Nice biochar kiln. I may make one at some point, but the pit method works pretty well too. I'm not too worried about getting less biochar, wood is abundant here. This was a quick and easy approach. I still have a large amount of char.
If I wasn't burning wood that was 7-10 feet in length, I would have tried a dryer drum set on the ground to plug the holes. It works as a great burn barrel when off the ground. I like to build things out of pallets and bedframes, so when I have a pile of scraps this burns it up fast.

