Liriodendron tulipifera (tulip tree) is relatively rare in Michigan. I have one growing in the yard, but it was from a nursery. Actually, once they get established, they do grow well here. I raise Prometheus moths on the tulip tree leaves.
Most populars here are Populus Deltoides (eastern cottonwood). Good chance that is what you've got in WI too. Don't know if the bees work them or not.