Tree Identification Field Guide. Our il.rated, step-by-step process makes it easy to identify a tree simply by the kinds of leaves it produces. Begin identifying .Single leaf identification. Or is your leaf composite like these? leaf of an ash leaf honey locust leaf tree of heaven horsechestnut leaf composite leaf identification.."CAUTION! --- Both Poison Sumac and Poison Ivy occur in Ohio. Read about them; know what they look like before you touch unknown trees, shrubs or vines!"..