Gum, Grey

Grey gum is a medium-sized hardwood tree growing up to 40 metres in height and one metre in stem diameter. Varieties of grey gum occur along the east coast of Australia, from the Hawkesbury River in New South Wales as far north as Maryborough, and inland to the Carnarvon Ranges and Blackdown Tablelands in Queensland.

The heartwood of this species is a red to reddish-brown colour, visually distinct from the paler sapwood. Grain is usually interlocked, with a coarse but even texture. Grey gum is similar in general appearance to the ironbarks, but often marked by characteristic grub holes.

Grey gum timber is extremely durable, with an in-ground life expectancy in excess of 25 years. For aboveground applications, life expectancy exceeds 40 years. Grey gum heartwood is termite-resistant, and untreated sapwood is not susceptible to lyctid borer attack. Grey gum sapwood is readily impregnated with commercially available preservatives.

The timber is very hard, rated 1 on a 6-class scale in relation to both indentation and ease of working with hand tools. It machines well, although care is required in working the timber’s interlocked grain. Grey gum readily accepts paint, stain and polish, and is amenable to the use of standard fastenings and fittings. As with most high-density species, machining and surface preparation should be done immediately prior to the application of adhesives.

Grey gum is widely used in heavy engineering and marine construction, where it is found as poles, piles, railway sleepers, cross-arms and mining timbers. In general construction it is used for building framework, flooring and decking. Grey gum is also extensively used in landscaping and boat building. It is renowned for making superior-quality butcher’s blocks suitable for use in both commercial and domestic environments.