SAN DIEGO -- A multi-agency narcotics task force seized nearly 200,000 marijuana plants from 150 locations throughout San Diego County over an 11-month period ending last month, officials announced Thursday.

More than 65,000 of the plants were seized from public lands, with the help of the Bureau of Land Management, the U.S. Forest Service and tribal partners on reservations, according to Bill Sherman, acting special agent in charge of the U.S. Drug Enforcement Administration's San Diego Field Division.

"We work together to get those marijuana plants off our public lands and make those lands safe for public use," Sherman said.

The team also seized more than $1.2 million in assets, including real estate, vehicles and cash, made more than 100 arrests and seized 71 weapons between January and November, down from previous years, Sherman said.

"It's a sign we're driving them out of San Diego County with our continued efforts," he said. "The fact that we're arresting more people associated with outdoor grows has really been a deterrent."

About 3.2 million plants were eradicated in the state this year, about 4 million less than last year, said Tommy LaNier, director of the National Marijuana Initiative.

The marijuana trafficking organizations may have reduced their efforts to cultivate cannabis, LaNier said.

"Major prosecutions on the federal and state side [have] had a significant impact on marijuana traffickers," LaNier said. "The trends from our focused operations that we continue to do will have an effect both on the outdoor marijuana as it relates to public lands, but also the medical marijuana as it relates to those that are producing medical marijuana in the outdoors, as well."

The task force seized 176,632 plants from 83 outdoor grow sites and 22,927 plants from 67 indoor sites. Most of the indoor grows could be tied to marijuana dispensaries, a DEA spokeswoman said.

The illegal cultivation also harmed the environment by removing native vegetation, diverting streams and public water sources and releasing pesticides, officials said.

Cultivators clear out the plants and animals, run irrigation pipe to streams that could be miles away and use fertilizer that could kill animals, according to a group called Health Advocates Rejecting Marijuana.

"These criminal enterprises pose a great risk to those simply seeking to enjoy these lands in the manner for which they were intended," according to HARM.