Wood Planks are the easiest non-natural block to obtain during the beginning of a world. They can be created by putting a block or more of wood in the crafting grid. When that is done, four wood planks are given per piece of wood. It appears as a series of interconnected planks. It is good for creating a support style for buildings and also making huts and shacks. Wood planks are a renewable resource. Despite being easily burnt down, wood is easy to obtain in biomes where trees can be found and thus useful as a building material. It can also be found in Creative Mode. Naturally generated wood planks can be found in Abandoned Mineshafts, and Villages. Oak wood planks are used in Villages and Mineshafts, and pine planks are seen in swamp huts. Wooden Planks can also be found in Bonus Chests. The bonus chest has a few pieces of wooden planks. (About 6 or so)
Wood planks have a wide array of uses. They are good for giving buildings and homes a cabin-like appearance. They're the essential material to making the most basic of Tools as well. Aside from tools, however, wood is a vital material to those beginning the game and attempting to survive. Other uses for wood include: Sticks, signs, doors, pressure plates, slabs, pistons, crafting tables, chests, stairs, bowls, boats, fences, jukeboxes, Note Blocks, bookshelves, beds, and fuel for furnaces. It is not advised to have a fireplace unless you can be assured that your wooden house will not burn down. Try putting non-flammable blocks around your fire area.