Benefits for controlling sagebrush in the Bighorn Basin with fire
March 12, 2012
Sagebrush can be a viable part of any western landscape, and is critical habitat for various wildlife species. However, when the sagebrush canopy becomes too dense, it chokes out other plant species, reducing habitat quality for wildlife and viable forage for livestock. University of Wyoming Livestock Systems Extension Educator Dallen Smith, highlighted various sagebrush control projects undertaken by the Cody BLM office during his presentation at WESTI Ag Days in Worland, WY, in early February.
The Cody, WY, BLM office manages 1.1 million acres of public land. Starting in 1990, the office started a resource management plan that implemented changes on 90 percent of their 235 allotments, and which focused heavily on sagebrush and woody plant control using fire.
“There was concern over low plant vigor, decreased herbaceous components, low plant diversity and competition between big game and livestock. They were also seeing a lot more woody species coming in because of missed fire cycles in some allotments, decreasing healthy aspen stands and cheatgrass invasions,” stated Smith of the reasons for implementing the large scale management plan.
Multiple use goals were set, and accomplished through working together with all partners in the project, implementing a Rest Rotation grazing plan for livestock, maintaining active range monitoring and making changes as needed, and by using fire as a treatment tool to control encroaching sagebrush and create a mosaic pattern for Sage Grouse habitat.
The Moss Ranch was among the allotments involved in the management plan. It housed a 40-60 percent sagebrush canopy in 1994, had missed at least one fire cycle, and was considered heavily grazed by livestock in addition to being important winter, parturition and summer range for deer, elk and bighorn sheep.
“They prescribed a 4,000 acre burn, reconstructed seven miles of water line, with five stock and two bighorn sheep tanks on it, and put in a four pasture rotation. Prior to treatment, this allotment was producing 754 pounds of sagebrush per acre. After being burned, that went down about a third, to 267 pounds per acre,” noted Smith.
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Key grasses on the allotment increased from 115 pounds per acre to 314 pounds per acre after treatment and forbs also increased. Total herbaceous matter stayed relatively similar, going from 1,018 pounds per acre prior to treatment, to 1,041 pounds per acre after treatment.
“Fifteen years later, in 2006, we were still at almost the same levels of production of sagebrush, key grasses, and total herbaceous matter as what was measured after treatment,” said Smith.
The Sunlight Allotment was another targeted area during the management project that involved 650 acres of prescribed burn to manage sagebrush and juniper trees, the installation of four miles of new fence to create a fifth pasture on the allotment, and five miles of water line and five stock tanks were reconstructed. The first year following treatment, grazing occurred from April 20 to May 4, on the second year it was grazed from May 5 to May 20, and on the third year it was grazed from May 21 to June 5, then it was rested for two years.
“The production on the Sunlight allotment went from 55 pounds per acre of key grass species in 1996, to 403 pounds per acre of key grass species in 2005,” said Smith of the results.
“Rattlesnake Creek is another allotment that had a lot of woody species and a high fire potential. It was 84 percent woody species and 11 percent key grasses in 1996. Again, this is another critical winter area for deer, elk and bighorn sheep, so they strip burned it in 1997 and implemented a timed pasture rotation where three pastures were spring grazed, three pastures were fall grazed, and three were pulled for the year,” stated Smith.
In 2003, the Rattlesnake Creek area was comprised of 83 percent key grasses and four percent woody plants. By 2009, some sagebrush was establishing in the area, with a high percentage of key grasses still making up the majority of the landscape.
“In a lot of these management areas, they did spring burns when there was still snow on the ground because they could get a mosaic pattern for Sage Grouse habitat that way,” explained Smith.
As monitoring has continued on these and other allotments, there have been years where residual forage was high, and others where it was undesirably low. Smith made suggestions for permitees on how defend their ability to maintain AUM numbers.
“Record keeping is important. Take precipitation measurements regularly, every year, and also note what the weather conditions were. If it looks rough, people may not be happy with it, but if that is the result of a drought year, or like this year in the Bighorns where the snow went off late, and you can show that, it will help. I also listened to man from Colorado speak recently who takes pictures of all the elk on his allotments so he can verify that it was likely overstocked by wildlife that year, and that it wasn’t his livestock that did the damage,” noted Smith.
In conclusion, Smith reiterated that taking care of the land is a critical and ongoing management effort. Sagebrush will grow back, and additional management of the plant will be necessary in the future for maintenance of desirable landscapes.