FIRE EFFECTS
SPECIES: Sequoiadendron giganteum | Giant Sequoia 



IMMEDIATE FIRE EFFECT ON PLANT : 
In Sequoia and Kings Canyon National Parks, a moderate-severity
prescribed fire contributed little to the mortality of giant sequoia
that were larger than 1 foot (0.30 m) d.b.h.  Additionally, there is no
evidence that previous fire scarring had any relationship to tree
mortality [5].  Low- to moderate-severity fires scorch the bark of giant
sequoia and usually cause scarring.  High-severity fires may reach the
crown and consume part or all of the canopy cover [2].  A direct
relationship exists between the size of the basal fire scar in mature
giant sequoias and the the likelihood of damage to the top or foliage of
the trees [23].  Reduction of supporting wood from scarring predisposes
the tree to falling, and provides an opening for fungi responsible for
root disease and heart rot [28].


DISCUSSION AND QUALIFICATION OF FIRE EFFECT : 
Despite the general belief that giant sequoia wood is not especially
flammable, it burns hotly when splintered and dry [10].


PLANT RESPONSE TO FIRE : 
High-severity fires will generally kill pole-size and younger trees.
Immediately following the passage of fire, seeds will drop as a reaction
to hot convectional air movement through the canopy.  Seeds will
germinate on the favorable mineral seedbeds created by the fire [5].

Postfire seedling establishment:  When high-severity fires burn in dense
stands of mature giant sequoias, as many as 40,485 seedlings per acre
(100,000/ha) may develop following heat-induced seedfall [11].  After a
prescribed burn in Sequoia and Kings Canyon National Parks, a
high-severity burn resulted in 40,000 seedlings per acre (98,800/ha) the
first year after burning.  A lower-severity burn resulted in 13,000
seedlings per acre (32,110/ha).  Not a single giant sequoia seedling was
found on the unburned control plot in this study [5].



DISCUSSION AND QUALIFICATION OF PLANT RESPONSE : 
NO-ENTRY


FIRE MANAGEMENT CONSIDERATIONS : 
Research on the importance of periodic fire in maintaining natural giant
sequoia forests has justified the need to restore a natural fire regime.
The principal goal of fire management in giant sequoia groves in
Sequoia, Kings Canyon, and Yosemite National Parks is to restore or
maintain the natural fire regime to the maximum extent possible.
Prescribed burns are now conducted by igniting fires in a spot pattern
and allowing nature to produce a mosaic of effects [20].

The long-standing fire suppression policy of federal and state land
agencies has created at least two major problems for the giant sequoia:
(1) the continuing reproduction of the species has been seriously
hampered and (2) the build-up of dead fuels and the growth of other
young trees in the understory pose threats of destructive forest fires
in the crowns of existing groves.  In 1969, the National Park Service
began a program or prescribed burning in Kings Canyon National Park.
Prescribed burning has produced relatively few deleterious side effects
on giant sequoia groves [27].

Prescribed burning is currently an active management strategy in giant
sequoia groves.  Fire prepares seedbeds, recycles nutrients, maintains
successional diveristy, decreases the number of trees susceptible to
attack by insects and disease, reduces fire hazards, and favors wildlife
[5,10,27].  A prescribed burn in Kings Canyon National Park resulted in
an increase in flycatcher and robin numbers [4,13].  A number of changes
in bird and mammal populations are forecasted if fire is reintroduced on
a large scale.  High-severity fire will increase the number of
trunk-feeding birds preying on the increased amount of insects [12].

Prior to protection under Park status in 1864, the Mariposa Grove and
Yosemite National Park sustained fires every 20 to 25 years [9].  Other
research found that in presettlement times, any given site in the middle
elevations of the Sierra was burned over every 5 to 10 years [18,27].

Related categories for Species: Sequoiadendron giganteum | Giant Sequoia