(a) For the purpose of nominating grower members and alternate members, the following districts within the production area are hereby established:

(1) District 1—The State of Washington, and Clackamas and Multnomah Counties in Oregon.

(2) District 2—Marion and Polk Counties in Oregon.

(3) District 3—Linn, Lane, and Benton Counties in Oregon.

(4) District 4—Yamhill County in Oregon.

(5) District 5—All other Oregon counties within the production area.

(b) The Secretary, upon the recommendation of the Board, may reestablish districts within the production area and may reapportion grower membership among the various districts: Provided, That in recommending any such changes, the Board shall give consideration to (1) the relative importance of production in each district and the number of growers in each district; (2) the geographic location of districts as they would affect the efficiency of administering this part; and (3) other relevant factors.