Jim Coulson, a board member of the Wood Technology Society (IOM3), is making short videos about wood with his grandson Spencer. In the first installment, we found out about wood grain. In the second they looked at the difference between hardwoods and softwoods. In the third, and latest, installment, they look at water in wood.
The amount of water in wood is (for wood products) expressed as the mass of the water, divided by the mass of totally dry wood. In the living tree the moisture content can exceed 100% by this measure – and can be more than 200% in the sapwood of softwoods.
Most of the properties of wood that are of interest for structural timber depend on the moisture content, so this is an important measurement. For a lot more information on this topic, check out the “American Wood Handbook” – it’s a fantastic free textbook.