RE: Field Saw - Sagen?
That looks like a nice saw. You should also check out a regular old Stanley folding utility saw. I've been using one for a few years and it works perfectly. I have a pretty fine toothed blade on mine (there are various blades readily available and are replaceable). It's compact, light, CHEAP and easy to use. You can get them at almost any hardware store. Worth checking out as well.