Lawrence Berkeley National Laboratory wages war against wildfires by deploying an unconventional force: goats, which were released Tuesday in the area surrounding the lab.

The lab is using goats to eat the underbrush in the grassy hills surrounding the building, which the lab’s fire marshal, Todd LaBerge, said can help keep fires from spreading.

For the next four to five weeks, there will be 400 to 700 goats at a time grazing on about 90 acres of land — roughly 68 football fields — surrounding the lab, according to Keri Troutman, a spokesperson for the lab.

The goats visit annually, and the lab has used them for 21 years.

Goats R Us, the company dispatching the goats, has a system in place to ensure the goats don’t damage the land — walking the tightrope between fire mitigation and erosion control, according to Troutman. Goats R Us also sets up fences to create areas which can be easily overseen by the herders.

“(The herders) watch carefully and move the goats once the grasses and brush have been ‘mowed’ to the correct level,” Troutman said in an email.

By eating away tall plants such as grass and various other underbrush, the goats prevent the “ladder fuels” from reaching higher levels of the trees where fire is more difficult to put out, LaBerge said.

According to LaBerge, wildfires move upward as if they’re a climbing a ladder. Fires that start in tall grasses eventually move up into medium-sized brush patches. The fire can then spread to trees, ending up in the canopy. By shearing down the size of tall grass and brush patches, goats help keep small fires from becoming devastating, LaBerge added.

“The biggest problem with a wildland fire is when it gets into the treetops,” LaBerge said.“It’s what we saw happen in Napa — you have to keep the fire out of the canopy.”

Therefore, the goats are useful for creating environments that make fires easier to control, but have little to do with preventing fires from happening in the first place, LaBerge said.

Prevention lies on the shoulders of people, according to Laberge, who emphasized using common sense and not having open flames during hot, dry and windy days. In addition, Laberge talked about how easily fires can start if people are not careful.

“You could have a flare-up from someone’s greasy hamburger,” Laberge said, “People throw beer bottles down the hillside; the glass reflects the sun like a magnifying glass that starts a fire.”

Keith May, spokesperson for the Berkeley Fire Department, or BFD, said this situation is outside of BFD’s jurisdiction, and that the BFD does not use goats.