It shall be the duty of the park board either directly or through the city forester to encourage the planting of trees within the city and to recommend the kind and character of trees to be planted which are suitable to the soil and will furnish the most practical results with a view of yielding shade and being ornamental in their nature. The city forester shall be courteous and attentive to the public in seeking advice and in aiding and assisting the public as well as encouraging the public in the planting of the proper kind of trees. No member of the park board nor the city forester shall be interested directly or indirectly in a pecuniary manner in selling or marketing any shade trees required to be used by the public but nothing in this section shall be construed to prevent the park board or the city forester from giving proper advice as to the kind and character of trees to be planted and the time when such planting shall be done and all other information that may be necessary for such purposes. (Code 1941, Art. 147-3; Ord. 8020)