No person shall place or maintain upon the ground in any public place any stone, concrete, brick or other impervious material or substance in such a manner as may obstruct the free access of air and water to the roots of any tree upon any public place, without first having obtained written permission therefor from the Director of Public Service. Unless otherwise provided for, there shall be maintained about the base of the trunk of each such tree at least nine square feet of open ground for a tree three inches in diameter and, for every two inches of increase of such diameter, at least one additional square foot of open ground.
(Ord. 1959-58. Passed 11-9-59.)