Durability testing of African mahogany
African mahogany (Khaya senegalensis) is being grown in Northern Territory plantations to produce timber for high value decorative panels, furniture, and flooring. In its home environment of west Africa, the timber is considered resistant to termites and borers, although until now that hasn’t been fully tested for Australian conditions. As a consequence, FWPA is helping fund an important study through the Queensland Governments Department of Agriculture, Fisheries and Forestry that will expand the potential markets for this exciting plantation product.
This research reports the results from the first year of ongoing research into the natural above-ground durability of plantation grown African mahogany.
Samples of timber from 10- and 20-year old trees are being tested in two test sites, one a fungal cellar laboratory and the other a field site in north Queensland in a region known to present a very high decay hazard. In the laboratory the timber samples are placed in racks close to soil beds in a controlled environment room (fungal cellar) where conditions are those that best promote decay.
The African mahogany samples are also being compared with control samples from spotted gum (Corymbia citriodora) durability class 1, jarrah (Eucalyptus marginate) durability class 2, messmate (Eucalyptus oblique) durability class 3 and slash pine (Pinus elliottii) durability class 4.
After one year the African mahogany samples are showing minimal decay, and it is not yet possible to determine if they are is consistent with durability class 3 or durability class 2 timbers above ground. In addition, no termite attack was observed; however, more time is required before reliable conclusions can be drawn.
Growers have previously identified that juvenile heartwood has reduced natural durability than the rest of the heartwood. Results from the field test suggest that samples cut from butt logs may be more durable that those cut from top logs which contained juvenile heartwood.
Future results from the trial will provide valuable data about African mahogany durability, and potentially lead to the development of new processes and products that will grow the market for the timber.