Here’s how to combat illegal marijuana grows in Stanislaus National forest

Craig Kohlruss/Fresno Bee file
·3 min read

While cannabis has been legalized in California for nearly five years, the illegal growing of marijuana on California’s public lands has steadily increased.

Thousands of cartel-controlled trespass grows are ruining California’s public lands by killing wildlife, depleting and contaminating our water sources, and making many places we love to visit potentially dangerous.

While most of these operations have been historically located in northern California, they are expanding throughout the state, including the Stanislaus National Forest where there have been multiple grow operations identified in the Tuolumne River drainage alone.

Trespass farms take a destructive toll on our environment. Cartel operators remove native riparian vegetation critical to many species of wildlife and they routinely use deadly pesticides that contaminate both soil and water. They use a tremendous amount of water as well, leaving little to support the native ecosystem.


In the San Joaquin Valley, every drop of our water is important, especially during drought. Water for residential use and farming, an integral part of our rural livelihoods, is threatened by operations that steal and divert water upstream of our farmers and residents. Statewide, it is estimated that trespass grows consume enough water to supply a town of 50,000 people for an entire year.

In recent years these trespass operations have been the cause of major wildfires, destroying homes, lives and watersheds. According to research done by the Cannabis Removal on Public Lands Project, trespass grows have burned a minimum of 285,000 acres on California’s public lands, costing billions in suppression efforts.

In addition to causing fires, trespass operations can keep firefighters from putting them out. Cal Fire has reported firefighters confronted by armed growers who often set booby traps and leave explosive ammunition to deter firefighters and law enforcement.

Officials commonly find banned and deadly pesticides including carbofuran, which can impair the nervous system and cause tremors, convulsions, and even death. One quarter of a teaspoon of carbofuran is enough to kill a 600-pound bear. Carbofuran’s combustibility makes it even more dangerous in a hot fire, where it could be inhaled by firefighters.

Law enforcement agencies across California often receive reports from visitors and residents living near national forests about trespass grows. Yet both the U.S. Forest Service and Bureau of Land Management are woefully understaffed to prevent or clean up after trespass operations.

In California’s National Forests, only one officer is responsible for approximately every 250,000 acres, an area larger than the entire city of San Diego. And over the past year, public officials are reporting that trespass grows have increased to pre-legalization levels.

If we are going to protect California’s public lands from the pollution and destruction from trespass grows, the federal government must increase its prevention and reclamation efforts. This can only happen through providing our public agencies the resources they need to carry out the work and succeed.

Fortunately, a bipartisan group of Congress members is now working to increase investment in enforcement and clean-up efforts. In a recent budget vote by the House of Representatives, members voted to increase funding for the Forest Service to over $4.14 billion, which is $680 million more than in the previous year. That includes language acknowledging the trespass grow issue and mandating action. It is critical for the U.S. Senate to affirm these increases and ensure that these funds are put toward preventing and cleaning up trespass operations.

With trespass grows steadily increasing, bold and swift action is needed to protect our land, water, and environment. The legacy of California’s wildlands is at stake.

Megan Fiske is executive director of Jackson-based Foothill Conservancy, and Ryan Henson is policy director of Cannabis Removal on Public Lands Project/CalWild.

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