During the prescribed burning season, the department shall maintain at least two prescribed burn crews, one each in northern and southern California, for the purpose of providing prescribed burn back-up in the event of an emergency during prescribed burning operations. The department shall prepare a schedule for each prescribed burning season so that the crews will be available to all persons or groups of persons participating in the program during that season. Crews may also be used for other firefighting operations engaged in by the department when not in use in connection with such prescribed burning operations.