Look in your local area (yellow pages, classifieds, web, etc.) for lumber
mills, saw mills, hardwood mills or dealers. A good, straight trunk should
be worth some money as lumber or for veneer. I WOULD NOT cut it up until
someone has a chance to look at it.

Walnut in our area (Central KS) brings up to $6.00 a board foot, a little
less in SE Kansas, Arkansas or Missouri. As I said before, good straight
trunks might be valued for veneer. If it is good wood you might be looking
a a couple thousand dollars (or more). Act quickly.