Decay protection threshold

Beckers etal. (1994) examined the decay resistance of acetylated beech and poplar against C. versicolor, finding that the decay protection threshold was around 12%, whereas acetylated pine required a WPG of 20 % to prevent attack by P. placenta. Attack by C. puteana and G. trabeum was prevented at about 17 % WPG, for acetylated beech and poplar, with pine requiring a slightly higher WPG of 20 %. 

Forster etal. (1997) found that butyl isocyanate modification was more effective in enhancing decay resistance compared to the anhydrides studied in the same experiment. Decay protection thresholds were of the order of 15-20 % WPG, with the fungi studied. 

The resistance of propylene and butylene epoxide modified wood to subterranean termites was studied (Rowell etal., 1979). A threshold of 34 % WPG was found to give good protection. Giant ipil ipil (Leucaena leucocephala) was modified with acetic anhydride, maleic anhydride - glycerol or propylene oxide (Mallari etal., 1988, 1990). All modified samples showed good decay resistance to C. versicolor and Tyromyces palustris. 

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