Terms of office. The term of the member composing Class I shall correspond to his official tenure. The terms of the members composing Class II and Class III shall be for one year or shall terminate at the completion of their respective terms of office, whichever occurs first. The term of a Class IV member who is also a member of the Environmental Commission shall be for three years or shall terminate at the completion of this term of office as a member of the Environmental Commission, whichever occurs first. The terms of all Class IV members first appointed pursuant to this chapter shall be so determined that, to the greatest practicable extent, the expiration of such terms shall be distributed evenly over the first four years after their appointment, as determined by resolution of the Township Council; provided, however, that no term of any member shall exceed four years, and further provided that nothing herein shall affect the term of any present members of the Planning Board, all of whom shall continue in office until the completion of the terms for which they were appointed. Thereafter, all Class IV members shall be appointed for terms of four years, except as otherwise hereinabove provided. The terms of an alternate member shall be two years; provided, however, that in the initial year of the adoption hereof, the Mayor shall designate one of the terms of the alternate members to be for one year. The alternate members shall be designated by the Mayor as "Alternate No. 1" and "Alternate No. 2." Alternate members may participate in discussions of the proceedings but may not vote except in the absence or disqualification of a regular member of any class. A vote shall not be delayed in order that a regular member may vote instead of an alternate member. In the event that a choice must be made as to which alternate member is to vote, Alternate No. 1 shall vote. All terms shall run from January 1 of the year in which the appointment is made.