FIRE EFFECTS
SPECIES: Quercus lobata | Valley Oak 



IMMEDIATE FIRE EFFECT ON PLANT : 
Moderate-severity fire top-kills seedlings and saplings.  Larger valley
oaks are resistant to such fire.  Moderate-severity fire on the Chews
Ridge of the Santa Lucia Range in Monterey County killed only one valley
oak larger than 12 inches (30 cm) d.b.h. [32].  Trees suffering basal
burning are most likely to be killed [59].  Hot surface fire may kill
large trees with extensive internal rot.  During the Chews Ridge Fire,
mortality occurred when the interior punky wood of older valley oaks
ignited, leaving exterior bark uncharred.  Trees less than 20 inches (50
cm) in d.b.h. are usually killed by hot surface fires.  Crown fire will
kill a large number of valley oak of all size classes.  Forty-eight
percent of valley oak were killed on portions of the Chews Ridge where
crowning occurred [32].


DISCUSSION AND QUALIFICATION OF FIRE EFFECT : 
NO-ENTRY


PLANT RESPONSE TO FIRE : 
Griffin [32] found that valley oak greater than 26.4 inches (66 cm) in
d.b.h. did not produce root crown sprouts following the Chews Ridge
Fire.  Ninety-three percent of trees with basal sprouts were between 4.0
and 15.6 inches (10-39 cm) in d.b.h.  Where fire was moderate, sprouts
averaged 18 inches (45 cm) in height at postfire year 1.  Trees sapling-
size or larger had grown a large number of epicormic sprouts as well.
Where fire was severe, surviving valley oaks produced mostly basal
sprouts, averaging 19 inches (47 cm) in height.  A minority (21 percent)
of saplings and larger trees grew epicormic sprouts, but many epicormic
sprouts were dying by the end of postfire year 1.  Many small trees had
severe basal scars where bark was peeling off.  Trees with burned crowns
grew no epicormic sprouts.  Basal sprouts of such oaks, however, were
taller than those from any other class of fire, averaging 24 inches (59
cm) in height.

Literature describing postfire natural regeneration and long-term fire
recovery of valley oak woodlands are lacking.  There are currently no
reports of fire research conducted in valley oak riparian forests.


DISCUSSION AND QUALIFICATION OF PLANT RESPONSE : 
NO-ENTRY


FIRE MANAGEMENT CONSIDERATIONS : 
The threat of severe fire has greatly increased where valley oak
woodlands border coniferous forests.  Due to fire suppression, these
woodlands frequently contain an understory of conifer saplings and small
trees, with a deep litter of oak leaves, needles, cones, and downed
woody fuels [32].

Prescribed burning would increase valley oak numbers.  Near coniferous
forests, fire would eliminate invading conifers such as Coulter and
ponderosa pine from valley oak woodland [32].  At lower elevations,
populations of live oaks and shrubs such as buckthorn (Rhamnus spp.) and
sumac (Rhus spp.) continue to increase in valley oak woodland in the
absence of fire [12,31].  Some authorities, however, fear that postfire
recovery of valley oak may be impaired under drought conditions [74],
and prescribed burning is not recommended in years of low precipitation.  

Fire scars provide entry points for various heart-rot fungi.  Badly
fire-scarred trees are susceptible to windthrow [60].

Scrub jays help facilitate postfire regeneration, as they prefer burn
areas as acorn-caching sites [54].

Related categories for Species: Quercus lobata | Valley Oak