FIRE EFFECTS
SPECIES: Sorghastrum nutans | Indiangrass 



IMMEDIATE FIRE EFFECT ON PLANT : 
Indiangrass is top-killed by fire.  


DISCUSSION AND QUALIFICATION OF FIRE EFFECT : 
NO-ENTRY


PLANT RESPONSE TO FIRE : 
Indiangrass density and apparent vigor [17,22], number of flowering
culms [9,38,45], and percent canopy and basal cover [5,57] increase with
late spring burning conducted prior to green-up.  Burning during other
seasons may increase flowering stems [38] or decrease percent
composition of indiangrass [72].  The greatest increase in canopy cover,
density, production, and flowering occurs following annual burns
[2,25,44,45].  Seeds are generally absent in burned soils, and most
reproduction following fire is vegetative [2].  Fire intensity affects
short-term rhizome reproduction.  Late summer fires (September 5th) were
conducted with both high-intensity and low-intensity fuels.  Little or
no damage occurred on the low-intensity fuel area, but tiller densities
were reduced on the high-intensity fuel area.  However, tiller density
returned to normal by the following August [26].


DISCUSSION AND QUALIFICATION OF PLANT RESPONSE : 
There was an increase in the number and height of flowering stalks on
Iowa prairie burned following snow-melt.  The area had been completely
protected for 9 years prior to burning.  Burns were conducted 1 of 3
years, 2 of 3 years and annually, with the greatest flowering occuring
on the annually burned area and the least on unburned areas [25].  A
significant increase in living shoot and flowering stalk production and
more rapid rate of phenological development occurred following spring
burns in Illinois.  Burns were conducted in February, March and April of
3 different years [36].  Indiangrass frequency increased significantly
following annual April and May burns using a strip headfire [78].


FIRE MANAGEMENT CONSIDERATIONS : 
Water availability for plant uptake may be initially higher in burned
tallgrass prairie, especially early in the growing season.  The
through-fall volume of precipitation is 1.3 times higher in burned than
in unburned prairie [34].  However, exposed mineral surfaces lose
moisture rapidly and are soon drier than unburned areas.

Late spring burning with headfires is an appropriate management strategy
in tallgrass prairies when the primary land use is cattle grazing [10].
The average daily gain of cattle increased on tallgrass prairie burned
in early to mid-April in Oklahoma [70] and in the Flint Hills of Kansas
[80].  The Oklahoma range was in good to excellent condition prior to
burning and post-burn precipitation was high.  Further research will be
necessary to determine impacts of burning on poor to fair range or
during dry years [70].

Annual spring burning maximizes indiangrass production and flowering
[1,17,25].  Six years without burning allowed big bluestem to increase
and replace indiangrass [42].  Indiangrass stem density decreased
following 3 years without burning on deep soil [21].  A marked reduction
in both living shoot and flowering stalk production may occur following
only a single year with no burning [36].

Related categories for Species: Sorghastrum nutans | Indiangrass