Pursuant to Section 280.03(a) of the Administration Code, the Tree Commission annually reviews, updates and prepares the official list of street tree species authorized to be planted in the City. At least one copy of said official list is on file with the Clerk of Council for inspection by the public. In addition, the Clerk of Council shall keep copies of such official list available for distribution to the public, at cost. No species other than those listed may be planted as street trees without written permission of the Tree Commission. The official list identifies trees by three categories, as follows:
(a) Large Trees. Such trees reach a height of forty-five feet or more at maturity. They are suitable for planting in tree lawns of eight feet or more where no overhead utility lines are present.
(b) Medium Trees. Such trees reach a height of thirty to forty-five feet at maturity. They are suitable for planting in tree lawns of six to eight feet where no overhead utility lines are present.
(c) Small Trees. Such trees reach a height of ten to thirty feet at maturity. They are suitable for planting in tree lawns of four to six feet, and in wider tree lawns where overhead utility lines are present.