On a cold morning this fall, I was clinging to a paracord line, descending through heavy brush on what felt like a near-vertical hill in Shasta-Trinity National Forest, in front of me a team of influential ecologists, behind me a team of affable, heavily armed law-enforcement agents. We were deep enough into the forest—bushwhacking into vegetation, miles and miles down a fire road—that anything human-made would have looked out of place. Then I saw a suitcase. A child’s coat. Pots and pans. A pair of jeans. Chapstick. Ramen packages. It looked a little like the site of a plane crash, except for the thousands and thousands of dead marijuana plants.
We’d arrived at a “trespass grow,” one of hundreds in the state of California. If you bought weed on the black market recently, there’s a good chance it came from a grow like this one. There’s a good chance, then, that your joint was contributing to a spiraling environmental catastrophe.
Trespass grows are not just an eyesore and a misuse of public lands. Growers on the sites use powerful illegal pesticides. That makes the grows a severe threat to the forest ecosystem, from the microbes in the dirt all the way up to apex predators like eagles. They are an object lesson in the invisible harms of the black market—and in the invisible harms of cannabis prohibition. As long as there is a strong incentive to produce and sell pot illegally, there will be a strong incentive for cartels to set up sites like the one I visited, and thus to damage delicate wildlands and poison countless animals.