Paragraph 33. The United States produces several varieties of birch trees, although it is hardly worth while to attempt to distinguish between them. The birch is easily recognized by its smooth bark. The outer bark cracks open and rolls back, leaving the inner bark of almost ivory appearance. It is this feature which makes it easily recognized. Every schoolboy knows that birch bark was valuable to the Indians in the construction of canoes. Wood of the birch tree is all of a fine texture, almost white in color and very hard. It is a beautiful wood and takes on a finish which causes it to resemble cherry somewhat, yet it is not so rich in color. When once thoroughly dried it holds its form well, although it shrinks badly during the drying process. Birch wood does not stand exposure to weather; for that reason it is used mostly for inside work, such as finishing lumber or cabinet work. It is recently gaining an important place in woodturning; shoe lasts, wagon hubs, and shoe pegs are usually made of birch. Considerable birch is used in the various lines of woodcarving. Birch is frequently used as an imitation for mahogany, and if properly treated a very excellent imitation can be effected because of the similarity in grain and general appearance.