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Wildlife, Animals, and Plants
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Introductory
SPECIES: Ceanothus leucodermis | Chaparral Whitethorn
ABBREVIATION :
CEALEU
SYNONYMS :
Ceanothus divaricatus
Ceanothus divaricatus var. eglandulosus
Ceanothus divaricatus var. laetiflorus
Ceanothus divaricatus var. grosse-serratus
SCS PLANT CODE :
NO-ENTRY
COMMON NAMES :
chaparral whitethorn
chaparral whitethorn ceanothus
TAXONOMY :
The currently accepted scientific name of chaparral whitethorn is
Ceanothus leucodermis Greene [18,34]. Hybridization is common within
the genus Ceanothus, although specific hybrids with chaparral whitethorn
have not been documented.
LIFE FORM :
Shrub
FEDERAL LEGAL STATUS :
NO-ENTRY
OTHER STATUS :
NO-ENTRY
COMPILED BY AND DATE :
D. Tirmenstein, June 1989.
LAST REVISED BY AND DATE :
NO-ENTRY
AUTHORSHIP AND CITATION :
Tirmenstein, D. 1989. Ceanothus leucodermis. In: Remainder of Citation
DISTRIBUTION AND OCCURRENCE
SPECIES: Ceanothus leucodermis | Chaparral Whitethorn
GENERAL DISTRIBUTION :
Chaparral whitethorn occurs from Mexico through the ranges of cismontane
southern California, northward along the inner Coast Ranges and Sierra
Nevada to northern California [33].
ECOSYSTEMS :
FRES20 Douglas-fir
FRES21 Ponderosa pine
FRES23 Fir - spruce
FRES28 Western hardwoods
FRES34 Chaparral - mountain shrub
STATES :
CA MEXICO
ADMINISTRATIVE UNITS :
KICA SAMO SEQU
BLM PHYSIOGRAPHIC REGIONS :
3 Southern Pacific Border
4 Sierra Mountains
7 Lower Basin and Range
KUCHLER PLANT ASSOCIATIONS :
K005 Mixed conifer forest
K029 California mixed evergreen forest
K030 California oakwoods
K033 Chaparral
K035 Coastal sagebrush
SAF COVER TYPES :
243 Sierra Nevada mixed conifer
247 Jeffrey pine
255 California coast live oak
237 Interior ponderosa pine
SRM (RANGELAND) COVER TYPES :
NO-ENTRY
HABITAT TYPES AND PLANT COMMUNITIES :
Chaparral whitethorn, along with other species of ceanothus such as
deerbrush (Ceanothus integerrimus), wedgeleaf ceanothus (C. cuneatus),
and desert ceanothus (C. greggii), occurs as a dominant or codominant in
a number of desert chaparral and mixed chaparral communities of southern
California. Chaparrral whitethorn also commonly occurs with the
following species: hoaryleaf ceanothus (C. crassifolius), California
white oak (Quercus lobata), interior live oak (Q. wislizenii), scrub oak
(Q. dumosa), bigberry manzanita (Arctostaphylos glauca), black sage
(Salvia mellifera), chamise (Adenostoma fasciculatum), silktassel
(Garrya spp.), sugar sumac (Rhus ovata), California buckthorn (Rhamnus
californica), and California buckwheat (Eriogonum fasiculatum)
[5,19,31,32,35].
Chaparral whitethorn is listed as a dominant, codominant, or indicator
species in the following publications:
Vegetation of the San Bernardino Mountains [31]
A vegetation classification system applied to southern California [37]
The vascular plant communities of California [45]
VALUE AND USE
SPECIES: Ceanothus leucodermis | Chaparral Whitethorn
WOOD PRODUCTS VALUE :
NO-ENTRY
IMPORTANCE TO LIVESTOCK AND WILDLIFE :
Chaparral whitethorn is a preferred food of many large ungulates. It is
an important mule deer food in parts of California, and is used by
bighorn sheep where stands are open and the browse accessible [7,48].
Sites dominated by chaparral whitethorn and birchleaf mountain-mahogany
(Cercocarpus betuloides) provide excellent winter habitat for bighorns
[4]. Heavy, wet snows frequently bend branches to within easy reach of
both bighorns and deer [13]. In some areas, winter mule deer utilization
of chaparral whitethorn may approximate 10 to 60 percent [13]. Fruits
and seeds of chaparral whitethorn are used by many small mammals, birds,
and insects [7].
