FIRE EFFECTS
SPECIES: Xerophyllum tenax | Beargrass 



IMMEDIATE FIRE EFFECT ON PLANT : 
Since the meristematic region of the rhizome usually is found near the
interface of organic horizons and mineral soil, beargrass is quite
sensitive to fire [15,81].  If the basal leaves are moist, they may
protect the meristem to some extent, but if they are dry they can be an
added fuel source which increases the heat pulse at the base of the
rosette [15].  Generally, if the fire is light enough or if the duff is
moist enough for the duff layer to remain intact, the rhizomes will
survive.  However, if severe fire removes most or all of the duff layer,
most beargrass rhizomes will be killed [81].


DISCUSSION AND QUALIFICATION OF FIRE EFFECT : 
NO-ENTRY


PLANT RESPONSE TO FIRE : 
The response of beargrass to fire is quite variable [15].  Two important
factors in beargrass recovery appear to be the impact of the fire on the
soil surface and the suitability of the site for beargrass.  Beargrass
initially decreases after wildfire or relatively hot broadcast burns,
although changes in its cover are variable or slight after light burns
[9,48].  When slash fires in the Rocky Mountains destroy beargrass
rhizomes, beargrass is frequently unable to recolonize the burned site
quickly despite its normal ability to persist and thrive in openings
[86].  Beargrass regrowth following fire in this area is often slow
[59,83,92].  However, in Oregon, while beargrass rhizomes may be killed
by hot surface fires, beargrass is likely to invade areas with exposed
soil [43].


DISCUSSION AND QUALIFICATION OF PLANT RESPONSE : 
Fire severity in the Rocky Mountains:  Historically, fires may have been
more frequent and less severe in Montana's relatively dry, open
subalpine fir/beargrass habitat type and severe but infrequent in moist
subalpine areas [23].  In this habitat type beargrass increases after
light broadcast fires but decreases after hot fires or scarification
[9].  After the Sundance wildfire in northern Idaho, beargrass survived
on lightly burned areas.  Increases in beargrass cover began 3 to 10
years after the fire, with a maximum cover of 11 percent [84,83].  Where
fires encourage fire-dependent shrubs, beargrass cover changes very
little once the shrubs become dominant [82].  Following a Montana
wildfire, beargrass reached 2 to 3 percent cover in 10 years and
remained at that level regardless of other plant community changes [61].

Site differences in the Rocky Mountains:  In the subalpine fir/beargrass
habitat type, beargrass increased after light broadcast burning, while
in the Douglas-fir/blue huckleberry (Vaccinium globulare) habitat type,
it decreased after light broadcast burning [9].  On colder sites in the
grand fir series in Montana, the cover of beargrass can be much reduced
following fire [4].  After clearcutting and broadcast burning in the
grand fir/myrtle pachystima (Pachistima myrsinites) habitat type of
northern Idaho, beargrass recovery may take up to 23 years [92].
Following severe fire on a subalpine fir/queencup beadlily (Clintonia
uniflora) habitat type, beargrass cover and volume did not recover to
prefire levels during the first 9 postfire years [81].

Variability in beargrass response on different sites is illustrated by a
Montana study comparing the results of different disturbances on several
habitat types.  Data from 177 plots are summarized as percent
constancy/average canopy cover of beargrass on three subalpine fir
habitat types [91]:

                      subalpine fir  subalpine fir  subalpine fir
                       /beadlily      /menziesia     /beargrass 

Wildfire:               47/15.3        88/18.8        93/27.2 
Clearcut & burned with
slash dozer piled:       9/00.5        50/07.0         -----
Clearcut & burned with-
out slash piling:       50/07.5        50/00.5         -----
Old growth:             31/14.4        50/01.8        62/21.6
Snowchutes:             38/15.8        50/03.0       100/37.5


FIRE MANAGEMENT CONSIDERATIONS : 
Fuel Loading:  Brown and Marsden [16] have developed an equation to
estimate fuel loading of beargrass, grass, and other grasslike plants
based on the relationship between plant height and ground cover.

West Coast Sites:  In the Pacific silver fir and mountain hemlock zones
of the Oregon Cascades, scarification or burning following clearcutting
encourages the spread of snowbrush (Ceanothus velutinus), beargrass, and
long-stolon sedge [49].  On some Pacific silver fir, mountain hemlock,
and western white pine sites in central and southern Oregon, beargrass
may be stimulated by fire or scarification and invade clearcuts where it
competes with tree seedlings [10,11,43,48].  In the coastal
tanoak/evergreen huckleberry (Vaccinium ovatum)-salal (Gaultheria
shallon) association, beargrass can be an aggressive invader following
fire [12].

Rocky Mountain Sites:  In the Rocky Mountains, clearcutting and burning
with fire hot enough to reduce duff will reduce beargrass cover [5,9].
Beargrass does not appear to be as invasive in this area as in the
Northwest.  If beargrass is desirable, then shelterwood or selection
cuts are better for its growth than clearcutting and burning [56].

Prescribed Fire:  In California, prescribed fires have been used to
provide young beargrass shoots for Native American basket makers.
Experience with these fires has shown that a fire that consumes between
90 and 100 percent of dead beargrass foliage and 75 to 95 percent of
live foliage will stimulate new growth [53].  Flame lengths between 0.75
and 3 feet (0.2-0.9 m) with a spread rate of 1 to 4 feet (0.3-1.2 m) per
minute will produce this consumption.  Traditional burning took place in
the summer and early fall.  Possible burning periods and prescription
details are given by Hunter [53].

Related categories for Species: Xerophyllum tenax | Beargrass