Specific Gravity of Wood

Specific gravity is defined as the ratio of the density of a substance to the density of water. Basically, any material with a specific gravity of higher than 1.0 sinks in water. Note that the definition of specific gravity for wood is different from other materials.

Specific Gravity Calculator
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Wood specific gravity may be referenced to the specimen’s volume at any moisture content VMC , but only based on oven-dry mass movendry .

specific gravity of wood formula equation calculation

Since the volume of wood changes based on moisture content, specific gravity varies depending on moisture content. That is why it is common to mention moisture content along with specific gravity. Many sources express specific gravity of species in their green state, which is called basic specific gravity Gb . Having the percent volumetric shrinkage from green condition to desired moisture content SMC , it is possible to calculate the specific gravity of the material at any moisture content GMC .

timber specific gravity of wood formula at a certain moisture content

The presented calculator extracts percent volumetric shrinkage values from our database. In the case that the value is not available in our database or custom basic specific gravity is used, the calculator uses the equation below for estimating percent volumetric shrinkage from green state to oven-dry moisture content (S0).

percent volume wood shrinkage formula calculations