Here is a great document with outstanding photos of a mapping project for the vegetation of the Alaska-Yukon Region by Fairbanks researcher, Torre Jorgensen and others. It is an attempt to refine vegetation classification systems using the latest technology.
Jorgensen, T. and D. Meidinger. 2015. The Alaska Yukon Region of the Circumboreal Vegetation map (CBVM). CAFF Strategies Series Report. Conservation of Arctic Flora and Fauna, Akureyri, Iceland. ISBN: 978-