Strategically placed buffers help slow the spread of wildfire 

California’s annual rangelands are famous for their green, rolling hills in winter and spring. But as the grass dries out, these landscapes become highly flammable and pose a significant fire risk. According to CAL FIRE’s Wildfire Activity Statistics Annual Reports, grass fires were the most common type of vegetation burned in the Central Sierra counties of El Dorado, Amador, Calaveras, and Tuolumne. From 2019 to 2023, they accounted for approximately 78% of all acres burned in the region, averaging about 3,033 acres annually (CAL FIRE, 2019–2023).

Mitigate wildfire risk by reducing fine fuels and adding fuel breaks

Reducing fine fuels is a critical proactive step in mitigating wildfire risk, especially in high-priority areas where grasslands border human activity. Fuel breaks are often most effective when placed near likely ignition sources, such as roads or powerlines, and around vulnerable assets like homes, communities, or critical infrastructure. In both cases, these strategically placed buffers help slow the spread of wildfire, improving the chances of containment and reducing the risk of catastrophic damage. Every year, fuel breaks are created and maintained by private landowners and livestock producers, county road and public works crews, local Fire Safe Councils, Resource Conservation Districts, CAL FIRE, private contractors, and others. 

Methods for creating and maintaining effective fuel breaks include targeted grazing

Common techniques include mowing, herbicide application, prescribed fire, grading, cultivating, and targeted grazing. Choosing the right method depends on many factors, including site conditions, ownership, ecological concerns, and available resources.

Targeted grazing can make a lot of sense on annual rangelands because it leverages livestock’s natural foraging behavior to turn fine fuels into marketable weight. This reduces labor for landowners and generates income for producers. Fuel breaks can protect ranchers from losing feed to fires that start along roads, and just as importantly, they help protect surrounding communities from fires that may start on the pasture. However, implementing fuel break grazing typically requires fixed or temporary infrastructure, often electric fences, parallel to the outer perimeter fence to concentrate grazing for the desired fuel reduction.

Virtual fencing as a flexible, labor-saving alternative to fenced fuel breaks

In June 2024, UCCE tested whether virtual fencing (VF) could provide a more flexible, labor-saving alternative to fenced fuel breaks by eliminating the need for an inner physical fence while still achieving comparable fuel reduction. The trial was conducted on a privately owned pasture adjacent to the city of Sutter Creek. After a productive growing season, the grass stood over 3 feet tall in many areas and averaged 4,269 pounds of dry forage per acre (the equivalent to about 71 bales of hay per acre, assuming 60 pounds per bale). Several homes stood within 50 feet of the fence line, making the fuel load a clear fire hazard. Removing such fuels could help achieve the 100’ of defensible space that CAL FIRE recommends.

Thirty-seven cattle of mixed age and breed with no prior exposure to VF were selected for this trial (Figure 1 Left). A single VF base station was placed near the trial site to allow the collars to properly communicate. After an 8 day training period, the herd was confined to a 150 foot wide grazing area between the outer hardwire perimeter fence and the VF boundary. The herd received salt and protein supplement during the trial to account for the decreasing forage quality of the dry grass. These were placed away from water and loafing spots to encourage more uniform utilization. Over 19 days, the herd grazed the 7.7 acre fuel break down to 780 pounds per acre (about 13 bales of hay per acre), an 82% reduction of flammable fuels (Figure 1 Right).

Figure 1. Left: Herd wearing VF collars. Right: Results of the fuel break grazing. The dashed line shows where grazing stopped along the VF boundary. 

The herd respected the VF boundary 99% of the time (Figure 2), being contained by the audio cues alone 81% of the time (Figure 3). Visually, the livestock appeared calm throughout the trial. The only water in the pasture were troughs placed inside the fuel break. As VF boundaries only prevent animals from leaving an area, the few cattle who did escape would eventually return voluntarily, drawn either by thirst, supplement, or the presence of the herd.

Figure 2. GPS locations (blue dots) of the herd during the 19-day trial. These points outline the location of the fuel break in relation to the city of Sutter Creek. 

Figure 3. Top: Percentage of audio and electric pulse cues received by the herd each day. The livestock learned to respond primarily to the audio cues alone as the trial proceeded. Bottom: Audio and electrical pulse count for the 37 member herd per day. Fuel Break 1 was the smallest and therefore required the most cues for containment. Given the herd size of 37 cows, ~600 cues per day equates to about 1 cue per animal every 1.5 hours.

