The Apple iPhone and iPod Touch application market has exploded with thousands of great educational references. Two North American tree identification applications are now available that I think are worth considering for purchase. The Sarafax TreeBook app promotes 100 common trees for beginning leaf identification - the perfect student companion. Audubon's Tree Guide has an extensive North American tree database available for the tree savvy.
The Sarafax TreeBook is leaf based and developed for students unfamiliar with tree identification. It is designed for use as a student guide using trees with leaves as primary markers. The app provides a system similar to the one on my About Forestry site for identifying the 100 most common trees found in North America with images, descriptions and links to more information. It supports a leaf key and provides a glossary for finding trees using common tree markers. The iTunes price is $1.99US.
The Audubon Tree Guide was developed for people more familiar with trees and includes more botanical jargon used in identification. It is an exhaustive database, developed as part of the famous Audubon Guide Series, that includes nearly every tree found in North America, with images and descriptions. It supports a search function for finding trees using dozens of tree markers and well worth the extra change for tree hobbyists and tree experts. I purchased this app and thought it adequate for those who already have some tree identification experience. The iTunes price is $9.99US.
I want to make it clear that I was involved in the technical development of TreeBook which took the designer and I nearly a year to complete. We struggled to make it student-friendly and available at a fraction of the cost of other nature identification apps.