According to my reference ("Log Rules & Other Useful Information" published by the Northeastern Loggers' Assoc.), the following species lose the indicated amount of weight when going from a green state to "air dried," which is defined as 20 percent moisture content. This is derived from estimates of the weight of sawn lumber. I got to thinking about this the other day during a discussion in another thread about how to figure out how dry your wood is. I think weight is the best indicator. If you take a green sample piece and weigh it and write down the result, you should be able to get a good idea of how much it's dried at any time by weighing it again and making a comparison. In this case, moisture content is the amount of water (by weight) relative to the amount of bone-dry wood. That's how wood moisture content is usually calculated, occasionally resulting in mc readings in excess of 100 percent for some species when green. Anyway: Beech - 24% Hickory - 27% Black Cherry - 28% Soft Maple - 29% Hard Maple - 30% Yellow Birch - 30% Red Oak - 31% Given the margin of error, I think it's safe to say that they're all in the 30% ballpark. Let me know if there's a species not listed that you would like a number for. When sawmills check mositure content of lumber in their kilns, they use a fancy (expensive) moisture meter which can be driven deep into the piece of wood. They also take their samples from the middle of a stack in the middle of the kiln. You should do your weight sampling from a piece in the middle of your pile, if possible. Firewood from the top and/or edges of the pile or stack dries faster and thus will not give you a representative sample.