Livestock make only low to moderate use of chaparral whitethorn. This
browse is generally not favored in areas where more desirable species
are available [43,48]. Domestic sheep and goats often feed on chaparral
whitethorn where abundant, although cattle seldom use this species [43].
PALATABILITY :
The spiny twigs of chaparral whitethorn render it somewhat less
palatable than many other species of ceanothus [13]. Tender young
sprouts and seedlings are generally much more palatable to wild
ungulates and livestock than are the spiny mature twigs [43]. However,
researchers have observed that the mature growth remains palatable to
deer [43]. The overall palatability of chaparral whitethorn to deer,
domestic sheep, and goats is described as low to moderate [43]. The
relish and degree of use shown by livestock and wildlife species for
chaparral whitethorn is rated as follows [43]:
CA
Cattle poor-useless
Sheep good-fair
Horses useless
Domestic goats good-fair
Deer excellent-good
NUTRITIONAL VALUE :
Calcium levels of stems and leaves decline as plants age, and magnesium
concentrations peak in plants of intermediate ages [41]. The crude
protein content of chaparral whitethorn drops as leaves mature [43].
Specific nutritional values are as follows [43]:
crude protein - %
young leaves 16
mature leaves 11
crude fiber - %
6.5 to 9.5
COVER VALUE :
Because of its height and growth form, chaparral whitethorn presumably
provides good hiding, resting, and nesting sites for many smaller birds
and mammals. Many stands or patches, particularly those with a more
open structure, also provide good cover for larger mammals such as deer
and bighorn sheep [7].
VALUE FOR REHABILITATION OF DISTURBED SITES :
Little is known about the potential value of chaparral whitethorn in
rehabilitation. However, many species within the genus Ceanothus are
well-suited for use in reclamation because of their rapid growth and
ability to improve soil fertility by fixing atmospheric nitrogen.
OTHER USES AND VALUES :
Flowers of chaparral whitethorn contain detergentlike substances known
as saponins. Many native peoples used the flowers of various species of
ceanothus to make soaps and shampoos [46].
MANAGEMENT CONSIDERATIONS :
Mechanical removal: Chaparral whitethorn is described as "well-suited"
for periodic harvesting of biomass for energy production [39]. Plants
typically sprout prolifically as soon as the first growing season after
removal [39].
BOTANICAL AND ECOLOGICAL CHARACTERISTICS
SPECIES: Ceanothus leucodermis | Chaparral Whitethorn
GENERAL BOTANICAL CHARACTERISTICS :
Chaparral whitethorn is an evergreen shrub which grows from 7 to 13 feet
(2 to 4 m) in height [34,43]. Branchlets are pale green and smooth, but
become gray-white, rigid and spiny-tipped at maturity [7,43]. Roots
tend to be well-developed and reach maximum depths of approximately 21
feet (6.4 m), with radial spreads up to 8.4 feet (3 m) [6,17]. Flowers
are white to pale blue and generally form short, dense clusters
[6,7,34]. Shiny, dark olive to brown, flattened or obovoid seed are
borne in sticky, globose capsules [6,34].
Chaparral whitethorn is capable of fixing atmospheric nitrogen [8].
RAUNKIAER LIFE FORM :
Phanerophyte
REGENERATION PROCESSES :
Chaparral whitethorn regenerates both through seed and by vegetative
means [36]. In many areas, seed production is of primary importance,
although sprouting may sometimes be vigorous [13]. Sampson and Jespersen
[43] report that chaparral whitethorn generally does not sprout after
disturbance from Tulare County northward, although sprouting is commonly
observed to the south.
Vegetative regeneration: Chaparral whitethorn frequently stump-sprouts
after fire or mechanical removal [7,25,30]. However, sprouting from the
rootcrown or burls, although less common, has also been reported
[17,26]. Sprouting of chaparral whitethorn is typically rapid.
Numerous resprouts were noted during the first growing season after
mechanical removal in chaparral communities of southern California [39].
Stump sprouts often grow quickly and can reach 7 feet (2.1 m) in height
within 10 years [19].
Seed: Seed of chaparral whitethorn averages 77,000 per pound (170 per
g) [48]. Three shiny dark olive-brown seeds are contained in each
sticky globose capsule [7,22,34]. The capsule matures in summer and
ejects seed explosively as it dries [9,24].
