Here we go again. Yet another article “Bill plans to use livestock grazing to lower wildfire risk” about how livestock grazing can reduce wildfires.
It seems that every month or so, someone (without much knowledge of fire ecology or even grazing impacts) rediscovers the fairy tale that fuel reduction by grazing will preclude large wildfires.
The U.S. House Committee on Natural Resources passed a bill last week to use livestock grazing to reduce wildfire risk. H.R. 1110, the Grazing for Wildfire Risk Reduction Act, requires the Secretary of Agriculture to develop and implement a strategy to increase opportunities to use livestock grazing as a means of wildfire reduction.
Like the Fix Our Forests legislation, all of these proscriptions use the fear of large wildfires as an excuse for more resource exploitation. In this case, the Grazing for Wildfire Risk Reduction Act legislation will promote more livestock grazing on our public lands.
Usually, the pronouncements suggest that livestock grazing is the panacea for eliminating large-range fires, but there are numerous reasons why this is not accurate.
Grazing might successfully reduce fuel over a small concentrated area, but it is ineffective at a landscape scale.
First, some of the largest wildfires in recent years have occurred on grazed rangelands. For instance, The Smokehouse Blaze that razed Texas is the largest in the state’s history and the second-largest fire in the nation’s history. It is larger than the top 20 largest wildfires in California over the past 90 years! The large wildfires that razed over 1.2 million acres in Texas occurred in the part of the state with the most significant livestock herds.
Similarly, the Holloway and Miller Homestead fires combined for just under a million acres, all in southeast Oregon occurred in sagebrush rangelands grazed by domestic cattle. I could give numerous other examples of the failure of grazing to reduce fire spread.
But what is overlooked is that livestock grazing can promote wildfire in several ways. The first is the impact of livestock hooves and trampling on biocrust.
Biocrusts are lichens, bacteria, and mosses that grow on the soil surface. Biocrusts tend to prevent the establishment of weedy and flammable grasses like cheat grass. Indeed, in many areas with livestock grazing, cheat grass has come to dominate the landscape. A recent study even suggests biocrusts act as a fuel break for wildfires.
Livestock also spread the seeds of cheatgrass and other “flashy” flammable vegetation. The increase in nitrogen from urine also tends to promote cheatgrass more than native vegetation.
Beyond the vegetation changes that are more susceptible to wildfire spread, the idea that grazing is a panacea for large fires ignores fire ecology science. Most large wildfires occur during intense drought, low humidity, high temperatures, and high winds. These conditions are “severe fire weather” or “red-flag” situations.
Under such conditions, embers are tossed miles ahead of a fire front, or over any heavily grazed landscape. Under high winds, I’ve witnessed fires racing across pastures that were cropped to putting-green height.
A widely cited research paper, “Targeted grazing in southern Arizona: using cattle to reduce fine fuels,” by the range department at Arizona State University. The study asserts that grazing can reduce wildfire spread. However, in the next to last paragraph, they only acknowledge: “Targeted grazing treatment did influence fire behavior in grass/shrub communities, but its effects were limited. Although it is a promising tool for altering fire behavior, targeted grazing will be most effective in grass communities under moderate weather conditions.”
Why are qualifications essential?
Because under low to moderate fire weather conditions, wildfires are easy to suppress or even self-extinguish. The fires that burn tens of thousands of acres occur during extreme weather conditions where grazing fails to alter fire spread.
Third, even under less severe fire weather conditions, livestock grazing results in significant collateral damage to the land, water and wildlife. Most of our public lands are already degraded by existing livestock grazing.
To influence wildfire, grazing must be severe, often cropping grasses to a height of only several inches to have any influence on fire spread.
Such a reduction in grasses has collateral damage to the landscape’s “health.” Severe grazing compacts soils, inhibiting water penetration (exacerbating drought).
Heavy grazing removes cover for wildlife that protects them during harsh weather (like winter snow) and hides them from predators.
For instance, the endangered sage grouse requires a minimum of 10 inches of residual grass cover to avoid predation. A study in Montana found sage grouse nests had a 60 percent survival rate at 10.2 inches of grass cover, but didn’t reach the 75 percent survival threshold until grass heights topped 15 inches.
Losing grass to the belly of livestock means there is less forage for native wildlife, which depends on the same grasses for survival. At the same time, the mere presence of livestock often socially displaces native wildlife. For instance, elk tend to avoid areas grazed at the same time by livestock.
Livestock grazing also tends to focus on riparian areas, the thin, green lines of vegetation that line streams, which is the habitat utilized at least part of the time by 70-80 percent of all western species. Such concentrated livestock use focuses manure and urine in small areas, contributing to water pollution.
Lastly, the probability that a wildfire will encourage any “fuel reduction” is minuscule and any grazed area quickly regrows vegetation. Thus, the public lands under the Grazing To Reduce Wildfire Risk will continue the ongoing livestock degradation of the public’s heritage.
All this collateral damage and more that is ignored by the advocates of livestock fuel reduction will preclude large fires. Livestock grazing has few benefits for reducing the large wildfires that people hope to limit, but it has a guaranteed impact on landscape health.
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