Decay and termite resistance of wood treated with tar oil obtained from a commercial pyrolysis process
of macadamia nut shells was evaluated. Vacuum-treated pinewood specimens were subjected to two
brown- and two white-rot fungi based on the soil-block test method specified by the American Wood
Protection Association after a 10-day-leaching process. Treated specimens were also subjected to the
subterranean termite attack according to Japanese Industrial Standards (JIS) for 3 weeks under laboratory
conditions. In the study, growth inhibition of selected fungi with the tar oil was also tested in vitro.
Treated wood specimens at a retention level of 460 kg m3
showed good protection against all the fungi
tested. Mass losses in leached specimens were less than those observed in unleached specimens. Similar
results were seen when the specimens were subjected to termite attack. Inhibition tests showed that
higher concentrations of the tar oil are critical for inhibition of the brown-rot fungi compared to the
concentrations required to impede the white-rot and sap-staining fungi tested