Virtual Fencing offers extraordinary levels of flexibility compared to traditional fencing

Compared to physical fencing, VF offers extraordinary levels of flexibility to adapt grazing and exclusion areas to meet ongoing management needs. In this trial, a newly paved road crossed the fuel break, so we split the fuel break into two VF zones to exclude livestock from the road. The herd was easily moved to the second fuel break after grazing the first.

The primary tradeoff with using VF in this trial instead of electric fence was the width of the fuel break. While John Allen, the participating rancher in this trial, typically installs 60 foot wide fuel breaks using electric fencing, we chose a 150 foot wide VF to account for GPS inaccuracy and to reduce stress on the animals from excess audio and electric pulse cues. While this wider area provided a greater level of protection from wildfire, it also took approximately twice as long to graze to the same level of fuel reduction. 

“VF is quicker, easier, and more reliable than the electric fence we use nearby to graze a firebreak along the roadway. Also, it’s probably better suited to cows rather than calves that are going to the market,” says rancher John Allen.

Trial suggests Virtual Fencing may be an effective way to create linear fuel breaks in rangelands

This trial suggests that VF is an effective solution to install linear fuel breaks in fire prone rangelands, and it will likely gain value as the technology continues to mature. This application seems most practical as an added benefit for ranchers and land managers who have invested in VF to improve other areas of their operation, such as monitoring and managing livestock across vast or difficult-to-fence areas, as is common in many summer ranges. In this scenario, VF collars could be deployed slightly earlier in the season to schedule fuel break installation in critical areas just before cattle are moved to summer pasture.

Want to learn more?
Reach out to Brian Allen at brallen@ucanr.edu

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This work was funded by the USDA Natural Resources Conservation Service.

References
1) California Department of Forestry and Fire Protection (CAL FIRE). (2019–2023). Wildfire Activity Statistics Annual Reports. https://www.fire.ca.gov/our-impact/statistics

Tech can save ranchers time and benefit animals and land, becoming more viable

After the Caldor Fire destroyed seven miles of fencing on their cattle ranch in 2021, Leisel Finley and her family needed to replace the fence.

Finley, a sixth-generation rancher at Mount Echo Ranch in Amador County, said reconstruction costs were bid at $300,000 and would take at least a year to build, leaving the family without summer pasture and a herd of hungry cows to feed. Additionally, the U.S. Forest Service mandates that grazing be withheld for two years in postfire landscapes. This put the family in a difficult position.

While watching a recording of a California Cattlemen's Association meeting, Finley learned about a pilot program for virtual fencing. Desperate to find an alternative solution, she registered to try the livestock containment technology, which uses GPS enabled collars to monitor each animal's location in near real time.

Livestock producers can draw a perimeter on a map of their pasture using a laptop or smartphone application and send those instructions to the collar. The collar then uses audio and tactile cues to contain the animal in the area.

Eager to discover the short- and long-term benefits of virtual fencing, Finley turned to Scott Oneto, farm advisor, and Brian Allen, assistant specialist, from the University of California Cooperative Extension office in the Central Sierra. Since partnering with Oneto and Allen, Finley said she has come to understand and uncover more of the technology's potential.

The team has consistently observed the technology's value in integrating with and enhancing traditional livestock production systems across California. Though still in its early stages of development, the location tracking and containment system appears to provide time- and cost-savings that make it a game-changer for ranchers.

Ability to monitor location of animals in real time

Virtual fencing really stands out in its ability to monitor each animal's location in real time. During roundups, ranchers can use their smartphones to see their own location relative to their herd. The system can also send alerts if an animal crosses the virtual boundary or if a collar remains stationary for an extended period, potentially indicating that the animal is sick or that the collar has fallen off.

Rounding up cattle on large, forested grazing allotments can be challenging, as the process generally requires a group of people and many return trips to find every animal. Prior to virtual fencing, Finley and her father could gather about 85% to 90% of the herd in a week. Since using virtual fencing, Finley said one of their most recent roundups lasted three days, and they located every single cow.

Something that every livestock producer dreads is the notorious call from a neighbor or California Highway Patrol alerting them that one of their cows is out in the middle of the road. It always seems to happen at midnight or while they are out with friends or family. This scenario changes with virtual fencing.

