The idea is simple. When you look at all the natural situations. One situation that I come to think about is when wood is touching water. Specially what happens when wood and saltwater come in contact. I wonder if the properties of wood has evolved to make itself useful for such situations.
So the question is. What benefits does driftwood have other than providing shelter and food. I mean stuff washes up on beaches so maybe its has something to do with cleaning the ocean.