Trees and shrubs growing upon or near the lot line or upon public ground and interfering with the use or construction of any public improvements shall be deemed an obstruction under this article. Said roots may be removed by the Street Superintendent at the expense of the owner of the property upon which the tree is located, should the owner fail or neglect, after notice, to do so. It shall be unlawful for any person, persons, firm or corporation to obstruct or encumber by fences, gates, buildings, refuse containers, satellite dishes, poles or other structures, any of the streets, street rights-of-way, alleys or sidewalks. No street right of way shall be covered with any material other than grass, unless otherwise authorized in writing by the Street Superintendent or Building Official.