57 to 59 percent of trees fruiting
in the following 3 years [6]. Seeds are disseminated primarily by the
coyote [7,40]. Because of its fruit-eating habit and broad range of
travel between water sources, coyote often transport seeds over
considerable distances [32]. The four California palm groves of
southern Nevada probably established from seed in coyote scat [7]. A
comparison of seed collected from the ground surface and seed collected
from coyote scat showed that the pericarp was missing from 94 percent of
coyote-consumed seed. Removal of the pericarp increases the probability
of germination. Sixty-three percent of coyote-consumed seed tested in
this study germinated, as compared to 34 percent of that in the control
group [8]. Seed in coyote scat are rarely consumed by passing animals
[7]. Gray fox also consume and disseminate seed. Birds generally
consume only the fruit, not the seed [32]. The western and mountain
bluebird and the cedar waxwing, however, eat both fruit and seed,
disseminating the seed in droppings. Seed in bird droppings are usually
disseminated within or close by the grove of the parent tree. The seed
appears to be difficult for these birds to digest, and are often
regurgitated. Regurgitated seed may still be partially covered by fruit
fragments, which reduces germination rates. Rodent predation of seed in
bird droppings or vomit is high [6]. Seed remains viable in seedbanks
for up to 6 years [19]. Germination is hypogeal [36]. Seedlings
require a moist mineral seedbed and partial shade to full sun. They
cannot establish on highly alkaline soils [39]. Seedling recruitment
frequently occurs in a flush during wet years [40].

California palm fruit allelopathically inhibits germination and growth of
other species under laboratory conditions [7].

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This species can be found in the following regions of the western United States (according to the Bureau of Land Management classification of Physiographic Regions of the western United States):

7 Lower Basin and Range

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More info for the terms: fire management, shrubs

California palm is moderately shade tolerant when young, becoming
intolerant with age [28,40]. California palm communities require moist
pioneer conditions [40]. They are invaded by shrubs in the absence of
fire, creating environmental conditions which eventually kill the palms
[1,40]. (See Management Considerations and Fire Management
Considerations.)

Washingtonia robusta Wendl.
Washingtonia arizonica Cook

The scientific name of California palm is Washingtonia filifera
(Linden) Wendl. [3,24,28].