Understanding intra-ring checking in Pinus radiata wood

Pinus radiata is the dominant plantation species of New Zealand. Sometimes it can develop wood quality flaw called intra-ring checking. The checks that appear in wood during kiln drying lower value of timber leading to loses for the forest industry. An exhaustive comparative study was conducted to see if the checked wood had some inherent properties that made it more susceptible to checking. It was found that checking could be influenced by tracheid geometry and cell wall thickness. If the wood had large tracheids with thin walls, it was more likely to develop checks during drying. Lignin distribution in the cell wall layers was also seen to play an important role in checking. Lower lignin levels and disruption in the pattern of lignification of the cell wall layers increased the tendency of the wood to develop checks. Similarly, if the tracheids had larger pits then their tendency to check increased. This study(funded by WQI Ltd, New Zealand) was undertaken as a part of collaborative work that was carried out to understand wood quality issues in Pinus radiata, with a vision of improving its wood quality.