A barrel smoker can definitely be used on a wood deck.  You would just have to do it with safety and responsibility in mind.  Being fire conscious is always a good thing.  It would be just like operating a firepit, except without the open flames.  They sell fire pit pads you can put underneath to create a barrier between your wood deck and the barrel.  Or, you can opt to have wheels added to your drum purchase if it already doesn’t come with them.  Placing bricks underneath or setting it on top of firestone is also a good method too.  Find out more about using a barrel smoker on a wood deck