I use the Silky Super Accel 210, Silky makes some of the best folding pruning saws out there.
Locks up tightly, no play, all metal, to my mind the best folding pruning saw made.
Perfect size, disappears in a backpack, small enough to carry in your pants pocket. I have cut 6" diameter Australian Pines in less than 2 minutes, which is completely bananas, not what a pruning saw was made to do, but...
The Super Accel has a metal body, strong enough for pro nursery work, can't recommend it enough. Blade change is a snap, and yes, you can actually get replacements.
A.M. Leonard is the only retailer I could find, not cheap, made in Japan, about $45, but it's the last one you will have to buy.
For hunting, clears lanes of fire in a second, cuts enough brush to break up your silhouette is a second, quietly, no chopping…
Sometimes you just need to cut ONE branch for your camp.
Perfect for your spotter walking an old trail that has overgrown slightly, carry it in your back pocket all day.
Keep one in my 4Runner box, with my jumpers, tie-wraps, hatchet, para-cord, Gorilla Tape, JB Weld…
Take a look:
http://www.amleo.com/silky-super-accel-folding-pruning-saw-825-inch-straight-blade/p/11921/