Relationships between shrinkage and specific gravity in the wood of Eucalyptus.

Summary

Thin sections of previously undried, collapse-free wood from Eucalyptus regnans demonstrated a positive relationship between shrinkage (S) and specific gravity (p) but a significant regression constant. It was shown that this lack of conformance with the traditional relationship S=f/7, where f may be regarded as a statistical constant equal to the fibre saturation point, derived from high variability in the measured fibre saturation point (Ip) and its negative relationship with specific gravity; this was manifested by a negative relationship between shrinkage from green to 17% EMC and specific gravity. When Ip was regressed against f (=S/p), the relationship was not significant, thus suggesting that f was not a good indicator of fibre saturation point. While the unit shrinkage-specific gravity relationship complied in principle, shrinkage after reconditioning was not significantly related to specific gravity, thereby confirming previous analyses for eucalypt blocks and further limiting the applicability of the S=fprelationship.