species in California [25,38,121]. It is most extensively distributed
in the southern Coast Ranges [20,26,48], but occurs in the Coast,
Transverse and Peninsular ranges from Mendocino County to Baja
California [20,26,48]. It also occurs in the Sierra Nevada foothills
 and on the Channel islands . Adenostoma fasciculatum variety
obtusifolium is restricted to southwestern San Diego County and Baja
Regional Distribution in the Western United States
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):
1 Northern Pacific Border
3 Southern Pacific Border
4 Sierra Nevada
Occurrence in North America
Chamise is a diffusely branched, resinous, native shrub [25,91,121] from
2 and 12 feet (0.6-3.5 m) tall . Plants are unarmed, spreading, and
branch very close to the ground [91,128]. The many slender stems are
erect and generally lack permanent branches . Young stems have
reddish bark; bark becomes gray and shreddy with age [38,91]. Linear,
needlelike leaves occur in alternate fascicles along the stem [18,121].
Leaves are 0.25 inch (0.6 cm) long, sharp-pointed, heavily sclerified,
and evergreen [18,38,65]. The inconspicuous, bisexual flowers are white
and occur in showy, 1- to 4-inch-long (2.5-10 cm) terminal clusters
[22,121]. The fruit is an achene [91,128].
Although rooting habit is variable [79,84], roots are usually deeply
penetrating, much branched, and widespreading [38,49]. The root system
is extensive in relation to the crown [78,79]. Chamise typically
develops several taproots which penetrate fractured rock to depths of 10
to 12 feet (3.0-3.7 m) ; extensive laterals originate from the
lignotuber . Longevity of chamise is estimated at 100 to 200 years
Chamise is the most common chaparral species throughout the foothills
and coastal mountains of California [13,38,39]. It is present in
approximately 70 percent of California chaparral [13,39]. It is most
often associated with hot, xeric sites  over a wide range of
elevations, soils, latitudes, and distances from the coast . In
southern California it is a ubiquitous dominant on outwash plains,
mesas, ridges, and dry, south- and west-facing slopes at elevations up to
6,000 feet (1,800 m) [18,35,38,52,91,100,121].
Sites supporting chamise commonly receive between 10 and 40 inches (250
and 1,000 mm) of annual precipitation, and have a temperature range from
32 to 100 degrees Fahrenheit (0-38 deg C) . In the southern Coast
Ranges, where average annual rainfall ranges from 16 and 20 inches
(400-500 mm), chamise occurs abundantly on all slopes and exposures and
grows on deep, fertile soils as well as shallow, rocky ones [48,121].
As precipitation increases farther northward, chamise is largely
restricted to the poorer soils and the drier, more exposed sites
Chamise occurs in both pure and mixed stands [38,39,120]. Nearly pure
(>80%) stands of chamise are impenetrable and are referred to as
"chamisal" [20,25,43]. Such stands usually have shallow, rocky soils
with a southern aspect [35,53].
Key Plant Community Associations
Chamise is a shrub component of chaparral, woodland, and forest
communities throughout much of California [13,51]. Within chaparral
communities, chamise typically dominates the shrub cover on the hottest
and driest sites . As available moisture increases, it codominates
with manzanita (Arctostaphylos spp.) and ceanothus (Ceanothus spp.)
species [42,51]. Chamise is an understory shrub in dry coniferous
woodlands dominated by Parry pinyon (Pinus quadrifolia), knobcone pine
(P. attenuata), or gray pine (P. sabiniana). Less commonly, chamise
occurs beneath scrubby "forest" communities dominated by either Torrey
pine (P. torreyana), knobcone pine, Piute cypress (Cupressus arizonica
ssp. nevadensis), Cuyamaca cypress (C. a. var. stephensonii), or Tecate
cypress (C. forbesii) . It is also present in the understory of
maritime Coast Range ponderosa pine (Pinus ponderosa) forests .
Common associates within chamise chaparral include :
northern Coast Range: hoary manzanita (Arctostaphylos
canescens), Parry manzanita (A. manzanita), wedgeleaf
ceanothus (Ceanothus cuneatus), wavyleaf ceanothus (C.
foliosus), and leather oak (Quercus durata).
southern Coast Range: oaks (Quercus spp.), ceanothus (Ceanothus
spp.), manzanitas (Arctostaphylos spp.), buckthorns (Rhamnus
spp.), sumacs (Rhus and Malosma spp.), California sagebrush
(Artemisia californica), California buckwheat (Eriogonum
fasciculatum), and sage (Salvia spp.).
interior: whiteleaf manzanita (Arctostaphylos viscida), Parry
manzanita, wedgeleaf ceanothus, Lemmon ceanothus (C.
lemmonnii), chaparral whitethorn, toyon (Heteromeles
arbutifolia), buckthorns, poison-oak (Toxicodendron
diversilobum), and yerba santa (Eriodictyon californicum).
southern California: bigberry manzanita (A. glauca),
Mexican manzanita (A. pungens), pink-bracted manzanita
(A. pringlei var. drupacea), hoaryleaf ceanothus (C.
crassifolius), and desert ceanothus (C. greggi var. perplexans).
