Without a doubt, burning has to be the longest practiced management tool for native grasses. Indians noticed free roaming herbivores were attracted to the succulent vegetation of areas which had been burned by wildfire. The Indians then began to burn specifically to attract game. In later years, in the Great Plains, white man noticed that cattle preferred grazing areas which had been burned, gains were higher and grazing distribution more even. Cattlemen, leasing pastures throughout the Great Plains, began requiring landowners to burn annually as a condition of their leases. Burning rangeland still continues to a large degree in the Flint Hills region of Kansas.
Grasslands and native warm season grasses evolved under fire, lightning strikes being the major ignition source. Only during recent history, with mans' suppression of fire, has this major natural influence been absent from the tall grass prairies and savannas of the U.S. east of the Flint Hills. The absence of fire is a major contributing factor (plowing and overgrazing are the others) to the decline or disappearance of native prairie and savannas through the same region. The suppression of fire has also allowed invasion of woody species in many traditional native grass sites.

Prescribed burning is the most commonly recommended management tool for native warm season grasses but raises the most fear and misunderstanding among new native grass managers. Thank Smokey Bear for that! Smokey has done as excellent job of getting out the word about wildfire and how destructive it can be but has failed miserably in letting the public know that prescribed burning can be beneficial. Please note the key words here are wildfire vs. prescribed burning. A prescribed burn when properly timed and implemented is the most cost efficient and effective management tool available. Because of Kansas' long history of burning there is a wealth of information about the effects of fire, both short term and long term. (Plots originally laid out in 1927 are still being studied.) We'll discuss some of the whats, whys, whens and hows of burning but as the old adage goes; "Experience is the best teacher." I strongly recommend before you try burning on your own, get with an experienced fire boss and participate in a controlled burn. At least participate in a prescribed burn workshop. Many state agencies or SCS offices offer them.

THE BENEFITS OF PRESCRIBED BURNING

A properly timed burn benefits the grass plants, livestock and wildlife in varying degrees. Burning recycles many trace nutrients into the soil. The right timing on a prescribed burn will help to eliminate weeds, woody vegetation and control unwanted cool season grass invasion. Forage quality is increased, therefore animal performance. There is some evidence in the higher rainfall regions (above 33" annually) that burning can also increase yields. Earlier grass growth is obtained in the spring on burned pastures and more uniform grazing distribution is promoted by burning. Burning pastures for livestock is usually done and though this provides better forage, annual burning is not desirable for wildlife; at least not all acreage each year.
Removal of accumulated litter at ground level by burning benefits wildlife in several ways. The reduced litter reduces rodent populations, subsequently predators. Indirectly this helps to reduce predation on wildlife. The removal of the litter also provides ease of movement for brooding birds which facilitates their capture of insects. Escape from predators becomes easier as well. Although nesting is very low or nonexistent in a newly burned native grass stand, nesting success is improved during the two years following a burn because of reduced predation. For some people, the most important benefit of removing litter is the reduction of wildfire hazard. Accumulated dead stems and leaves can fuel an explosive fire which can be impossible to control. Finally, and what is attractive to many wildlife managers, burning is cost efficient.

Generally speaking, prescribed burns which benefit livestock also benefit or have the least impact on the grass plants. However, for wildlife management it is necessary to occasionally prescribe a burn which will be a short term detriment to the grass plants. Understanding the effects of fire is necessary to get the desired benefits for wildlife.

EFFECTS OF FIRE

The most important influence of fire on grasslands is the significant decrease in soil moisture. This decrease is interrelated to several factors. A native grass stand covered with vegetation intercepts raindrops and slows water movement which helps infiltration. Burning removed that vegetation. Raindrops now impact the soil surface destroying the soil structure, erosion becomes a concern, runoff is increased and infiltration is decreased. The blackened soil warms quicker and evaporation increases, further reducing soil moisture. With the increase of soil temperature the grasses break dormancy earlier and begin growing, additionally increasing soil moisture loss. Timing of the burn is most critical for this reason.
The effects of a wildfire during the wrong time of year or a poorly timed prescribed burn can be devastating. The influences can have a profound effect which could last for several years. From early May to mid-August a steady decline in soil moisture naturally occurs in native grasses. Inadequate soil moisture to start the season compounds this trend. In dry years forage production is significantly reduced, and if improperly harvested, plant vigor decreases making them susceptible to competition.

Study plots which were burned in late spring (when emerging grasses were 1" tall) showed the least reduction to soil moisture. Fall and early spring burned plots showed the most moisture reduction. Fall and early spring burned grasses are also more susceptible to soil erosion and damage to exposed plant crowns. When prescribing a burn it is important to consider the soil moisture condition, both immediate and general, before burning. Burning while the soil is dry can damage plant crowns, destroying plants. Knowing what we know about the effects of burning on soil moisture, burning following a dry year should be considered carefully. The desired benefits need to be weighed against the known effects of burning. In some cases you could do more damage than good. In those instances it is best to postpone burning until the next year.

PLANT SPECIFIC RESPONSES TO BURNING

Fall and early spring burns decrease Big Bluestem, Indiangrass and Switchgrass. Late spring burns increase Big Bluestem and Switchgrass and increase or maintain Indiangrass. Little Bluestem reacts inconsistently and its response is generally unpredictable. Sideoats Grama seems not to be overly influenced by any burn dates. Cool season grasses and woody vegetation are most effectively controlled by late spring burns. In reference to forage quality, native grasses burned in mid and late spring increase in nutritive value, digestibility and palatability.

CONCLUSION AND GENERAL RECOMMENDATIONS

Native grasses managed for livestock should be burned annually or biannually. When managing for wildlife habitat burn no more often than once every three years. Ideally burn 1/3 of total acreage each year to provide differing stages of post burn succession. Burning can be done on a four or five year rotation if no problems exist. Carefully consider burning before prescribing a burn following a dry year; paying particular attention to soil moisture at the time of burning. To control excessive cool season grasses or woody invasion, burning for two or three consecutive years may be necessary. Burning late favors grasses. Burning early favors forbs, but don't manipulate the burning dates with new stands. It is best to manage for the grasses until the stand is solidly established. Burning early to increase forbs can then be done to increase a plantings attractiveness to wildlife.