Councils of second-class cities and towns may provide by ordinance, for a board of park commissioners, not to exceed seven in number, to be appointed by the mayor, with the consent of the city council, from citizens of recognized fitness for such position. No commissioner shall receive any compensation. The first commissioners shall determine by lot whose term of office shall expire each year, and a new commissioner shall be appointed annually to serve for a term of years corresponding in number to the number of commissioners in order that one term shall expire each year. Such board of park commissioners shall have only such powers and authority with respect to the management, supervision, and control of parks and recreational facilities and programs as are granted to it by the council.