Trees of Australia the Salmon Gum

The Salmon Gum or Eucalyptus salmonophloia (salmon-barked) is a most attractive eucalypt which is native to only a small area of Western Australia. The tree was named in 1878 by Ferdinand von Mueller, an eminent Australian botanist. Early settlers were already calling the tree Salmon-Barked Gum Tree as the bark, when starting to peel off the tree, has the colour of cooked salmon flesh. External colouring of the bark changes with the seasons from a brownish pink at the end of summer to almost white in winter, usually with greyish-purple patches, although the mottling is not always evident. The presence of salmon gums in an area was taken to be an indication of good loamy soil suitable for the production of wheat. The town of Salmon Gums is situated in the south-east of Western Australia, about midway between Esperance and Kalgoorlie.

The foliage of the salmon gum is deep green with a lustrous, burnished appearance. The leaves are 7 to 12cm long, rather sickle-shaped with copious oil dots.  Both sides are a shiny grey green colour. If the trees are crowded together, the crowns are relatively small but with space to spread the trees branch up and out to form an umbrella shape providing good shade and shelter. It is a stately tree and long lived with individuals being recorded as over 150 years old.  In the southernmost regions of its habitat trunks with a diameter of 1 metre are not uncommon.  The root system is shallow and spreads widely, resulting in competition with other flora for nutrients and moisture. In its native habitat a characteristic of salmon gum areas is the sparseness of understorey shrubs and scrub.

The timber is deep red when first felled then fades to a reddish-brown.  It is straight grained, strong and dense but is subject to the ravages of termites. The timber has been used as supports in mining operations and, to a lesser extent, for railway sleepers and firewood. In agricultural areas, it provides shade, shelter and windbreaks for livestock.

In its native areas the annual rainfall is around 10 inches annually and the salmon gum is drought tolerant and moderately frost tolerant. It also tolerates relatively high levels of lime and salt. It is a fast growing species reaching 8 feet tall in around four years and up to at least 78 feet at maturity. It is a popular ornamental tree, one of the most attractive of the eucalypts. The blossoms are white to cream. Its nectar is highly attractive to birds and bees. Honey produced from salmon gum blossom has a mild flavour and is clear and light amber in colour, much favoured by apiarists. The hollow trunks provide suitable hives for naturalised bees. As an ornamental tree is does well in poor soils and has low nutrient needs. It has been successfully grown throughout Australia and overseas. It is low maintenance, fast growing and is prized as suitable for rehabilitation areas and for soil stabilisation. Although its oils haven’t been commercially exploited, it is rich in cineole (eucalyptol).