This post is brought about from a link that was recommended by lonewolf. At that link & saw a popular image of an "all night burning fire". Now on a winters night an all night fire may seem like a good idea, & there are several ways of accomplishing this, but post shtf an all night fire in my opinion is not a good idea.
Any fire small or large, day or night has the potential to attract unwanted guests, so an all night fire is going to at least double that risk. Post shtf, there will be no safe wilderness areas, people will be on the move, raiders are opportunists & a fire glowing in the night or the smell of smoke will draw them like ants to honey. Because I am a living historian, my historical treks have to be as authentic as possible. Now even today there are risks in camping out, but back in the 18th century those risks were far greater. So I set myself scenarios. Some nights I have camped with no fire, this requires knowledge of how to stay alive in winter with little bedding, because bedding is bulky & adds weight to your pack. It also requires knowledge regarding what foods to carry, because with no fire, you can not cook food, so you need to carry some food that can be eaten without having to cook it.
Other nights I do light a small fire in a fire hole. This is a scrape in the ground to contain the fire surrounded by rocks back & sides. The heat reflects off the rocks back into my shelter, & they help hide the fire from prying eyes. But a small fire does not last long once I have fallen asleep, & at some time in the night the cold will wake me & I will stoke the fire from my supplies under cover behind my bed & from a supply of wood at the end of my shelter. Despite the fact that I am always mindful & therefore alert to sounds in the forest, this waking up from the cold is for me a security measure. It is an opportunity to look & listen to the sounds around me before I make up my mind as to whether or not I should re light or stoke the fire.
If I had placed a large log on the fire to keep it going all night I would probably sleep soundly, certainly I would not be waking frequently because of the chill seeping through my bedding. This would create a security risk, one because as I have already said, the fire would be noticeably visible from a distance at night, & secondly because I would not be so alert. Just something for you to think about next time you are camping out & practicing your skills.