you could go to the local supermarket in the summer.all the ones in my area of mn have hedge ball for sale in the summer months.
they are good for keeping spiders out of the house.
i live in the st cloud area.if i was you i would look for black locust,or being your south of the TC you may be able to find the occasional
hickory tree.i met a guy 2 yrs back that was from farmington and he had a farm in southern mn.he had a cut and seasoned hickory stave
that he gave me.he said it was from his farm in southern mn.or else ash,oak,hop hornbeam aka iron wood,apple,plum,crab apple,choke cherry etc.
good luck,let me know what ya find and if ya need help dropping them and splitting them,i work cheap,just ask for some for my own use.
i got a nice new chain saw thats just waiting to drop a tree or three