Going Green

Thursday, December 6, 2007

Prescribed Burning for Rangeland

Extremely low humidity, dry conditions and an abundance of grass from excellent summer rains have created conditions of high fire risk in our area. Besides the risk to property and to life, wildfires can potentially damage pastures.

Fire was one of the principal forces that formed and maintained the Great Plains grasslands. Before European settlement of the plains, fires were generally set by lightening or by Indians. Unchecked, the fires typically burned extensive acreages before encountering natural barriers such as streams or green vegetation. Such fires helped to suppress the growth of woody plants and cacti.

In the 1960’s range managers began to examine the use of fire as a tool for manipulating plant communities. They saw prescribed burning as a way to rid pastures of invasive species and as a way to rejuvenate grasslands that had become overburdened with old growth. In studying the use of fire as a management tool, it was found that the timing of the fires was critical in achieving the desired results. Burning at the wrong time of year can in fact damage beneficial species, exacerbate erosion by wind and water, and create opportunities for invasive species to enter.

Prescribed burning has gained credence as a management tool for pastureland in recent years. It has been used extensively in the Flint Hills of Kansas since the 1880’s when it was found that steer weight gains increased on burned areas. It was not until recently however that the reasons for the increased gains were understood. Removing the old-growth overburden allowed tender new shoots to become readily available to the grazing cattle. These new shoots were both higher in nutritive value and more palatable. Other benefits included increased grass yield and suppression of woody species.

In short-grass species such as blue grama, black grama, and buffalograss that are common to our area, there is typically little benefit to burning. Such grasses do not form the heavy overburden of dried stems that are common in mid-height and tall grasses. In short-grass pastures, burning can be used to control invasive weeds such as kochia and Russian thistle. Timing of such burning is critical. Due to the typical low humidity, dry soil conditions and wind, burning at the wrong time may cause heavy erosion and general degradation of the pasture.

It has been found that prescribed burns should be conducted on entire pastures rather than spot-burning. This is because the new growth in burned areas attracts cattle and is typically overgrazed while unburned areas are underutilized. The result is damage to the grasses in the burned areas and establishment of invasive species in unburned areas. This brings us back to fire damage to pastures.

Many of the grass fires during the winter months are due to careless burning of trash or from cigarettes thrown out the windows of vehicles. They typically are suppressed before burning large areas. This results in a “patchy” burn across pasture. When the new spring growth occurs, these burned areas are typically the first areas in which the new grasses are visible and available for grazing. The shoots are tender and free of dried stems from the previous season. Cattle gravitate to such areas in the pasture and not only keep the grass cropped extremely short, their hooves damage the new shoots and destroy many plants. This causes bare areas in which invasive weed species may become established.

The best way to manage such problems is to prevent them from happening. It is a good idea to keep roadside areas free of heavy growth during seasons of high fire risk. Reducing the available fuel supply can prevent wildfires from occurring because there is no fuel to sustain them. If however, you experience accidental fire damage to your pasture, consider a controlled burn in the spring to reduce the potential damage from overgrazing of the spot-burn. Burning the entire pasture can rejuvenate the grasses, reduce many unwanted species and stimulate new growth. If you have burned areas, or use prescribed burning, make certain that you hold off grazing until sufficient growth has occurred to prevent damage by the cattle.

Prescribed burning is an excellent management tool when used properly. Wildfire is not. Prevent range fires by taking steps to reduce your risk.


Rivenrock Gardens said...

I agree completely. And it's a wonder that it's taken the college boys so long to come to grips with this truth.
Also also think that mowing can have a similar effect.
Here in California I also advocate grazing by goats to thin the chapparell and lower the grasses. This can be done yearly on a short term basis. This will also reduce wildfire danger and the resulting soil-baking and later erosion after rains.
Panhandle Poet, I love the work you are doing in bringing all this news to the public. I don't know how you keep up with so much news from so many sources. Do keep up the good work...you are educating us a great deal.

Panhandle Poet said...

Thanks! I really appreciate the comment. Some days I do better with keeping up with the news than others.