In the mountains 60 miles north of Los Angeles, they hike through the steep canyons of the Angeles National Forest and after pushing through miles of unforgiving underbrush, they find their target.
"What we have is multiple marijuana plants throughout this plantation," said U.S. Forest Service spokesman Nathan Judy.
A team of 20 men and women are part of a marijuana eradication task force made up of rangers with the U.S Forest Service and deputies from the Los Angeles County Sheriff's Department. They were busy Friday destroying an operation that consisted of six different sites.
These kinds of plantations are not found out in the open. The growers use the canopy of the forest to hide their operation.
"With our aircraft, you look down, you can notice the bright green that's within the darker green patches, and that's how we detect some of these plantations," said Judy.
Judy says the operation had probably been in place for about a year.
"These are ready to harvest," said Judy. "They'll hang them and dry them within the site itself. And then they'll haul it out."
In a typical irrigation system used by illegal growers, thousands of feet of black plastic tubing feed into drip lines that are fed directly into the plant. In this case, the source of water was a manmade reservoir.
"What they've done here was dug a hole, they put plastic in that hole to hold the water in so they'll wait for rains, or if they find another source of water, they'll bring that source of water down into second pools," said Judy.
The caretakers of this operation lived at a campsite consisting of bunks and a ramshackle kitchen. Sheriff's deputies say the two men who were living here managed to escape moments before Friday's early-morning raid.
"After the marijuana's out, our next important thing is to get all the chemicals out, such as the gasoline, the propane, the illegal fertilizers that are out here," said Judy.
This eradication team makes trips like these at least once a week during the peak growing season of March through October. The plants are cut down, then hauled away by helicopter. The marijuana is later incinerated.
"So a lot of these loads are usually ranged anywhere between 300 and 700 pounds of marijuana," said Judy.