BANGOR, Maine — Three men meticulously planned, carefully tended, and then scrutinized the harvest of one of the most sophisticated marijuana operations in the state’s history in Township 37 in Washington County, a federal prosecutor told jurors Wednesday.

Not so, defense attorneys insisted in their opening statements to the jury as the trial of Malcolm French, 52, of Enfield, Kendall Chase, 57, of Bradford and Rodney Russell, 50, of South Thomaston began in U.S. District Court.

The men face a variety of charges in connection with the operation on a plot from which the Maine Drug Enforcement Agency seized 2,943 mature marijuana plants. The pot farm was discovered on Sept. 22, 2009, in a 10-acre swamp on 22,000 acres of land owned by Haynes Timberland Inc. French is part owner of the company.

In his opening statement, Assistant U.S. Attorney Joel Casey on Wednesday called the marijuana farm “a big business” with mid-level managers, of which Russell was one; a product developer, who was Chase; and workers, most of whom were undocumented and in the country illegally. He said that at the end of the trial, the jury of 12 women and three men, including three alternates, would find all the defendants guilty as charged.

French’s attorney, Walter McKee of Augusta, told jurors they would find his client not guilty because he “didn’t know some people were growing marijuana on his property.”

“The government wants you to believe that because Malcolm French owned a haystack, he must have known there was a needle there,” McKee said.

The defense attorney said that French allowed many people access to the land including wildlife biologists looking for hibernating bears and people involved in groups advocating for salmon restoration. He asked jurors to consider why he would do that if he were trying to conceal an illegal pot farm.

“Mr. Chase knows only what the government has provided us in this case,” defense attorney Jeffrey Silverstein of Bangor said in his opening statement. “Mr. French may have been operating a business as the government has charged, but Mr. Chase was not his professor of marijuana cultivation.

“The government’s theory of the case seems to be — if I teach you to bait a hook, I’m responsible four years later for the illegal fish you catch,” he told jurors.

Russell’s attorney, Steven Peterson of Rockport, reserved his right to make his opening statement after the prosecution rests its case.

In addition to charging Haynes Timberland, the prosecution has asked that the firm forfeit all or part of the land in Township 37 where the marijuana was grown. If a forfeiture were to be ordered and if the land was sold by the government, the law enforcement agencies that helped gather evidence and remove the plants could receive a portion of the sale price. Traditionally, money that state, county and municipal law enforcement agencies have received from forfeitures has been used to purchase equipment.

Thomas Marjerison, the Portland attorney who represents Haynes Timberland, said in his opening statement that the prosecution’s intention in charging the firm “is in taking the 22,000 acres that is Township 37.”

“The government wants to take the whole haystack because there’s a needle there,” he said.

French and Russell are charged with one count each of conspiracy to manufacture 1,000 or more marijuana plants, manufacturing 1,000 or more marijuana plants, maintaining a drug-involved place, harboring illegal aliens and conspiracy to distribute and possess with the intent to distribute marijuana.

Kendall was indicted on charges of conspiracy to manufacture 1,000 or more marijuana plants, manufacturing 1,000 or more marijuana plants, and conspiracy to distribute and possess with intent to distribute marijuana.

All remain free on bail.

Haynes Timberland Inc. was indicted on one count of maintaining a drug-involved place.

The trial will resume Thursday with testimony from law enforcement officers who spotted the plot from the air and those who were first on the scene.

It is expected to last three weeks.