An index to the grazing use that is made of forage species, based on a system of range management that will maintain the economically important forage species. Evaluating land based on usability under present and forecasted socio-economic conditions. If erected after the enactment of the ordinance it may be ordered removed. If it is in being before the enactment, it may continue in use, but a new nonconforming or different nonconforming use may not be substituted. Its extension or enlargement is not permissible.
Many ordinances permit rebuilding the nonconforming premises when destroyed by fire.
Once the use is abandoned, however, the right to its restoration falls, and the future use of the premises must conform to the zoning. Some states allow for the abatement of such uses at the end of a prescribed and usually lengthy period of time. A land use that does not conform to a zoning ordinance but that existed before the enactment and that therefore may not be banned until its abandonment. The degree and time of use of current year's range growth which, if continued, will either maintain or improve the range condition consistent with conservation of other natural resources. USGS U.S. Geological Survey, U.S. Department of Interior.