Published classifications listing chamise as a dominant or indicator
The chaparral vegetation of Santa Cruz Island, California 
Vegetation and floristics of Pinnacles National Monument 
Vegetation types of the San Gabriel Mountains 
Preliminary descriptions of the terrestrial natural communities of
Vegetation types of the San Bernardino Mountains 
A vegetation classification system applied to southern California 
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):
More info for the term: shrub
FRES21 Ponderosa pine
FRES28 Western hardwoods
FRES34 Chaparral - mountain shrub
FRES35 Pinyon - juniper
Habitat: Cover Types
This species is known to occur in association with the following cover types (as classified by the Society of American Foresters):
239 Pinyon - juniper
245 Pacific ponderosa pine
246 California black oak
248 Knobcone pine
249 Canyon live oak
250 Blue oak - Digger pine
255 California coast live oak
Habitat: Plant Associations
This species is known to occur in association with the following plant community types (as classified by Küchler 1964):
K009 Pine - cypress forest
K023 Juniper - pinyon woodland
K030 California oakwoods
K035 Coastal sagebrush
K036 Mosaic of K030 and K035
Fire Management Considerations
Fire frequency: Chamise is adapted to a fire cycle range from 10 to 100
years. It can regenerate after fire intervals of over 100 years,
however [68,74,90,116]. Its capacity for canopy rejuvenation without
fire allows chamise to persist through long fire-free intervals.
Stohlgren and Rundel  suggested 30 to 80 years as a "typical" fire
frequency for chamise chaparral communities in Sequoia National Park.
Influence of ryegrass seedings: Ryegrass (Lolium multiflorum) is often
seeded onto recently burned chaparral as a means of emergency
revegetation . Ryegrass, however, inhibits growth and development of
chamise seedlings , and ryegrass substantially reduces postfire
chamise seedling establishment [4,33]. On seeded burns in southern
California, almost no chamise seedlings established where first-year
ryegrass cover ranged between 40 and 90 percent .
Ryegrass seedings also produce an easily ignitable fuel bed that
increases the likelihood of an early reburn. Fires occurring at short
intervals have the potential to cause significant changes in species
density and composition within chamise chaparral . Not only do
frequent fires produce high mortality of sprouted plants , but
postfire seedlings (derived from the previously dormant seedbank) are
also killed, thereby depleting the on-site seed reserve [66,136].
Consequently, chamise is unable to reestablish, and gaps in the shrub
matrix are subject to invasion by coastal sage scrub species such as
black sage, California sagebrush, and California buckwheat. The site
may be dominated by coastal sage scrub species for 100 years or more
Deer browse: Deer use of chamise is often extensive immediately
following fire [9,113,121]. Browse value of sprouts lasts for only 2 to
3 years because plants quickly mature to less nutritious stages or die
from overuse . To enhance deer use of sprouts, cattle access to
burns should be restricted during the first postfire season .
Because of the lack of adequate escape cover, only the periphery of large
burns receive extensive deer use prior to the second postfire season.
The center of large burns are rarely if ever utilized during the first
several seasons . Close utilization within the first year may kill
chamise, and mortalities of up to 64 percent are possible under intense
browsing pressure .
Late winter or early spring fires are most favorable for production of
deer browse because succulent sprouts with a high nutrient value are
produced almost immediately, and subsequent sprout growth is rapid
during the spring growth period . If fires are conducted after
mid-September in northern California, sprouting may not be profuse until
the following spring . Fires resulting in total plant consumption
produce the most usable browse, since deer tend to avoid burned chamise
with main scaffold branches remaining [9,24].
Plant Response to Fire
Postfire regeneration in chamise involves a combination of sprout
regeneration and seedling recruitment [48,54,69,120].
Vegetative regeneration: Although considerable plant mortality may
occur following fire, at least some percentage of the chamise population
survives and sprouts [39,42,61,120]. Residual plants typically sprout
within 6 weeks of fire regardless of season . On sites in southern
California, chamise along moist ravines sprouted within 10 days of a hot
July wildfire . Sprouts originate on the lignotuber from a narrow
band of tissue located 0.2 to 1 inch (0.5-2.5 cm) below the soil surface
. Perennating buds along the periphery of the lignotuber are the
first to initiate sprouts, followed by buds near the base of charred
stems . Sprout production varies by lignotuber size. Large plants
usually possess large lignotubers which produce as many as 500 sprouts
. During the first year sprout numbers are drastically reduced as
larger stems gain dominance [6,111].
