(a) It shall be the duty of every owner or occupant of a lot or open area to keep all trees upon such lot or open area trimmed to a clear height of 13 feet six inches above the surface of any public street, alley or highway, and eight feet above any public sidewalk.

(b) It shall be the duty of every owner or occupant of a lot or open area to correct or remove any tree upon such lot or open area, the roots of which interfere with any public sidewalk or city-owned utility facility.

(c) It shall be the duty of every owner or occupant of a lot or open area to correct or remove any unsafe tree upon such lot or open area.

(d) All city-installed trees on the City's right-of-way shall be maintained by the City in accordance with this section. (Code 1979, § 40-54.1)