I agree with BruceZed. For the majority of people, the large knife is a liability. A good Swiss Army with a saw and preferably a locking blade is much better. A saw in general is much better for most tasks involving wood anyway. Like any other tool (or weapon) it is only as good as the person using it, and if the person does not know how, it is dead weight.

I have carried large blades, mostly in my Army days, and they were not used for survival (or fighting) but as a tool. I abused my big knives (and broke K-Bars frequently), but always pampered my Swiss Army Knife.

Most young troops that I knew always had to go buy a large knife as soon as they reported into their units. The first thing they cut with it was usually themselves. My Boy Scouts are much better, they learn how to handle blades properly and carrying one is a privilege that can easily be lost. They show much more maturity with a knife. And we don't generally like for them to carry anything over 3.5 to 4 inches anyway.