I thought this was a really good idea for a quick, emergency shelter- winter or otherwise. http://paulkirtley.co.uk/2015/emergency-winter-survival-shelter-forest/ I've slept out with long fires, lean-tos and raised beds- a very effective shelter, but really (really) time consuming. In many scenarios (most?), you simply won't have time (or maybe the energy or both) to construct such a time/work intensive shelter. But, finding a spruce or similar tree with low hanging branches is usually not a problem- at least in northern climes. Add some boughs for insulation underneath, add some additional branches to the tree if needed, start a small fire and voila- you don't die I'm going to give this a go this late fall/winter.