FIRE EFFECTS
SPECIES: Cercidium microphyllum | Yellow Paloverde 



IMMEDIATE FIRE EFFECT ON PLANT : 
Although entire yellow paloverde trees are rarely consumed during a
fire, they are top-killed or killed.  Surviving yellow paloverde
rootstocks sprout following fire.  Resprouting plants are susceptible to
death from repeated fires [39].

A fire on a southern Arizona rangeland during the 1900's burned for 2
days and killed paloverde species.  Postfire recovery of the vegetation
was not mentioned in the article [29].


DISCUSSION AND QUALIFICATION OF FIRE EFFECT : 
NO-ENTRY


PLANT RESPONSE TO FIRE : 
During May 1981 in the Tonto National Forest, Arizona, the prefire mean
density of yellow paloverde was 30 plants per acre (75 plants/ha).
Following a controlled fire of moderate severity during June 1981,
yellow paloverde mean density was 24.8 plants per acre (62 plants/ha).
Heat-damaged plants subsequently died.  Nine months after the fire,
yellow paloverde mean density was 17.2 plants per acre (43 plants/ha)
[13].

Yellow paloverde was completely eliminated by fire at one site on the
Tonto National Forest, Arizona [13].

Yellow paloverde may require 20 years to return to prefire plant
densities and community species composition following fires in
paloverde-saguaro communities [13,39,72].

Wildfire during June 1979 in Arizona top-killed 83 percent of yellow
paloverde present.  Twenty-five percent of top-killed plants sprouted
about 2 years following the fire.  There was 63 percent mortality for
yellow paloverde after about 3 years [49].

Fire burned during June 1974 in two desert scrub communities of
south-central Arizona.  Before the fires, yellow paloverde had not
sprouted; no seedlings were present on one site (Dead Man Wash Site),
and five seedlings were present at the other site (Saguaro Site).
Prefire data concerning yellow paloverde were not given.  Fire killed 78
percent of the photosynthetic tissue on the Dead Man Wash Site and 92
percent on the Saguaro Site.  For both sites, approximately 10 percent
of the yellow paloverde present after fire were not top-killed;
approximately 14 percent were top-killed and resprouted.  Five seedlings
were found on the Saguaro Site in postfire year 1 [71,72].

Yellow paloverde occurred in two different communities that were
prescribed burned during different years, one in 1983 and the other in
1985.  Control and prefire communities were similar in composition.  No
information specific to yellow paloverde was given.  The fires consumed
70 percent of the perennial vegetation.  Plants were two-thirds less
dense immediately after than before the fire.  In 1986, plant densities
were still below prefire levels [39].

Yellow paloverde was codominant with triange bursage and buckhorn cholla
(Opuntia acanthocarpa) on rocky slopes on the Tonto National Forest.  A
prescribed fire during June 1985 burned 9.9 acres (4 ha).  The fire
burned vigorously in washes and on lower slopes.  But fire decreased on
the upper slopes due to a lack of fuel between the shrubs; vegetation
patches were ignited with flares.  The spotty burning reduced shrub
cover by 49 percent.  No specific effects on yellow paloverde response
to fire were given in the article [81].


DISCUSSION AND QUALIFICATION OF PLANT RESPONSE : 
NO-ENTRY


FIRE MANAGEMENT CONSIDERATIONS : 
Introduced annuals in desert habitats may create sufficient fuel to
increase fire frequency and severity [71].  Native annuals probably
provided less fuel [39,71].

In the soils on which yellow paloverde occurs, nutrients are quickly
translocated following fire.  Two years after fire, soil nitrogen levels
can drop below prefire levels [13,101].

Related categories for Species: Cercidium microphyllum | Yellow Paloverde