FIRE EFFECTS
SPECIES: Eragrostis curvula | Weeping Lovegrass 



IMMEDIATE FIRE EFFECT ON PLANT : 
Weeping lovegrass culms and blades are probably killed by fire.  Burned
clumps tend to retain about 2 inches of densely packed, unburned stems
at the soil surface [12].


DISCUSSION AND QUALIFICATION OF FIRE EFFECT : 
NO-ENTRY


PLANT RESPONSE TO FIRE : 
Weeping lovegrass numbers generally increase [59] or remain stable after
burning.  Weeping lovegrass does not decrease after fire in sandy areas
in Oklahoma shortgrass prairie [60].  In western Texas, neither high nor
low fireline intensities caused a negative impact on weeping lovegrass
burned in both headfires and backfires during late winter in 1982 and
1983.  Vegetation response was not correlated with fireline intensity or
any of the environmental parameters measured [44].

A central Arizona chaparral watershed was burned by wildfire in June
1959.  The watershed was seeded with weeping lovegrass in May 1960, and
herbicides were used to remove shrubs to increase forage and water
yields, reduce fire hazard, and "improve" wildlife habitat.  The
watershed was prescribed burned in the winter of 1971 to kill returning
shrubs; weeping lovegrass frequency increased slightly on burned plots
and decreased on unburned plots.  In other areas in central Arizona,
weeping lovegrass in mixed bunchgrass stands and in pinyon-juniper areas
converted to grassland decreased when protected from grazing and fire.
Pase and Kruse [37] hypothesized that weeping lovegrass decreases would
continue due to the "smothering" effect of old growth on new growth.


DISCUSSION AND QUALIFICATION OF PLANT RESPONSE : 
From February 2 to April 15, 1982, and from March 14 to April 28, 1983,
17 plots were burned in headfires and 10 plots were burned in backfires
in western Texas.  Plots were located in a relatively homogeneous,
ungrazed, decadent weeping lovegrass stand established in 1976.  Fires
were ignited at different times and under a variety of weather
conditions to obtain a wide range of fireline intensities.  Headfires
generated from 67 kW/m to 12,603 kW/m; backfires generated from 117 kW/m
to 474 kW/m.  Weeping lovegrass plant yield, plant height, and number of
seedstalks were measured after one growing season to evaluate the
effects of different fireline intensities.  There was no significant
relationship between fireline intensity and subsequent plant response
[44,45].

In June 1956, a wildfire burned over rough mountainland in central
Arizona chaparral between 5,000 and 6,500 feet (1,524-1,981 m)
elevation.  The area was aerially seeded with weeping lovegrass after
the fire.  Below 6,000 feet (1,830 m) weeping lovegrass quadrat
frequency increased from 3.7 percent in 1956 to 12.1 percent in 1961.
Above 6,000 feet weeping lovegrass frequency increased from 0.5 percent
in 1956 to 6.0 percent in 1961.  Weeping lovegrass herbage production
also increased over that time [38].


FIRE MANAGEMENT CONSIDERATIONS : 
Weeping lovegrass production is stimulated by periodic burning. Winter
burning can be used to maintain dominance by weeping lovegrass in
chaparral [37].  A fast-moving fire with long flame lengths will not
damage weeping lovegrass any more than a slow moving fire with short
flame lengths.  A prescribed fire can be conducted under conditions
favorable for a variety of intended effects without reducing weeping
lovegrass yield or vigor [44].

Weeping lovegrass should probably not be seeded after fire if management
objectives include establishing or maintaining native grasses.  Weeping
lovegrass declines in palatability if not grazed or burned, but it does
not usually disappear from a site.  As it becomes less palatable,
livestock shift grazing pressure to other species, which then decline.
Increases in weeping lovegrass after fire can be impeded under very
careful management of grazing allotments, however [63].

In the Pinal Mountain area, weeping lovegrass was aerially seeded
following a 1951 wildfire that killed aboveground vegetation.  A
relatively vigorous stand of lovegrass grew among the sprouting shrubs
during the first summer; seed was produced, germinated the following
year, and thickened the stand.  An exclosure was constructed in the
stand in 1952; grazing occurred around the exclosure.  Percent basal
area of weeping lovegrass was as follows [41]:

                          1952        1956        1958

            Grazed        0.51        0.46        0.08
            Ungrazed      0.68        1.25        0.39

To renovate a decadent weeping lovegrass stand, the plants can be burned
just prior to spring green-up to remove most of the old material.  If
the plants are shredded before being burned, burning is more effective
in removing dead plant centers [12].  Weeping lovegrass in Oklahoma
showed consistently improved forage yields when burned annually with
damp to wet soil conditions just before spring green-up between February
26 and March 10 [24].

Weeping lovegrass was planted on the Tonto National Forest in central
Arizona after the Boulder Mountain Fire of June 1959, in which wildfire
swept over steep, broken chaparral habitat.  Weeping lovegrass was
broadcast planted with a hand seeder on the fresh burn before loose
surface ash had been disturbed by rain.  Weeping lovegrass maintained a
fair stand with good to excellent vigor during the 1959 and 1960 growing
seasons.  However, drought in 1961 killed many of the plants, and vigor
of those remaining was listed as fair [34].

Weeping lovegrass cover is actually many times the basal area of the
plant because of its long, spreading leaves.  Five years following the
1956 Pinal Mountains wildfire, weeping lovegrass made up 97.6 percent of
the vegetation cover on the burn [7].  Weeping lovegrass cover was
decreasing on grazed areas by then, but still increasing in exclosures.
By 1958, basal area on both sites had dropped below that of 1952 and
many of the weeping lovegrass plants were dead.  Weeping lovegrass died
out in ungrazed areas as chaparral crown cover approached that of
unburned areas [41].

A wildfire in 1987 in southeastern Arizona completely burned 11 native
grass plots and 11 plots seeded to weeping lovegrass and Lehmann
lovegrass.  The fire reduced grass and shrub cover, and increased forb
cover, for 2 postfire years in both plot types.  Bird numbers increased
greatly on burned plots in both habitats for 2 autumns, probably in
response to increased seed production and availability.  Fire improved
weeping lovegrass areas for some summer birds in the short run by
reducing otherwise heavy accumulations of litter.  There was no evidence
that fire can permanently restore the diverse native flora to
species-poor plantations of weeping lovegrass [5].

Related categories for Species: Eragrostis curvula | Weeping Lovegrass