Well, I wouldn't normally build a "white man's fire" on a snag and then bivvy out. For an unexpected night out, I like a fire about the right size that I can feed it by hand without getting up and losing thermal energy. Burn a snag and you might have to set back 20' to get comfy.
Years ago, I was moose hunting up near the NW Territories. The tracked rig meant to get us to base camp broke down. I made a nice little fire and slept in my woolies pretty comfortably. One of my best memories of the hunt was waking up to stoke the fire and seeing an artic fox looking at me.
Hunting success is 90 percent hunter, 10 percent weapon.
