The number of chunks that you require to smoke ribs depends on the smoker that you are using. Some use wood as their primary heat source whilst others do not. If your smoker does not solely depend on the use of wood, you will likely find 2 to 4 chunks of wood sufficient when smoking your food. Of course, when using another type of wood such as wood chunks, you will need to add around 10 to 12 ounces to your smoker.
When determining how much wood you require, you must also evaluate the size of the chunks that you are likely to use. For prolonged burning, you will require larger chunks of wood, as they will last longer. You may also need to replenish the wood chunks as they burn if you are cooking for multiple people over a prolonged period.