One of the most striking vistas for me around the Centre, especially on the road between Uluru and
Kata Tjuta is the sight of the Desert Oaks (Allocasuarina decaisneana) in all its stages of growth. The juveniles are almost comical with their single straight trunk sprouting short branches giving them a hairy triffid or feather duster appearance.
Image Could Not Be FoundThe juveniles remain like this until their long tap roots reach water, about 30 metres down, which may be 20 to 30 years and then they transform to beautiful, many-branched, 12metre tall adults.
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The Desert Oak ranges from as far north as Bililuna at the northern end of the
Canning Stock Route to between the Mann and Musgrave Ranges in South Australia. (It was used for
well construction on the CSR between 1908 and 1910.) Its stands tend to run in lines across the country and is mostly found in swales in red sand with spinifex groundcover. Some she-oaks have male and female parts on separate plants and others have male and female parts on each plant. The Desert Oak has male and female on separate plants and its cones are the largest of all the species.
Most Australians know the she-oak with its gracefully hanging needles ssshhhhing in the breeze or making a soft carpet beneath the tree. But she-oaks,
Casuarinas and Allocasuarinas, are neither oak nor pine. They are of the family Casuarinaceae which is not closely related to any other family. They can be found on a wide variety of habitats from coastal foreshores to desolate rocky sites or swampy flats and are also found in nearby Pacific islands and SE Asia. The genus Casuarina was split some years ago and now 5 species of Casuarina and 58 species of Allocasuarina are recognised in Australia.
The name Casuarina (or Allocasuarina, "Allos" meaning like Casuarina) is derived from the Malay word for cassowary, ‘Kasuari’ and refers to the foliage which is said to resemble the cassowary's quills.
She-oak was a name given by early colonial craftsmen who considered it inferior for joinery! However, it became widely acclaimed for its beauty in fine inlay work and small items such as boxes.
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The Shrubby She-oak (A. distyla) above, grows in NSW from south of Port Stephens to the ranges east of
Cooma and usually grows 2 to 3 metres tall. Shown are the flowers and branchlets. In this case the branchlets stand up rather than hang down. If you look closely, or better still, under a magnifying glass, on each needle or branchlet you will see evenly spaced joints. These are scale-like leaves which encircle the branchlet and the number of leaves in each whorl is the best way of to identify the species.
Young eyes and steady hands are best for this task! It is easy to count the Desert Oak leaf-teeth as there are only 4.
Most
Casuarinas flower in early spring. The female flowers are usually small red, fluffy globules and grow along the branches. When mature the bracts become woody to form the characteristic woody cone. Male flowers are usually insignificant, brown, elongated spikes and grow on the ends of the branchlets. Plants produce a large amount of pollen which is dispersed by wind.
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The A. torulosa (sorry for misspelling in
pic above) has many common names. It grows from NE Qld to SE NSW in wet sclerophyll forest and on the margins of rain forest. Note the beautiful cones.
Mature she-oaks are generally protected from fire by their thick bark but can be killed by hot fires if there is a build-up of litter. During fire they shed their seeds and with suitable conditions, prolific germination occurs after on the sterile nutrient rich ash bed. Damaged trees regenerate by buds that lie dormant under the bark (epicormic buds) which grow when the tree is defoliated (in the same way that Eucalypts do).
Once successfully germinated the dense mass of seedlings crowd out other native plants.
Young she-oaks need to have at least 5 to 7 years of growth before they start to produce seed bearing cones and at least 10 years before they have a reasonable number of cones in their canopy.
I understand that the Wooly Oak or Stringybark She-oak (below) which is predominantly and inland species of northern NSW and southern QLD does not tolerate fire
well.
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The craft wood potential of the hard, beautifully grained, reddish timber was recognised by early settlers and exported to England. Here it was treated as a prized wood, only to be used sparingly on highly prized projects. She-oak was used as roof shingles and axe handles and to construct kegs and casks. Aboriginal people used it for making spears and clubs and
young she-oak cones were chewed to promote salvia in dry mouths, as they travelled through the hot, dry landscape. Water could be extracted from the roots.
Give me a
campsite near a clump of she-oaks with a gentle breeze murmuring through the branches. Complete the scene with red sand and a glimpse of ancient hills in the distance. Paradise.
I look forward to seeing your pics of
Casuarinas.
Min