The deal with wood-gas stoves is 'secondary combustion'.

As has been noted - in an open fire wood gasifies and the burning flame is in the gas - not on the wood.  I guess you'd call that the primary combustion - and it generally isn't all that efficient or hot, and tends to be sooty.

Secondary Combustion / Gasification burners have
 - a primary fire chamber
 - an introduction of heated air after the primary chamber

The secondary air at the output of the primary chamber results in a flame that more completely burns the wood gas - hotter and more effienciently.

I've got a fireplace insert that pretty much does that - she burns very hot, and doesn't use much wood.  My buddy put in a external wood-fired boiler that really only uses primary combustion - he's thinking about re-working it with baffling to get some secondary combustion to work.

I've played around with some coffee canish stoves trying to get a good burn - but haven't gotten around to adding a fan yet.

There's not too many fire setups less effiencient than a BWCAW official fire grate....

You don't just have to burn wood gas - you can actually run combustion engines with it.