The Superintendent of Schools is the Board's key employee and, while you may well have a friendly relationship with him, never forget that he's there to carry out the Board's direction and that it's the trustees responsibility to ensure that that happens. He's the Board's employee, not their buddy. Trustees first responsibility is to the students of the district, and if you believe that the Superintendent has done something that goes against the interests of students, your fiduciary duty obliges you to speak up and take the necessary action. Trustees should generally concentrate on setting the policy direction for the school district and leave administrative matters to the Superintendent and his staff. It can sometimes be a delicate balance around the edges of policy and administration, and some superintendents have a more finely developed sense of political astuteness than others. Good communication both ways is essential for a successful Board/Superintendent relationship.
As the 2004-2007 Board discovered, there can arise circumstances where the Superintendent loses the confidence of the Board. In such cases, termination usually results. Always unpleasant, but sometimes necessary.
To begin a productive relationship right off the bat, I'd suggest the new Board have a private meeting with the Superintendent that would include a discussion of each others expectations and a review of his employment contract. The Board, as the Superintendent's employer, should be fully aware of it's provisions regarding remuneration, evaluation, expiry date, provisions for terminating the contract, etc.