FIRE EFFECTS
SPECIES: Quercus douglasii | Blue Oak 



IMMEDIATE FIRE EFFECT ON PLANT : 
Fire top-kills seedlings and saplings [16,47,50].  The bark of young
blue oak catches fire and burns easily, providing little protection from
fire.  Mature trees are resistant to the quick heat of grassland fire
but are top-killed or killed by the sustained heat of most chaparral
fires [16].


DISCUSSION AND QUALIFICATION OF FIRE EFFECT : 
NO-ENTRY


PLANT RESPONSE TO FIRE : 
Top-killed saplings and seedlings sprout during the first postfire
growing season following low-severity fire; even first-year seedlings
are capable of this.  Sprouts may grow above the browse line more
rapidly than true seedlings, and therefore have a greater probability
of survival to sexual maturity [47].  McClaran [44] reported that 70 to 85
percent of blue oaks in a stand probably originated as sprouts that emerged
within 1 year of fire.

Mature crown-scorched trees subjected to surface-level grassfire replace
their leaves the next year with no apparent ill effects [16].


DISCUSSION AND QUALIFICATION OF PLANT RESPONSE : 
Blue oak may recover poorly following moderate-severity fire, and some
ecotypes within this species will fail to sprout following even
low-severity fire [19,72].  A prescribed fire was conducted on a cattle
ranch in Madera County to eliminate dense brush stands.  Preburn
vegetation consisted of blue and interior live oaks with an understory
of mixed chaparral brush.  Many blue oak seedlings and mature trees were
completely killed by the fire.  A few new seedlings emerged at postfire
year 1.  Blue oak recovery was as follows:

                    Plot One            Plot Two           Plot Three
                ________________    ________________    ________________ 
                 % canopy cover      % canopy cover      % canopy cover
preburn                15                  23                 40
postfire yr 0           3                  24                 35
postfire yr 1           1                  29                 35

                seedlings present   seedlings present   seedlings present
preburn                17                  18                 51
postfire yr 0           0                   0                  0
postfire yr 1           6                   0                  6


FIRE MANAGEMENT CONSIDERATIONS : 
Blue oak has evolved under a regime of low-severity grassland fires at
intervals of 8 to 14 years [46,50].  Based upon limited research,
low-severity fire appears to favor species establishment [50].  Frequent
fire decreases the relative dominance of the annual grasses which
frequently outcompete blue oak seedlings while increasing the relative
dominance of forbs [58].  Fire also eliminates the thatch layer that
inhibits establishment of aboveground germinants.  Blue oak sprouts may
have a higher probablity of survival to sexual maturity than true
seedlings, although the data are not yet conclusive [47].  Managers
should be aware of the sprouting capability of blue oak recruitment
within their jurisdiction before conducting prescribed burning over
large areas of blue oak woodland.  Cool or low-severity fire is
recommended when using fire as a managemnent tool for this species.

Related categories for Species: Quercus douglasii | Blue Oak