Directors aren't required to make every meeting. Without going back to look at the charter, I think there are only three mandatory board meetings.
Having said that, it is always best that a director attend frequently to be in the loop of things going on.
I looked at the bylaws, and only found this:
SECTION 5. TIME OF MEETING
The Board shall meet at least two (2) times annually, and at such times as called by the
President, or by three (3) Board members. Notice of each meeting shall be sent to each Board
member in writing at least fourteen (14) days prior to each meeting. The Secretary shall give
notice of each special meeting to each Board member Not less than three (3) days before the
meeting, unless each member shall waive notice before, during, or after the meeting.
I also read that all new board members and officers will begin their duty cycle on Jan 1.