Mass density

What is Mass Density?

Mass density or particle density of wood describes the density of the pure wood material without any pores or cavities. It measures how heavy the wood itself is if all voids (lumina) within the wood were compressed to be nonexistent. The mass density is nearly the same across all wood types and is approximately 1.50 g/cm³. This value relates to the chemical components of wood, such as cellulose and lignin, independent of natural pore structures or external factors.

Mass Density vs. Wood Density

Unlike mass density, wood density includes the mass of the wood along with its hollow spaces, which vary based on each wood type’s unique structure and porosity. Since wood density is highly influenced by moisture content, wood comparisons are only meaningful if their moisture content is consistent. Two standard measurement points are the absolutely dry state (0% moisture) and the air-dry state (approximately 15% moisture).

Classification of Wood Types by Density

The density of wood types can vary significantly and often serves as a criterion for determining their suitability in applications.

Below is a classification of wood types based on their wood density:

Examples of Various Wood Types

The lightest wood is balsa, with a density between 0.14 and 0.44 g/cm³. Oak, classified as a moderately heavy to heavy wood, has a wood density of approximately 0.65 to 0.80 g/cm³ and is widely used for construction and furniture. Among the very heavy woods are quebracho (1.12 g/cm³), ebony (1.18 - 1.33 g/cm³), and pockholz (1.20 - 1.30 g/cm³). These examples highlight the wide variations in wood density and related material properties across different wood types.

In Summary - Simply Explained

Mass density measures the density of pure wood material without any cavities and remains constant at about 1.50 g/cm³ across wood types. In contrast, wood density accounts for pores and voids and varies based on wood structure and moisture content.