In 2017, California cattle ate an estimated 11.6 billion pounds of grass that could become wildfire fuel; researchers say grazing can reduce fire hazards in some rangelands

Cattle are typically associated with food production, but scientists in California have also examined their potential role in reducing wildfire fuel. Researchers assessed how much fine vegetation cattle consume across California's rangelands and examined how that reduction in available fuel could affect fire behavior.

Grass is basically wildfire kindling.

To understand the potential role of grazing in wildfire management, it is important to first consider how grass and other fine vegetation contribute to fire behavior. Like any wildfire, fire in rangelands depends on the availability of combustible vegetation. The investigation focused on about 1.8 million beef cattle foraging on around 19.4 million acres of California rangeland, about half of the state’s overall rangeland.


In 2017, cattle consumed an estimated average of 596 pounds of non-woody plant material per acre, although the amount varied substantially by location and forage supply. Grass, the mainstay of many, but not all, California rangelands, can produce as much as 1,000 pounds or more of vegetation per acre during wet years, while cattle consumption in some drier environments was estimated at approximately 174 pounds per acre.

The number: 11.6 billion pounds

Using statewide cattle inventory records, brand-inspection data, and land-use information, researchers estimated that cattle removed approximately 11.6 billion pounds, about 5.3 billion kilograms of non-woody plant material from California’s rangelands in 2017.

The investigation focused on about 1.8 million beef cattle foraging on around 19.4 million acres of California range, about half of the state’s overall rangeland. In 2017, estimates of daily non-woody material consumption rates averaged around 596 pounds per acre for grazing cattle in the state; the rate varies a great deal depending on location and forage supply. Grass, the mainstay of many, but not all, California rangelands, can easily supply as much as 1,000 pounds or more of vegetation per acre during wet years, while cattle consumption in some drier environments was estimated at approximately 174 pounds per acre.

Why that actually matters for fire risk

The amount of vegetation consumed by cattle is only one part of the question. Researchers also examined whether reductions in available fuel could affect wildfire behavior.

Researchers used fire-behavior models to examine how reductions in available fuel could affect modeled fire behavior. Flame length was the primary measure used to assess potential changes in fire behavior. Flame length was the primary measure used to assess potential changes in fire behavior because longer flames can make fires more difficult and dangerous to control.

The models indicated that many of the rangeland areas and scenarios examined could experience shorter flame lengths and potentially more manageable fire behavior when grazing reduced available fuel, although the effects were not uniform.

Areas with naturally greater forage growth showed larger absolute decreases. However, this did not necessarily translate into a low enough residual fuel load to have short flames everywhere. Researchers in another study reached a similar conclusion, but the effect of grazing differs by region. A 2024 study in Napa and Sonoma counties found that current grazing was associated with a 45% reduction in average annual burn probability compared with a modeled scenario without livestock.

A separate 2022 regional study found that the relationship between lower burn probability and grazing was present in the Central Coast and North Bay but was more complex in the Central Valley and foothills.

Grazing patterns can affect wildfire fuel.

Cattle do not consume vegetation uniformly across a grazing area. Grazing intensity can produce heavily grazed patches alongside areas with relatively little vegetation removal, creating variation in vegetation height and fuel loads rather than a uniform layer of dry material. This spatial variation may influence how fire spreads across the landscape.

The effects of grazing depend on grazing intensity, plant-community composition, and the spatial distribution of vegetation. The same area may be grazed repeatedly, while seasonal conditions, weather, and forage availability influence how much vegetation cattle consume. As a result, the effects of grazing can vary substantially across different parts of a landscape.

Not a total fix, but a real one

These findings do not mean that grazing is a standalone solution to California's wildfire risk. The researchers pointed out that the estimate might very well be a conservative one; it only counts fuel that is actively consumed by the cattle and does not account for fuel losses attributable to trampled areas or other alterations in grass and vegetation structural complexity. These grazing operations are also generally not managed primarily for wildfire-risk reduction; ranchers typically make management decisions based on factors such as herd health and forage availability.

Yet, the scientists who wrote the study, "Cattle grazing reduces fuel and leads to more manageable fire behavior,” published in the peer-reviewed journal California Agriculture in 2022, argued that the fuel-reduction benefits of grazing could potentially be enhanced by managing livestock more deliberately near wildlands. In the future, rancher-managed livestock could be used more deliberately to consume fine fuels in targeted areas near communities and other fire-prone landscapes.

These studies are important because California is subject to increasingly intense and damaging fire seasons, and no single management approach can address California's wildfire risk on its own. Prescribed burns, mechanical fuel removal, forest management, and grazing each contribute distinctly, and none of these methods work effectively alone.

The cattle study provides a quantitative estimate of how much fine vegetation cattle already remove from California's rangelands each year. That removal does not automatically translate into reduced wildfire risk everywhere, but the findings suggest that grazing can contribute to fuel management in some landscapes.