When you need to be sharp
Improvised bow saw.
One could easily make a bow saw if you have a saw blade. I sometimes carry one in a tobacco tin.
One could also carry one behind ones belt. Fastened With to small Chicago bolts or a long strip of duct tape.
Cut a suitable sapling, saw a inch long cut Down the middle of each end.
I have two bolts With nuts in my tin, but you could also use rope or wooden pegs. Put them trough the holes in the saw blade, and bend the sapling in an U-shape. Heat from a fire will help you bend the Wood if you have a fire.
The saw Works suprisingly well.
Another type bow saw
You could also make a little more sturdy bow saw with your saw blade.
The pictures below should be self explaining.
Some notes on making this saw.
This saw could be tricky to get "balanced". It is very easy to get a somewhat wobly saw that doesnt work well.
I`ve countered this With an extra support stick, making the stretcher piece an V shape.
One could also use Nails trough the handle sticks into the support stick if you have them.
A better way is to make real carpentry joints.