HOOD -- The lush rows of Bartlett pear trees appear boundless from where Pasqual Aragon stands. They make his small crew's fruit-picking mission seem impossibly daunting.

"The truth is that there's a lot of work and not enough people," said Aragon, 26, as a dozen men beside him hoisted ladders and stuffed pears into heavy pouches strapped over their shoulders.

California farmers warned for years of a future without enough skilled pickers and packers, of fruits and vegetables rotting in place. Critics accused them of crying wolf to win sympathy for relaxing labor and immigration rules.

This year, however, the evidence seems stronger that the farm workforce is shrinking, and Northern California farmers say the future could hold more mechanization and imported crops.

Aragon and the others had no time to waste Friday as they plucked from the orchards that hug the fertile banks of the Sacramento River about 20 miles south of the state Capitol. Bartletts aren't as sensitive as cherries and other summer fruits, but wait too long and the crisp, green pears ripen on the tree into unsalable mush.

Aragon once belonged to a bigger crew of southern Mexican workers who arrived here between five and 32 years ago, but the team keeps getting smaller, and older.

"This year, for the first time, there seems to be not as many people out there looking for work in agriculture," said Jess Brown, director of the Santa Cruz County Farm Bureau.

The changing workforce is hard to track because the jobs are seasonal and studies have shown that most are immigrants living and working in the country illegally.

At fruit festivals, county fairs and statewide meetings this summer, growers from Salinas to Sonoma are voicing similar concerns. Many consider a declining workforce inevitable. How they will adjust is the bigger question.

Morgan Hill grower Tim Chiala abandoned a 50-acre string bean field in the fall because he couldn't recruit enough workers to harvest both the beans and a more lucrative pepper crop. This year, he planted fewer crops.

"I kind of got gun-shy until we figure out this labor issue," Chiala said.

To explain the dwindling number of workers, most point to the U.S.-Mexico border, where the Pew Hispanic Center this year found net migration to the United States fell to zero and may have reversed.

"It's more difficult to get across the border now. It's more dangerous because of the drug cartels, our government is doing a better job of enforcing the borders and the Mexican economy is doing better," said Jim Lincoln, a vintner and former president of the Napa County Farm Bureau.

Wine Country laborers are among California's best-paid farmworkers, earning well above minimum wage because the high-priced commodity demands a highly skilled and reliable workforce, Lincoln said. Still, he said, vintners are investing in costly machines to help prepare for a future in which recruiting able workers becomes more difficult.

"The trend will only go more mechanized," Lincoln said. "The machines are so good now, they're so gentle, that it doesn't affect wine quality."

Not everyone believes California is losing its thirst for a large, low-cost farmworker force.

UC Davis labor economist Phil Martin estimates the number of farm laborers has remained steady in recent years at around 800,000 people, but that's down from the 1.1 million farmworkers reported in 2001 as the migrant farmworker population peaked during the 1990s. These days, however, most are working for contractors, not directly for farmers. The contractors are more willing than farmers to absorb the risks of employing such an unstable, undocumented labor pool.

Worker advocates are skeptical of shortage claims because the farm industry often uses the stories to appeal for foreign guest labor programs with lighter regulations.

Mike Meuter of California Rural Legal Assistance said if the workers were in such short supply, you would think they would be treated better but many still report wrongful terminations and poor conditions.

And wages have not risen as they might if workers were hard to find, he said. "We haven't really seen any significant effort by 'ag' employers to increase wages, employment benefits or anything like that," Meuter said.

The Bay Area may be one of the most food-conscious regions in the country, prizing produce that is organic, local and fresh, but Chiala said the region won't be able to sustain its high-quality expectations if a declining workforce leads to more food imports and machinery.

"What makes California so great is all these specialty crops we get, the heirloom tomatoes, the blackberries, the raspberries," Chiala said. "All these things people love to eat -- there's no machines to harvest them."

The region's food production, Chiala warned, is "going to be like everything else. They'll outsource it to another country."

In the small Delta towns where Aragon and his crew follow the crops, picking pears has hardly changed since Courtland farmer Doug Hemly's great-great-grandfather first planted some Bartlett orchards in the mid-1800s.

"You can't just walk out and do this work. You have to know what you're doing," Hemly said. But finding people who know what they're doing, he said, is becoming harder every year.