I collected up a truck bed full of logging slash from a newish clear cut a few miles down the road. Mostly red alder and maple branches about 1/2 to 1 inch (12.7-25mm) diameter.
The piles closer to the middle of the clearing should be much drier, as they get better sun/airflow.
I packed it into my modified/inverse Hookway charcoal retort and lit it up.
4 hours of constantly feeding it kindling later, I let it die out. Never had a self-sustaining flame in the chimney tube from expelled woodgas. Never burned off any paint from the barrel, even on the uninsulated top surface. (My insulation is on the inside of the barrel).
It's pretty obvious that the wood was still quite green/wet: about 20 minutes after the first firing, maybe a quart/liter of liquid water seeped out from my barrel lid (on the bottom no seal yet, just gravity and a ring clamp holding it shut.)
I'll try firing it again tomorrow after I spent all this energy driving off so much water.
Will post pictures and more words to a dedicated thread later.