California’s initial USDA/NASS 2007-08 Navel orange forecast is 86.0 million 37.5-pound cartons, 26 percent above last season’s crop of 68.0 million cartons.

Of the total forecast, 84.0 million cartons are estimated to be in the Central Valley. Bearing acreage for the state is estimated at 137,000, resulting in a yield of 628 cartons per acre.

The forecast is based on the Navel Orange Objective Measurement Survey conducted in the Central Valley. Survey data indicated an average fruit set of 390 oranges per tree, with a Sept. 1 diameter of 2.25 inches.

A sample of 569 Navel orange groves was randomly selected proportional to county and variety bearing acreage and 543 of the groves were utilized in this survey. Once a grove is randomly chosen and grower permission is granted, two trees are randomly selected. Trunk and branch measurements, along with fruit counts, are then made on each tree.

Fruit diameter measurements are made on the right quadrant of four trees surrounding the first sampled tree. Of the 543 utilized groves, 13 were in Madera County, 89 were in Fresno County, 304 were in Tulare County, and 137 were in Kern County.

The Navel orange crop was looking good. Fruit, however, appeared smaller than usual for this time of year. The average fruit diameter as of Sept. 1 is the lowest since the 2002-2003 crop year.