Dale, what species of tree do you recommend in Minnesota?
I would say red pine (Norway pine) would be good, it doesn't tend to have extreme taper, its not extremely heavy, easy to work, and strong. If you can find a stand of straight jack pine, that should be good too, but its usually branchy and tapered. I have seen really nice jack pine in places too. White pine sap stains bad, hard to find in the right size too, otherwise its nice to work with. White cedar is light and lasts long, but it usually tapers very fast, making for difficulties in the corners. We built ours out of white cedar, and the big butts and the small tops were very difficult to notch and fit tight.
I'm building my sauna with an old time summer kitchen attached out of red pine, cause that is what I have. I will have to line the sauna room with cedar or poplar, cause pine knots will burn you and drip hot sap in the hot sauna room.
My dad planted a few acres of red pine 50 years ago, and I need to thin the plantation.
I am going to build a hewn log building with Scandinavian scribe fit and corners. I'll get the foundation ready this summer and cut the wood next winter.
I don't remember the formula for shrinkage. I'll have to look it up, its different for different species. It might be 3/4 inch for 4 of vertical wall, but that might be wrong. You have to make telescoping flashing for brick or stone chimneys so the building can slide down the chimney as it shrinks.