All employees of the State Forestry Commission appointed as forest law enforcement officers by the State Forester are hereby constituted peace officers of the State of Alabama with full police power and may exercise such powers anywhere within the state. They are hereby authorized to carry firearms or other weapons when they are actually in the discharge of their duties as such officers as provided by law. They shall be clothed with the power to arrest with or without warrant any person who shall violate any of the laws of the State of Alabama or any rule or regulation of the Alabama Forestry Commission and take him before a proper court for trial. All employees of the State Forestry Commission and all duly appointed officers of the United States whose duty it is to prevent and suppress forest fires are empowered to enter any lands and to construct thereon fire lines, fire lanes or fire breaks, to set back fires thereon if necessary to prevent the further spread of fire then actually burning and to do all other work necessary in the performance of their duties, including the right to enter any lands for the purpose of making investigations for the cause or causes of fires, without liability for trespass or damage therefrom.