The net interest or income from investments made of the fund created by ACC 3.04.090 shall be used only and exclusively in the care of the lots and in the improvement or embellishment of the cemetery or the erection or preservation of any buildings or structures, fences or walks erected or to be erected upon the cemetery or for the repair, preservation, erection or renewal of any tomb, monument, grave, stone, fence, railing or other erection in or around the cemetery lot or plat or for planting and cultivating trees, shrubs, flowers or plants in or around the lot or plat or for improving or embellishing the cemetery in any other manner or form consistent with the design and purpose of the city; provided, the expenditure of the income from the fund and the purpose for which it is to be used shall be first authorized by the city council and such authorization entered upon its minutes. (1957 code § 1.36.033.)