California Illegal Marijuana Grows Killing Wildlife, Damaging Environment

The environmental damage from illicit marijuana operations in California is getting worse.  Experts say illegal growers are killing wildlife by diverting water from streams, using pesticides, fertilizers and poisons. With the legalization of recreational marijuana, some law enforcement agencies fear the problem will only get worse – especially on National Forest land.

Sleeping bags, empty pesticide packets, and other debris. U.S. Forest Service/ Courtesy

In Lassen National Forest, just above Deer Creek, law enforcement agents discovered the largest illegal marijuana grow ever in the forest, spread across 290 acres.

“Once they get into an area, and if they become undetected by the public or law enforcement they go ahead and get greater in size. It’s all about profit and money,” says Tony Magarrell, special agent for the US Forest Service. He’s responsible for investigating international drug trafficking organizations and cleaning up illicit grow sites.

Magarrell says the organizations cause major environmental damage. At the site in Lassen, the agency has had to use helicopters to clean up the trash. It’s taken more than three months.

“We removed almost seven tons of trash and infrastructure that included over 18 miles of just drip irrigation line.”

The irrigation pipes were removing water from streams that feed into Deer Creek, says Lassen National Forest Service hydrologist Carol Thornton.

“They totally dry up some of the smaller streams,” says Thornton.

Deer Creek flows into the Sacramento River. Thornton says drying up small streams that feed into the system is a big deal in a drought.

Law enforcement found more than 18 miles of irrigation pipe diverting water from small streams in Lassen National Forest. U.S. Forest Service / Courtesy

“From all the way down in the Sacramento, all the way up, people have to stop using the water that have legal water rights. These guys are using them and totally drying up the creek all year round.”

Very few peer-reviewed studies have looked at environmental damage from marijuana grows. Jake Brenner, an assistant geography professor with Ithaca College in New York published one study this year in the journal Environmental Research Letters. He examined 4000 marijuana grow sites in Humboldt County from Google Earth imagery and found the operations are clustered near headwater streams that are habitat for threatened fish species.

“Grows tend to be clustered away from roads, in remote areas that have steep slopes,” says Brenner. “So we see a lot of potential for erosion and sedimentation of streams. We see a lot of potential for mass wasting or landslides.”

Dr. Mourad Gabriel discovered a dead gray fox near a food bait pile. A likely victim of rodenticide placed near marijuana crops. Dr. Mourad Gabriel / Courtesy

Brenner says there is also potential for agro-chemical runoff. Illegal growers are using copious amounts of fertilizers, pesticides and poisons. At the site in Lassen, law enforcement agents found bromethalin, a neurotoxic rodenticide. Tony Magarrell says the illegal growers use it to bait animals, and prevent them from eating plants or damaging the crop.

“We actually had a dead bear. On top of it, and even more disturbing, was a dead turkey vulture,” says Magarrel. “So whatever that was, that chemical, pesticide, poison, went through the bear, that turkey vulture trying to eat it, and also killed it.”

Dr. Mourad Gabriel with the Integral Ecology Research Center is one of the one of the few researchers studying the ecological damage from illegal marijuana operations.  He’s found threatened fishers are dying from exposure to rodenticides.

Dr. Gabriel uses gloves and other protective material to sample food piles for poisons. Dr. Mourad Gabriel / Courtesy.

“What we’ve been demonstrating is now you have these chemicals that are now contaminated water, soil, other wildlife species besides fishers, and now potentially leaving what we fear is a legacy effect where it’s going to take either months or years before they are fully dissipated,” says Gabriel.

Law enforcement agents say drug trafficking organizations are supplying the rest of the nation, not just California. Tony Magarrel believes grow sites like the one in Lassen are not going to go away just because California has legalized recreational marijuana. Instead, he fears local and state agencies will no longer be able to help clean up illegal grow sites on federal public land. They’ll be too busy enforcing state and local regulations.

“We can’t deal with this by ourselves, we do not have the resources.”

The US Forest Service says since 2000, almost 80,000 acres of national forest land in California has been environmentally damaged or degraded from illegal marijuana grows.