Easily Identify the Trees You Find! This essential guide by celebrated ecologist May Theilgaard Watts helps readers identify native (and some widely introduced) trees of the United States and Canada, east of the Rocky Mountains. With this handy, easy-to-use guide, you'll be able to identify all sorts of trees in no time. Features include: A dichotomous key, leading the user through a series of simple questions about the shape or appearance of different parts of a tree Includes 161 species Illustrated with line drawings Small (6- by 4-inch) format that fits in a pocket or pack to take along on a hike