This gorgeous piece of work is in the woods at Fallen Timbers. Let me give you some sense of scale. When I stand beside it (all of my five feet and nine inches), my head comes about to the middle of this gall. My fingers can just touch when I reach around the trunk of the (otherwise healthy) white oak tree it is growing on. This gall is easily three feet in diameter. That is one big chunk of gall.
I do not know the specifics of gall growth, though what I can find says they are caused in some way by insects that enter the plant and somehow stimulate the growth of the plant’s cells at a rapid rate. The insects then can live in the gall — or live one stage of their lives — safe from predators. I suppose some version of that has happened here. I’ve never seen any insects emerging from anywhere on this gall, but this oak is located in one of the more inaccessible areas of Fallen Timbers, and I would be less likely to hike there in the summer when insects are more active.
I know that some woodcarvers prize galls for their craft, but I don’t know how anyone could possibly get this gall out of our forest in one piece. First of all, the oak tree would have to be taken down. That alone might smash the gall. Then the gall would have to be removed (or the length of the trunk bearing the gall would have to be separated from the rest of the trunk). Then someone with super powers greater than my own would have to lift the massive gall into the bed of a truck, if a truck could even be lead down to this point in the forest. (Note: trespassing would be required.) And it may be that the gall is hollow or rotten or infested or otherwise unuseable. Who wants to go to all that trouble just to find out it’s a rotten gall?
I wonder if I have a record holder. Is there some gall registry I could check?
Here is a picture of the backside of the gall. Looks monstrous, doesn’t it?