Larrea tridentata (Sesse & Moc. ex DC.) Coult.

More info for the term: shrub

creosote bush
greasewood


TAXONOMY:
The scientific name of creosote bush is Larrea tridentata (D.C.) Cov.
It is a member of the caltrop family (Zygophyllaceae) [52,98]. Varieites
include [98]:

Larrea tridentata (DC.) Coville var. arenaria L.D. Benson
Larrea tridentata (DC.) Coville var. tridentata


LIFE FORM:
Shrub

FEDERAL LEGAL STATUS:
No special status

OTHER STATUS:
NO-ENTRY




DISTRIBUTION AND OCCURRENCE
SPECIES: Larrea tridentata
GENERAL DISTRIBUTION:
Creosote bush occurs throughout the Mojave, Sonoran, and Chihuahuan
deserts [11].  Its distribution extends from southern California
northeast through southern Nevada to the southwest corner of Utah and
southeast through southern Arizona and New Mexico to western Texas and
north-central Mexico [67].

More info for the term: forest

Creosote bush occurs throughout the Mojave, Sonoran, and Chihuahuan
deserts [11].  Its distribution extends from southern California
northeast through southern Nevada to the southwest corner of Utah and
southeast through southern Arizona and New Mexico to western Texas and
north-central Mexico [67].



Distribution of creosote bush. 1970 USDA, Forest Service map digitized by Thompson and others [117].

More info for the terms: fuel, litter

Fire can be used to control creosote bush and promote the growth of
grasses in desert grasslands and shrublands.  Prescribed burning should
be conducted in spring or early fall following 2 years of above average
plant growth.  Britton and Wright [20] describe specific procedures for
burning shrub-invaded grasslands.

Soils under some creosote bush are water repellant because of associated
soil microorganisms.  The hydrophobic characteristic of such soils
precludes the establishment of annuals normally occurring under
creosote bush.  The degree to which the soils are hydrophobic may be
intensified by fire [5].

Standing biomass, deadwood, and leaf litter from creosote bush can fuel
desert fires.  Dead fuels are increased by drought, and live fuels are
increased after rainy seasons.  The shoot volume, dry weight, and
biomass production of creosote bush all increase in sigmoid fashion with
age.  The period of most rapid increase is from 20 to 50 years of age.
From 20 years onward, leaves average 53 percent of total shoot
cumulative production, stems with leaves average 13 percent, and the
stem trunk averages 4 percent [28].  Woody remains of creosote bush take
about 60 years to decay beyond the point of recognition [71].

More info for the terms: association, codominant, cover, density, natural, phase, tree

Creosote bush is a dominant or codominant member of most plant
communities in the Mojave, Sonoran, and Chihuahuan deserts.
Creosote bush occurs on 35 to 46 million acres (14-18.4 million ha) in
the Southwest [25].  Creosote bush usually occurs in open, species-poor
communities, sometimes in pure stands.  It also occurs as a transitional
species in desert grasslands [59], viscid acacia (Acacia
neovernicosa)-mariola (Parthenium incanum) chaparillo [60], mesquite
(Prosopis spp.)  woodlands [90], Joshua tree (Yucca brevifolia)/big
galleta (Hilaria rigida) communities [57], and xeroriparian areas [14].

The creosote bush-burrobush (Ambrosia dumosa) association covers
approximately 70 percent of the Mojave Desert [42,67,91].  Ackerman [3]
estimated the density of creosote bush at 959 plants per hectare on
Mojave Desert sites in Rock Valley, Nevada.  Relative abundance was 10.8
percent and relative plant cover was 19.6 percent.  Species associated
with creosote bush-burrobush communities in the Mojave Desert include
Shockley's goldenhead (Acamptopappus shockleyi), Anderson's wolfberry
(Lycium andersonii), range ratany (Krameria parvifolia), Mojave yucca
(Yucca schidigera), California jointfir (Ephedra funerea), spiny hopsage
(Grayia spinosa), and winterfat (Krascheninnikovia lanata) [88].
Creosote bush also occurs in the Mojave Desert scrub association with
desertholly (Atriplex hymenelytra), shadscale (A. confertifolia), white
burrobrush (Hymenoclea salsola), blackbrush (Coleogyne ramosissima),
Joshua tree, desertsenna (Cassia armata), and Nevada ephedra (Ephedra
nevadensis) [54,97].

