Evaluating less-used timber species for marine construction

Naturally durable species of timber are used as an alternative to preservative-treated timber for marine structures, but many species have not been evaluated for their potential for use in this environment. BS EN 275 evaluates marine borer resistance and specifies a 5-year test period: too long a period for screening tests to be economically viable. Furthermore, the test does not evaluate abrasion resistance. Novel fast-track screening methods were used in this study to evaluate the marine borer and abrasion resistance of 18 less-used timber species. Comparative resistance was assessed by comparing the feeding rates of marine borers and abrasion resistance observed in candidate species against greenheart and ekki, which were used as benchmark species. A number of less-used species, originating from South America and West Africa, performed better than the benchmark species in laboratory tests and over an 18-month exposure period in the sea. A number of species also performed comparatively well in abrasion trials although resistance to abrasion does not necessarily correlate with resistance to attack by marine borers.