A potent tension is disturbing the aromatic green fields and verdant centers of marijuana commerce in California as pot farmers and weed merchants brood over a future that is even more uncertain as the corporate world cozies up to the smokable herb.

A ballot measure that would legalize recreational pot has divided people who produce the mind-altering and medicinal plant, particularly the small growers in Humboldt, Mendocino and Trinity counties, the cannabis mecca known as the Emerald Triangle.

Some in the industry believe legitimacy would boost their bottom line, but others fear the Adult Use of Marijuana Act, labeled Proposition 64, would allow venture capitalists to drive out the small farmers who provided the troubled former timber towns on the North Coast with an economic engine and made California the weed capital of the world.

It’s a crisis of conscience for people who have fought for years to decriminalize marijuana. And if those closest to the crop turn away, so too may the state as a whole.

“The North Coast growers and every other stakeholder from law enforcement to the Legislature are deeply divided,” said Hezekiah Allen, executive director of the California Growers Association, which advocates for marijuana farmers, business owners and patients. “The growing consensus is that this is a really bad regulatory framework, but a lot of people are going to vote for it anyway because there is not a viable alternative.”

Evenly split on Prop. 64

The 646 members of the association are split almost evenly, Allen said. The lack of consensus was clear this month when members agreed to remain neutral on the initiative — at least until July 30, when the group will resume discussions.

The cannabis trade is already under pressure. Pot prices have plummeted from about $3,200 a pound a decade ago to between $1,200 and $1,600 today, Allen said, making it harder for mom-and-pop gardeners to turn a profit. The legalization dilemma is playing out at places like HappyDay Farms, north of Laytonville in Mendocino County, which supplies organic medical pot to patients and dispensaries — but barely makes ends meet.

“The regulatory hurdles and costs are really high,” said Casey O’Neill, the co-operator.

Nevertheless, he foresees opening a “bud and breakfast” if the proposed regulations pass. He worries about the cost of doing business under the new system but said he is a “huge fan of lowering penalties and of people not going to jail for cannabis.”

The proposition, backed by Lt. Gov. Gavin Newsom and funded largely by venture capitalist Sean Parker, will be on November’s statewide ballot, and voters in four other states will weigh in on legalization as well.

Parker’s role has fueled suspicions by some growers that the campaign aims to corporatize the sale of sinsemilla, but the former president of Facebook insists he is motivated only by social justice.

The measure would legalize the use and possession of up to an ounce of marijuana for people 21 or older and allow adults to grow as many as six plants for personal use — though using pot would remain illegal in public. California would establish a business licensing system and could bring in an estimated $1 billion or more annually in tax revenue.

Growers’ stance key

There is plenty of conservative opposition to Prop. 64, but it has become clear that the pot community’s support, or lack thereof, will be pivotal.

When California’s last bid to legalize recreational weed went to voters in 2010, traditionally marijuana-friendly counties like San Francisco, Marin and Santa Cruz gave it nearly two-thirds support. But voters in all three counties in the Emerald Triangle rejected it, and it fell statewide by 7 percentage points.

No doubt the political landscape has changed since then, with Colorado, Washington, Oregon, Alaska and the District of Columbia legalizing adult use of the drug. But what hasn’t changed is anxiety over whether corporations will run the game.

“We’re in a situation now where the toothpaste doesn’t go back into the tube,” said Joe Rogoway, a Bay Area lawyer involved in drafting Prop. 64 who argues legalization will benefit communities by drumming up revenue and jobs and hurting drug cartels.

The 2010 campaign, Rogoway said, was plagued by disorganization and infighting. Moreover, the earlier proposal would have given local governments leeway to pass their own laws, possibly weakening provisions of Prop. 215, the 1996 law that legalized medical marijuana.

Some in the existing pot industry have been soothed by language in the proposition that gives preference to small operators by, among other things, delaying for five years the issuance of licenses to people who plan to grow 22,000 square feet or more of marijuana. Even after five years, large cultivation licenses would be granted under the discretion of state regulators, whose job would be to prevent monopolies.

Jason Kinney, a spokesman for the Yes on 64 campaign, said the Blue Ribbon Commission on Marijuana Policy that was formed to study legalization “bent over backwards” to meet the demands of small farmers.

“We didn’t want a big corporate takeover of this emerging industry, so we put in probably more specific protections to give preference to small operators than any other state in the country,” Kinney said. “The goal is to hit the sweet spot, so we’re not flooding the system with supply or so strictly regulating it that it encourages the black market.”

The problem, critics say, is that the initiative doesn’t ultimately set limits on the size of commercial gardens. High rollers are already snapping up ranches, logging tracts and forested parcels in Humboldt County, which was the first county in the state to adopt a commercial marijuana land use ordinance. And big growers are expected to stampede into the Central Valley as well if mass production is permitted.

“We believe there should be a cap on the size of the cultivations,” said Allen, who is officially neutral on the measure but has deep reservations. “Proposition 64 favors corporate consolidation, and the market response has already reflected that.”

More transparency sought

The current marketplace is far from ideal. Growers enter into cooperative agreements with medical dispensaries or simply sell to whoever comes along with a big black bag. The hope is that regulations would provide more transparency and accountability and give growers more options.

Prop. 64 would give priority licensing to existing growers, but Jonathan Collier said it won’t help him. He had to stop raising weed on his farm in Nevada County this year when the Board of Supervisors — in a move that was recently reversed — banned outdoor cultivation, one of several conservative counties to do so in an attempt to preempt the law. Under the new law, local governments could ban nonmedical marijuana businesses as long as adults are still allowed six plants and possession of an ounce.

“I’m not in position to make the investments necessary to put in the infrastructure and bring my land up to code,” said Collier, chair of the Sierra foothills chapter of the California Growers Association. “If you aren’t already in compliance by September, you’ll be disqualified from priority licensing, meaning we would be at the end of the line. Anyone living in a banned county, and there are quite a few, are in a no-win situation.”

Pot growers say a fundamental question is whether Prop. 64 will preserve the “California way,” which hemp horticulturalists define as the growing of small, carefully tended, hand-cured batches of aromatic bud. The seasoned pros in the Emerald Triangle have recently been marketing this approach as the ganja gold standard.

“We are in favor of small grows because good quality marijuana can only be grown organically in the sun, and it requires intensive care,” said Robert Sutherland, the founder of the Humboldt/Mendocino Marijuana Advocacy Project. He claims members of his group started the artisanal trend in 1979 by smuggling into the area 5 pounds of seeds from a tribal area of Pakistan, where hashish is produced.

Tradition or new market

The strand replaced Mexican weed as the preferred brand and, Sutherland claims, is responsible for turning the Emerald Triangle into a kind of Angkor Wat of pot, much like the Napa Valley is the epicenter of wine.

The connoisseurs of cannabis aren’t willing to let that brand go up in smoke even for a law designed to lift them out of the shadows.

“The question is not whether we are pro or against regulation,” Allen said. “It is whether they are regulations that will allow us to continue long-standing sustainable cannabis farming traditions, or whether new markets will sweep away what we’ve built over the last 40 years.”

Peter Fimrite is a San Francisco Chronicle staff writer. Email: pfimrite@sfchronicle.com Twitter: @pfimrite