Sprouts use stored carbohydrate reserves to achieve rapid growth
[109,111]. Rapid shoot elongation typically occurs during the first
spring following fire [60,108]. After fires in northern California,
sprouts averaged 20 inches (50 cm) by the end of the first postfire
growing season . Shrubs with a large prefire biomass typically
produce the most vigorous sprouts and can be expected to dominate the
postfire community . Baker and others  indicated that sprout
biomass of residual plants at the end of postfire year 1 is positively
correlated with prefire biomass. Stem growth slows during postfire
years 2 and 3 [54,108], and growth during subsequent years declines
until it is almost negligible by 20 years after fire [54,108]. Horton
and Kraebel  reported that 5-year-old sprouts reached an average
height of 33.6 inches (84 cm), while 20-year-old sprouts were only 40.4
inches (101 cm) tall .
The pattern of postfire sprout growth usually follows that of mature
plants. Time of fire, however, may alter the initial pattern of
postfire shoot growth. On sites in the southern Sierra Nevada, plants
burned in late June or early August produced sprouts that grew
continuously until the second postfire summer . The reduced leaf
area of sprouted plants limited transpiration losses and resulted in
higher shoot water potentials, permitting shoot growth through the
summer drought period [46,47]. While summer fires (at a time of reduced
carbohydrate reserves) initially resulted in significantly shorter
plants, shoot heights of plants burned in different seasons were similar
by the end of the second postfire year .
Seedling regeneration: Chamise produces an abundant crop of seedlings
from soil-stored seed [17,39,45]. While a flush of initial seedling
establishment may occur immediately following fire, subsequent mortality
is quite high [59,73,85]. On sites in southern California, seedling
densities in March ranged from 91,427 to 180,383 seedlings per acre
(37,000-73,000 seedlings/ha) but dropped to 29,652 to 34,594 pere acre
(12,000-14,000/ha) by June . The degree to which seedlings
contribute to the postfire recovery of chamise is quite variable and
appears related to site conditions, amount of fire-induced adult
mortality, and stand age [39,58]. On sites where the majority of plants
survive fire, prefire shrub density is maintained and little seedling
establishment occurs. Conversely, seedling establishment is often
substantial and critically important in regaining prefire levels on
sites where adult survival is low [3,66].
Recovery: Because of hot, dry site conditions, postfire growth of
chamise chaparral is slow compared to other chaparral types [53,100].
Initial sprouting response may be substantially reduced following
intense summer fires, since more of the meristematic tissue in the
lignotuber is killed . Four months after a July wildfire in
southern California, chamise plants produced up to 12 sprouts per plant,
but sprouts rarely exceeded 12 inches (30 cm) in length . In
southern California chamise communities, chamise rapidly dominates the
postfire community and commonly comprises at least 33 percent of the
vegetation on 10-year-old burns. In stands 22 to 40 years of age, it
reaches a maximum of approximately 50 percent of the total vegetative
Broad-scale Impacts of Fire
Small plants with a prefire biomass between 2 and 11 pounds (1 and 5 kg)
are particularly prone to fire mortality  because of their shallow
lignotubers and presumably smaller carbohydrate reserves [3,116].
Individuals with larger lignotubers are generally more fire tolerant,
although large shrubs which have survived previous fires may have more
dead material in their crowns, making them more prone to fire mortality
. Fire susceptibility of larger plants also increases in older
stands where high fuel loads produce severe fires . Mean lignotuber
area of fire-killed plants in a 90-year-old stand was 35 square inches
(227 sq cm) compared to 12 square inches (79 sq cm) for plants in a
23-year-old stand . Very large chamise lignotubers tend to rot in
the center and are less capable of sprouting after fire . While
young seedlings are readily killed by most fires, fire tolerance
increases with age. In southern California, large numbers of 4-year-old
chamise sprouted following intense summer grassfires [58,136].
Immediate Effect of Fire
Chamise is a fire-sensitive species , and mortality may be
substantial following fire [54,74,105]. Perennating buds are located
just beneath the soil surface and are quite susceptible to fire damage
[3,136]. Mortality patterns are related to season of fire, fire
intensity and severity, and fire frequency .
The following photographs show top-killed chamise immediately after
the 2003 Otay Mountain Wildfire in San Diego County and chamise sprouting
in postfire year 2. Photos are courtesy of the San Diego Wildfires Education
|Burned chamise in Otay Mountain Wilderness Area, 2003.|
|Sprouting chamise in Otay Mountain Wilderness Area, 2005.|
|Close-up of chamise sprouting from the root crown in 2005.|
Season of burning: Season of fire affects chamise lignotuber survival.
