Forgive me for the length:
I watched a show once, likely on PBS. A man tried his luck as a treasure hunter. Had SCUBA gear and looked for Caribbean shipwrecks. No joy. He was relaxing in his (IIRC) Northeastern US hometown and enjoying some SCUBA time in a neighborhood lake. He noticed the bottom of this fairly brackish lake was littered with logs. He did some homework and learned this lake had been used as a holding area for timber when the nation was young. He discerned that these logs had simply sunk to the bottom because of their density. The local sawmill had no interest in logs that would not float. Now let's go backward in time....
Antonio Stradivari and other violin makers used to put select wood under water for a time before using them to make instruments. Years, not months, are needed for this. This practice survives today. The airliess environment somehow seasons the wood striations to make the more resonant. There is underwater wood today, waiting.... The airless environment somehow seasons the wood striations to make them more resonant. Now lets move back to modern times....
Treasure Hunter got a permit to mine those logs. In the video I saw, they brought a log to the surface and placed it onto a bandsaw jig. This log was maple. It was about 3 feet in diameter according to my imperfect recollection. It was black. They did some measuring and made a horizontal cut, exposing about an 18" wide straight slab of wood. The wood was a gorgeous honey color. The entire log was packed with birdseyes at least as big as my thumb.
Treasure Hunter found his treasure.