Hi Michael Gibb i got mostly cotton wood from the saw mill, some times pine. im gessing the the moisture by the weight, because the cotton wood at 30 percent air dryed in about a year is supper light, this wood im burning has much heavyer, not sure the weight per size is too hard too calculate probbly. Im only estomateing the moisture content, dont have one of them wood moisture meters yet, though i am happy too have a clean burn type wood heating stove. since my top chimney plate was leaking i closed it off from the wood hopper. That was when it started not smokeing while running. so now i just shut the air inlet down and wait 1/2 hour too refill so i dont get smoke inalation while refilling, that works, later i may fix a different top plate chimney shut off design that dont leak or plug with tar.