ISA Ontario is a Chapter of the International Society of Arboriculture. On average, we represent just over 1,000 members. We are a volunteer-based organization with our office administrative services located in Milton, Ontario. ISAO HEAD OFFICE For all member and general public inquiries on any ISA Ontario Chapter or arboriculture-related issue, contact¬†Admin at: 7856 Fifth Line South Milton, Ontario L9T 2X8 Ph.¬†1-888-463-2316 or 416-493-7022 Fax 1-855-329-4726 (1-855-FAX-ISAO) [email protected] Emails sent using the form below are automatically forwarded to the ISAO office.