Radial permeability of timber

A procedure is described for monitoring the uptake of
liquids under pressure, into small blocks of dry wood, Tests
with eight softwood species showed that rates of uptake in the
radial direction correlated well with the known treatability of
these species in relation to commercial pressure impregnation
with wood preservatives.
Several different patterns of radial penetration were
observed and it was found that the most important morphological
feature influencing these was the nature and condition of the
ray parenchyma cells, the crossfield pits in particular,
Examination of the structure of water-stored spruce
showed that the bordered pit membranes and tori had been
destroyed, probably by bacteria. It is suggested however, that
the main factor causing increased permeability in this material
was the partial destruction of some of the crossfield pit
membranes.
The possibility of developing biological pre-treatment for
the preservation of poles of refractory species is discussed.