Once a prominent urban and riparian species, the American elm has faced significant population decline from two severe pandemics caused by Dutch elm disease (DED). Over a century after the arrival of DED, the US Forest Service is planning seed farms of resilient wild populations to be used for reintroductions. This study aims to bridge the knowledge gap surrounding the historic genetic structure of American elm populations by identifying geographic features associated with population groups to develop an appropriate seed-sourcing plan for restoration. We are using both herbarium and surviving elm specimens to investigate the genetic diversity of American elms. 

We expect the genetic structure of elms to be associated with watersheds, so the REU student will investigate the genetic diversity of elm before and after Dutch elm disease in the Great Lakes watershed and the Upper Mississippi watershed. The student will gain experience in DNA extractions from fresh and old leaf samples, next-generation sequencing methods, and data analysis. There is a possibility of assisting with field work and visiting a herbarium to collect more samples, if the student is interested.