What do macadamia nuts and fine timbers have in common?

Abstract

Macadamia trees are best known for their nutritious edible nut which supports a $291 M/annum industry in Australia. What was a source of bush tucker for the indigenous tribes of sub-tropical Queensland and New South Wales has developed into a high value commodity in domestic and export markets. Australian orchards produce 30% of the global crop and exports to over 40 countries across Asia, Europe and North America.

Although industry benchmark data has shown that macadamia orchards have a commercial life span of more than 40 years, it is likely that trees will be replaced at earlier ages due to improvements in productivity and health in new varieties developed through research and development projects. Trees are also removed from time to time to reduce inter-tree competition, make way for roads, nurseries, farm buildings and other crops. Although some orchard managers can chip these removed trees for re-use as mulch on-farm, there is interest in the wood’s potential for higher value products such as craft wood.
The project reported here investigated the potential of the wood salvaged from trees cleared for a nursery on an orchard near Bundaberg, Queensland. The wood was provided to a test team comprising fourteen craftspeople based in south-east Queensland to create objects and appraise the wood’s attributes.
The test team were unanimous in their praise for the appearance of the wood and concluded that it’s similarities to the well-known silky oak timbers (especially Cardwellia sublimis, northern silky oak and Grevillea robusta, southern silky oak) indicate that it could do well in the craft and fine wood turning markets. As with other members of the Proteaceae family, the wood has wide medullary rays which provide this recognisable ‘oak’ appearance, but also form zones of weakness and during drying can provide sites for splitting. Careful drying after harvesting is required to minimise losses due to splitting. The application of end-sealer is recommended to retard the rate of drying and assist with reducing degrade during drying. The patient wood craftsperson will be rewarded with an attractive wood suitable for craft items such as knife handles, salt and pepper mills, pens, walking sticks and turnery. The light colour of the wood provided was also well suited for pyrographic art.