FIRE EFFECTS
SPECIES: Quercus emoryi | Emory Oak 



IMMEDIATE FIRE EFFECT ON PLANT : 
Small-sized Emory oak may be top-killed by fire.  Large trees survive
fires of low severity [12].  Well-developed root systems of mature Emory
oak buffer the effects of drought and allow rapid regeneration by
sprouting vigorously from root crown and stump after top-damage [19,28].
It recovers quickly from the effects of burning [92].  Unless covered by
an insulating layer of soil, acorns are probably killed by fire.


DISCUSSION AND QUALIFICATION OF FIRE EFFECT : 
NO-ENTRY


PLANT RESPONSE TO FIRE : 
Most fires move quickly through oak woodlands that have a continuous
grass understory.  Fire effects on Emory oak depend on tree size, fire
severity, and drought stress, especially after the fire.  A wildfire
during June 1983 burned a Madrean evergreen oak woodland in the Santa
Catalina Mountains of Arizona.  Two years later, 89 percent of the
sampled Emory oak survived, 38 percent with some portion of the original
crown alive.  Significantly (P=0.011) more Emory and Mexican blue oak
sprouted on burned plots (94%) than trees in unburned control plots
(8-16%).  Emory oak produced 15 to 53 sprouts per tree on burned plots
[19].

In a Madrean evergreen woodland in Arizona with an understory of grasses
and herbs, a prescribed fire in May 1984 was of low intensity and short
duration.  The fire did not affect scattered mature Emory oak.  Emory
oak and other oak seedling densities did not differ between burned and
control sites during the first 2 postfire seasons [12,13].

During June 1959, an accidental fire burned an oak-juniper woodland in
the Santa Rita Mountains of Arizona.  The fire moved rapidly over dry
grasses.  Drought stress may have increased tree mortality.  On unburned
controls, 19.7 percent of Emory oak trees died, and 22.3 percent died on
the burned sites.  Only 21 percent of Emory oaks sprouted on the
control, while 47 percent sprouted on the burn [55].

Emory oak seedling establishment and survival were assessed 1 year
following a fall prescribed fire of interior chaparral in the Mazatzal
Mountains of Arizona.  Sites where fire severity was low had more than
twice the number of seedlings (147 seedlings/ha) than the unburned
control (48 seedlings/ha) or sites where fire severity was high (58
seedlings/ha) [18,89].

One or two years following fall prescribed strip fires in interior
chaparral, 47 Emory oak seedlings were tagged.  Three years later, only
13 seedlings had survived.  Nearly half (48%) of tagged seedlings had
died due to drought.  The surviving seedlings stood 3.3 inches (8.4 cm)
high, and roots had penetrated 20 inches (50.8 cm).  Uniform acorn depth
and seedling spacing across the burned areas indicated that scrub jays
probably cached the acorns.  Clustered seedlings, possibly from rodent
caches, were not included in the study [90].

An oak-mountain-mahogany (Cercocarpus spp.) chaparral stand in the
Sierra Ancha Experimental Forest, Arizona, was prescribed burned after
desiccation with herbicides.  Emory oak seedling emergence steadily
dropped from 33 seedlings per acre (13 seedlings/ha) during the first
postfire year to 0 seedlings the fifth postfire year [63,93].


DISCUSSION AND QUALIFICATION OF PLANT RESPONSE : 
NO-ENTRY


FIRE MANAGEMENT CONSIDERATIONS : 
Prescribed fire is used to manage the interior chaparral where Emory oak
occurs.  It reduces fuel loads and improves wildlife habitat [28].  In
interior chaparral, prescribed fires must be combined with other
management methods to control Emory oak and other shrubs [18,29].
However, on arid rangelands where Emory oak occurs, prescribed burning
for brush control is not usually effective due to insufficient fuel for
widespread fire [47,92].

The open oak woodland can carry fire [85].  Oaks usually survive quick,
low-intensity fires in the open oak woodlands.  However, fires in
closed-canopy oak woodlands are probably high-intensity, stand
replacement fires [75].

Emory oak should be included in fuel moisture sampling programs.  In the
Chiricahua National Monument of Arizona, where Emory oak can make up a
significant portion of the understory fuels, Emory oak foliage had a
mean live fuel moisture content of 106 percent when sampled during
November 1987.  Live fuel moisture measurement methods are discussed in
the literature [100].

A downed woody material summary is useful for assessing fire potential
and danger.  Downed woody material ranged from 2.8 to 9.2 cubic feet per
acre in pine-oak woodlands and from 40.1 to 81.7 cubic feet per acre in
moist woodlands [33].

Pine-oak woodlands where Emory oak occurs are more open in the Sierra
Madre Occidental of Mexico than in southern Arizona.  Higher amounts of
litter and dead fuel exist in the Arizona pine-oak woodlands due to fire
suppression and increased grazing [69].

Related categories for Species: Quercus emoryi | Emory Oak