Cleistanthus collinus (Roxb.) Benth. ex Hook. f. and Wrightia tinctoria (Roxb.) R. Br. -- two timbers with promising durability under marine conditions

IRG/WP 05-10552

M V Rao, M Balaji, V Kuppusamy, K S Rao

During the course of natural durability studies on indigenous timber at Visakhapatnam harbour, two species, namely, Cleistanthus collinus (Karada) and Wrightia tinctoria (Dudhi) were found to resist marine borer attack for reasonably longer periods. The panels of C. collinus completely resisted borer attack for 9 months but became susceptible to teredinid attack thereafter. The teredinids gradually attacked the panels in increasing numbers and by the end of 24 months of exposure trials, the apparent destruction caused by the borers reached >50%. However, on splitting open the panels, the internal destruction was found to be only 8% as majority of teredinids could not penetrate deep into wood, leaving only superficial pits. The panels of W. tinctoria completely resisted borer attack only for 3 months unlike C. collinus. Subsequently, this species became susceptible to pholadid attack but continued to resist teredinid attack for 12 months. The wood borer attack, especially of pholadids followed by teredinids gradually increased and by the end of 30 months, the apparent destruction reached >50%. However, on inspecting the split open panels, the internal destruction was observed to be 60%.


Keywords: Natural Durability, Cleistanthus collinus, Wrightia tinctoria, marine environment, marine borers, India

Conference: 05-04-24/28 Bangalore, India


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