A study by the University of California suggests that grazing cattle can help keep brush down and limit the spread and intensity of wildfires.

In the preliminary results of a study funded by the California Cattle Council and done by the University of California Agriculture and Natural Resources (UCANR), cattle grazing “plays an important role in reducing fine fuels on grazed rangelands in California.”

Around 1.8 million cattle graze California rangelands in every county except San Francisco, and ate 11.6 billion pounds of brush and grass in 2017 on 19.4 million acres of mostly privately owned grazing land, found report primary author Devii Rao, a UCANR researcher and cooperative extension instructor in San Benito County.

While the study was done in California to examine the effects of grazing on California wildfires, Pat Ryan, an assistant division manager with the Washington Department of Natural Resources’ Product Sales and Leasing Division of the department’s Agriculture and Grazing Program, said the study is generally applicable to the mountains and rangelands of Eastern Washington.

“We do have some different fuels,” Ryan said. “We do have sagebrush, lots of grassland, it’s probably fairly similar.”

In his report, Rao and his co-authors found that cattle consumed varying amounts of fine fuels — plants that easily dry out and become highly combustible — on dry coastal and inland grasslands, enough to lower flame heights even in brisk winds and limit the spread of fire.

Ryan said that in Eastern Washington, the majority of grazing land is privately owned, though DNR has around 800,000 acres it leases out for grazing, split fairly evenly between forest and grassland range.

However, Rao and his co-authors also found that grassland needed to be carefully grazed to ensure there was enough brush on the ground to prevent erosion.

“We look at what’s right for the ecosystem,” Ryan said. “You don’t graze it down to nothing. You have standards and if you follow those standards, you can reduce the fuel.”

Ryan said that fire burns hotter and spreads more quickly through brush that has not been grazed.

“Anytime you can reduce the fuel out there, you can lower the intensity of the fire,” he said.

Both California and Washington were plagued with massive wildfires this summer, and land and forest managers are looking for long-term ways to reduce the fire risk. Grazing cattle is one possible way to manage future fire risk, with Rao and his co-authors noting that the state’s diminished cattle herd — the number of beef cattle in California has fallen by nearly half since the 1980s — can graze patches of land well enough to reduce the fire risk.

“A well-managed piece of ground has a lower change of having a severe fire, and grazing can be a tool for managing the environment,” Ryan said.

Charles H. Featherstone can be reached at [email protected].