I know the tree you're talking about. I hunted under it with a metal detector about ten years ago, but all I found was a brass box cover or something that I have never been able to identify.

The problem with finding relics on the Mansura battlefield is the large size of the "battlefield". I've known people who have searched for the "center" of the battlefield for years, and have never turned up any kind of concentration of artifacts. Then again, I have a friend who found a 6-pounder ball lying on the surface in his bean field a mile or so down the Hessmer highway, and the same fellow found a solid shot from one of Boone's Battery's guns while digging a hole for a water line over near the Marksville airport. The items you're looking for are scattered over several thousand acres, so there's a lot more luck than science involved.

I don't remember the title of the book, but will find out and post it here when I do.