re: the test
What its like depends on what you know and what you have seen and read. It is 200 multiple choice questions with a section on tree ID from a visual reference ( could be pictures, samples etc) Read and learn the study guide, read and learn the book "Arboriculture..." by Harris, Clark and Matheny. Get some experience, touch trees. Take the test and if you don't pass it first go round, re-take the sections you miss. To take the test you need a reference from an employer of sorts with a statement of hours in the tree industry, I think the minimum is 2000, might be 3000, sorry don't remember, it is probably on the ISA website.