A Bowsaw will cut through a 10cm+(4inches+) Log using 1/4 Kcal of an Axe; which is a far more efficient tool than a big knife. Even using a knife and baton is not nearly as efficient as a good quality 50cm+(21inches+) Bowsaw.

Big knives may be good in the jungle to replace a machete, but they are very ineffective in the Northern Forest.

I would have to agree with you about the bowsaw, but respectfully, not so much the knife comment. Maybe 'overkill' but I don't see 'ineffective'....chopping holes in ice, prying, chopping branches, splitting wood, digging holes in the dirt and many other bushcraft tasks are easier with a large blade.

Here is one representation of a knife pattern (from Blade Forums) that was very popular in Canada and northern Minnesota from the fur trade era. It is the Hudson Bay Knife... The link will take you to some more of these beautiful knives.

http://www.bladeforums.com/forums/showthread.php/747098-Hudson-Bay-designs

Let form follow function.

Byrd..super knife.i have seen these in a book by Carl Russell about the tools of the mountain men.however in the era before good small saws could be made because of the metals and the proper treatment of those metals that a knife was easy to make and care for in the wild and yes it was a "do everything" tool.
Bruce Z..do they say Zed up in Canada like in the UK?..but anyway good info on the calorie count.thats the stuff i like to see on sites like this.

IMHO, it's a trade off. Chopping tools are more versatile and easier to maintain in the field, but are heavier, require more exertion, are more hazardous to the user, and require the work to be held rigidly or the flexing will absorb the energy of the strike. FWIW, that's my primary grievance with Nuttinfancy's Fiskars axe demo. He's chopping on the middle of a branch suspended in mid air and the thing’s bounding up and down like it's on a pogo stick.

Sawing tools do one thing really well. They cut through hard materials and are generally lighter, cheaper, safer and more efficient then choppers. The downside is it's harder to maintain and not as versatile as the big choppers.

Locally, the ecosystem is primarily chaparral with some conifer forests and riparian areas. My primary wood processing tools would be a brush hook (Kaiser blade) or a fine toothed pruning saw on a long handle.

Not sure how we're defining "big" but I will say this, I never carried a fixed blade until I became and ETSer, and even then it took time convince me that I need one. I always carry a a folder/multi-tool, but now I also carry a 4 - 5 incher when I'm in the bush. Bryd speaks the truth. They're just so versatile. I don't chop logs with mine, but I do use it to pry, dig, chop through ice, split branches to get dry kindling, etc.

Zed up here in Canada

Yes, that is a key point that has not been addressed in this discussion.

Another question to ask regarding "Calorie Burn" is how many extra calories you burn by carrying a "big knife" (whatever that is) around all day long? Or to think of it another way, what other useful item(s) could I carry for the same weight penalty as that 6 or 8 or 10 or 12 inches of steel on my belt?

Everyone's situation and operating environment will be different. Therefore people are likely to come to different conclusions regarding what knives to carry in the field.

In my case, my default is to carry a modest folder in my pocket, and a smaller lightweight folder in my junk bag in my pack as a spare. Since I live/work/play in a region which can have a very severe climate, I generally opt to use that additional weight to carry an extra insulating layer in my pack (rather than steel on my belt). I'm not a gram-nazi, but especially as I get older I like to at least consider the weight penalty of everything I carry.

If I expect to be using a lot of wood (as opposed to a stove), and/or I'm traveling in a mode where weight is not such an issue (kayaking, or pulling a sled in winter), I would opt for a bow saw and/or a small hatchet.

About the only time I carry a fixed blade is when hunting. In that case it is a blade in the 5-6 inch range.

I consider Big to be Two Definitions for knives. For Instance the Becker bk2, While its not a 10 inch blade its still a 1 pound Chunk of wide steel.

For me 4 and 7 inches are the breaking point for small/medium/large fixed blades. Obviously this is assuming the "normal" thickness and width for blade, not like the super thick bk2 mentioned above.