Density (weight

per unit volume) is

probably the single most

important indicator of

strength in wood and may predict such characteristics as hardness, ease of machining and screw and nailing resistance.  Dense woods generally shrink and swell more and usually present greater problems in drying.

Density is expressed as weight per unit volume and customarily is the weight of one cubic foot of 62.4 lbs. per cubic foot.  A wood weighing 37.4 lbs. per cubic foot is six-tenths as heavy as water and has specific gravity of 0.6 (divide 37.44 by 62.4).

Woods weighing over 62.4 lbs per cubic foot or a specific gravity of 1.0 weigh more than water and will not float.

Specific gravity varies depending on green weight or oven dried weight (no moisture content)

U.S. Hardwoods

Specific Gravity is based on the weight when oven dry and the volume when green or at 12 percent moisture content.