The Commissioner of Emergency Services and Public Protection may, upon application of the Commissioner of Energy and Environmental Protection, appoint, during his pleasure, one or more persons employed upon the public reservations in charge of the Commissioner of Energy and Environmental Protection and designated by him, who, having been sworn, may arrest any person in such reservation for any offense committed therein and take such person before some competent authority. Each such policeman shall, when on duty, wear in plain view a shield bearing the words “State Park Police” or “State Forest Police”, whichever is appropriate.