By administrative adjudication is usually meant the exercise of quasi-judicial functions upon and in the control of vested property rights, or personal rights secured by constitutional guaranties. It often accompanies and effectuates regulative power of a quasi-legislative nature. A large measure of this quasi-legislative power has been given to the departments and bureaus dealing with the lands of the United States, but the enforcement of such regulations, insofar as they affect rights of person or vested rights of property, is chiefly by process of the regular courts. Thus the regulation of the occupancy and use of lands reserved for national forests is entrusted to the secretary of agriculture. His regulations usually prohibit acts that were theretofore innocent and customary though not vested rights. Sometimes they restrict the use of land in which there exists a vested private right of use for a particular purpose only, but the restriction does not affect the right itself.