Reply by Schwieb

That walnut nut inside the wood is too cool. The odds of that surviving and finding those boards is huge. Great find. I should check out ebay, but I prefer to find my own when I can. I would use a very clear epoxy resin to fill in the voids. You can machine and sand it without harming tools and it will be like you are looking inside the tree but the surface will be smooth. I’ve become a bit of an expert at this in working with spalted woods

-- Dr. Ken, Florida - Durch harte arbeit werden Träume wahr.