(Dec. 19, 9:00 a.m.) California’s San Joaquin Valley citrus crops escaped the season’s first potential freeze when temperatures failed to reach predicted lows Dec. 18.

There were some readings below 32 degrees, said Joel Nelsen, president of California Citrus Mutual, Exeter, but the below-freezing temperatures lasted only a short time.

The value of the fruit still awaiting harvest is $1 billion, Nelsen said. Damage to citrus crops can occur when the temperature drops below 28 degrees for several hours, he said.

The vast majority of the state’s projected 2008-09 navel crop of 64 million cartons is grown in the San Joaquin Valley.

Nearly 50 million cartons of the valley’s forecast volume of 62 million cartons remain on the trees, said Bob Blakely, director of grower services for California Citrus Mutual.

The projected volume for the satsuma and clementine crops is 40.3 million cartons, according to the California Citrus Growers Association, Visalia. About 32 million cartons have yet to be harvested.

About one-third of the state’s 2008-09 lemon crop, which the association said will be 43.5 million cartons, is grown in the valley. More than 11 million cartons of lemons are still on valley trees.