FIRE EFFECTS
SPECIES : Bromus hordeaceus | Soft Chess 


IMMEDIATE FIRE EFFECT ON PLANT : 
Fire has little direct effect on soft chess.  Wildland and prescribed
fires usually occur after soft chess has dried and shattered seed
[44,45,46].


DISCUSSION AND QUALIFICATION OF FIRE EFFECT : 
NO-ENTRY


PLANT RESPONSE TO FIRE : 
Fire may reduce soft chess in the short term [48].  Species composition
in the postfire plant community is difficult to predict, however.
Year-to-year plant composition in annual grassland is highly dependent
upon local weather patterns, and even slight differences in annual
precipitation can alter species assemblages [61].  Fall weather
patterns, especially interactions of precipitation and temperature after
rainfall, appear to be overriding factors in soft chess establishment
[45,46,57].

Fire affects plant species composition in annual grasslands largely by
removing mulch, which affects germination and seedling establishment
rates of soft chess relative to associated herbaceous species.
Bartolome [7,9] found that soft chess reached highest densities when
mulch biomass was at intermediate levels.  Little quaking grass (Briza
minor) was favored when mulch biomass was low, as it would be in the
immediate postfire environment.  Fescues (Vulpia and Festuca spp.) were
favored when mulch biomass was high.  Heady [45] reported that without
heavy grazing the mulch layer usually recovers by postfire year 3, and
soft chess and other annual bromes regain dominance.

Decreases with fire:  Hansen [40] found that fall prescribed fire in
Tulare County, California, significantly increased dominance of annual
forbs relative to soft chess.  Greatest reduction soft chess and other
annual grasses (and greatest increase of annual forbs) was achieved by 3
years of successive fall burning.  Response of native grasses was
similar to that of soft chess:  Native grasses were reduced by fall
burning, with greatest reduction achieved after 3 years of consecutive
fall burning.  Percent cover of soft chess the spring after fall burning
follows.

        unburned     single     twice-     thrice-             
         control      burn      burned     burned
        ________     ______     ______     _______
      
1982       10          <1         --         --
1983        8           5          2         --
1984       23          44         16          2
1985       12          23         15         10

A July 1947 prescription fire reduced soft chess on ungrazed annual
grassland near Berkeley, California.  Precipitation in the fall and
winter of 1947-1948 was slightly below average for the area (20.4 inches
with the average being 22.6 inches).  Average height and yield of soft
chess on two burned and two unburned sites in May of 1948 was as follows
[48]:

                  burned     unburned
                  ______     ________
height (cm)
  exclosure I      29.9        29.9
  exclosure II     35.0        39.1
yield (g)  
  exclosure I       0.8         3.1
  exclosure II      4.6        13.9
 
Mixed effects: Chaparral and oak woodland - Density of soft chess
increased greatly from prefire levels 5 years after prescribed fall
burning in a nonsprouting manzanita-Lemmon ceanothus (Arctostaphylos
spp.-Ceanothus lemmonii) community in Mendocino County.  However,
density of soft chess had changed little 5 years after prescribed fall
fires in nearby nonsprouting manzanita (Arctostaphylos spp.)-Lemmon
ceanothus and interior live oak-blue oak (Quercus wislezenii-Q.
douglasii) woodland communities.  Average density (plants/milacre) of
soft chess was [80]:

                                        Postfire year    
                               ______________________________
Community             Prefire   1     2      3      4      5
_____________________________________________________________
nonsprouting
manzanita-ceanothus     0.0    2.8   7.3   11.2   24.6   30.3 

sprouting 
manzanita-ceanothus     0.3    4.1   6.5    3.8    5.1    2.8

live oak-blue oak       1.5    6.6   6.7    5.8    3.0    1.3

No effect:  Neither spring nor fall prescribed fire had significant
effect on soft chess in annual grassland of Sequoia National Park,
California.  Precipitation averaged about 200 percent of normal during
postfire years 1 to 4.  Soft chess formed an important component of the
vegetation (between 10 and 27%) on plots measured before fire and on
spring-burned, fall-burned, and unburned plots measured 4 years after
fire [75].

