The tensile strength of wood is least affected by drying, as a rule.
In drying wood no increase in strength results until the free water is evaporated and the cell walls begin to dry[49].

This critical point has been called the _fibre-saturation point_.
(See Fig.

24.) Conversely, after the cell walls are saturated with water, any increase in the amount of water absorbed merely fills the cavities and intercellular spaces, and has no effect on the mechanical properties.

Hence, soaking green wood does not lessen its strength unless the water is heated, whereupon a decided weakening results.
[Footnote 49: The wood of _Eucalyptus globulus_ (blue gum) appears to be an exception to this rule.

Tiemann says: "The wood of blue gum begins to shrink immediately from the green condition, even at 70 to 90 per cent moisture content, instead of from 30 or 25 per cent as in other species of hardwoods." Proc.Soc.Am.For., Washington, Vol.