Marijuana grown illegally in national forests is causing serious ecological harm: Report

Illegal marijuana farming in U.S. national forests is substantially damaging the local ecosystem and water, a new report found. 

Due to the vast size and thick canopies of the forests, forest police and researchers told NPR that these sites have been operating undetected for years.

“The true crime here is the fact that they’re killing off basically America’s public lands, killing off the wildlife, killing off our water,” Kevin Mayer, U.S. Forest Service law enforcement assistant special agent in charge, said. “This is stuff that, you know, it’s not gonna repair itself.”

One marijuana cultivation site recently discovered in a California forest yielded 3,000 pounds of trash, including old clothes, propane tanks, and three miles of irrigation pipes.

But as wildlife ecologist Greta Wengert said, the worst environment damage from the sites is the result of various fertilizers and insecticides used by pot harvesters. 

“It is incredibly toxic,” Ms. Wengert says. “A quarter teaspoon could kill a 600-pound black bear. So obviously just a tiny amount can kill a human. It remains in an ecosystem for a long period of time.”

“We have detected [carbofuran] in the soil, in cannabis plants, in native vegetation, the water, the infrastructure. You name it, we have detected it,” Ms. Wengert says. “It’s horrible.”

Ms. Wengert says that while growing pot discreetly in the forest isn’t new, the cartel’s use of heavy chemicals is an addition permeating it’s way into the forest’s entire food network and waterways.

“The mountain lion population in California is exposed to anticoagulant rodenticides at a rate well over 90%,” she says. “We’re just getting data on rodents, the prey base for all the species that are of concern when you’re talking mountain lions, fishers, foxes, spotted owls other forest raptors, the prey base that is supporting these species is contaminated.”

Police said they have arrested 148 people at 345 raided grow sites in California’s Campaign Against Marijuana Planting program, which brings together the Forest Service with local, state and federal enforcement.

Ms. Wengert’s colleague, Mourad Gabriel, said that they continue to find more grow sites, but if the forest service doesn’t get more funding, they grow sites will become active again.

“The solutions are very simple: You prevent it. You eradicate it. You remove the infrastructure and remove the chemicals,” Mr. Gabriel “But if there’s no funding mechanism and we don’t remove this infrastructure, it will be reactivated in the next couple years.”