Sagebrush steppe - In central Idaho, fire had little effect on soft
chess coverage in either the long term or the short term.  A long-term
study was conducted above the Snake River Canyon, after a July wildfire
occurred 1961 in a rubber rabbitbrush (Chrysothamnus
nauseosus)-cheatgrass community.  At postfire year 12, soft chess had
declined on both burned and adjacent unburned plots.  (Weather data were
not given.)  Soft chess coverage was as follows [24]:

                       Unburned                 Burned
                 ____________________     ___________________
Postfire year      2      4      12         2      4     12
                 ____   ____    _____     _____  _____  _____
                 4.80   1.45    trace     trace  trace  trace 

A short-term study was conducted nearby when an August 1972 wildfire
occurred in a rubber rabbitbrush-cheatgrass stand within the Snake River
Canyon.  The following spring, soft chess frequency was 21 percent on
unburned plots and 18 percent on burned plots [24].


DISCUSSION AND QUALIFICATION OF PLANT RESPONSE : 
NO-ENTRY


FIRE MANAGEMENT CONSIDERATIONS : 
California:  annual grassland - Use of prescribed fire to increase the
balance of natives relative to non-natives such as soft chess has had
mixed results.  In all cases, "remnant" California prairie contains
exotic annuals, and attempts to eliminate the exotics have been
unsuccessful [61].  However, fire sometimes tips the balance toward
natives.  Perennial bunchgrasses are well adapted to frequent fire
[20,94].  Some authors have reported that fire favors native
bunchgrassses over exotic annuals [1,70].  However, Garcia and Lathrop
[33] reported no increase in purple needlegrass after burning, and
Lathrop and Martin [66] found that native deer grass (Muhlenbergia
rigens) decreased under some burning regimes.  In view of the
differences in phenology and life histories between perennial
bunchgrasses and annual grasses such as soft chess, it would be
instructive to know how burning in different seasons affects the ratio
of native to non-natives.  Since annual grasses produce seed about a
month earlier than perennial grasses, precise timing of burning may
alter the balance of reproductive success between annual and perennial
grasses [61].

When used with prescribed grazing, fire may favor purple needlegrass and
reduce soft chess and other annual grasses.  Langstrotti [65] found that
on the Jepson Prairie (a relict perennial grassland reserve in Solano
County, California), short-term, intensive grazing by domestic sheep in
early spring (late March or early April) combined with late summer
(early September) prescribed fire favored tillering and seedling
establishment of purple needlegrass over exotic annual grasses including
soft chess.  Purple needlegrass had been declining on the reserve for a
number of years.  Frequency of soft chess was significantly reduced
(p=0.05) by early spring grazing and late summer fire.  The treatments
reduced soft chess cover to less than 2 percent.  Early spring grazing
reduced average seed mass, and the number of soft chess seeds was
reduced by 76 percent (p=0.25).  Late summer fire reduced soft chess
cover by 50 percent (p<0.001).  Summer grazing and late summer fire also
reduced soft chess, but not as much.  Data from the spring
grazing/late summer fire treatments follow.

                            grazed-     ungrazed-     
                             burnt       unburnt
                            _______    __________
soft chess frequency (%)      39.7         3.0
soft chess seeds/sq dm       198       1,343
soft chess seed mass (mg)      0.57        0.97

Effects of postfire seeding of ryegrass on soft chess:  Seeding Italian
ryegrass (Lolium multiflorum) to reduce postfire erosion had little
effect on postfire growth of soft chess and other exotic bromes in
southern California chaparral.  Coverage of annual bromes was similar on
unseeded plots and on plots seeded with Italian ryegrass [15].

Oregon: big sagebrush - Prescribed fire had little effect on soft chess
in a basin big sagebrush/bluebunch wheatgrass community in John Day
Fossil Beds National Monument, Oregon.  Weather patterns occurring after
fire greatly influenced plant community composition, however.  One study
area was prescribed burned on September 25, 1987; an adjacent study area
was prescribed burned on May 24, 1988.  Prescription burning was
followed by 3 years of drought, which appeared to greatly reduce soft
chess cover.  By the third postfire year, soft chess was absent from all
treatments including the unburned control.  Density of other annual
grass species was also greatly reduced on all treatments including the
unburned control.  Density of annual forbs increased on all plots, and
density of native perennial grasses did not change.  Density of woody
shrub species was greatly reduced on burned plots but did not change on
control plots.  Average density of soft chess (plants/sq m) on unburned
control, fall-burned, and spring-burned plots is given below.  Numbers
in parenthesis are the standard errors of the mean; different letters
denote a significant difference between years (p<0.1) [82].

                 1987      1988      1989   
              _________   _______   ______
control       160a (87)    0b (0)   0b (0)  
fall burn      82a (28)   10b (8)   0b (0) 
spring burn    --         37a (16)  0b (0)




FIRE CASE STUDIES : 
NO-ENTRY

Related categories for SPECIES : Bromus hordeaceus | Soft Chess