Spring or summer fires may kill up to 50 percent of plants, while fall
fires result in relatively little mortality [3,74,124]. Differential
mortality is related to seasonal fluctuations in the carbohydrate
reserves of lignotuber and large roots. High starch concentrations are
apparently necessary for the onset of sprouting [89,119]. Starch
concentrations may be insufficient to ensure sprouting when chamise is
burned in the late spring or summer, since carbohydrate reserves have
been depleted during spring growth [61,81]. Over the summer months,
however, starch reserves are recharged as carbohydrates are translocated
to the lignotuber, and most plants sprout following fall fires. In dry
years, major carbohydrate mobilization does not take place; under these
conditions, spring or summer fires might produce lower level mortality
than in more "normal" years .
Fire intensity: Mortality increases with increasing fire intensity.
Following low-, moderate-, and high-intensity June fires in old-growth
chamise in Sequoia National Park, approximately 46, 64, and 80 percent
of chamise plants died, respectively. Seasonal patterns of fire
mortality are further accentuated by differences in fire severity
associated with spring/summer versus fall fires. Early season fires
move slowly through a stand and the downward heat pulse is greater than
that produced by rapidly carrying, fall fires. As a result, fall fires
are generally less severe than spring/early summer fires and produce
less mortality. In one case, a moderately intense spring (June) fire
resulted in 64 percent chamise mortality, whereas a moderately intense
fall (October) fire resulted in only 14 percent mortality .
Fire frequency: Chamise is extremely susceptible to short-interval
fires. High mortality of both seedlings and sprouts is likely when
fires recur on burns seeded to annual grasses. Chamise density
(seedlings and sprouted individuals) was reduced up to 97 percent
following a grass fire on a 1-year-old burn . Chamise seedlings
are more sensitive to frequent fire than sprouted plants . In
northern California, Hedrick  reburned 1-, 2-, and 3-year-old burn
sites which had been seeded to grass and mustard. Mortality of
established chamise was 77 percent on the 1-year-old burns, 24 percent
on the 2-year-old burns, and 34 percent on the 3-year-old burns.
Seedling mortality was 99, 98, and 100 percent on the 1-, 2-, and
3-year-old burns, respectively. Fires occurring at very short intervals
may completely eradicate postfire seedling reproduction if the soil seed
reserve is not well established and reproductive maturity has not been
reached [58,136]. Although sprouts are generally capable of heavy seed
production by the second year after fire , chamise seeds exhibit
poor viability. A number of years are required to build up the
Seedbanks: Chamise seed is sensitive to high temperatures [16,40,130].
Depending on fire intensity and seed position in the soil, a large
portion of the seedbank may be destroyed as the soil temperature rises
during burning . While abundant seed is present beneath the shrub
canopy and in gaps between shrubs, burning modifies the seedbank by
concentrating readily germinable seed in the shrub interspaces. Soil
temperatures during burning are lower in the shrub interspaces, and more
seeds survive fire in these interspaces than below the canopy .
Fire sensitivity is increased if seeds have imbibed water [23,99], and
seed mortality is high following spring fires, which are often severe
. Reduced seed mortalities can be expected when fires occur under
dry soil conditions associated with late summer and fall.
Tall shrub, adventitious-bud root crown
Small shrub, adventitious-bud root crown
Ground residual colonizer (on-site, initial community)
Following fire, chamise sprouts from dormant buds on the lignotuber
[60,68,73]. The lignotuber has a stored supply of carbohydrates,
nutrients, and water which support vigorous growth . Chamise also
produces abundant seedlings from fire-activated, soil-stored seed
[16,68]. Chamise rapidly reoccupies the postfire community.
Chamise possesses a number of adaptations that enhance its flammability
[39,93,104,116]. These adaptations result in intense, fast-spreading,
potentially large fires which have an increased probability of occurring
as a stand matures . Chamise chaparral produces fuel loadings
capable of supporting a moderately intense fire within approximately 15
years . Adaptations which enhance flammability are discussed below.
Chemical: The chemical composition of foliage includes high energy
ether extractives (waxes, resins, oils, terpenes, and fats) and
inorganic minerals that affect pyrolysis of carbohydrates .
Ether extractives in the foliage increase burning rate because of
their high heat content and may account for as much as 34 percent
of the available heat content of chamise . In older plants, a
significant increase in the ether extractive content of 1- and
2-year-old leaf and stem tissues apparently contributes to the
increased flammability of older stands . Volatile, high
energy essential oils on the leaf surface also ignite at low
Physical: Structural characteristics produce rapid rates of
energy release [21,116]. Approximately 60 percent of chamise stems
are less than 0.5 inches (1.27 cm) in diameter . Large amounts
of small-stemmed material, distributed continuously from ground
level throughout the multistemmed canopy, lend spatial continuity
to the fuelbed and facilitate heat transfer . Chamise also
retains dead material in the crown . As a stand ages, this
material accumulates and within 30 years may account for 50 percent
of the fuel loading . Besides igniting easily and burning
fast, dead fuels preheat live fuels, further increasing stand
Physiological: Chamise is most flammable in the fall . Fuel
moisture drops significantly during hot, dry weather and increases
the concentration of extractive chemicals .
