California Code, Corporations Code - CORP § 7221

(a) The board may declare vacant the office of a director who has been declared of unsound mind by a final order of court, or convicted of a felony, or, in the case of a corporation holding assets in charitable trust, has been found by a final order or judgment of any court to have breached any duty arising as a result of Section 7238, or, if at the time a director is elected, the bylaws provide that a director may be removed for missing a specified number of board meetings, fails to attend the specified number of meetings.

(b) As provided in paragraph (3) of subdivision (c) of Section 7151, the articles or bylaws may prescribe the qualifications of the directors. The board, by a majority vote of the directors who meet all of the required qualifications to be a director, may declare vacant the office of any director who fails or ceases to meet any required qualification that was in effect at the beginning of that director's current term of office.