FIRE EFFECTS
SPECIES: Larrea tridentata | Creosotebush 



IMMEDIATE FIRE EFFECT ON PLANT : 
Fire kills many creosotebush.  During a low-severity California fire,
many creosotebush were scorched and few burned, but overall mortality
was still 97 percent [115].  Dalton [33] reported mortality rates of 69
and 63 percent for moderately and lightly burned plants, respectively.
A low-severity fire near Florence, Arizona, top-killed 97 percent of all
creosotebush; however, 37 percent of those sprouted.  Overall
creosotebush mortality was 61 percent [72].



DISCUSSION AND QUALIFICATION OF FIRE EFFECT : 
NO-ENTRY


PLANT RESPONSE TO FIRE : 
Creosotebush may sprout if its root crown is not killed by fire [64].
In a southern California brushfire, creosotebush successfully sprouted
and regained its estimated former cover within 5 years [83].  In a
low-severity Arizona fire, 37 percent of top-killed creosotebush
sprouted [72].  However, Brown and Minnich [115] reported that
creosotebush rarely sprouted even though most shrubs were incompletely
burned in a low-severity fire near Palm Springs, California.

Dalton [33] reported good creosotebush seedling establishment on a
burned site in Arizona, possibly due to reduced competition for soil
moisture.  No seedling establishment occurred on unburned sites.
Seedling establishment also occured after a low-severity fire in
Arizona.  Prefire density of creosotebush was 45 plants per hectare, and
creosotebush cover was 1.3 percent [72].  In postfire year 1, the
density of creosotebush was 125 plants per hectare and creosotebush
cover was 0.3 percent.  In postfire year 2, the density of creosotebush
was 95 plants per hectare and creosotebush cover was 0.6 percent.


DISCUSSION AND QUALIFICATION OF PLANT RESPONSE : 
Season of burning, fuel quantity, fire temperature, and age of existing
creosotebush may affect the ability of creosotebush to sprout.  White
[108] noted that burning creosotebush during different seasons at the
Sant Rita Experimental Range near Tucson, Arizona, resulted in
significant differences in sprout production.  The most sprouts were
produced following February and August fires.  The least sprouts were
produced following June and July fires.  The seasonal pattern of sprout
production closely followed trends in growth of terminal shoots.
Sprouting in creosotebush decreased with increasing fuel quantity and
decreased as soil temperature and duration of heating increased
[108,109].  Young plants produced fewer sprouts after burning than
mature plants [108].


FIRE MANAGEMENT CONSIDERATIONS : 
Fire can be used to control creosotebush 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 creosotebush are water repellant because of associated
soil microorganisms.  The hydrophobic characteristic of such soils
precludes the establishment of annuals normally occurring under
creosotebush.  The degree to which the soils are hydrophobic may be
intensified by fire [5].

Standing biomass, deadwood, and leaf litter from creosotebush 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 creosotebush 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 creosotebush take
about 60 years to decay beyond the point of recognition [71].

Related categories for Species: Larrea tridentata | Creosotebush