Sky Pup, Not being in 3 D I can't tell from the pix but in some it looks like the heat would be getting to the overhanging branches.
Ideally a fire is not out till in the words of Smokey The Bear, it is DEAD OUT. When you are doing a controlled burn of 40 to 400 hundred acres and downed logs and dead trees are involved you don't have the luxury of ensuring that there is not a glowing ember somewhere.
About the best you can do from a practical standpoint is to exercise management by exception which is where you concentrate your management effort on the exceptional cases and let the not so important go less attended, a rationing through priorities, not unlike triage.
The goal is to get a nice wide "Good Black" all around the perimeter by employing various controlled burn techniques as applicable to the particular circumstances. The next priority is to get as good a burn as possible within the area surrounded by this good black.
Typically, man power limitations are such that you can't keep a close watch on everything all the time, especially as some of the stuff may smolder for a couple days or more. This is why it is so important to get a good black all around so that any changes in wind speed or direction will not let the fire out of the established perimeter.
So far the smallest contingent on scene during the most active portion of a controlled burn in which I have participated has been two tractors with spray rigs, 3 each 4 wheelers, and 2-3 drip torches. Some of us wear more than one hat and you may work a drip torch for a while and later drive a tractor to respond to potential problem areas identified by your radio equipped "eyes on wheels" (two of the 4 wheelers who do nothing but ride around to look things over and report via radio.) We have some truck mudflaps on long poles for beating on fires, rakes, shovels and such too.
The standard accepted rate of pay for showing up and participating several hours is the expectation that you can get the same help when you need it, plus cold Gator Ade, sodas, snacks, and an offer of an all you can eat catfish dinner the next Friday night at the local emporium of fine food.
The burn pile location I am using repetitively is in my back yard. The house is surrounded by a circular drive (firebreak) and the burn pile is backed up to two ponds within garden hose reach of the nearest hydrant. There are only a couple possible avenues where the fire could potentially get out of the containment area and those can be hosed down.
A large hot fire sends columns of embers pretty high so I have to mind the weather pretty closely and wait for rain or heavy dew and high humidity as well as low wind with a northern component in it (keep smoke away from house and fresh air intake ducts.) We are about to get rain and or snow in the next two days with temps dropping from overnight lows of 65F to the teens day and night. This will be a good opportunity to torch off a really big burn with 20-30 dead trees over a foot in diameter plus a lot of smaller stuff. I am consolidating brush piles to feed this one.
Pat