In the Sonoran Desert, creosote bush commonly occurs in the
creosote bush-triangle bur ragweed (Ambrosia deltoidea) [7],
creosote bush-burrobush [91], and Sonoran Desert scrub [54]
associations.  Other species associated with creosote bush in the Sonoran
Desert include yellow paloverde (Cercidium microphyllum), tesota (Olneya
tesota), big galleta, prickly pear (Opuntia spp.), acacia (Acacia
paucipina), fourwing saltbush (Atriplex canescens), ocotillo (Fouquieria
splendens), western honey mesquite (Prosopis glandulosa var.
torreyana), brittle bush (Encelia farinosa), and pachycereus
(Pachycereus schottii) [7, 26, 91].  The densities of creosote bush in
the subdivisions of the Sonoran Desert are 448 plants per hectare in the
Lower Colorado River Valley, 437.7 plants per hectare in the Arizona
Upland Subdivision, and 1.1 plants per hectare on the Central Gulf Coast
[67].

The creosote bush scrub phase covers 40 percent of the Chihuahuan Desert
[67].  Associated species include tarbush (Flourensia cernua), acacia
(Acacia spp.), leucophyllum (Leucophyllum spp.), mesquite, palma (Yucca
filifera), ocotillo, small-leaf geigertree (Cordia parviflora), and
anisacanthus (Anisacanthus spp.)  [49, 73].  Creosote bush also occurs in
the sand dune scrub phase in the Chihuahuan Desert [49].

Publications listing creosote bush as a dominant or codominant species
include:

  The structure and distribution of Larrea communities [9]
  Sonoran Desert [24]
  Vegetation and community types of the Chihuahuan Desert [49]
  Preliminary descriptions of the terrestrial natural communities of
    California [54]
  The natural vegetation of Arizona [81]
  Vegetation of the Santa Catalina Mountains: community types and
    dynamics [82]
  Plant communities of Texas (Series level) [94]
  Vegetation and flora of Fort Bowie National Historic Site, Arizona
    [103]

More info for the term: shrub

Shrub

More info for the terms: competition, root crown, shrub, shrubs

Creosote bush invades desert grasslands [6,17,22,56,58].  In 1904,
creosote bush was confined to about 950 acres (380 ha) at the Santa Rita
Experimental Range in Arizona [56].  By 1934, the number of acres
occupied by creosote bush had increased more than 12-fold to 11,900 acres
(4760 ha).  By 1954, creosote bush occupied an area 73 times as great as
it had 50 years before.  Humphrey and Mehrhoff [56] attribute
creosote bush expansion to a reduction in range fires.  Buffington and
Herbel [22] cite heavy grazing and periodic droughts as the major causes
of the rapid increase of creosote bush and other shrubs in desert
grasslands.

Controlling creosote bush can be difficult because it can sprout from the
root crown following disturbance [16].  A variety of herbicides may be
used to kill creosote bush [37,51,77,50], but Flores and others [40]
suggested that revegetation of former creosote bush sites with more
desirable species is very difficult.

Bush muhly (Muhlenbergia porteri) often grows under creosote bush
canopies where their ranges overlap.  Where creosote bush is 3.3 feet (1
m) or less tall, bush muhly shades the lower branches of creosote bush,
causing its leaves to fall.  In some instances, this competition may
kill creosote bush [106].

Creosote bush is susceptible to severe drought during short-term climate
changes like El Nino [102].  During dry years, creosote bush undergoes
severe moisture stress and subsequent defoliation.  Older branches do
not produce new foliage, but sprouting may occur.  The cumulative result
of El Nino can be a 60-80 percent stem dieback.  Dead stemwood remains
standing within the shrub biomass for several years.

Pollution from electric power generating facilities may adversely affect
creosote bush.  Creosote bush showed sensitivity to sulfur dioxide and
nitrogen dioxide fumigation [112].

More info on this topic.

Creosote bush leafs out in response to spring, summer, or fall rains [1].
Creosote bush usually flowers in May [1] in the Mojave Desert, but it can
flower anytime during the summer if it receives enough rain [1,3,9].  In
the Sonoran Desert, most creosote bush seeds are shed in the summer, but
creosote bush in the Chihuahuan Desert does not shed its seeds until fall
[10].  Creosote bush seeds germinate after rains from mid-June to
mid-September in the Mojave Desert [2].

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

   Secondary colonizer - off-site seed
   Tall shrub, adventitious-bud root crown


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".

The scientific name of creosote bush is Larrea tridentata (D.C.) Cov.
It is a member of the caltrop family (Zygophyllaceae) [52,98]. Varieites
include [98]:

Larrea tridentata (DC.) Coville var. arenaria L.D. Benson
Larrea tridentata (DC.) Coville var. tridentata