Why are prescribed
burns conducted? Fire prevents brush
and trees from overtaking the prairie, prevents build-up of dead vegetation
that encourages weeds and retards new growth, and improves habitat for
prairie birds, mammals and butterflies, many of them endangered. Many
"exotic" grasses (introduced from Europe or Asia) such as
Kentucky bluegrass and smooth brome, threaten to overwhelm the native
prairie community. These cool-season grasses which grow quickly and
flower in spring can be set back by burns in May, allowing the summer-flowering
native prairie grasses to flourish. How are burns
controlled? Each individual on
a six-person crew is responsible for the success of the burn. Burns
will be undertaken only within "prescription" conditions--weather
that permits safe burning. Mowed fire breaks or burned strips (black
lines) outline the prairie unit to be burned. The "ring firing
technique" is used: Using drip torches, crew members start by setting
a back fire into the wind along a specified line. Generally several
hours later a head fire is set. This eventually meets the back fire,
extinguishing them both. Using water tanks and "flappers,"
crew members extinguish flames as necessary. The last step is "mop
up". The crew makes certain that old fence posts, cow chips or
tree limbs near the burn perimeter are completely free of smoke or flame
before leaving the site. Permits are obtained from local offices of
the Department of Natural Resources. Local fire departments, county
sheriff's offices and preserve neighbors are notified the day of the
burn.
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