Invasive, no wildlife value & most elm will die before they get really big anyways (dutch elm's disease). I'd prefer putting oaks in their place and using the elms to create a nasty thicket after I cut em otherwise. Partially opinion here but, in my case, I almost eradicate them, replacing them with desirable oaks, (I'm starting to do chestnuts now), wildlife trees or timber value trees and other good trees we need more of in IA.