151.07 DUTY TO TRIM TREES.  
   The owner or agent of the abutting property shall keep all trees in the City right-of-way trimmed so that all branches overhanging a sidewalk are at least eight (8) feet above the surface of the sidewalk. If the abutting property owner fails to trim the trees, the City may serve notice on the abutting property owner requiring that such action be taken within five days. If such action is not taken within that time, the City may perform the required action and assess the costs against the abutting property for collection in the same manner as a property tax.
(Code of Iowa, Sec. 364.12[2c, d & e])