A few years ago, Sequoia and Kings Canyon National Parks was overrun with illegal marijuana growth sites. Trees were cut down and destroyed. Water was dammed and reoriented to help cultivate hidden pot plants. Growers would use illegal pesticides, herbicides, and rodenticides on the land, killing off endangered species and damaging local resources, according to park officials.
In 2010 alone, the parks' Marijuana Interdiction Group task forces destroyed some 42,000 plants, or about $169 million worth of weed, National Park Service data shows. Since 2002, they've destroyed nearly 241,000 plants -- some $545 million of marijuana.
But the two abutting parks, which are operated under the same management, haven't seen a new marijuana site in two years -- an accomplishment officials attribute to thorough foot patrols and deterring tactics that seek signs of planting early on and squash them before the plants have a chance to grow.
"We do a lot of early season operations and high profile patrols on canyon roads," said Todd Bonds, Marijuana Interdiction Group supervisor for Sequoia and Kings Canyon National Parks. "We discourage them from even starting to plant because we want to reduce resource damage before it starts."
Keeping the parks clean is a concerted effort. Sequoia and Kings Canyon authorities work to educate visitors and employees and raise awareness of the environmental damage caused by illegal sites. People are now increasingly reporting seeing potential marijuana sites, Bonds says.
Growing tactics have also changed, he adds -- sites moved away from the mountains to areas like California's Central Valley and Fresno, where people can grow pot under medicinal marijuana laws. And the problem persists in California's national forests where lack of funding and more acres to watch over are unmet challenges.
While illegal marijuana growth on public lands has been around for some 30 years (and is worst on the West Coast), the parks were hit hardest by the plants around 2007, Bonds says. Sequoia and Kings Canyon had the worst pot problem among western national parks when Congress granted additional funds to counter illegal growth in those areas.
That increase in funding led the parks to create the Marijuana Interdiction Group -- a group of rangers dedicated to fighting marijuana cultivation.
"It all comes down to money," Bonds says. "People look at the bottom line, but when you get out to the field you see this is about damage to the environment. The more people you have, the more results you get."