Some notes on the effect of wet-storage on timber

The storage of logs under water sprays has proved to be a highly effective method to preserve logs over prolonged periods against drying defects and infestation by staining fungi. Wet-storage has little effect on wood quality apart from some degradation of the thin outer layer of the log, as well as an increase in moisture content. Strength loss seems to be rare and when it occurs it develops slowly. The only changes to the wood of practical significance are caused by the activity of anaerobic bacteria during the storage period. The porosity of the wood tends to increase while the colour of the wood might change towards a darker tinge. While a slight colour change might be problematic in some avenues of utilisation, the increased porosity could either be a friend or a foe. The increased porosity allows chemicals and moisture to diffuse quicker through the wood, making drying and preservative treatment somewhat faster and easier. However, difficulties have been reported which probably relate to differences in porosity caused by differences in bacterial activity within the log during wet-storage. These include differences in drying rates, causing differences in moisture content between and within boards at the end of a drying cycle, and uneven absorbance of surface finishing layers in pine furniture manufacture. P. taeda saw logs containing large amounts of abnormal compression wood, which were kept in wet storage for prolonged periods, yielded boards that were considerably less prone to distortion during processing. The wet-storage of eucalypt logs has proved to be a useful method of reducing growth stress related defects such as log splitting and board distortion. Wet-storage was also found to be an effective means of rendering susceptible timber more immune to powder-post beetle (Lyctus) attack. In general it appears that the advantages of wet-storage outweigh the problems associated with it which, in any case, can be dealt with relatively easily in practice.