Sources
https://mdc.mo.gov/discover-nature/field-guide/elms
https://ufi.ca.uky.edu/treetalk/ecobot-american-elm
https://connecticuthistory.org/a-beautiful-and-goodly-tree-the-rise-and-fall-of-the-american-elm/
https://memorialmuseum.com/experience/the-survivor-tree/
https://archive.org/details/sixtreesshort00freerich/page/4/mode/1up
https://www.arborday.org/programs/nationaltree/elm.cfm
https://www.museum.state.il.us/muslink/forest/htmls/trees/U-americana.html
https://jefpat.maryland.gov/Pages/education/plants/american-elm.aspx
https://www.adkinsarboretum.org/programs_events/ipp/slippery-elm.html
https://www.srs.fs.usda.gov/pubs/misc/ag_654/volume_2/ulmus/rubra.htm
https://historycambridge.org/Cambridge-Revolution/Washington%20Elm.html
http://www.penntreatymuseum.org/treaty.php