I read Kephart over and over and over...and love him. And when I was a boy trapping muskrats and a teenager building a log cabin, I became somewhat handy and practiced with an ax and hatchet...and used a saw a lot also...

But assuming if you want such things at all for backpacking, which is the first item to consider....:a saw or a hatchet.?

My personal opinion, partly based on recent use of Sierra Saw.....and many years of no fire or reliance on "squaw wood"...is that a saw is clearly the first choice, based on weight-and benefit analysis.

Saws are notably more efficent for cutting firewood relative to hatchet... in my opinion.

Having both a saw and an ax, or maybe a hatchet, would be optimal for firewood cutting, if weight considerations are disregarded.
To say nothing of safety....