FIRE EFFECTS
SPECIES: Andropogon virginicus | Broomsedge Bluestem 



IMMEDIATE FIRE EFFECT ON PLANT : 
Fire apparently has little effect on broomsedge bluestem except for
removal of aboveground living and dead biomass.  Small bunchgrasses are
generally not harmed by fire and recover relatively quickly [40].


DISCUSSION AND QUALIFICATION OF FIRE EFFECT : 
NO-ENTRY


PLANT RESPONSE TO FIRE : 
Broomsedge bluestem depends on frequent disturbance to maintain itself.
Fires at 1- to 3-year intervals favor this species and tend to maintain
its abundance [21].  In loblolly pine (Pinus taeda) stands in South
Carolina, broomsedge bluestem was rare in unburned areas, infrequent in
areas periodically burned in the summer or winter, but common in areas
burned annually in the summer or winter, or biennially in the summer
[21,39].  Broomsedge bluestem is most abundant during the first few
years after fire.  After a few years without fire (or other
disturbance), litter builds up and plant vigor declines [19].  In
eastern Arkansas, broomsedge bluestem was the dominant grass on prairies
burned and hayed annually for decades, but without these disturbnaces
was eliminated after 16 years [15].


DISCUSSION AND QUALIFICATION OF PLANT RESPONSE : 
NO-ENTRY


FIRE MANAGEMENT CONSIDERATIONS : 
Grazing considerations:  The nutritional quality and digestibility of
new broomsedge bluestem growth are significantly increased following
fire.  When burned in January or February in Georgia, protein content on
March 15 was 13 percent for plants on burned sites but only 5.5 percent
for plants on unburned sites.  However, nutrient increases are
short-lived.  By June 15, protein content of burned and unburned plants
was similar at 6.2 and 6.0 percent, respectively [20].  Tender and
nutritious, this new growth is palatable to cattle and horses.
Following a July wildfire on Cumberland Islands National Seashore,
Georgia, horses heavily grazed broomsedge bluestem regrowth but avoided
nearby plants that had not burned [3].

Prescribed burning considerations:  Studying the fuel characteristics of
broomsedge bluestem, Fujioka and Fujii [5] found the leaves and stalks
have a surface area-to-volume ratio 2.5 times as large as that in the
National Fire Danger Rating System model for perennial grass.  After a
few years without fire, broomsedge bluestem stands contain much of this
dead, highly flammable material which carries fire well.  It burns at
relatively high relative humidities (80-90%) and high fuel moisture
(20-25%) [14].  On a 4-year-old loblolly pine clearcut in South
Carolina, an early February prescribed fire in cured broomsedge bluestem
carried fire at a rate of spread of 2.5 to 3.6 feet per minute (0.76-1.1
m/min).  Burning took place only 4 days after a rain of 0.42 inch (1 cm)
and 7 days after a rain of 0.91 inch (2.3 cm).  Flame heights were
generally 1 to 3 feet (0.3-0.9 m) and occasionally reached 4 to 5 feet
(1.2-1.5 m) [38].

Related categories for Species: Andropogon virginicus | Broomsedge Bluestem