FIRE CASE STUDIES
SPECIES: Quercus arizonica | Arizona White Oak 



CASE NAME : 
Lyle Canyon Prescribed Fire, Arizona (Arizona white oak)



SEASON/SEVERITY CLASSIFICATION : 
spring fire/low- to moderate-severity


STUDY LOCATION : 
The study was conducted at the National Audubon Appleton-Whittel
Research Sanctuary in foothills on the west side of the Huachuca
Mountains of Arizona.  The research focused on two areas:  a grassland
and a Madrean evergreen woodland.  This case study presents only the
Madrean evergreen woodland results since Arizona white oak did not occur
in the grassland.  Study plots were located in Lyle Canyon, which is
leased by the Sanctuary from the Coronado National Forest.


PREFIRE VEGETATIVE COMMUNITY : 
Lyle Canyon is covered by a Madrean evergreen oak woodland.  The
overstory consisted of Arizona white oak and Emory oak.  The burn
treatment study plots had a total of 15 Arizona white oak and 20 Emory
oak; control plots had a total of 10 Arizona white oak and 20 Emory oak.
Common understory shrubs were wait-a-minute bush (Mimosa biuncifera),
velvet-pod mimosa (M. dysocarpa), and yerba de pasmo (Baccharis
pteronioides).  Grasses and forbs most commonly present were sideoats
grama (Bouteloua curtipendula), plains lovegrass (Eragrostis
intermedia), annual goldeneye (Viguiera annua), and Arizona poppy
(Kallstroemia parviflora).


TARGET SPECIES PHENOLOGICAL STATE : 
Phenological stages of plants were not specifically mentioned.  At the
time of burning in May, Arizona white oak would be past flowering, and
fruits would be developing.


SITE DESCRIPTION : 
The study site was located in a steep-sided canyon at 4,922 feet (1,500
m) elevation.  Spring months are dry and warm in the semiarid climate.
The average annual precipitation is 16.9 inches (430 mm) and occurs
bimodally.  No information was given on specific topography, slope, or
soils.


FIRE DESCRIPTION : 
A total of 10 plots, 65.6 by 98.4 feet (20x30 m), were assigned either
to burn or control treatments.  Plots were paired for physiognomy and
vegetation.  Twenty quadrats, 7.9 by 19.7 inches (20x50 cm), were
located in each plot for a total of 200 quadrats.  The fire burned
between 10 a.m. and 12 m. on 25 May 1984.  Air temperature was from 90
to 92 degrees Fahrenheit (32-33 deg C).  The relative humidity ranged
from 16 to 18 percent.  Winds were variable and gusted from 5 to 10 mph
(8.1-16.1 km/h).  Dead fine fuel moistures were between 5 and 6 percent.

Fires moved slowly (1.6 to 4.9 feet per minute [0.5-1.5 m/min]) with
flame lengths of 0.7 to 1.6 feet (0.2-0.5 m) in four of the five burn
plots.  This was a heat release of 2.3 to 16.8 Btu per second per foot
(8-58 kw/m).  The fire moved rapidly (98.4 feet per minute [30 m/min])
with a heat release of 75.2 Btu per second per foot (260 kw/m) over the
remaining burn plot.


FIRE EFFECTS ON TARGET SPECIES : 
Mature Arizona white oak were not affected by the fire [7].  Postfire
vegetation was sampled during two growing seasons in 1984 and 1985.
There was no significant (P>0.05) difference in numbers of Arizona white
oak seedlings on the burn plots compared to the controls. 


FIRE MANAGEMENT IMPLICATIONS : 
Fire is a part of the historic Madrean evergreen woodland [83].  This
prescribed fire did not have any lasting effects on woody vegetation in
the study area.  Burning had little detectable effect on the seedlings
of Arizona white oak.  This is probably due to short duration and low
heat released by the fires.  The authors noted that Arizona white oak
were killed by fire in nearby O'Donnell Canyon during 1974 on the
Appleton-Whittell Sanctuary.

Related categories for Species: Quercus arizonica | Arizona White Oak