As cannabis production has ramped up in Northern California to meet the demand for medical and black-market marijuana, the ecological impacts of its cultivation have ballooned. From shrunken, muddy streams to rivers choked with algae and wild lands tainted with chemical poisons, large-scale cannabis agriculture is emerging as a significant threat to the victories that have been won in the region to protect wilderness, keep toxic chemicals out of the environment, and rebuild salmon runs that had once provided the backbone of a coast-wide fishing industry.
River advocate Scott Greacen has spent most of his career fighting dams and the timber industry, but now he’s widened his focus to include the costs of reckless marijuana growing. Last year was a time of region-wide rebound for threatened salmon runs, but one of his colleagues walked his neighborhood creek and sent a downbeat report that only a few spawning fish had returned. Even more alarming was the condition of the creek bed: coated with silt and mud, a sign that the water quality in this stream was going downhill.
“The problem with the weed industry is that its impacts are severe, it’s not effectively regulated, and it’s growing so rapidly,” says Greacen, executive director of Friends of the Eel River, which runs through the heart of the marijuana belt.
That lack of regulation sets marijuana’s impacts apart from those that stem from legal farming or logging, yet the 76-year-old federal prohibition on cannabis has thwarted attempts to hold its production to any kind of environmental standard. As a result, the ecological impact of an ounce of pot varies tremendously, depending on whether it was produced by squatters in national forests, hydroponic operators in homes and warehouses, industrial-scale operations on private land, or conscientious mom-and-pop farmers. Consumers could exert market power through their choices, if only they had a reliable, widely accepted certification program, like the ones that guarantee the integrity of organic agriculture. But thanks to the prohibition on pot, no such certification program exists for cannabis products.
To understand how raising some dried flowers—the prized part of the cannabis plant—can damage the local ecosystem, you first have to grasp the skyrocketing scale of backwoods agriculture on the redwood coast. Last fall, Scott Bauer of the California Department of Fish and Wildlife turned a mapping crew loose on satellite photos of two adjoining creeks. In the Staten Island–sized area that drains into those streams, his team identified more than 1,000 cannabis farms, estimated to produce some 40,000 small-tree-sized plants annually. Bauer holds up the maps, where each greenhouse is marked in blue and each outdoor marijuana garden in red, with dots that correspond to the size of the operation. It looks like the landscape has a severe case of Technicolor acne.
“In the last couple of years, the increase has been exponential,” Bauer says. “On the screen, you can toggle back and forth between the 2010 aerial photo and the one from 2012. Where there had been one or two sites, now there are ten.”
Each of those sites represents industrial development in a mostly wild landscape, with the hilly terrain flattened and cleared. “When someone shaves off a mountaintop and sets a facility on it,” Bauer says, “that’s never changing. The topsoil is gone.” The displaced soil is then spread by bulldozer to build up a larger flat pad for greenhouses and other farm buildings. But heavy winter rains wash some of the soil into streams, Bauer explains, where it sullies the salmon’s spawning gravels and fills in the pools where salmon fry spend the summer. Ironically, these are the very impacts that resulted from the worst logging practices of the last century.