It's about the weight of the dry wood in the appliance folks. That's where your heat comes from. There is no heat gain in boiling the water from the wood.
Controlling the heat output of your appliance by using green/wet wood is wasting the potential heat that the green/wet stuff could have made for you if it was dry.
If you have enough time, and access to enough wood, that burning half of it off just so that the other half might give you some heat, you have more time and wood than I do.