Welcome climber Jay, here is a simmilar thread,
http://www.arboristsite.com/arborist-101/85038.htm
I read and did the ISA Certified Arborist study guide (S. Lilley), A New Tree Biology(Dr Alex Shigo), Tree Climbers Companion,& To Fell A Tree(Jeff Jepson), the ANSI Z133 safty standards for tree care, ISA best management practices Pruning,Planting, NAS Field Guide To Trees, western region, Temperate Zone Pomology, the Texas Forestry web site on Tree ID, also read up on HAZ COM, there were a couple questions I missed on that, it is all on OSHA site long boring read, need to know for aplicators license, some of the Tree ID questions had common and scientific names but a couple had only Genus and no specific epethit and no common names, it is by region but Texas was concidered a region, go figure, that was my lowest score tree ID, higest was soil science, I filled out the answers on the work sheets after each chapter on a blank paper so I could go back and test my self later, also I took the San Antonio Colloge study guide prep class that was 8 weeks every Friday, was real rushed but it helped, and they let me borrow the 10 dvr ISA basics of Arborculture set,(they are pricey but also have CEU at end of each section) and those helped a lot, the problem with the cd and the study guide questions is they are all on one subject at the end of the review or chapter and thy are black and white stand out easy 3 wrong,1 right, easy
On the real test they are all mixed up and there are alot of grey answers you really have to answer the exact question, hope this helps and good luck.
Paul