EXETER (CBS SF) – Citrus growers in the San Joaquin Valley have so far been spared, despite potentially damaging cold weather that had been forecast this week.

California Citrus Mutual President Joel Nelson said very few locations dipped below 32 degrees in the Central Valley. They also used wind machines and frost protection tools to help protect the crop.

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“We’ve got a lot of vulnerability out there. There’s 75 percent of the naval orange crop still on the tree. So there’s $1.5 billion to $2 billion worth of citrus hanging on the tree,” Nelson said. “That’s why we’re so nervous about these forecasts.”

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The last critical freeze for the industry occurred in December 2013.

“A year ago, it was the first week of December that we had a bad freeze and we lost a lot of fruit,” said Nelson. “These 30 days means we’ve got a little more fruit off the tree and that fruit is more mature and does a better job protecting itself.”

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California produces 85 percent of the nation’s fresh citrus supply year-round. The industry creates approximately 12,000 jobs directly, and another 10,000 in support industries. It generates $1.5 million in economic activity statewide.