More info for the terms: climax, cover, shrub, shrubs
Chamise is a long-lived, shade-intolerant shrub  which dominates
lower elevation chaparral throughout much of California [20,42].
Disagreement exists over whether its dominance is a reflection of a
climatic climax [5,20] or is a fire-induced subclimax . Hanes
[43,44] stated that chamise chaparral is unable to perpetuate itself in
a vigorous condition without recurrent fire and terms it a true
"fire-type vegetation". Chamise stands older than 60 years of age are
sometimes termed " decadent" [39,48]. Old stands have low species
diversity and produce little annual growth, with dead stem biomass far
exceeding live stem biomass [40,43]. Stand stagnation has been
attributed to the accummulation of biochemicals in the soil that
inhibit decomposition, humification, and nitrification [40,94,131].
Limited nutrient availability, especially of nitrogen, may partially
contribute to the decline of chamise chaparral . Fire rejuvenates
stagnant stands by removing phytotoxic substances from the soil,
increasing the concentration of available nutrients, and stimulating
sprouting of adults and germination of dormant seed .
Chamise is present soon after fire and remains present in all stages of
succession. It achieves initial postfire dominance through vigorous
sprout production and establishment of large numbers of seedlings
[9,74,120]. Typical vegetal cover on 1-year-old chamise chaparral burns
also includes a high percentage of herbaceous vegetation and the
seedlings and sprouts of associated shrubs and subshrubs. As chamise
seedlings and sprouts grow during the first postfire decade, herbaceous
vegetation rapidly declines; likewise, subshrubs and short-lived shrubs
are restricted to smaller and smaller openings [29,45]. A dense stand
of chamise typically develops within approximately 8 to 10 years ,
with chamise frequently comprising one-third of total cover .
Stands often exhibit complete canopy closure by 22 years of age .
In pure stands of chamise in southern California, chamise may reach 25
percent, 50 percent, and 55 percent cover within 10, 40, and 70 years of
fire, respectively .
Short-lived shrubs and herbaceous cover are largely lacking from
undisturbed stands of chamise chaparral . Chamise probably
produces allelopathic toxins which inhibit germination and growth of
other species [16,17]. During summer drought, chamise leaves accumulate
water-soluble phenolics as a result of normal metabolic activity; fog
drip and rain transport the toxins into the soil [43,83]. Competition
for light may also be a factor controlling seed germination beneath
mature stands [67,69].
Although chamise has only a limited ability to colonize disturbed areas
, it is capable of pioneering broken rock surfaces and alluvial
washes . Chamise may invade woodlands where grass cover is sparse
and sometimes invades productive soils following fire . On sites
with relatively deep soils, decadent chamise may be replaced by annual
Chamise reproduces sexually and vegetatively. Since chamise seed
germinates at high rates only after fire, seedling recruitment and
population expansion are fire dependent [68,69]. Canopy rejuvenation
through the production of new basal sprouts occurs with or without the
influence of fire [68,70].
Reproduction by seed: Onset of seed production occurs early in chamise,
often by 3 years of age . Seed production does not appear to
decrease with age. Ninety-year-old shrubs generally produce
substantially greater quantities of seed than those 20 years of age
. Seeds are dispersed during the summer . Because the small
achenes are not highly specialized for wind dispersal, most seeds fall
near the parent plant . Although the seed crop is abundant, the
majority of seeds are not filled and viability is quite low, in some
cases 0 to 4 percent [38,69,88,126]. Maximum seed production occurs
following winters with above-average rainfall [3,38].
Chamise produces a dimorphic seed population composed of dormant as well
as readily germinable seeds [16,126]. Dormancy is imposed by a more or
less impermeable seedcoat. Heat from fire scarifies the seedcoat and
stimulates germination [16,69,126]. Christensen and Muller  found
that germination was enhanced when seeds were exposed to temperatures of
160 to 180 degrees Fahrenheit (71-82 deg C) for 15 minutes. Keeley 
suggested that heat shock from fire and the presence of charate (charred
wood) may act synergistically to stimulate germination. In laboratory
studies, Keeley found that addition of charate significantly increased
germination (11%) relative to controls (4%). Maximum germination (18%),
however, occurred when heat-treated seeds were incubated in the presence
of charred wood . Black sage (Salvia mellifera) apparently inhibits
chamise germination .
