Sonoma County Supervisor Efren Carrillo and former Supervisor Ernie Carpenter traded sharp jabs Wednesday night over a controversial timber-to-vineyard conversion project that is sure to become a key election issue in the race for the 5th District supervisorial seat.

The issue — and the intensity of the exchanges in a bid to win environmental votes in the west county district — took center stage in a candidates' forum in Graton that included former Santa Rosa City Councilwoman Veronica Jacobi.

Carrillo accused Carpenter of being a paid lobbyist for what he characterized as an early incarnation of the Preservation Ranch project, a forest-to-vineyard conversion proposal on 20,000 acres outside of Annapolis.

"Make no question about it. Mr. Carpenter was hired as a lobbyist by a vineyard developer," said Carrillo, adding that he objected to questions about the issue coming from "The father of Preservation Ranch."

Carpenter repeatedly called Carrillo's claim a "prevarication," pointing out that the consulting work he did in the late 1990s was not tied to Preservation Ranch, but rather to 80,000 acres of coastal forestlands.

"I never worked on Preservation Ranch. I worked on the Coastal Forestlands project of 80,000 acres of which now 40, 000 are owned by the Nature Conservancy and the other 20,000 are put into a bank for carbon mitigation," he said.

"If he wants to call me a lobbyist that's fine, I'll call him the father of asphalt plants in biotic areas," Carpenter said, referring to Carrillo's key vote approving the Dutra Materials asphalt plant south of Petaluma.

Carpenter repeatedly said he was opposed to Preservation Ranch and directly asked Carrillo to state his position.

Carrillo, who refused to say how he would vote, insisted that taking a position on Preservation Ranch prior to the completion of the county environmental review process would be "irresponsible" given the "quasi-judicial" role of the Board of Supervisors in the process.

The barrage of attacks between Carpenter and Carrillo dominated the first part of the forum at the Graton Community Building hosted by the Sonoma County League of Women Voters and the American Association of University Women.

Jacobi, who served one term on the Santa Rosa Council, tried to stay clear of the back and forth, while saying she opposed such timber-to-vineyard conversions such as Preservation Ranch.

After the first hour of debate, candidates were asked questions that ranged from what would do to create jobs and stabilize the economy to whether they supported medical marijuana.

Carrillo said that while he supported the use of medical marijuana, illegal growing operations were becoming a major safety and environmental degradation issue.

On creating jobs, Jacobi suggested focusing on turning the county into an incubator for green jobs. She also said she supported the union-backed "living wage," as did the other candidates.

"When the conditions are right everybody can pay a living wage," she said.

The candidates agreed on a number of issues, including the need to focus on local farming and bridging the gap between longtime traditional farmers and the county's new breed of farmers.

Carpenter said that fostering the creation of "direct markets to consumers will help local growers."

Carpenter, who left the board 16 years ago, jumped into the race the day before the March 9 filing deadline. His said he was running because Carrillo's record on land-use issues troubled him and that he felt he had the best chance to beat Carrillo.

In the debate, Carrillo defended his environmental record and said he was a strong supporter of preserving open space as well as creating parks for the county's low income communities.

The League of Women Voters is hosting other debates among candidates for supervisorial races.

Today, candidates for the 1st District seat will square off at 7:30 p.m. at the Sonoma Community Center.

Candidates for the 3rd district race will debate each other during a forum at 6 p.m. on May 2 at Rohnert Park City Hall.