So lately, I've been burning that old dead oak tree I referenced in my last thread. It's burning real nice, but I've noticed that the ash isn't building up, and there more often than not is no coals left in the morning. I'm burning this wood almost exclusively, and before this, I was burning my usual mix of stuff, including oak, black & white birch, and a lot of maple. When I was running that stuff, the ash built up quicker, and there were more coals left. I'd just like to confirm that it's the oak causing this condition, although I can't imagine what else would cause it.