Field test of resistance of modified wood to marine borers

Abstract

The resistance of modified wood to marine borer attack was tested in a field test according to the European Standard EN 275. The wood modification methods were: 1) furfurylation; 2) treatment with methylated melamine resin (MMF); 3) acetylation; 4) acetylation followed by furfurylation; 5) acetylation followed by treatment with MMF resin; 6) maleoylation (using water solution of MG, maleic anhydride esterified glycerol, or organic solvent solution of maleic anhydride); 7) succinylation (with or without post-treatment with copper sulphate solution); 8) modification with reactive linseed oil derivative; 9) treatment with modified rape seed oil; 10) thermal modification in nitrogen gas (Le bois retifié); 11) thermal modification in fresh rape seed oil; and 12) thermal modification in modified rape seed oil. The wood species used for all treatments was Scots pine. The test specimens were put on the test rigs in a bay on the Swedish west coast. The marine borer (mainly Teredo navalis) activity at the test site is very high, always resulting in failure of control specimens within a year. Many of the modification methods result in modified wood with poor resistance to marine borers. In some cases the modified wood samples seemed even more severely attacked than the controls. However, some of the methods (furfurylation, MMF-treatment, and acetylation followed by MMF-treatment) seem to provide excellent resistance to borer attack.