DocCanada is a local expert around the Great Lakes Areas. I'm interested in improving my wild edible skills a bit more this spring. One of my favorite books at present is Samual Thayer's - The Forager's Harvest. Why I like this book so much is it goes into a pile of detail for 30 or so plants and shows photos and provides I.D. at different growth stages, what parts are edible and how to process them. Most edible books have a tonne of plants, but the I.D. keys often involve flowering parts (which are often not coincident with when the plant is edible) and very little information about how to use them.
As for trees, there are several great books out there. One thing that is really helpful is if you have a frequent walk area, get to know a few different types of landmark trees in your forest and return to them during different seasons, just so you get a feel of their characteristics. Especially in the winter. Also, having some application of your knowledge to trees really helps. For example, learning bowdrill techniques really helped me to identify different species useful for this application and I began looking for identifiable traits more often then just walking around the forest. Trying to understand the characteristics of wood for carving or firecraft also provides a good inertia of motivation for learning species identity.
