Someone on this forum mentioned a guy who was building an airplane with oak spars and longerons instead of spruce as written in the plans, oak seemed stronger to this novice builder. Apparently the empty weight exceeded the MTOW so the airplane was beautiful but never managed to take off and fly. Even boats which need to be light have some ribs made of ash for additional strength. Some wooden airplanes have reinforcements of ash but not oak which is considered too heavy. Whoever has the chance to see a comparison chart of wood properties can notice right away that oak in fact is NOT that much stronger than spruce for it's role in an airframe. But hey, what the hell, if the guy wants to build an airplane made of oak it's his choice. A time and money consuming one, without a guarantee for flying. In that case shrinking of the wood should be the least of all concerns.