Seed dispersal: Seed casting of wedgeleaf ceanothus can occur within a
relatively short period. Approximately 95 percent of the seed was cast
within a 14-day period in the Sierra Nevada Mountains of California [9].
Most seed falls within fairly close proximity of the parent plant.
Evans and others [9] found that approximately 36 percent of all
wedgeleaf ceanothus seed dropped to the ground beneath the canopy of the
parent plant, with 42 percent falling at the plant's edge. The
remaining 1.9 percent was dispersed outward up to 30 feet (9 m) from the
parent shrub. Most seeds were cast in a southeasterly direction. Birds
and rabbits sometimes serve as important dispersal agents for many
species of ceanothus, and ants are also known to transport large numbers
of seed [6,22].
Seed production: Production fluctuates annually and appears to depend
on flowerbud initiation in the previous year, which is in turn largely
determined by the amount of precipitation and nutrients received during
this time [22,30,36]. McDonald [30] reported annual chaparral
whitethorn seed production of approximately 5.2 million per acre (12.9
million per hectare). Annual seed production was found to vary from
18,800 to 11,600,000 per acre (47,000 to 29,200,000 per hectare) in
southern California chaparral communities [6]. Research results
indicated the following production and viability estimates [22]:
year seeds/hectare seeds/m sq aerial coverage viability
1973 2.7 x 10 6th 230 53%
1974 29.2 x 10 6th 2,454 44%
1975 47.6 x 10 3rd 4 ---
Seed predation by insects and rodents can be heavy. As much as 80
percent of all seed is removed by insects in some areas [21], and rodent
predation can eliminate up to 90 percent of annual ceanothus seed
production in certain locations [6].
Germination: Seed of chaparral whitethorn is noted for its pronounced
dormancy mechanisms [30]. Germination is significantly improved by
exposure to heat which ruptures the secondary seed coat allowing water
to enter the seed [14]. In laboratory tests, up to 67 percent of seeds
germinated when heated in water at 158 degrees F (70 degrees C), and
then stratified at 36 degrees F (2 degrees C) for 3 months [48].
Germination dropped to 43 percent when seeds were heated to 194 degrees
F (90 degrees C), and then cooled [48].
Seed banking: Chaparral whitethorn is noted for its seed banking
properties which enable it to persist in fire-prone chaparral. Large
numbers of long-lived seed tend to accumulate in the soil, duff, or
litter beneath the parent plants [9,14,31]. McDonald [30] found an
average of 0.3 million chaparral whitethorn seeds stored within the soil
of 1 acre (0.8 million per ha). Other researchers have reported an
average of 352,227 per acre (870,000 per ha), with estimated viability
of up to 96 percent [22]. However, seed pool dynamics of chaparral
whitethorn are poorly known [1]. Although seed longevity is
considerable, the amount of seed contributed to the seed bank in any
given year has not been documented [1].
Seedling establishment: Most seedlings emerge during mid-March and
April [2]. Although germination is often good, mortality of young
chaparral whitethorn plants is generally high. Seedlings are quite
susceptible to the effects of drought [19] and herbivory.
SITE CHARACTERISTICS :
Chaparral whitethorn grows on dry, rocky slopes, erosion channels,
gullies, and canyons [34,49]. It is an important component of many
chaparral, coastal sage, and oak (Quercus spp.) woodlands of southern
California [16,34]. Chaparral whitethorn also grows as scattered
individuals or in patches in dry foothill forests dominated by ponderosa
pine (Pinus ponderosa), Coulter pine (Pinus coulteri), or various
woodland oaks (Quercus spp.) [16,33,49].
Elevation: Chaparral whitethorn typically grows at low to middle
elevations, and is generally found below 5,500 to 6,000 feet
(1,678-1,800 m) [7,43]. Hanes [15], notes that the most extensive
stands often occur at higher elevation chaparral sites.
SUCCESSIONAL STATUS :
Facultative Seral Species
Chaparral whitethorn is generally most abundant in earlier seral stages
of chaparral or coastal sage communities [16]. This relatively
short-lived, rapidly growing shrub disappears in stands which have not
been burned for 40 to 70 years [21,31].
SEASONAL DEVELOPMENT :
Flowering of chaparral whitethorn has been reported as early as
February; however, most plants flower from April through June [7,34,48].
