Dimensional Change with Time of Green Increment Cores Taken for Growth Stress Measurement


  • A. P. Wilkins
  • R. K. Bamber


increment cores, growth stress, Eucalyptus pilularis, Pinus patula


Cores of green wood taken from Eucalyptus pilularis and Pinus patula trees with a standard 5-mm increment borer reduce in diameter with time. This reduction occurs in both the longitudinal and tangential axes. The rate of reduction is exponential and is at a maximum immediately after sampling, cores reaching a constant diameter in about 24 to 48 hours. In some cases the reduction approaches 0.05 mm and is considered to be a significant variable where such cores are used for the Polge/Thiercelin method of growth stress analysis. As this reduction was not reproducible in cores taken from rewetted dry wood, it is considered to be due to growth stresses rather than the cutting action of the borer.


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