The Public Works Director shall remove, on the order of the Council, any tree on the streets of the City which interferes with the making of improvements or with travel thereon. The Director shall, additionally, remove any trees on the street, not on private property, which have become diseased, or which constitute a danger to the public, or which may otherwise be declared a nuisance.
(Code of Iowa, Sec. 364.12[2c] and 372.13[4])