Minecraft wiki entry for The_second_day, associated text: You can build with wood, and converting the logs to planks quadruples the number of blocks you have to work with. However, wood has two liabilities: First, it is flammable, and lava or lightning can start a fire that can destroy much of your house. Secondly, it has low blast resistance, so if a creeper explodes near a wooden house, it can demolish a good deal of work and perhaps damage the inside of the house as well.