The Quaking Aspen, Popple, Poplar, or which ever name is popular in your area. It is a common species for most of the state and in cold weather parts of North America. The Aspen is a pioneer species and thrives in areas of disturbance, usually repopulating new shoots up from it's roots. In new clearcuts there will be a thick forest of small trees(Popple Whips), that eventually thin out and give way to longer lived trees.
The Aspen wood is soft and it's highest value is for pulp or furniture. It rots quickly and does not work well in outdoor construction.
In the summer months you know when there are Aspen nearby by the unique sound that their leaves make in the wind. It is on of my favorite sounds.
http://plants.usda.gov/core/profile?symbol=potr5