The item ID for Firewood in Skyrim on Steam (PC / Mac) is:
To spawn this item in-game, open the console and type the following command:
player.AddItem 0006F993 1
To place this item in-front of your character, use the following console command:
Firewood is an abundant item in Skyrim that can be sold to many characters including merchants, mill workers and innkeepers (for a price of 2-5 gold). You'll need either a Woodcutter's or Poacher's axe in order to cut down wood that is firewood. Firewood isn't just an item that can be sold to merchants, it's also an ingredient in crafting recipes, such as those for items such as arrows and bolts.