Why we couldn't turn wood to charcoal

Sorry about the failure last week - yes i don't think we let enough oxygen into the kilns so the fires went out...the theory is that the oxygen is limited so that not all the carbon turns to carbon dioxide...but there's no smouldering without oxygen (as the saying goes). anyway i've checked it out and fingers crossed we should do better tomorrow...if not i will abandon my plans to live in the woods. Will try and post some more techical info, or links to other website once i've found some.