Under natural conditions, dormant seeds accumulate in the soil until
stimulated by fire to germinate [66,126]. Chamise seeds are unpalatable
and seedbanks apparently are not subject to heavy predation .
Consequently, chamise seed densities increase over time . Seed
density in the seedbank beneath 9-year-old stands was estimated at 2,000
seeds per square meter while in 85-year-old stands, seed density was
approximately 21,000 seeds per square meter . Abundant germination
from soil-stored seed occurs during the first rainy season after fire;
germination during the second year is uncommon [54,67,111]. Although
emergent seedling populations are quite high , mortality is
substantial during the first several years [39,54,120]. On sites in
southern California, approximately 90 percent of the seedlings that
germinated during March and April died within the first year .
Drought stress during late spring and summer is a major cause of
first-year seedling mortality [59,86]. By the end of the second growing
season, drought-induced mortality decreases as seedlings develop
sufficient root biomass . Taproots of newly germinated seedlings
are barely 2 inches (5 cm) long by July, whereas taproots of 2-year-old
seedlings range between 8 and 12 inches (20-30 cm) . Small mammal
herbivory contributes significantly to mortality , particularly in
the fall . First-year mortality due to rabbits may be as high as 25
percent . Failure to establish may also be due to lack of suitable
microsites and competitive interference [43,86]. On southern California
burns, survival of first-year seedlings was not affected by the presence
of residual shrubs or herbaceous perennials; annuals, however,
significantly reduced seedling growth .
Many chamise plants die during subsequent years [48,120], but some
survive [48,54]. Twenty-five years after a fire in central California,
chamise resulting from seed were still growing and had reached an
average height of 31.9 inches (80 cm) .
A portion of chamise seed germinates without fire scarification under
favorable moisture and temperature conditions [126,133]. A study of the
seedbank beneath an 85-year-old stand of chamise indicated that 20
percent of the chamise seedbank (density averaged 9,500 chamise seeds/sq
m) was readily germinable . Although initial establishment
sometimes occurs without the influence of fire [35,54,101], seedling
survival beyond the first year is extremely low and usually limited to
areas recovering from human disturbance or overgrazing . In mature
chaparral, seedlings occasionally establish in canopy gaps, but
successful establishment almost never occurs directly beneath the canopy
Vegetative regeneration: Chamise rejuvenates its crown by continually
producing new sprouts from an established lignotuber [48,69,70].
Following disturbances such as fire or cutting, chamise sprouts
vigorously from surviving adventitious buds on the lignotuber [57,120].
Growth Form (according to Raunkiær Life-form classification)
Broad-scale Impacts of Plant Response to Fire
generally considered facultative [43,68]. Chamise relies primarily on
vegetative reproduction for postfire establishment on foothill sites in
the southern Sierra Nevada [116,118]. Although as many as 2.73 million
seedlings per hectare may emerge following fire, they are usually
outcompeted by faster growing sprouts . Likewise, vegetative
reproduction is the predominant mode of postfire regeneration at higher
elevations in southern California mountains [71,73,129].
As chaparral sites become increasingly arid, however, sprouting tends to
be less successful and seedling recruitment more prevalent following
fire [39,136]. On droughty, low elevation sites in southern California,
chamise depends to a large degree on successful seedling establishment
for population replacement after fire [56,58,71,72,136]. Howe and
Carothers  found that chamise seedlings grew vigorously and
contributed significantly to postfire stands at elevations between 1,312
and 1,968 feet (400-600 m) near Newhall, California, in Los Angeles
County. Chamise seedlings comprised approximately 86 percent of the
chamise population on 6- to 9-year-old-burn sites. Although seedlings
grew more slowly than sprouts during the first few postfire seasons,
they reached heights equal to that of sprouted plants within 8 to 9
years. On 6-year-old, north-facing burns, however, vegetative
reproduction was the predominant mode of regeneration . Hanes 
indicated that altitude also influences mode of postfire reproduction.
He found that seedlings comprised a higher proportion of the postfire
vegetation on burn sites between 1,000 and 2,000 feet (300-600 m) than
between 2,000 and 4,000 feet (600-1,200 m).
Life History and Behavior
More info for the term: lignotuber
Stem elongation occurs from February through May [2,130]. Shoot
organization in chamise consists of short and long shoots and has been
described by Jow and others . New leaves appear in late January or
February and continue to develop as shoots elongate . New foliage is
not limited to the current season's growth; short shoots remain active
and produce leaves on 2- to 8-year-old branches . Leaves are
retained for two growing seasons .
