Illegal marijuana cultivation harms natural resources

Issue Date: December 18, 2013
By Christine Souza
Devon Jones, executive director of the Mendocino County Farm Bureau, left, leads a breakout session on marijuana cultivation on agricultural and resource lands during the California Farm Bureau Federation Annual Meeting in Monterey.
Photo/Christine Souza

Illegal marijuana grows on agricultural and resource lands cause extensive damage to wildlife and the environment, according to researchers and agency officials who spoke during the California Farm Bureau Annual Meeting in Monterey last week. In response to the ongoing impact to rural areas, CFBF delegates voted to forward policy language to the American Farm Bureau Federation to guide national response to the problem.

Mendocino County Farm Bureau Executive Director Devon Jones, who led a panel discussion on the impacts of marijuana production, said the county Farm Bureau had proposed the CFBF policy on narcotics and substance abuse.

"We want the American Farm Bureau Federation to have policy in the books that will allow staff at the California Farm Bureau level to work with elected officials and legislators to come up with a joint solution," Jones said. "We've got trespass marijuana grows on resource properties or rangeland properties and the growers are using all kinds of chemicals. That liability will fall back on us if there is an issue with water quality, even though it is something that we're not aware of or had nothing to do with."

Among its provisions, the policy statement—originally adopted by CFBF delegates last year—calls on law enforcement to notify landowners when they become aware of trespass marijuana grows. The language adopted by CFBF will be part of the policy discussion during the AFBF Annual Meeting next month in San Antonio.

During the panel discussion, Scott Bauer, an environmental scientist with the California Department of Fish and Wildlife, described resource impacts in Humboldt County from illegal marijuana cultivation, such as water diversions, pollutants—including sediment, petroleum products, fertilizers and killing agents—and poor management, which harm the resource land and destroy habitat for fish and wildlife.

Bauer reported that thousands of gallons of water are used daily to grow marijuana plants, which has "significant negative effects on watershed health and sensitive aquatic species." He suggested that more fish kills are likely.

Mourad Gabriel, a wildlife disease ecologist at the University of California, Davis, reported on the extreme use of anticoagulant rodenticides and insecticides by marijuana growers, and their impact on the survival of the fisher, a carnivore with two isolated populations in California.

"We found widespread cases of exposure. This is very surprising to have that many fishers exposed to this toxicant," Gabriel said. "We were able to show that marijuana cultivation sites were exposing individuals and causing individual (fisher) deaths."

At one illegal marijuana grow site on resource land, Gabriel found as much as 90 pounds of rodenticide and other products, including those banned in North America.

"If we're lucky, we only find two or three pounds of this stuff out there. Ninety pounds can kill thousands upon thousands of rodents and hundreds possibly of other species," Gabriel said.

In discussing the impact of grow sites on water quality, Stormer Feiler of the North Coast Regional Water Quality Control Board said the "environmental damages that we see are intense."

"This cultivation activity occurs at the source of our headwaters of our streams, and at the top of our mountains. It is going to affect the whole watershed; it's just a matter of time," Feiler said. "The diversions are taking the water right out of the sources. There's less water downstream because of it."

The problem, Feiler added, is there has been a tremendous increase in the number of marijuana grow sites that result in waste discharges to water and to land from grading, road construction, use of fertilizers and soil amendments, pesticides, fuel, garbage and human waste.

"We're also sitting on a large increase in water diversions that appear to be decreasing summer-based flows, and we have a lot of habitat loss and habitat fragmentation," said Feiler, who emphasized the high cost of cleaning up the damage.

Fresno County Sheriff Margaret Mims reported that following passage of Proposition 215, the 1996 California initiative legalizing the use of medical cannabis, there has been an increase in marijuana growing in the Central Valley.

"Farmers know that you can get several thousand dollars for your crops. For marijuana, we're talking about several million dollars. It is not about the medicine; it's about the money," Mims said. "We have illegal marijuana from Fresno County going across our nation. We don't have enough sick people in Fresno County to account for the marijuana growing there. They sell it in our area for $1,200 a pound, but on the East Coast it goes for $4,200 a pound."

She warned farmers and landowners to be careful when a stranger offers a large sum of money to lease a portion of property.

"When you lease property to others, make sure that you have everything in writing. Make sure that when they sign, they agree that they are not going to violate any state or federal regulations and keep an eye on what is going on on your property," Mims said.

Fresno County Sheriff's Narcotics Detective Phil Lodge said many former foothill cultivation sites have moved to the valley floor.

"All of the same problems and disregard for public safety and health-related issues got pushed from public lands down onto private property," Lodge said. "Individuals are armed, and that same trend is happening on the valley floor, where the population is much higher and there is a lot more violence."

Illegal marijuana growers are using any method they can to protect their crops, Lodge said, including guard dogs, booby traps and trip lines rigged to a noisemaking device, and are hiding the plants by growing them in and around legitimate agricultural crops.

(Christine Souza is an assistant editor of Ag Alert. She may be contacted at

Permission for use is granted, however, credit must be made to the California Farm Bureau Federation when reprinting this item.