I imagine with a good bed of coals in that thing, it would burn almost anything. Do you have an infrared thermometer? I would be curious how hot you could get it.

No thermometer but it's very hot work - it's like being in a sauna working around it. You can feel the heat radiating from the iron quite a few metres away. When you put a branch with leaves in it, they seem to spontaneously combust in a ball of hot air. It wasn't until I did my own burn that I fully grasped how clever the design was.