The commissioner is given authority to exercise the police power of the state in preventing and extinguishing fires upon any state lands, including lands under lease or contract of sale, and for such purposes he may enter upon private lands and may employ such assistants as may be necessary. He may allow such assistants while in actual discharge of their duties, per diem, in lieu of subsistence, at a rate not exceeding two and one-half dollars [($2.50)] and actual necessary transportation expenses, which shall be paid out of the state lands maintenance fund.