Durability of Mahogany (Swietenia Macrophylla)

In 1989, Forest Research established a field test of 20 x 20 x500mm stakes to compare the natural durabilities in ground contact of Fijian grown Mahogany (swietenia Macrophylla) and western red cedar (Thuja plicata) imported from USA. At the same time, a number of plantation species from Western Samoa were put in the test. These were;

Also included was NZ-grown Cupressus lusitanica

The average life of mahogany was 10.2 years, putting it at the top end of the moderately durable class (Australian durability class 3), very similar to that of western red cedar. Because it is at the top end of Durability Class 3 when tested in ground contact, it is logical to assume that it would be rated Class 2 in above ground situations. We are confident that the product will perform as decking for a minimum of 15 years.

Toonahad an average life of 2.8years (Durability Class 4) Amoora had an average life of 7.6 years (durability class 3) only 2 of the 10 Teak stakes had failed (provisional Durability Class 1) Cupressus lusitanica had an average life of 6.2 years (durability class 3). On this basis, mahogany could be considered to be slightly more durable than Cupressus lusitanica (and all other cypresses), but less durable than plantation grown Teak.

Yours Faithfully

Mick Hedley
Project Leader, Wood Preservation
Scion Wood and Biofibre Technologies

Australian Durability Class grade for reference.

Class 1: In ground applications (25 years) above ground applications (40 years)
Class 2: In ground applications (15-25 years) above ground applications (15-40 years)
Class 3: In ground applications (5-15 years) above ground applications (7-15 years)
Class 4: In ground applications (0-7 years) above ground applications (0-7 years)

Fijian Mahogany Decking is available in Toronto Through Green World Lumber.

Signed PDF Version of Document:  Durability of Mahogany Decking (swietenia macrophylla)