http://www.arborday.org/trees/wtit/

Use this handy guide to begin identifying those trees.
You can download it as a pdf for free.

You can identify most trees by studying their leaves, seeds, and fruit.
This animation will help you learn to identify these characteristics and take a “step-by-step” approach to arrive at the name of your tree.
Once you master these skills, it will be a breeze to identify any tree using our What Tree is That? Booklets or our online Tree ID Guide.

In order to view this animation, you must have the latest Adobe Flash player installed on your computer.
If you do not, you can download it for free from Adobe or by clicking on the “Get Flash” icon.