SELMA, Calif -- "We have to try to find a system that is not going to cause a major disruption to our industry," said Bryan Little, director of labor affairs for the California Farm Bureau Federation. The industry group favors letting undocumented farmworkers stay in the country while applying for legal status, as well as drawing in seasonal guest workers to replenish the labor force.

California agricultural interests estimate that as many as 70 percent to 90 percent of farmworkers in the state may be here illegally, often presenting counterfeit documents to secure work.

Those who face the least danger of deportation - and who are least likely to flee in immigration raids - tend to be veteran workers, whose U.S. residency is more established.

Bill Chandler, 73, runs the family ranch in Selma with his son, John, who is 35. Chandler says his workforce largely consists of older laborers who got permanent residency or U.S. citizenship under a 1986 immigration reform law signed by President Ronald Reagan.

"There are always people in the ag labor force who don't have (proper) papers," Chandler said. "So we're all scrambling for what labor is here. And they're older folks."

He added: "They're special. They're really special."

On a recent day, as more than a dozen men set to work pruning Chandler's raisin vines, all but one was over 40.

Adrien Rosales, 22, was that one younger worker. He said he is proud of his father, Salvador, 46, who was pruning alongside his son.

"It's tough work. You get tired, worn down, and no one wants to do this," Adrien said. He said he plans to study heating and air-conditioning - and to grab at the first opportunity to get out of farm labor.

"It's very hard to find people who work in the fields whose parents migrated from Mexico to work in the fields," said Taylor of UC-Davis. "The second generation doesn't do farm work. That's why we've relied on a steady influx of newcomers. And the newcomers are in dwindling supply."

Taylor said economic factors may continue to drive down the number of farmworkers - even with immigration reform - and prompt growers to convert to less labor-intensive crops.

That is already happening at the 480-acre Chandler Farms. Because of difficulty finding workers for harvesting fruit, the family decided to cut back by 40 acres on peaches and plums and use more land to grow almonds, which can be harvested by machine.

"I don't know if it is going to get better for awhile," Chandler said. "If you want peaches or plums, or strawberries or lettuce or tomatoes, we need a program in which we can have labor. I don't have the answers."

For years, the Chandler family hired seasonal workers, often younger men who were put up in a bunk house on the ranch.

These days, the farm mostly finds workers through word of mouth. Many are older laborers who worked at the ranch years before and now have their own homes and, in many cases, have sent their children off to college.

"That's the success story," said John Chandler. "You see the next generation moving on."

Manuel Cunha Jr., president of the Fresno, Calif.-based Nisei Farmers League, representing 1,100 farms, packing and processing firms and dairy and poultry outlets, worries about the future.

Cunha says his group's workforce fell by 20 to 30 percent during last year's harvest season compared to the year before. By September, some farm crews were as much as 60 percent short of needed workers, Cunha said. He blamed stepped up farm audits by U.S. Immigration and Customs Enforcement and the increased perils facing migrants along the border with Mexico.