Quaking Aspen

 
Populus tremuloides

Quaking aspen, Populus tremuloides. By Scott Catron (Own work) [GFDL (http://www.gnu.org/copyleft/fdl.html), CC-BY-SA-3.0 (http://creativecommons.org/licenses/by-sa/3.0/) or CC-BY-2.5 (http://creativecommons.org/licenses/by/2.5)], via Wikimedia Commons

Populus tremuloides

Common names: 

Quaking aspen
Trembling aspen
Golden aspen
Trembling poplar
White poplar
Mountain aspen