The board of trustees of the firefighters’ retirement system shall have the exclusive authority and discretion to invest and reinvest the funds in property of any kind, real or personal. The board of trustees shall invest and manage the fund as a prudent investor would, by considering the purposes, terms, distribution requirements, and other circumstances of the firefighters’ retirement system. In satisfying this standard, the board of trustees shall exercise reasonable care, skill, and caution. No trustee shall have any interest as a trustee in the gains or profits made on any investment, except benefits from interest in investments common to all members of the plan, if entitled thereto.