The initial 2011-2012 Navel orange forecast is 88.0 million cartons, according to the National Agricultural Statistics Service’s California Navel Objective Report.

About 85.0 million cartons are estimated in the Central Valley.

Survey data indicated a fruit set per tree of 318, below the five-year average of 353. The average Sept. 1 diameter was low at 2.27, above the five-year average of 2.246.

The varieties forecast in the report include conventional, organic, and specialty Navel oranges including Cara Cara and Blood orange varieties.

Beginning in the 2010-11 marketing season, NASS has used 40 pound equivalent cartons for all California citrus crops.

The forecast is based on the results of the 2011-12 Navel Orange Objective Measurement Survey conducted from July 15 to Sept. 2, 2011. Estimated fruit set per tree, fruit diameter, trees per acre, bearing acreage, and oranges per box were used in the statistical models estimating production.

A sample of 575 Navel orange groves was randomly selected proportional to county and variety bearing acreage, and 535 of the groves were utilized in this survey. Once a grove was randomly chosen and grower permission was granted, two trees were randomly selected.

In the last week of the survey period, fruit diameter measurements were made on the right quadrant of four trees surrounding the two trees of every third grove. These measurements were used to estimate an average fruit diameter per tree.

Of the 535 utilized groves, 8 were in Madera County, 85 in Fresno County, 305 in Tulare County, and 137 in Kern County.