Swelling gross wood

In the discussion that follows, the volumetric shrinking and swelling of the gross wood will be treated first, followed by discussion of anisotropy, and finally the effect of stress. 

Volumetric Shrinking and Swelling. The volumetric swelling of the cell wall of wood is proportional to the volume of water absorbed. The gross wood however contains air spaces therefore, its volumetric swelling depends on what happens to the air spaces during water sorption by the cell wall. 

On ammonia treatment, the gross swelling behavior and changes in the strength and the structure of wood are very similar to those observed during and after steaming of wood with water vapor. The changes described below refer to wood saturated with ammonia. 

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