Every now and then they’ll come across an ancient body in the bogs of Britain, tannin contained in the peat almost perfectly preserves the features.
Perhaps the pine box combined with tannins in the soil influenced the natural preservation.
Yeah... she’s not in a peat bog. Key ingredients for bog bodies: perennial low temperatures (Nope), nearby saltwater seas (nope), humic acid (nope), pickling effect on body (nope), sphagnum mosses (nope).
Missouri has had some pretty dry years lately - and there are places where the soil is some kind of PIA clay that can be quite impervious to water/air movement.