In November 2016, California voters gave a thumbs-up to Proposition 64, a measure to regulate and tax the cultivation, transportation, and sale of marijuana. As a result, marijuana will be more visible in our daily lives, and taxation revenue will help fill the state coffers. Although projections are highly uncertain, analysts estimate that the state could garner up to $1 billion in taxes. What isn’t known is if the new law will help slow illegal trespass grows in wilderness areas, and if the revenue will be sufficient to fix the damage the grows have already caused.

The language of Proposition 64 states that a portion of the revenue will go to programs that prevent, reduce, or reclaim environmental damage from trespass grows, the illegal growing and harvesting of marijuana on remote public or private lands. These grows are not restricted to the Emerald Triangle of Trinity, Humboldt, and Mendocino counties. They occur in abundance right here in the San Francisco Bay Area, and they are pervasive, ecologically damaging, and a threat to public safety.

In 2017, the Sonoma County Agricultural Preservation and Open Space District hired a consultant to head into the backcountry of the proposed Mark West Regional Park and Open Space Preserve to check on ecological conditions. While ecologists (and hikers) continue to be aware of mountain lion and bear trails in remote areas, they must also now be on the lookout for irrigation piping, fencing, and signs of encampments. In this case, the consultant came upon a partially cleared, mixed-hardwood forest with a thousand marijuana plants hanging upside down to dry. For his own safety, he turned and left. Trespass grows are often run by drug-trafficking organizations, and the growers can be armed.

It’s not just in Sonoma. This summer, according to The Mercury News, the San Mateo County Narcotics Task Force found 11,400 plants on Midpeninsula Regional Open Space District property, including the Skyline Ridge Open Space Preserve. In Santa Clara County, the Sheriff’s Office Marijuana Eradication Team arrested 126 people, seized nearly 339,000 marijuana plants and 27 firearms, and removed 18.5 tons of grow operation trash from public and private lands over a four-year period ending in 2016. “Trespass grows are pretty much everywhere — canyons, parklands, public parks, and Bureau of Land Management land — areas where people can hide and grow,” said Joseph Deviney, agricultural commissioner for Santa Clara County.

Brian Malone, land and facilities manager for the Midpeninsula Regional Open Space District, said his organization discovers several sites a year with 1,000 to 10,000 plants, along with scenes of environmental destruction. At a trespass site, growers clear native vegetation, dam creeks and divert waterways, leave behind trash, and use fertilizer, pesticides, and rodenticides. The results of an illegal grow can be long-lasting: poisoned water leaches into the soil and water table, raptors hunt chemically treated rats and small mammals, and birds eat scattered fertilizer pellets.

The grows also impact the organizations that care for the land. “Dealing with trespass grows takes up a larger percentage of staff time than it used to,” said Sheri Emerson, stewardship program manager at Sonoma Ag and Open Space, which had three big grow sites on its properties this year. Land managers must also coordinate clean-up with law enforcement agencies, because even abandoned sites are considered active crime scenes.

When Sonoma Ag and Open Space staff returned to the Mark West site this summer, they found a camp with abandoned gear and three fortified water basins, the largest of which was 9 feet deep and 15 to 20 feet long. Funded by a CalRecycle grant, a clean-up crew shoveled dirt and vegetation into the water basins, bagged the garbage, and scattered brush around the scarred, one-and-a-half acre grow site.

It seems unlikely that Proposition 64 will stop these grows. As Sergeant Richard Glennon with the Santa Clara County Sheriff’s Office wrote in an email to the Monitor, “We predict this practice of trespass marijuana cultivation to increase dramatically with the public’s changing attitudes towards marijuana, the expanding California cannabis market, and the fact that this remains an ideal geographical/climate for growing operations.”

Malone is also skeptical. “I think we’ll continue to have a problem with grow sites on public land because of the black market. We have to prepare for that possibility,” he said.

Proposition 64 will, however, contribute to remediating damage, though that is low on the list of funding priorities. Matt Clifford, staff attorney for the fish preservation nonprofit Trout Unlimited, explained that annual tax revenue needs to reach $25 million before any funds can go toward the environment. The language in Proposition 64 states that tax funds must first go to administration costs, research studies, protocols for driving safety, and social services support. After those monies are allocated, any remaining funds will go to youth education (60 percent), law enforcement (20 percent), and environmental restoration and protection (20 percent). These funds will be distributed through the California Department of Fish and Wildlife (CDFW) and the California Department of Parks and Recreation. CDFW is preparing for funds that might come their way to mitigate damage to fish and wildlife habitats.

“Marijuana cultivation is a huge issue for us because the areas of heavy cultivation overlay almost exactly with California’s most important salmon and steelhead habitat,” said Clifford. Trout Unlimited is looking to Proposition 64 to regulate operations that follow the law, and provide resources to control those that don’t.

Trespass grows are the dark side of cannabis cultivation. Hezekiah Allen, executive director of the California Growers Association, a membership group representing the interests of cannabis cultivators, said that bringing the crop into the light and working with legitimate growers (many of whom grow indoors) will help get rid of bad actors. “There are 55,000 growers in California, and only 3,000 to 5,000 of those are thugs. Trespass grows by no means reflect the industry,” said Allen. He noted that for years, people in the industry have pushed for regulations (although the California Growers Association did not support Proposition 64 for a variety of reasons), and have grown an environmentally-friendly, high-quality product. He contended that “any regulated cannabis will be sustainable. We are deliberately holding ourselves to a higher standard.”

California grows more pot than is consumed here, and as long as there is a black market for the product outside of California, trespass grows are likely to continue. “There will always be a demand,” said Allen. “We can either regulate the supply, or it can hide in our wildernesses. That’s up to the policymakers.”

Aleta George covers open space for the Monitor.