It is unlawful as a normal practice for any person or City department to top any street tree, park tree or other tree on public property. Topping is defined as the severe cutting back of limbs to stubs within the tree’s crown to such a degree so as to remove the normal canopy and disfigure the tree. An exception to this prohibition may be made by the Street Superintendent when a tree is severely damage by a storm or other causes, or when trees are located under utility wires or other obstructions where appropriate pruning practices are impractical.