FIRE EFFECTS
SPECIES: Purshia mexicana var. stansburiana | Stansbury Cliffrose 



IMMEDIATE FIRE EFFECT ON PLANT : 
There are conflicting reports on fire's effect on Stansbury cliffrose.
One source [100] classifies Stansbury cliffrose as a strong sprouter
after fire; others [25,50] classify it as strictly nonsprouting.  Other
reports conclude that fire effects are variable:  Fire may kill or
severely damaging plants [35,68,73,95].  Western Nevada populations have
been described as "quite sensistive" to burning [89].  When mortality
occurs, it is most likely in single-stemmed and/or old individuals
[35,95].  Late-season fire also increases risk of mortality [100].


DISCUSSION AND QUALIFICATION OF FIRE EFFECT : 
NO-ENTRY


PLANT RESPONSE TO FIRE : 
Stansbury cliffrose appears to be a weak sprouter that is generally
killed by severe fire.  Some populations, however, are very sensitive to
fire and the majority of individuals may not sprout after even
low-severity fire [11,25,74].  Sprouting ability may be genetically
fixed, with the proportion of individuals able to sprout varying between
populations [107].

Field managers report that Stansbury cliffrose is usually killed by
prescribed fire [104,105].  Mortality is greatest in large, decadent
plants [104].  Cool fires promote some resprouting, especially if green
foliage remains.  Spring burning with high fuel moisture and soil
moisture conditions increase the likelihood of sprouting.  Top-killed
Stansbury cliffrose may take 5 years or more to sprout [105].

Thirteen to fifteen years after a crown fire in pinyon-juniper in Grand
Canyon National Park, Stansbury cliffrose was observed in unburned
areas, but few plants were present in burned areas.  Densitities of
Stansbury cliffrose greater than 2 feet (0.6 m) in height averaged 5
plants per acre (burned) and 44 plants per acre (unburned).  For
Stansbury cliffrose less than 2 feet tall, densities averaged 8 plants
per acre (burned) and 314 per acre (unburned) [54].

In Death Valley National Monument, Stansbury cliffrose density following
a lightning-ignited fire in creosotebush ranged from five to eight
plants per square meter.  Frequency was 20 percent [49].

Prescribed fire used before the 1960's to remove blackbrush (Colegyne
ramosissima) from Nevada rangelands generally removed the blackbrush,
which was replaced by Stansbury cliffrose, Nevada ephedra, and several
other desert shrubs [Jensen and others in (5)].


DISCUSSION AND QUALIFICATION OF PLANT RESPONSE : 
NO-ENTRY


FIRE MANAGEMENT CONSIDERATIONS : 
Since Stansbury cliffrose's sprouting ability is apparently variable,
fire probably should not be used on this species unless postfire
sprouting ability of the population under consideration has been
confirmed.  Fire used on sprouting Stansbury cliffrose should be low
severity surface fire since the dormant buds of Stansbury cliffrose root
crowns are apparently killed by severe, and possibly moderate-severity,
fire.  Prescribed fires may burn around Stansbury cliffrose growing on
rocky outcrops [106].

Related categories for Species: Purshia mexicana var. stansburiana | Stansbury Cliffrose