Are Rays and Resin Canals Causal Sites for Intra-Ring Checking in the Wood of Pinus Radiata?

Abstract

Pinus radiata D. Don (radiata pine) wood can develop a wood quality defect called ‘intra-ring checking’ (checks) during kiln drying. A study was conducted to examine if rays and resin canals were the initiation sites of checks, and if the presence of the rays and resin canals increased the susceptibility of radiata pine wood to checking. The structural features associated with checking were observed in images of thirteen oven-dried radiata pine disks. Six of the sixty checks observed were associated with rays and resin canals. It is clear from the observations that rays and resin canals could not be the primary sites for check development. A comparative study showed some differences between the checked and non-checked wood with respect to rays and resin canals. Checked wood showed a higher amount of tissue area occupied by rays than the nonchecked wood. Hence, it is possible that rays can influence the tendency of wood to check. Such a relationship was not seen with respect to resin canals. However, a difference in the arrangement of resin canals was observed between checked and non-checked wood. Checked wood showed a scattered arrangement of resin canals, while the non-checked wood showed a linear arrangement.