Online Resources
Know Your Trees – Cornell
http://cortland.cce.cornell.edu/resources/know-your-trees
Tree Anatomy Manual: Twigs – University of Georgia
Winter Tree Identification – Champaign County Forest Preserves
https://www.ccfpd.org/Portals/0/Assets/PDF/WinterTreeIDpocketguide.pdf
Winter Tree Identification Key – Leafprogram.org
http://www.mntreesource.com/uploads/2/0/7/0/20706756/winter_tree_id_key.pdf
Northern Forest Atlas Woody Plants Chart
https://northernforestatlas.org/2016/07/16/woody-plants-chart-in-winter-colors-two-sided/
Virginia Tech Dendrology
http://dendro.cnre.vt.edu/dendrology/twigkey.htm
Ohio Plants
https://ohioplants.org/twiginfo/
Depauw Nature Park Field Guide to Trees
https://www.depauw.edu/files/resources/brochure—nature-park-trees.pdf
Books:
Woody Plants in Winter. Core & Ammons.
Bark: A Field Guide to Trees of the Northeast – Michael Wojtech
Fruit Key & Twig Key to Trees and Shrubs – William Harlow
Video:
Six trees you can identify by smell. Adam Harritan. Learn Your Land.