Chainsaw ?

TxGearhead wrote:
A bowsaw works well, but...if you already have a set of cordless tools...drill, impact, etc., look at that brands sawsall. I've got Dewalt cordless tools and their sawsall. It worked well to cut a 6x6.

Nearly as quick (in my experience, at least) for firewood cutting and pruning as a reciprocating saw (Sawzall) is the Corona razor tooth pruning saw. It's a lot quicker and so easier than a bowsaw, and quite reasonably priced. The reciprocating saw, at least for me, tends to bog down on things much larger than an inch or so because the stroke isn't long enough to clear out the accumulating sawdust.

A decent real chainsaw is, of course, a whole lot faster than either one.