Lee, There are many tree options for your site. Currently you have all ash trees. Are you looking for one variety to replace them, or a multitude of different trees? Here is a list of trees I would suggest you consider. Serviceberry, Summertime Amur maackia, Weeping Katsura, Red Fox Katsura, Fringe tree, Japanese tree lilac, European plum, and 42 varieties of crab apple trees.

Here is a link to an article on trees and shrubs for Minnesota co-written by Julie: https://extension.umn.edu/trees-and-shrubs/trees-and-shrubs-minnesota-landscapes

Here is a more extensive list of woody plants, including deciduous trees, published by Urban Forestry Outreach & Research (UFOR). I don't see reference to whether they are Minnesota releases or not. https://trees.umn.edu/woody-plants-catalog

Paul

Tree Care Advisor volunteer

Lee, I see that Summertime Amur Maackia is a UMN release but other than that I am only aware of fruit trees, i.e. apples, plums, cherries, etc. and fruit shrubs, i.e. blueberries, raspberries, grapes, pears, etc. that have been researched at UMN. Here is a link to growing  fruits with many varieties listed. Buried in this publication you will find varieties released by UMN. They are denoted with a date in parenthesis, which is the year of release. I hope this helps, if not feel free to reply back for more information. https://extension.umn.edu/find-plants/fruit#stone-fruits-2394860

Paul