VALENCIA C.A.S.S. ESTIMATE

VALENCIA ORANGE PRODUCTION FORECAST

AT 28 MILLION

The initial 2011-12 Valencia orange forecast is 28 million

cartons. This forecast was based on the results of the 2011-12

Valencia Orange Objective Measurement (O.M.) Survey, which

was conducted from January 13 to February 23, 2012.

Estimated fruit set per tree, fruit diameter, trees per acre,

bearing acreage, and oranges per carton were used in the

statistical models estimating production.

Measurements and weather conditions are indicating a normal

crop year. Cold winter temperatures did not appear to

negatively impact the crop. Survey data indicated an average

fruit set per tree of 611, relatively close to the five-year average

of 591. The average March 1 diameter was 2.583 inches, very

close to the five-year average of 2.585.

SURVEY HISTORY

A Valencia Orange Objective Measurement Survey was

conducted from the 1985-86 to 1993-94 seasons before being

suspended due to a lack of funding. The survey has been

conducted since it was reinstated for the 1999-00 season, with

the exception of the 2006-07 season due to a substantial

freeze. The data from the first three years after the survey was

reinstated were used for research purposes in developing

crop-estimating models.

SURVEY SAMPLE

A sample of 578 Valencia orange groves was randomly

selected proportional to acreage, county, and variety

representation for the state, with 533 of these groves being

utilized in this survey. Once a grove was randomly chosen and

grower permission was granted, two trees were randomly

selected for each grove. For each randomly selected tree, its

trunk was measured along with all connected branches. A

random number table was then used to select a branch, and

then all connected branches from the randomly-selected

branch were measured.

This process was repeated until a branch was reached with no

significant limbs beyond it. This randomly-selected branch,

called the terminal branch, was then closely inspected to count

all fruit connected to it, as well as all of the fruit along the path

from the trunk to the terminal branch. Since each selected

path has a probability of selection associated with it, a

probability-based method was then applied to estimate a fruit

count for the entire tree.

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 sampled grove. These

measurements were used to estimate an average fruit

diameter per tree. Of the 533 utilized groves, 219 were in

Tulare County, 102 were in Kern County, 53 were in San Diego

County, 57 were in Ventura County, 34 were in Fresno County,

36 were in Riverside County, 13 were in San Bernardino

County, 14 were in Madera County, 2 were in Imperial County,

and 3 were in San Luis Obispo County.