Here are additional Tree Identification web sites that may prove useful in studying for the Invitational tree identification contest. Click on the yellow icon to link to the specific Tree Identification web site.  Use the 'Back Arrow' on your web browser to return to the Invitational web site.

USDA NRCS Plant Database -- Good source of pictures for Identification (once in this web site, click on Factsheets in the left column and select a tree from the list of species)