The 2025-26 California forecast for only the Tango and W. Murcott Afourer Mandarin varieties is 33.0 million 40-lb. cartons. This forecast is based on the results of the 2025-26 Mandarin Objective Measurement (O.M.) Survey, which was conducted from July 1 to August 28, 2025. Estimated fruit set per tree, fruit diameter, trees per acre, bearing acreage, and mandarins per box were used in the statistical models estimating production.
Survey data indicated a fruit set per tree of 504, down 24% from the previous year. The average diameter from the survey was 1.359 inches, up 1% from last year for these varieties. Bearing acreage is estimated at 35,000, which results in a yield of 943 40-lb. cartons per acre.
Funding for the survey was provided by the California Citrus industry.
SURVEY HISTORY
This is the third year the USDA, National Agricultural Statistics Service, Pacific Regional Office has published a production forecast of Tango and W. Murcott Afourer Mandarin varieties. Fruit counts and size measurements have been collected each year since 2020 to build the dataset for the statistical models.
SURVEY SAMPLE
A sample of 337 Tango and W. Murcott Afourer Mandarin groves were randomly selected proportional to county and variety bearing acreage, with 332 of these groves utilized in this survey. Once a grove was randomly chosen and grower permission was granted, two trees were randomly selected from 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 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 collected on the right quadrant of four trees surrounding the two sampled trees. These measurements were used to estimate an average fruit diameter per tree.




