FIRE EFFECTS
SPECIES: Quercus garryana | Oregon White Oak 



IMMEDIATE FIRE EFFECT ON PLANT : 
Crown fire generally kills this species.  Moderate-severity surface fire
rarely kills large trees, but smaller oaks may be killed or suffer
severe cambium damage [13].  Low-severity surface fire rarely harms
mature trees, but seedlings and saplings are commonly top-killed.
Animal-buried acorns are usually not affected by fire [41,49].


DISCUSSION AND QUALIFICATION OF FIRE EFFECT : 
NO-ENTRY


PLANT RESPONSE TO FIRE : 
Most researchers report vigorous sprouting of top-killed Oregon white
oak [17,36,41,43,53], although at least one researcher [25] has
classified this species as a weak sprouter.  Sugihara and Reed [48]
report more vigorous sprouting in 40-year-old than in 70-year-old oaks.
Studies conducted on young, even-aged stands show good postfire recovery
of these trees.  Oregon white oak top-killed by fall prescribed burning
in Shasta and Tehema Counties, California, exhibited vigorous sprouting
during the first postfire growing season [53].  In Humbolt and Trinity
Counties, California, three-year-old sprouts had grown above the browse
line [36].

In the absence of further fire, these sprout clumps form dense,
even-aged stands.  Most Oregon white oak woodlands of today are of this
type due to fire supression.  When subjected to further fire, however,
weaker meristematic tissue is killed, and individual root crowns produce
fewer sprouts per clump with each fire.  Continued periodic fire
ultimately results in an open savanna with widely scattered, large oaks
[27].

Fire research on Brewer oak is extremely limited.  One study followed
the postfire recovery of this variety for 3 years after the Three Creeks
Burn in Humbolt County, California.  This "intense" wildfire top-killed
most oak shrubs.  At the end of postfire year 1, sprouts varied in
height from 4.4 to 11.2 feet (1.3-3.4 m), with an average of 18 sprouts
per clump.  At postfire year 3, many of the weaker sprouts had died, and
sprouts were reduced to an average of 10 sprouts per clump.  Sprout
height at postfire year 3 was not recorded [43].


DISCUSSION AND QUALIFICATION OF PLANT RESPONSE : 
NO-ENTRY


FIRE MANAGEMENT CONSIDERATIONS : 
Fire appears to be the dominant controlling factor involved in
converting invading coniferous forests back to Oregon white oak
woodland.  If a conifer forest is the objective, managers can simply
allow young invading conifers to grow.  In order to halt conifer
establishment and facilitate oak regeneration, a minimum frequency of
prescribed burning every 5 years is recommended.  Ideally, prescribed
fire should be set annually.  When existing conifers are 10 feet (3 m)
or more in height, oak woodlands can be restored by removing conifers by
cutting or girdling.  A program of prescribed burning is then necessary
for long-term maintenance [48].

Related categories for Species: Quercus garryana | Oregon White Oak