No person shall maintain upon any lot of which he or she is the owner, either individually or as one or two or more tenants in common, joint tenants or tenants by the entireties, any tree which is so located as to extend its branches over a public alley or highway, unless the same is kept so trimmed that there is a clear height of not less than twelve feet above that portion of the surface of sidewalks unobstructed by branches. No such person shall fail to remove all dead branches or stubs on such trees which are or may become a menace to persons on the street.
(1979 Code Sec. 13.40.030)