California Code, Food and Agricultural Code (Formerly Agricultural Code) - FAC § 8601

(a) The county assessor, in making the annual assessment of property in each and every year after the organization of the district, shall assess any parcel of real property with 25 or more citrus trees on it and enter as a separate item, on the assessment roll for each such parcel of real propety  1 included in the district, the value, as improvements on the parcel, of all citrus trees which are growing on it.

(b) For the purpose of this part, the county assessor shall assess all citrus acreage at a uniform value per acre. The assessment shall be upon an acreage basis and the number of acres shall be determined conclusively, except as otherwise provided in this section, by the assessor counting the trees and dividing the total number by the number of trees per acre of average planting. The county assessor in counting the citrus trees shall not, however, count any more than 200 trees on any one acre of land, and for any citrus acreage which has from 70 to 100 trees per acre the number of acres to be determined by the county assessor shall be the actual acreage of the parcel.

(c) Upon completing the assessment roll of the county in each year, the assessor shall separately compute and certify, to the board of supervisors, the total assessed value, as shown by the assessment roll, of all the citrus trees in the district.