According to the previous owner, wind uprooted this red oak and it fell across the driveway. he cut off the piece across the driveway and rolled it into the woods with the rest of the tree. Then he pushed the stump back in the hole. The stem is about 22" where it's cut and flares to about 6 or 7 feet at ground level. What causes this?Looks like some good wood there waiting for me.