A number of Boundary Waters Canoe Area paddlers pack this Irwin coarse cut saw for clearing Portage and camp areas, giving it great reviews. Somebody makes a sheath for it, but I don't have his contact info.

https://www.irwin.com/tools/handsaws/15-protouch-coarse-cut-saw

Irwin makes 15 and 20 inch versions.

Oddly, I once ordered the 20 inch coarse cut saw, but Amazon delivered the wrong model - Irwin's much more traditional hand saw. I returned it and never reordered the coarse cut saw.