IRG/COIPM INTERNATIONAL MARINE TEST - to determine the effect of timber substrate on the effectiveness of water-borne salt preservatives in sea-water: Final report
R A Eaton
Three timbers chosen as reference species were treated with 3, 6 and 10% solutions of CCA and CCB preservatives and exposed for up to 93 months at 8 tropical and temperate marine sites. Eleven local species treated in the same way were exposed at 4 of the 8 sites. There was no apparent difference in performance between CCA and CCB treated specimens. The severest test site was Panama Canal but marine borer damage of specimens was recorded at all the test sites. Treated specimens of the reference species Alstonia scholaris and Pinus sylvestris were markedly superior in performance at all sites and Homalium foetidum was considered the best local species. Along with the reference species Fagus sylvatica, treated specimens of the remaining local species performed relatively poorly. All treated species were attacked by soft rot fungi, except treated Alstonia scholaris and Homalium foetidum which were superficially decayed by bacteria. The relative success of treated Alstonia scholaris in this trial is attributed to its permeability characteristics and acceptance of high preservative loadings, even preservative distribution and its high lignin content.