Program Note: Watch Randi Kaye’s full report tonight on AC360° at 10 p.m. ET.

Randi Kaye kneels beside a marijuana plant on her visit to a 'marijuana garden' with a team of sheriff's deputies and officials who destroy the plants.

Randi Kaye | Bio

AC360° Correspondent

The helicopter waiting for us was bright blue and yellow. That was our ride into the Los Padres National Forest in California. We were about two hours north of Los Angeles. After the dirt and sand swirling around us settled down, we climbed aboard.

Our pilot flew during Vietnam so I wasn't too worried when he took us into the canyon of the forest and hovered there while our photographer shot video of the "marijuana garden" below us.

Hovering in a canyon in a chopper is not for the faint of heart. We came to do a story for AC360° on the "marijuana gardens" that exist on public land - like national parks and U.S. forests. About 80 percent of marijuana grown outdoors is grown in those areas.

We came to the right spot here. As we hovered we could see the plants below us as well as the irrigation system the growers illegally installed in the forest. The system diverts the rain water to these “gardens,” so the rest of the forest is deprived of water while the marijuana plants thrive.

Our pilot dropped us on a ridge. I was glad we didn't see where we were landing until after we climbed out of the chopper. We were with deputies from the Ventura County Sheriff’s Department and they gave us green floppy hats to wear to help blend in among the trees so "they" wouldn't see us.

Who are "they?" I'm told “they” are Mexican immigrants who have been smuggled across the border. They’re the ones who are allegedly responsible for growing this stuff. They bring in the seeds, the fertilizer and everything else they need when they enter the U.S. It's all financed, according to law enforcement, by the drug cartels in Mexico.

It’s a basic exchange: immigrants rely on the cartels to get them across the border, and the immigrants re-pay their debt by tending the "marijuana gardens" for the cartels.

It’s an uphill battle for law enforcement, which doesn't have enough money or manpower to keep destroying the drug.

When we came upon the first plants I was floored. Never had I seen so much marijuana. The smell was overpowering. Overall, our group estimated we found about 7,000. We’re told the street value of that amount is about $3.5 million.

We watched as the officers from the sheriff's department and US Forest Service destroyed every single plant they came across. I ripped one out of the ground and it uprooted easily. They broke most of them in two.

All the while I kept wondering if the growers were watching us. Our guys were carrying rifles and handguns and they said during a raid like this the growers usually hide in a bunker stocked with food built under the forest floor for a day or so to make sure the coast is clear. That was very unsettling since we also were told the growers carry AK-47 rifles and military-style weapons to protect the pot plants.

After hiking about a mile deep into the forest (I've never seen or touched so much Poison Oak!)we found what our team calls the "hooch". It’s the camp where the growers live in the forest from spring until fall while they grow the marijuana. There was a tent and some canned food items. Also some bb's which apparently they use to kill rodents and small animals to eat while they are camped there.

The sheriff's deputies went through the camp to make sure there weren't any weapons or drugs and then destroyed it. Once the job was done and thousands of plants uprooted, we hiked our way back out of the forest. It was tougher going back uphill, trust me! It was a relief to be out safely. We stood on top of the same ridge where we were dropped, muddy and smelling of marijuana, waiting for our ride to arrive. A few minutes later the helicopter brought us out of the forest.

The "garden" was destroyed but even our team had to admit there's a good chance it will all be replanted again.

Be sure to check out Randi's video : Pot growing in parks