Minecraft wiki entry for Planks, associated text: Planks are used in many crafting recipes. Doors, fences, fence gates, slabs, stairs, boats, trapdoors, pressure plates, and buttons must be crafted from planks of the same type, and the crafted result depends on the type used. For other products, planks of different types can be mixed freely and the wood types in the product is indeterminate. Crimson and warped planks cannot be used to make boats.