Establishing the comparative durability of African mahogany (Khaya senegalensis) in weather exposed above-ground applications

Abstract

This study was established to evaluate the natural durability of ten- and twenty-year-old plantation-grown Khaya senegalensis (African mahogany) above ground.
Whilst mature African mahogany heartwood is expected to last five to 15 years in ground, Australian natural durability standards and specifications do not currently provide information on the durability performance of African mahogany when used above ground.
A ground proximity field test was installed at DAFF’s South Johnstone Research Facility in north Queensland and modified ground proximity tests were also installed in a fungal cellar at DAFF’s Salisbury Research Facility near Brisbane.
Whilst the plantation African mahogany tested appears more durable than pine, it is not yet possible to determine if its’ durability is consistent with expectations for durability class 3 or durability class 2 timbers above ground. Minimal decay of test specimens had occurred after 12 months and more time is required before reliable conclusions can be drawn. Data gathered, however, are vital for any future durability modelling for plantation African mahogany, to calculate the lag for decay initiation and rates of decay.