The term of the Class I member shall correspond to his official tenure.

The term of the Class II and Class III members shall be for one year or terminate at the completion of their respective terms of office, whichever occurs first, except for a Class II member who is also a member of the Environmental Commission.

The term of a Class II or Class IV member who is also a member of the Environmental Commission shall be for three years or terminate at the completion of his term of office as a member of the Environmental Commission, whichever occurs first.

The term of a Class IV member who is also a member of the Zoning Board of Adjustment or Board of Education shall terminate when he is no longer a member of such other body or at the completion of his Class IV term, whichever occurs first.

The term of all Class IV members shall be for four years, except as provided otherwise herein.

The term of alternate members shall be for two years.

All terms shall run from January 1 of the year in which the appointment is made.

Nothing contained herein shall affect the terms of any present members of the Planning Board, all of whom shall continue as members until the completion of the terms for which they were appointed.