Upon the adoption of a resolution consolidating two or more districts, the board of supervisors shall immediately appoint a board of directors of at least five members, including at least one member from each of the districts which are included in the consolidated district. If any of the districts which are included in the consolidated district includes more than 15,000 acres of citrus acreage, the board of directors shall be increased to a number equal to the number of districts which are included in the consolidated district, plus one additional director for each 10,000 acres, or major fraction of 10,000 acres, in any one district which is included in the consolidated district.