I have been using a pruning saw for camping like the Corona RS-1720 instead of bow saws to cut firewood. There are any number of similar brands and styles available but Corona has an excellent reputation for fine tools.
A number of sportsman’s saws made along the same design are available, they are more expensive, shorter and straighter than pruning saws. The shape and length of a good pruning saw will cut a large stack of firewood much quicker than a sportsman’s saw. Smaller folding saws are lighter, however, and better suited for a backpacking trip.
Japanese pattern teeth like those on the Corona cut aggressively and quickly on the pull rather than the push stroke like western saws. Cutting on the pull stroke may take a little getting used to but I have found it requires less effort, lends more control and is faster. The model pictured here has a 13″ blade for wood up to about 8″ wide.
Corona 13″ Saw at Amazon