Abstract:
Wood shrinkage mainly occurs along two main directions: radial (R) and tangential (T). Volumetric
shrinkage measures the magnitude of the shrinkage. But T/R ratio measures the uniformity of the
shrinkage. This is very good indicator of wood’s stability. To be a good stable wood it must have both
low volumetric shrinkage and low T/R ratio. This study was attempted to identify the variations of
T/R ratio of 32 timber species in Sri Lanka in year 2019. The T/R ratios of 32 different timber species
were analyzed and classified into three classes based on the results. These classes are: T/R ratios
below 1, T/R ratios ranging from 1 to 2, and T/R ratios above 2. It was observed that a T/R ratio of 1
indicates uniform shrinkage. Timber species with T/R values ranging from 1 to 1.50 were found to
have stable dimensional effects and are thus recommended as good timber species. However, no
significant correlation was observed between the density of timber species and their radial
shrinkage, tangential shrinkage, or T/R ratio. To minimize defects when combining different timber
species in furniture manufacturing, it is recommended to use three timber groups that have been
prepared based on T/R values. This approach helps in selecting the best matching timber pieces for
the furniture making process
