Mass. Gen. Laws ch. 132A § 7
The commissioner, in consultation with the director of the division, may make rules and regulations for the government and use of all property under the control of the division, including all roads and highways wholly or in part within the boundaries of such property, including rules and regulations relative to hunting and fishing, except in great ponds not inconsistent with the laws protecting fish, birds and mammals. Such rules and regulations may also provide for the payment of fees and other charges for the parking of vehicles and for the enjoyment of other special privileges within the territory under such control. The commissioner shall cause such rules and regulations to be posted in the territory to which they apply. The sworn certificate of the director of the division that the same have so been posted shall be prima facie evidence thereof. Violation of such a rule or regulation shall be punished by a fine not exceeding twenty dollars. The commissioner may grant concessions for the sale of refreshments and other articles and the furnishing of services within any such territory.
Forest supervisors, park superintendents and laborers employed by the division, while employed in state forests, state parks or reservations, including roads and highways, shall, within the limits of said forests, parks or reservations, except great ponds, have and exercise all the powers and duties of constables, except service of civil process, and of police officers, if so authorized in writing by the commissioner.
The enforcement officers of the office of law enforcement shall, within the limits of such forests, parks or reservations, including roads and highways, except great ponds, have and exercise all the powers and duties of constables and of police officers except service of civil process.
Mass. Gen. Laws ch. 132A, § 7