A length of bi-directional chainsaw chain with a handle on each end. Loop it over the limb, pull alternately, and it cuts.

This is the tool that handles the log a hatchet cannot. An axe is for splitting; a saw is for cutting through. A six-inch limb takes a couple of minutes with this and ten minutes of bad swings with a hatchet.

No engine, no fuel, no bar oil, nothing to maintain. It rolls into a pouch the size of a fist and weighs almost nothing, which is why it ends up in a recovery bag or under a seat permanently.

Also the right tool for clearing a downed limb across a trail when turning around is not an option.