It shall be unlawful for any person or firm to engage in the business or occupation of pruning, treating or removing street or park trees within the city without a certification from the International Society of Arboriculture (ISA). The applicant shall also file evidence of possession of liability insurance in the minimum amounts of fifty thousand dollars ($50,000.00) for property damage and five hundred thousand dollars ($500,000.00) for bodily injury, indemnifying the city or any person injured or damaged as the result of any endeavors herein described. An ISA certification shall be condition precedent to the issuance of a city business license as required by title 3, chapter 1 of this code.