Folding saw...
Very seldom need a saw when out & about in the woods. Have a Gerber saw/snipper combo for brush trimming around a blind/shooting lane. The snipper broke & I replaced it, but the Gerber saw is good for easy, small, few & far between sawing jobs. Very agressive teeth; handle with care.
For in-camp use, to actually prepare firewood, the best saw IMHO is an old-fashioned wood framed bucksaw. These take down easily, with a turnbuckle tightening arrangement, and the blades are heavy enough to not turn and misdirect. (My chief complaint about more modern D-frame saws, with razor-blade-thin blades.) Blade can also be sharpened with a small file, if needed. Taken down, a bucksaw does not occupy much space in one's truck. Be careful not to lose the 2 pins which hold the blade.
AFAIK, bucksaws are no longer made, however they can often be had for not much $$, at farm auctions. Antique dealers are another source, however, if something is in the hands of an antique dealer, it becomes rare, precious, and expensive. Even if you have 2 just like it at home.