VALUE AND USE
SPECIES: Larrea tridentata | Creosotebush 



WOOD PRODUCTS VALUE : 



IMPORTANCE TO LIVESTOCK AND WILDLIFE : 
Many animals bed in or under creosotebush.  Domestic sheep dig shallow
beds under creosotebush because it provides the only shade in the desert
scrub community [105].  Desert reptiles and amphibians use creosotebush
as a food source and perch site and hibernate or estivate in burrows
under creosotebush, avoiding predators and excessive daytime
temperatures.  Desert tortoises dig their shelters under creosotebush
where its roots stabilize the soil [12,30].  Seventy-one percent of
desert tortoise burrows studied near San Bernadino, California, were
associated with creosotebush [12].  Banner-tailed kangaroo rats
frequently use creosotebush for cover [76].  Merriam's kangaroo rats
often make their dens under creosotebush [76].  Some special status
subspecies of kit fox rest and den in creosotebush flats in the Sonoran
Desert [111].

Many small mammals browse creosotebush or consume its seeds.
Creosotebush comprised 14.6 percent of black-tailed jackrabbit diets on
Isla Carmen in the Gulf of California.  Terminal twigs of creosotebush
were consumed in proportion to their availability in black-tailed
jackrabbit habitat.  Ninety percent of creosotebush were browsed, and
52.5 percent of twigs on those plants were browsed [53].  Creosotebush
dominated the diet of desert woodrats in the Mojave Desert of
California; the desert woodrats strongly preferred creosotebush foliage
of relatively low resin content [74].  Boyd and Brum [19] found that
27.5 percent of creosotebush seed mericarps on a Mojave Desert site
showed signs of postdispersal rodent predation.



PALATABILITY : 
Creosotebush is unpalatable to livestock and most browsing wildlife
[8,55,70,95].  Consumption of creosotebush may be fatal to sheep [35].
A few researchers have treated creosotebush chemically to make it
palatable [95,36,4].  Such treatments can produce a feed that is
relatively palatable and nutritious.


NUTRITIONAL VALUE : 
Catlin [27] evaluated the nutritional content of creosotebush browse in
Arizona:

Water			4.79%
Ash			8.06%
Crude protein	       13.37%
Crude fiber	       11.21%
Fat			9.13%
Nitrogen-free extract  43.38%

Reichman [86] estimated that creosotebush seeds contain 4,966 calories
per gram or 11.37 calories per seed.


COVER VALUE : 
Creosotebush in Utah provides good cover for small mammals and nongame
birds, fair cover for pronghorn and upland game birds, and poor cover
for bighorn sheep, mountain goats, and waterfowl [113].


VALUE FOR REHABILITATION OF DISTURBED SITES : 
Creosotebush may be used to rehabilitate disturbed environments in
southwestern deserts.  Once established, creosotebush may improve sites
for annuals that grow under its canopy by trapping fine soil, organic
matter, and symbiont propagules.  It may also increase water
infiltration and storage [8].

Creosotebush should be transplanted rather than spot-seeded [47].
Miller and Holden [75] increased germination success by leaching seeds
in running water for 12 hours.  At Organ Pipe National Monument, the
survival rate for creosotebush was 78 percent when seeds were germinated
in grow tubes filled with nursery soil mix and allowed to harden-off
before being transplanted outside.  Creosotebush should be planted in
the spring or fall [31,96].  Bainbridge and Virginia [8] recommend
pruning seedlings heavily 1 month before transplanting.  Rodent
protectors are necessary [31].


OTHER USES AND VALUES : 
Creosotebush has been highly valued for its medicinal properties by
desert peoples.  It has been used to treat at least 14 illnesses [80].
Twigs and leaves may be boiled as tea, steamed, pounded into a powder,
pressed into a poultice, or heated into an infusion.

Creosotebush is host to an insect, Tachardiella larreae, which produces
lac and deposits it on the stems of creosotebush [39].  Lac is plastic
when heated but hardens again on cooling, forming a strong bond like
commercial sealing wax.  Lac has been used by desert peoples to seal
lids on food jars [39,80].

Creosotebush contains phototoxins in its leaves that inhibit the growth
of Escherichia coli and Saccharomyces cerevisiae cultures [35].

Creosotebush is used as an ornamental throughout its range [42].


MANAGEMENT CONSIDERATIONS : 
Creosotebush invades desert grasslands [6,17,22,56,58].  In 1904,
creosotebush 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 creosotebush had increased more than 12-fold to 11,900 acres
(4760 ha).  By 1954, creosotebush occupied an area 73 times as great as
it had 50 years before.  Humphrey and Mehrhoff [56] attribute
creosotebush 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 creosotebush and other shrubs in desert
grasslands.

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

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

Creosotebush is susceptible to severe drought during short-term climate
changes like El Nino [102].  During dry years, creosotebush 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
creosotebush.  Creosotebush showed sensitivity to sulphur dioxide and
nitrogen dioxide fumigation [112].

Related categories for Species: Larrea tridentata | Creosotebush