"How does cooking on a woodfire and leaving a small pile of ash (which is likely buried), or small fire scar if you will, compare to landfills full of empty steel canisters, Japanese titanium factories, chemical factories, propane production..."
I certainly have no problem with subjecting all stoves to the same criteria. That alone should put canister stoves out of business or at least force mfr's to charge a deposit large enough to guarantee return for re-cycling. However, I doubt that a fully enclosed wood stove would lose to an open campfire if only owing to risk reduction.
I think human impact is an inevitable product of our existence, and the best we can do in the near term at least, is manage it. The minuscule increase in titanium or steel production and concomitant environmental impact is more than balanced by the reduction in damage -- elimination of fire scars and virtual elimination of campfire-caused forest fires -- a fully enclosed stove affords to the lands we've set aside for protection an preservation.