"Vegetative buffer" or "buffer" means an area extending landward from the ordinary high water mark of a lake or stream and/or from the edge of a wetland which is maintained or otherwise allowed to provide, under optimal conditions, adequate soil conditions and native vegetation for the performance of the basic functional properties of shorelines or critical areas as set forth in Chapter 11.50. It is understood that optimal conditions do not always exist due to degradation of the vegetative buffer before establishment of this title, or due to colonization by nonnative species. Such conditions still provide functional properties, though at a lower level, depending on the difference from natural conditions. (Ord. 2123, § 1 (Att.), 2021.)