No obstruction to view in excess of two feet in height shall be placed on any corner lot within a triangular area formed by the street right-of-way lines and a line connecting them at points thirty feet from the intersection of the street lines, except that street trees are permitted which are pruned at least eight feet above the established grade of the roadway so as not to obstruct a clear view by motor vehicle drivers. (Ord. 1989-51. Passed 8-28-89.)