Having just passed through Earth’s hottest July on record and with summer skies thick with smoke from massive forest fires burning through parts of Siberia, Greece, and California, humanity is in urgent need of solutions to its global wildfire problems. It is crucial to take on the broader anthropogenic causes of forest fires, such as climate change, but, when disasters are already at your door, it is necessary to look for solutions to mitigate one problem without adding to another.
A recent study in the western US has demonstrated success over the past four years in slowing the spread of rangeland wildfires through the utilization of ‘targeted grazing,’ thus bringing new focus to a tactic that has been studied with increased interest over the past couple of decades. In light of the study’s success, a story with a familiar cast— environmentalists, fragile ecosystems, invasive species, ranchers, and the like—could be due for a new chapter. Has the plot been thickened with enough smoke to get everyone on the same page?
The study, conducted by researchers from the US Department of Agriculture’s Agricultural Research Service (ARS), is an attempt at establishing ‘fuel breaks’ to help contain wildfires while avoiding typical grazing-related damage to rangelands.
After four years under development, the project has achieved some verified successes.
Targeting Grazing Method is Put to the Test
By using cattle-grazing to create firebreaks in open spaces of land invaded by what is known as cheatgrass—an invasive species to the US—the project has contained three rangeland wildfires in four years in the Great Basin region of northwestern US. As recently as July 18, 2021, the latest success contained the huge Welch wildfire near Elko, Nevada.
The cattle used in the ARS study graze in the early spring on large areas of highly flammable cheatgrass. They eat the cheatgrass down to two- to three-inch stubble in strategically chosen places. This method greatly reduces what researchers call the ‘fuel load’ that would likely turn a smaller fire into a megafire within hours.
ARS research scientist Pat Clark, with the Northwest Watershed Research Center in Boise, Idaho, directs the project. "These fuel breaks are intended to slow a fire's rate of spread, make it less intense, and provide time and space for firefighters to arrive and more safely attack and contain the fire," Clark explained. "That's just what appears to have happened for the Welch fire."
As it burned its way to the project’s grazed fuel break, the Welch fire was producing flames two to four feet tall and was spreading at a rate of about 1300 feet per hour, according to the official fire report. Once it reached and began to burn its way through the fuel break, the Welch fire’s flames dropped to below two feet, and its spread slowed to less than 300 feet per hour. The rapid slowdown gave firefighting resources enough time to arrive and take on the fire. If the fuel break had not been in place and winds had been stronger, the fire could have burned through tens of thousands of acres of the South Tuscarora Range, according to the report.
The ARS study targets nine sites across Nevada, Idaho, and Oregon with extensive, highly-flammable cheatgrass infestations. The three real-life tests of the study’s fire break method, including the one from the Welsh fire, have all occurred in Nevada. A 2020 fire was contained by the fire breaks to only fifty-four acres from what would probably have been thousands. Fire breaks spared a habitat for sage-grouse fowl from a 2018 fire that was limited to about one thousand acres.
Promising Results Lead to Further Questions
Through this study, ARS researchers are trying to determine just how much the fuel load is being reduced by sending cows out to graze on the cheatgrass in early spring—when it is preferable to the cattle—and if those reductions can be sustained until the fire season begins in July.
They are also trying to monitor the effects of grazing on the environment, a point of contention for some environmentalists. They argue that the short-term benefits of grazing for fire-mitigation are outweighed by its longer-term effects on biodiversity through such stressors as trampling. Soil is degraded by trampling, is the argument, and water is fouled, affecting birds and other species. There are also concerns that grazing, if not managed properly, can actually contribute to the spread of cheatgrass or other weeds, at the expense of the Great Basin’s 24 million acres of fragile native sagebrush.
Why did the ARS choose the Great Basin for its study? To begin with, the Great Basin is actually a large area made up of many smaller basins. It includes most of Nevada, half of Utah, and sections of Idaho, Oregon, and California. Wildfires in the Great Basin usually surpass forest fires in acreage destroyed. In addition, according to the ARS, cheatgrass covers more than 100 million acres of Great Basin lands.
Cheatgrass covers more than 100 million acres of the Great Basin and serves as fuel for wildfires. Managing cheatgrass is important for reducing wildfire risks.
Though targeted grazing has been accused of trampling its way across fragile ecosystems, defenders describe trampling as part of an eco-friendly grazing technique that can accomplish several objectives. As opposed to traditional grazing for meat and dairy production purposes, targeted grazing is used primarily for exfoliation or targeted elimination of undesired plants. Contrary to arguments that trampling reduces biodiversity, defenders describe targeted elimination as a way to increase biodiversity through the elimination of dominant invaders. To address the concerns of animal rights activists, defenders advocate the use of fencing or herding to focus grazing on targeted areas and to protect cattle from predators. The strategic placement of supplements also assists with animal control and helps to keep the animals healthy.
Targeted grazing also compares favorably to chemical or mechanical exfoliation in terms of costs and sustainability and for that reason is used widely in wildfire mitigation in Mediterranean forests where wildfires pose a serious risk to ecosystem services and human life. Many wildfire-prevention programs in southern Europe use the services of local grazers, including the long-standing Andalusian RAPCA program that works with over two hundred local shepherds who establish fire breaks with their flocks in the region’s public forests.
Should Targeted Grazing Even Be Extended Through the Winter?
The US Bureau of Land Management (BLM) which regulates grazing on public lands had limited grazing to the spring and summer months through several administrations based in part on a concern for the effects of overgrazing on biodiversity. However, this practice has come under scrutiny for having a possible role in the development of dangerous fuel loads. Therefore, targeted winter grazing has been studied as a way of further lowering fuel loads.
One study investigated dormant season grazing by cattle in the northwestern US for five years, comparing grazed areas with those that had not been grazed. Results showed that winter grazing decreased fuel loads and increased fuel moisture, thereby reducing flame height and depth, spread rate, and total area burned. Winter-grazed areas also emitted lower maximum temperatures during fires than did un-grazed areas, thereby decreasing the overall mortality of important plant groups.
In the absence of effective climate mitigation strategies, targeted and strategic livestock grazing, if done with care, is probably the most and perhaps the only feasible fuel load reduction strategy at this time that can be applied at the scale required to influence wildfire spread and intensity across Earth’s vast rangeland ecosystems.