Wood-boring crustaceans and bivalves can cause severe damage to wooden structures in the marine environment, warranting the need for novel protection systems, such as chemical modifications. Furfurylation increases mechanical properties and resistance of timber species that would usually be susceptible to biodegradation by these borers, such as pine. In rapid laboratory and field testing, furfurylated wood reduces settlement by the wood-boring bivalves, shipworm, and the feeding rate of crustaceans, Limnoria. Rapid laboratory testing using Limnoria can be used to supplement longer, standardised marine tests, such as those outlined in the European standard EN275, and provide early indication of product performance. It is difficult to determine the mode of action of resistance to Limnoria attack and the extent to which different factors affect durability. A combination of the chemical modification disrupting digestive enzymes and increased hardness may interrupt feeding and/or digestion. Hardness will only affect Limnoria on a nano-scale due to the size of their mouthparts, so testing of wood hardness should also be measured at this scale. Exploring the use of nanoindentation, as a method to test wood hardness after saturation with seawater, may be beneficial for products designed for marine applications, in order to mimic the cutting mouthparts of Limnoria. After long immersion times in the sea, water-soluble extractives will leach out and microbial colonisation can begin to occur, softening the surface layer and may reduce protective effectiveness of the treatment over time. Nanoindentation was used to measure the hardness of furfurylated, Pinus radiata sticks that were exposed to Limnoria in laboratory, forced-feeding conditions. Sticks were exposed for short and long time periods (five weeks or one year) to natural or sterilised seawater, to examine the effects of immersion time and microbial degradation on wood hardness, and how this might correspond to the ability of Limnoria to feed. Softening by leaching time or microbial action was not found to be a factor in reducing feeding by Limnoria in this study, however, the increased hardness from furfurylation did correlate with a lower vitality and faecal pellet production.

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