Populus tremuloides

The Quaking Aspen is the most widespread tree throughout North America. This tree doesn't often reproduce using seeds but instead sprout up from the roots of already growing trees. The new trees are called clones. A whole forest of clones is just one organism. It is a deciduous tree that has pretty leaves that change colors before falling off in the fall. They cannot survive long floods or overly wet areas. Their bark can look a lot like that of the Paper Birch.

http://extension.usu.edu/range/Woody/quakingaspen.htm

http://www.arborday.org/treeguide/treeDetail.cfm?id=122

http://www.techtrees.net/index/trees/decidous/aspen/quaking_aspens/quaking_aspens_populus_tremuloides.html