One of California's top ambassadors often comes lightly salted and travels in a vacuum-sealed can. Eat an almond anywhere in the world and chances are that it was grown in the Golden State.

California produces 82% of the globe's almonds, harvesting about 800,000 acres of the tree nut across a 400-mile stretch from northern Tehama County to southern Kern County.

Fueling the boom is robust foreign demand, particularly from emerging consumer markets like China and India, where the industry has been promoting almonds as a healthful snack.

About 70% of California's almonds are sold overseas. That made the crunchy nut the No. 1 state agricultural export in 2012 at $2.5 billion. That's 21/2 times more than wine, the second-most-valuable California agricultural export, according to the U.S. Census Bureau.

"The U.S. is the 800-pound gorilla of the global almond industry," said Karen Halliburton Barber, assistant vice president and senior analyst for produce at Rabobank, a leading agricultural lender. "They're the dominant producer."

The Almond Board of California forecasts that the state will harvest its third-largest crop this year at 1.85 billion pounds — slightly less than last year's 1.88 billion pounds.

That's more than three times what the state was producing in the late 1990s. Experts are

optimistic that the industry can maintain that sort of volume in the coming years. Foreign

demand is expected to increase. Competition should remain light. The main barriers to continued growth are access to land and tightening water supplies.

"We'll run out of dirt and water before we run out of almond markets," said Daniel Sumner, director of the Agricultural Issues Center at UC Davis.

The biggest of those worries is water. Almonds are a relatively thirsty crop, and farmers need to water them even during dry spells.

California suffered its worst drought conditions in 90 years between January and May, leaving reservoirs dangerously low and state water allocations to farmers well below historical averages, according to the Bureau of Reclamation. The stingy water supplies resulted in smaller almonds this year.

"Water is a huge challenge," said Richard Waycott, chief executive of the state almond board. The group has partnered with UC Davis to promote a variety of water conservation plans using micro sprinklers and soil moisture monitoring systems.

Growers are harvesting more almonds and using less water per acre than in years past. But the sheer acreage of California's almond industry means water will remain a concern.

Still, with almond prices nearly doubling in the last five years to $2.58 a pound, it's little wonder that growers have been abandoning crops such as cotton and

furiously planting almond trees. There's twice as much almond acreage in California as there was two decades ago. Meanwhile, cotton acreage has dwindled to about 400,000 acres from 1.3 million acres over the same period.

"It feels like almonds became rock stars overnight," said Karen Ross, secretary of the California Department of Food and Agriculture. "But they've been building in bits and pieces for years. I look at almonds as a great case study because they were very strategic and willing to make long-term investments."

Central to that plan are nutritional research and clever marketing. The Almond Board of California has funded a number of studies, including an October report in the European Journal of Clinical Nutrition showing that eating dry-roasted, lightly salted almonds could sate hunger without increasing body weight.

Almonds are a major part of the farming portfolio of Beverly Hills billionaires Stewart and Lynda Resnick, who own brands such as Wonderful Pistachios, Pom Wonderful pomegranate juice and Halos mandarin oranges.

The couple's Paramount Farming Co. has been expanding its almond acreage in Kern and Madera counties to meet growing global demand for the tree nut. It farms 46,000 acres of almond orchards, a space the size of 13 Los Angeles International airports that produces 6% of the state's almonds.