Seed is typically dispersed during the summer as capsules mature and
dehisce explosively [24]. Evans and others [9] observed that most seed
casting occured during July, with lesser amounts dispersed in August in
the central Sierra Nevada. In some parts of California, seed does not
mature until September or October [43].
FIRE ECOLOGY
SPECIES: Ceanothus leucodermis | Chaparral Whitethorn
FIRE ECOLOGY OR ADAPTATIONS :
Chaparral whitethorn is largely dependent on fire for establishment.
Without fire, this relatively short-lived shrub typically disappears
within 40 to 70 years [31]. Historic fire frequencies in chaparral
whitethorn stands appear to be less than the time required for plant
senescence. Many coastal sage communities in which chaparral whitethorn
is well-represented formerly burned at 20-year intervals [51].
Chaparral communities often dominated by this or other ceanothus species
burned at approximately 25- to 40-year intervals in southern California,
and at 30- to 60-year intervals in central California [11,28,51].
Chaparral whitethorn exhibits numerous specialized adaptations to fire.
Plants are capable of abundant seed production and, in many instances,
sprout prolifically after fire [6,13,17]. Large numbers of long-viable
seed accumulate in "banks" in soil, duff, or litter beneath parent
plants during fire-free intervals [9,23,32]. Many, if not most, of the
small seeds survive even hot fires, protected from lethal temperatures
by overlying soil [14]. Seeds stored in the soil can apparently survive
for decades until stimulated by heat to germinate in great numbers
[14,49]. Vegetative modes of postfire regeneration appear to be best
developed toward the southern part of this shrub's range [43]. Prolific
stump-sprouting is common, but sprouting of deeper seated rootcrowns and
lignotubers or burls has also been reported [6,17,20,25].
Chaparral whitethorn is highly flammable due to its growth form and
chemical composition, and occurs across vast contiguous acreages with
other flammable broadleaf sclerophylls [30,40]. These factors
contribute to the huge, fast-moving fires so typical of chaparral [30].
The lack of a widespread seed dispersal mechanism, the apparent
importance of seed banking, and its ability to resprout make chaparral
whitethorn particularly well-adapted to persist following these sorts of
large-scale fires [23].
POSTFIRE REGENERATION STRATEGY :
Tall shrub, adventitious-bud root crown
Ground residual colonizer (on-site, initial community)
FIRE EFFECTS
SPECIES: Ceanothus leucodermis | Chaparral Whitethorn
IMMEDIATE FIRE EFFECT ON PLANT :
Fire-caused mortality of mature chaparral whitethorn is described as
"moderate" [26]. Up to 50 percent of the sprouting population may be
killed by a single fire [22]. Young plants which typically have a
smaller rootcrown, and thus a reduced capacity to sprout from latent
buds, tend to be more susceptible to fire than mature individuals
[15,26]. However, larger underground, burllike structures of mature
chaparral whitethorn often survive despite significant damage. Keeley
and Zedler [26] observed that less than 20 percent of the "burl" area in
burned chaparral stands was actually killed by fire. Since plants do
not survive when these underground regenerative structures are
destroyed, overall adult mortality in this stand was approximately 20
percent.
Postfire mortality of mature chaparral whitethorn is typically slight
following prescribed burns of light intensity [29]. However, extremely
hot fires often kill both young and mature plants [42]. In chaparral, a
shorter fire cycle contributes to less intense fires and greater
survivorship whereas a longer fire regime results in higher fire-caused
mortality of sprouting shrubs such as chaparral whitethorn [26].
Large numbers of seed accumulate in the soil during fire-free periods
and many survive most fires.
DISCUSSION AND QUALIFICATION OF FIRE EFFECT :
NO-ENTRY
PLANT RESPONSE TO FIRE :
Chaparral whitethorn regenerates vegetatively after fire in some areas,
but is also capable of producing an abundance of seedlings [13,22,43,50].
Both modes of regeneration appear to be important, although the relative
value of each varies significantly according to geographic location and
season of burn [13,43]. Sampson and Jespersen [43] report that chaparral
whitethorn tends to sprout in southern California, but not from Tulare
County northward. A number of researchers have observed much greater
sprouting than seedling production [19,26], while others have noted
greater relative importance of regeneration through seed [25,50].