Chamise produces nearly twice the amount of reproductive tissue as it
does new stems and leaves . In Sequoia National Park, flowers
develop on the current year's growth in June followed by fruit
development in July . Fruit ripening and dispersal is completed by
August. At this time, inflorescences die back and new growth becomes
woody . Although flower bud development and flowering occur at a
time of decreasing water potential, reproductive growth is somewhat
resistant to summer drought conditions. Water stored in the lignotuber
allows chamise to maintain reproductive growth despite low water
potentials . Ample rainfall during the season directly preceding
major growth activity increases the quantity of reproductive as well as
vegetative growth [2,38].
Root growth: The period of root growth lasts considerably longer than
the seasonal flush of shoot growth . Fine roots may grow for 5 to 7
Carbohydrate reserves: Onset of shoot growth is preceded by
carbohydrate mobilization to the shoot apex and correlated with a
decrease in the starch concentration of the roots and lignotuber .
Demand for nutrients during canopy and reproductive growth is quite high
and by the end of the spring growth season, carbohydrate reserves in the
roots and lignotuber are largely depleted . During the summer,
water stress-induced suppression of photosynthesis results in a
reduction in carbohydrate availability at the shoot apex, and shoot
growth ceases [1,5,38,108]. Cessation of growth is followed by a
gradual increase in root starch reserves over fall and winter [61,81].
Molecular Biology and Genetics
Barcode data: Adenostoma fasciculatum
Statistics of barcoding coverage: Adenostoma fasciculatum
Public Records: 1
Specimens with Barcodes: 1
Species With Barcodes: 1
National NatureServe Conservation Status
Rounded National Status Rank: NNR - Unranked
NatureServe Conservation Status
Rounded Global Status Rank: G5 - Secure
fire, and chamise is fairly tolerant of concentrated use at this time
[9,76]. Moderate cropping by deer prolongs the period of enhanced
palatability by keeping sprouts in younger growth stages and by
stimulating additional browse production . Without browsing sprout
bases become woody and are no longer preferred [6,9]. Continued close
browsing, however, kills most plants within 2 to 3 years [9,10].
Chamise is heavily browsed on Santa Cruz and Santa Catalina islands.
Decades of severe overgrazing by feral animals (pigs, sheep, and goats)
has removed more palatable species and given chaparral stands an open,
arborescent structure. Chamise exhibits a noticeable browse line and a
trend towards increased trunk diameter, canopy coverage, and height
. Chamise produces few basal sprouts under such intense browsing
and is very susceptible to eradication [15,87].
Herbicides: Chamise is sensitive to 2,4-D [14,37,63,97].
Plants exhibit a wide range of response to ammonium sulfide or benzoic
acid application .
Relevance to Humans and Ecosystems
Value for rehabilitation of disturbed sites
Chamise is suitable for revegetation because of its well-developed root
system and drought resistance. Horton  listed it as useful for
roadside erosion control plantings within chaparral. Recommended
locations include sunny sites with deep or shallow soils at elevations
between 500 and 3,500 feet (152-1,067 m) and sites with deep soils at
elevations between 3,500 and 6,000 feet (1,067-1,829 m). Planting of
pot-grown, bareroot stock produces satisfactory results . Bareroot
stock showed a 58 percent survival at the end of 2 years when planted at
2,700-foot (823 m) elevation in soils 2 to 6 feet (.6-1.8 m) deep;
surviving plants reached heights of 4 to 6 feet (1.2-1.8 m) within 8
years. Two-year-old seedlings transplanted from a burn, however, had
only 5 percent survival .
Plants may be propagated in flats from seed sown in winter or spring
. Seeds should be soaked in 10 percent sulfuric acid for 15 minutes
prior to sowing. Within 4 to 6 months, seedlings usually reach heights
of 2 inches (5 cm) and can be transplanted to pots. Most seedlings are
ready for field planting after approximately 1 year in the pot stage
. Plants may also be propagated from green wood cuttings taken in
the spring .
Chamise provides escape, bedding, resting, and thermal cover for mule
deer [18,96]. In southern California chaparral, bighorn sheep prefer
relatively open habitats on steep, south-facing slopes where the
vegetation consists of a 30 percent cover of chamise, birchleaf
mountain-mahogany (Cercocarpus betuloides), and chaparral whitethorn .
Importance to Livestock and Wildlife
Chamise is important forage more because of its abundance and widespread
distribution than its palatability . It furnishes a large quantity
of low to medium quality browse for both livestock and big game .
Chamise is a staple deer food (by volume) throughout much of California
[76,121]. Deer use is often year-round, particularly in northern
California [9,121], but is most concentrated during the summer and fall
[9,50,76,121]. Limited livestock use occurs, primarily during the
spring and summer [95,121,123]. Chamise in mature chaparral is seldom
browsed because stands are too dense for livestock or big game species
to penetrate, making the current growth largely inaccessible
Chamise sprouts on recently burned sites contribute greatly to total
available forage within chaparral communities [9,76,113,121,123].
