Deep inside Northern California’s Shasta-Trinity National Forest, wildlife ecologist Mourad Gabriel is dressed in camouflage, waiting for the raid.

He’s accompanied by more than a dozen armed officers with the U.S. Forest Service, local sheriff’s office, and other agencies on a hot August afternoon. Their plan: to seize and dismantle a nearby illegal marijuana grow site, hundreds of which are discovered on California’s national forests each year.

At this site—just off Route 36, east of Redding, and down a rocky forest valley—more than 4,000 marijuana plants grow beneath sugar pine and Douglas fir. There is also a campsite with several tents, two cisterns, and hundreds of feet of irrigation pipe.

During the raid, officers arrest two alleged growers. Once the site is secured, Gabriel and his partner, Greta Wengert, move in to assess the environmental damage and clean it the best they can. For the last six years, the pair has warned about the dangerous pesticides found at many of these sites and the associated impact on local wildlife. Growers often use pesticides, some of them banned and highly toxic, to protect the marijuana plants and their camps from insects and animals. [Read more at National Geographic]