Containment based on animal behavior

The containment system that virtual fencing is built on is based on animal behavior. When the animal crosses an invisible boundary, the collar emits an audio warning, prompting most animals to instinctively turn back into the desired area. If the animal doesn't respond, the collar delivers a mild electric pulse as a secondary deterrent.

Field trials by Oneto and Allen demonstrated the system's success. Recently, the team trained a herd of 37 cattle of mixed ages that had no previous exposure to virtual fencing. During the initial six-day training period, the cattle responded to the audio warning alone about 75% of the time when they approached a virtual fence boundary, with the remaining 25% of cases requiring an electric pulse.

After about three weeks, the herd was responding to audio cues alone about 95% of the time. The field trials also showed that the collars contain the livestock within the desired areas 90% to 99% of the time when the entire herd wears virtual fence collars and their basic needs for safety, connection to the rest of the herd, water, forage, shade, etc. are met.

Opportunities for improvement

While the technology is effective in its current capacity, there are notable areas where it can improve. One limitation to the system is the current reliance on cellular networks to operate. If an animal wanders into an area outside of coverage, the collar will continue to operate based on the last instructions but won't receive updates or report locations. This is especially a concern in many areas of California with poor cell reception, including the steep forested rangelands where many livestock producers have summer grazing allotments.

Another limitation is that some companies require a solar-powered base station with radio and cellular antennas to be placed on the pasture. These facilitate the transfer of animal locations and updates to the virtual fences. A base station going offline would create the same conditions as a drop in cell signal until the base station is repaired. Some companies are currently developing collars that bypass the need for these base stations.

The other major concern for ranchers is the cost for a virtual fencing system. The average rancher can expect to pay an estimated $20,000 to $30,000 in upfront costs. The cost to set up a base station alone is $5,000 to $10,000. However, this cost is highly dependent on several factors, including the manufacturer, the number of livestock to be collared, if the livestock are large or small ruminants, and the number of GPS base stations to cover the range.

According to Allen and Finley, the high cost of virtual fencing can be offset by the unique animal and land management benefits it can provide. “While physical perimeter fencing remains essential, VF is rapidly emerging as an innovative tool to control livestock with ease, precision, and flexibility in ways that were not previously feasible with traditional fencing,” Allen said.

Finley described the technology as a “game-changer” for her family.

Virtual fencing helps control invasive grasses, installing fuel breaks

While virtual fencing is designed to contain livestock without physical fencing, it is not intended to outright replace secure perimeter fencing. Instead, it operates best as a highly dynamic and adaptable cross-fence, allowing for more intentional grazing on the landscape to meet livestock production and natural resource conservation objectives within a secure physical perimeter.

With grant funding from the USDA Natural Resources Conservation Service, the UCCE team continues to work with Finley and other livestock producers to test these applications on California's diverse rangelands.

Within the Sierra Nevada and Coast Ranges foothills, these trials include using virtual fencing on cattle for targeted grazing of invasive grasses to support the recovery of native forage and installing fuel breaks within the wildland-urban interface to remove vegetation where the edge of a pasture meets urban housing.

Using virtual fencing, 25 cattle were successfully concentrated on a field of Medusahead (Elymus caput-medusae), an invasive annual grass. The herd respected the virtual fencing boundary 99% of the time despite nearby preferable forage. Grazing reduced medusahead seed heads from 2,072 per square meter in the ungrazed control area to just 68 per square meter in the grazed section.

In a different trial, 37 cattle with virtual fencing collars were contained within 120-feet-wide fuel breaks along the boundary of an annual rangeland and residential area. Cattle stayed within the boundaries 99% of the time, leading to an 81% reduction in fine fuel biomass and lowering wildfire risk in the wildland-urban interface.

Within rangelands on conifer forests, these UCCE trials concentrate cattle on brush to reduce the flammable plants and vegetation that competes with desirable timber species. It also can prevent livestock from entering sites that are sensitive to livestock presence.

Upcoming grazing trials will focus on how virtual fencing works with goats and sheep. In addition to Oneto and Allen, UCCE's contribution to virtual fencing research is in large part due to Leslie Roche, UCCE specialist and associate professor at UC Davis, Dan Macon and Jeff Stackhouse, UCCE livestock and natural resources advisors, Kristina Horback, associate professor at UC Davis and Lone Star Ranch in Humboldt County.

To learn more about the trials led by the UCCE team,visit https://cecentralsierra.ucanr.edu/Virtual_Fencing/