Essays

Moseying: Living La Vida Llanero

Brush control
February 23, 2005

“At first you doze and then you spray
And then you grub it the old fashioned way.
You want to burn but it might get away,
Danged old Brush.”

Nigh on to every rancher in west Texas knows the refrain to a poem written by the esteemed range specialist Dr. Jake Landers of San Angelo. Brush control is a constant topic when members of the livestock industry gather. If you have driven down any highway in west Texas, you have seen the results of the war on brush. An easily seen successful example is seen driving from Midland to Odessa on SH 191 and looking towards the Midland International Airport east of FM 1788.

Brush affects a rancher’s bottom line. Woody plants, especially mesquite and juniper, compete with grass and other forage plants for moisture and nutrients. After considerable brush control on Rocky Creek west of San Angelo long dried up springs began running again. As water supplies have become a subject of concern, city, state, and federal agencies have initiated brush control programs west of I-35.

It is well documented that species of woody plants have increased throughout the arid Southwestern United States over the last 150 years. Overgrazing, fire suppression, climate change, exotic plant introduction, and prairie dog eradication have been blamed. Prairie dogs ate germinated seedlings of woody plants. Salt cedar, introduced as an ornamental, spread along every waterway. The Little Ice Age ended in the mid-1800s and the region has become drier. Lightning-lit range fires no longer burn unchecked. Cattle and sheep are confined to a specific range even in droughty times, instead of migrating as did buffalo and pronghorn, with severe overgrazing occurring as a result.

I have grubbed my share of mesquite while expanding garden space. Each multitrunked plant has a “crown” a foot or two underground where the trunks meet. If cut below the crown and a splash of diesel is applied, it will not come back. Each crown takes at least thirty minutes of digging and sawing. When the crowns are only ten feet apart, grubbing seems interminable. I have also used several different herbicides. It is easier on the back, but repeated applications are necessary. And, sooner or later, mesquite seed transported by animals or water will germinate in the cleared area.

We humans always seek an easier way to do a job. Herbicide has been applied from low-flying aircraft, fourwheeler spray rigs or backpack units. Heavy machinery, from bulldozers and backhoes, to brushhogging tractors, and even hydraulic machinery specifically designed to grasp the crown and yank it from the ground have been used. In cedar (juniper) country, I have seen the results of a mammoth chipper that chews up a standing tree, leaving behind a pile of fragrant chips to be spread and used as a soil and moisture conserving mulch.

Some landowners leave brush piles spotted across the land for quail and wildlife cover, while others burn the refuse. Land reclamation projects have utilized the wood (chipped and unchipped) over pipelines, well pads, old roads, and other land disturbances. Some brush control companies have begun to bag the chipped wood for sale as mulch. The end result of brush control is habitat modification – ecological changes big and small are stimulated.

As an amateur naturalist, I am fascinated with observing how animals and plants react to our human endeavors. At the Gone Native Arboretum, in 1987 I had 10 acres brushhogged, and then I sprayed a herbicide on the resprouting mesquite. Bigpad prickly pear, brought to the site by the cattle drives of the drought stricken 1930s, was chewed up by the brushhog, leaving circular bare areas where the prickly pear had been.

Within a few days of the first rain on the site, the ground was “fuzzed over” by a species of grass I had never seen before – six-weeks grama. The lifespan of that species gives it its name. Its seeds, buried in the soil, had been waiting for untold years for the perfect conditions for germination. Within a year a significant population of habitat specific (grassland loving) lizard previously unrecorded on the property immigrated to the cleared acreage from similar grassland a quarter mile away. The spectacular flameflower, which blooms within two days of a rain event, proliferated, creating a constellation of yellow stars in the new grassland. In the mesquite, the population of flameflower remained at low levels. The annual winter rosettes of spring wildflowers are denser in the cleared area.

The cleared area recovered from the recent long drought quicker than adjoining mesquite brushland. Grass and herbaceous plants cover 85 percent of the soil, while in the mesquite the soil remains almost bare, with less than 25 percent cover. The diversity of the plant material in the cleared acreage is four times as great as in the mesquite.

Many variables will affect the ecological changes brought on by brush control. The above results were not duplicated in similar soils with small-scale herbicide applications at the Sibley Nature Center. After the herbicide application, one gently sloping site became bare from a lightning caused grassfire. With the soil bare, subsurface transference of the broad-spectrum herbicide occurred with rainfall. The rainfall removed any loose soil and organic material and a hardpan resulted, baked by the sun. The area has minimally recovered from the drought. Another area became wonderful grassland after the herbicide application. The soil became compacted by the feet of hundreds of school children studying painted grasshopper populations in the grassland. The area has not recovered from the drought because of the compaction.

After brush control a landowner will seed grasses to improve the rangeland. A number of exotic grasses were used in the earlier days of brush control work. As a result, several such species have become invasive. To the east, King Ranch (KR) bluestem spread beyond the project areas and became a dominant grass in the hill country. KR bluestem also now lines highways on the Llano Estacado, with its reddish seedheads bringing fall color to the roadside. To the west Lehmann’s lovegrass was introduced, and miles of the countryside from Penwell to Kermit to Hobbs are covered with it. Neither grass is as nutritious as natives such as sideoats grama grass, so land managers are now recommending native species.

In a broad ecological context, we humans are a “disruptor species.” Everywhere a daytripper wanders, the results of the “hand of man” is visible, even in the wildest country far from towns, roads, fencelines, pipelines, or electric lines. Brush control is one of the more obvious of our efforts.