surface tension causes the wood to remain on the surface of the water, and is a result of the cohesion of water molecules being stronger than the force of the wood on the surface
Thats odd my answer didnt get published stranged, anhow what I was saying is that due to the surface area and mass of the tree is has enough bouyency to stay afloat because of the surface tension on the water with the tree.
Good question! Hamburgers actually get their name from Hamburg, Germany, home of a cut of beef called the Hamburg steak that eventually evolved into what we now consider hamburgers