Meant to mention, Amey, that isn't driftwood and its not mounted. It actually is part of the tree. I don't remember the name for that style but essentially what is done is bark is removed from a section of the trunk. That area is now basically dead. The dead area may then be sanded and shaped. If I recall correctly, the wood is then stained to give it the appearance of being old/weathered. I do not remember if any sort of sealant is then used to prevent molds from causing the exposed heartwood to rot away.