State Sen. Scott Wiener, who has adopted the cannabis industry as one of his major concerns, is taking aim at new state regulations for recreational marijuana that will allow for big growing operations in California.

“By not limiting the amount of land that can be cultivated by any one operation, we are basically inviting mega industrial-scale operations into the state,” the San Francisco Democrat said. “It will squeeze out the small farmers that have been at the forefront of the industry for many, many years.”

Wiener’s anger is directed at rules issued last week by three agencies — the Department of Health, Department of Food and Agriculture and the Bureau of Cannabis Control — that do not limit the number of licenses a grower can hold or the total acreage one can farm. He said he hopes to make some changes when the Legislature is back in session next year.

Although there were no limits written into the voter-approved Proposition 64 that legalized recreational marijuana sales, small growers had hoped the state would set a cap of five acres per farmer for the first five years. One of the 2016 initiative’s biggest backers, Lt. Gov. Gavin Newsom, said there would be no “new gold rush” of corporate cannabis as a result of legalization.

Newsom, who is now running for governor, appears to be fine fow now with allowing for big growers.

“Legalization is a process unfolding over many years,” and regulations will need “constant re-evaluation,” Newsom said in a statement from Mexico City, where he is talking marijuana issues with trade officials.

But he added, “I'm not ideological about this; I'm watching closely to ensure that the rules are being applied with tough anti-monopoly standards that create favorable market conditions for small legal businesses.”

San Francisco Chronicle columnists Phillip Matier and Andrew Ross appear Sundays, Mondays and Wednesdays. Matier can be seen on the KPIX TV morning and evening news. He can also be heard on KCBS radio Monday through Friday at 7:50 a.m. and 5:50 p.m. Got a tip? Call (415) 777-8815, or email matierandross@sfchronicle.com. Twitter: @matierandross