Vegetative regeneration: Chaparral whitethorn often sprouts from the
stump or rootcrown area [15,17], although sprouting from burllike
structures has also been reported [20,26]. Stump-sprouting apparently
occurs when aboveground stems are not seriously damaged by fire. Old
snags with multiple sprouts "clusterd about the base" are commonly
observed after fire in chaparral communities [19]. It should be noted
that all forms of sprouting are much less likely following fires of
relatively high intensity [42].
Regeneration through seed: The long-lived seeds of chaparral whitethorn
accumulate in large numbers beneath the parent plant during fire-free
intervals [9]. Seeds buried at depths so that they receive heat
scarification rather than exposure to lethal temperatures, are
stimulated to germinate [1,14,49]. Generally, seedling establishment is
favored by fall burns which provide stratification for seeds [13].
Overall postfire seedling establishment potential is described as
"moderate" [26]. Seedling mortality may be high, particularly during
dry periods [19]. However, seedlings often number more than 886 per acre
(355/ha) within a few years after fire [50].
Postfire recovery time: Resprouts generally grow much faster than do
seedlings [15]. Typical heights of stump sprouts measured 10 years after
fire ranged from 26 to 29 inches (66-74 cm) in southern California
chaparral, although heights of up to 7 feet (2.1 m) have been reported
on particularly good sites [19]. Comparative postfire growth of sprouts
and seedlings are as follows [19]:
years after burn - (in inches)
1 2 3 4 5 7 10 15
sprouts 6.0 21.0 --- 30.0 30.0 50.0 84.0 70.0
seedlings 2.5 8.3 11.6 14.6 15.6 18.0 24.7 30.7
Postfire recovery of this fast-growing shrub is rapid regardless of the
type of primary regenerative strategy employed.
DISCUSSION AND QUALIFICATION OF PLANT RESPONSE :
Numerous studies have compared the relative importance of chaparral
whitethorn seedlings and resprouts after fire [19,22,25,50]. Preliminary
evidence suggests that resprouts may be relatively more important toward
the southern portion of the shrub's range [43]. However, factors such
as season of burn, community composition, weather conditions, fire
intensity and severity, years since the last fire, and geographically
expressed genetic variation may also represent important determinants of
the type of response. Pertinent observations are summarized below
[22,25,50]:
1) location: southern California
season of burn: October 1967, September 1968
1967 burn 1968 burn
sprouts ----- 2
seedlings 1,556 670
2) location: southern California chaparral
season of burn: September
#/ha
resprouts 1,170
seedlings 2,050
3) location: southern California chaparral
season of burn: November
intensity: all aboveground vegetation removed
site 1 - density -10 3/ha cover m sq. /ha
March June March June
resprouts --- 2.1 --- 189
seedlings 17.7 88.1 5 109
site 2 -
resprouts --- 30.0 --- 1,200
seedlings 85.6 70.5 26 223
FIRE MANAGEMENT CONSIDERATIONS :
Fuels and flammability: Chaparral whitethorn tends to be highly
flammable because of its chemical composition and growth form. It
possesses substantial amounts of fine fuels, a low moisture content, and
high proportions of resin, oil, wax, and volatile products [30]. Leaf
energy content is estimated at 20.16 kJ/g -1 [40]. In addition, plants
tend to have much dead material, and form expansive acreages of dense
shrub growth with interlocking crowns [30]. Thus, fire in shrub
communities dominated by species such as chaparral whitethorn have the
potential to become "huge and violent" in a relatively short period of
time [30]. Natural fire intervals in California chaparral or coastal
sage communities range from 20 to 60 years [11,28,51]. Where chaparral
whitethorn occurs as an important understory species in drier coniferous
forests of California, it can increase overall stand flammabilty as dead
woody material accumulates in the shrub's crown when plants become
decadent [49].
Wildife considerations: The nutritional value of chaparral whitethorn
may be altered by fire. Foliar nitrogen concentration of chaparral
whitethorn begins a rapid decline during the first 6 years after fire
[41]. Potassium content is typically elevated during the first few
years after fire, but then begins to decrease [41].
Production: Postfire production of chaparral whitethorn was found to
average approximately 360 pounds per acre (403 kg/hectare) 5 years after
a fall burn [13].
REFERENCES
SPECIES: Ceanothus leucodermis | Chaparral Whitethorn
REFERENCES :
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29. Martin, Bradford D. 1982. Vegetation responses to prescribed burning in
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Index
Related categories for Species: Ceanothus leucodermis
| Chaparral Whitethorn
|
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