Drugs, poisons, murders... its not something you would expect in National Forest.

The marijuana industry is big business and Mexican cartels are expanding that business to California's public lands. One area plagued with illegal grows is the Plumas National Forest. Narcotics teams are finding illegal marijuana grows every week.

"We live next to a marijuana grow," said cattle rancher Mike Grubs. "They had pit bulls running free and they attacked 2 cows and bit their ears off."

Grubs runs his cattle in Plumas and Butte Counties. He does his best to avoid the grows but sometimes his cattle wander into the wrong area.

The Plumas National Forest is rugged, remote and has numerous water sources. Marijuana is often grown in deep canyons under the cover of dense forest growth.

"What we encounter is a number of Mexican nationals or people not from the United States running the gardens," said Plumas County Sheriff Detective Chris Hendrickson.

Hendrickson says the narcotics task force team is really busy during the summer months. Deputies, Forest Service Rangers and sometimes the National Guard are raiding illegal marijuana grows every weeks.

To give you an idea on the number of people entering the country illegally, US Customs and Border Protection apprehended more than 330,000 people at the US/Mexico border last year. Most of those people are trying to escape the cartel, but that's not the case with the growing number of foreign nationals found in Plumas county.

"The Mexican nationals we do catch," Hendrickson said. "Some are out here for 3 or 4 months and are promised $10,000 or $20,000 to grow." Hendrickson said.

The Plumas National Forest is a popular place for campers and hikers. Safety is now a serious concern.

"We had instances where hunters were walking in the fields and killed and bodies found later," Hendrickson said.

Finding funding to raid marijuana grows can be challenging for Plumas and surrounding counties. Multiple law enforcement agencies often team up to cut costs, but the drug cartels don't seem to be slowing down. As long a there is a market for marijuana there will be grows.