Sprouts provide a large volume of medium quality browse for domestic
sheep and goats, and mule deer [9,34,48,121] but are browsed for only
one to two postfire seasons because they rapidly become unpalatable
[9,76,112]. Mule deer and domestic sheep frequently strip the leaves of
sprouts, which are larger, more succulent, and less sclerophyllous than
those of unburned plants [76,121]. Seedling leaves are eaten by
domestic sheep and cattle . Dusky-footed woodrats gather chamise
leaves and bark and store them in dens for year-round consumption .
Chamise provides habitat for a variety of small and large wildlife
species . Dense stands serve as hiding, resting, and nesting sites
for many smaller birds and mammals. Wirtz  compiled a list of
common mammals, amphibians, reptiles, and birds associated with southern
Other uses and values
purposes. Chamise oils were used to treat skin infections, and an
infusion of the bark and leaves was used for syphilis . A binding
agent for arrows and baskets was made from scale insects found on
chamise plants .
satisfactory source of digestible energy, but it is not high in
digestible protein . Crude protein values are highest in newly
initiated leaves . Seasonal trends in the crude protein content of
the current growth (stems and leaves) are as follows :
winter (Dec.- Feb.) 7.0
spring (Mar.- May) 13.3
summer (Jun.- Aug.) 8.3
fall (Sept.- Nov.) 5.8
Sprouts contain nearly twice as much water, minerals, and crude protein
per unit of total dry weight as does the current growth of mature plants
. Chemical composition (percent of oven-dry weight) of samples
taken in August in Lake County is compared below .
young mature stems/
crown sprouts seeds formed
silica-free ash 6.16 1.79
calcium 1.26 0.38
phosphorus 0.55 0.08
calcium:phosphorus 2.3 4.7
crude protein 17.53 2.89
crude fiber 12.89 28.71
moisture content 130 39
burning, however, greatly enhances its palatability . Domestic goats
often show a preference for chamise on recently burned chaparral
[34,122,123]. Following goat depletion of California scrub oak (Quercus
dumosa), the animals readily consumed chamise, preferring it over
Eastwood manzanita (Arctostaphylos glandulosa) and desert ceanothus
(Ceanothus greggii) [34,96].
Chamise browse has been rated useless for horses, useless to poor for
cattle, and fair to good for sheep, goats, and deer . Goats
preferentially select the flower clusters .
Adenostoma fasciculatum (chamise or greasewood) is a flowering plant native to Oregon, Nevada, California, and northern Baja California. This shrub is one of the most widespread plants of the chaparral biome.
Adenostoma fasciculatum is an evergreen shrub growing to 4m tall, with dry-looking stick-like branches. The leaves are small, 4–10 mm long and 1mm broad with a pointed apex, and sprout in clusters from the branches. These clusters are known as fascicles, and give the species its Latin name. The leaves are shiny with flammable oils, especially in warmer weather. The branches terminate in bunches of white tubular flowers five mm diameter, with five petals and long stamens. The fruit is a dry achene.
The oily leaves give rise to the common name greasewood.
There are two varieties which differ from each other in minor characters; they are not accepted as distinct by all authors:
- A. f. var. fasciculatum - Leaves 5-10 mm, apex sharp; shoots hairless.
- A. f. var. obtusifolium - Leaves 4-6 mm, apex blunt; shoots slightly hairy.
It is very drought tolerant and adaptable, with the ability to grow in nutrient-poor, barren soil and on dry, rocky outcrops. It can be found in serpentine soils, which are generally inhospitable to most plants, as well as in slate, sand, clay, and gravel soils. Chaparral habitats are known for their fierce periodical wildfires, and like other chaparral flora, chamise dries out, burns, and recovers quickly to thrive once again. It is a plant that controls erosion well, sprouting from ground level in low basal crowns that remain after fires, preventing the bare soil from being washed away.
Chamise grows in dense, monotypic stands that cover the dry hills of coastal California. These thickets of chamise are sometimes called chamissal. The species also gives its name to a specific chaparral (i.e., Adenostoma fasciculatum chaparral) dominated by A. fasciculatum, according to C.Michael Hogan. In this chaparral type toyon may also be a co-dominant.
- USDA, 2008
- Jepson Flora Project, 1993
- C.M. Hogan, 2008
Names and Taxonomy
fasciculatum Hook and Arn. (Rosaceae). Chamise and red shank (A.
sparsifolium) are the only members of this genus [38,91]. Chamise has
two recognized varieties which are differentiated on the basis of leaf
size and shape [64,91]: A. f. var. fasciculatum and var. A. f. var.
obtusifolium S. Watson [18,91].
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