We’re from Northern Michigan too. Beech is a good easy to find option.
Besides Beech, so far we’ve collected and used Magnolia (my favorite), Walnut and Mulberry. Our shrimp devoured the Mulberry once if softened up a bit.
I usually boil for ~10 min. They can take a day or so to sink.
The leaves get a nice biofilm that is grazed on by our snails, shrimp, guppies and ricefish. We also use them to make a leaf litter bed for a pair of wild type Betta hendra.