Australian Red Cedar
Australian red cedar (Toona ciliata var. australis) is possibly Australia’s most celebrated native timber. Soon after European settlement the cedar cutters began scouring the rainforests up and down the east coast from south of Sydney to the Atherton Tablelands in search of cedar logs. Red Cedar has a light, fine-grained timber with a beautiful even deep-red colour. The heartwood is naturally durable, dries with splitting and is easy to work.
In its natural tropical environment Red Cedar is actually deciduous losing it leaves in winter to avoid the ‘dry season’. It thrives on deep well drains basalt soils or along rivers and creeks in areas of high summer rainfall.
The problem facing tree grower wanting to produce high quality logs is the dreaded Cedar Tip Moth (Hypsipyla robusta). The moth lays its eggs on the tree’s leading shoot and the larvae burrow in to the stem causing dieback. The attack doesn’t actually kill the tree but in response secondary buds develop behind the main stem causing a multi-branched tree with little commercial value. The difficulty is that the tree actually produces a natural chemical that attracts the female moth and the destructive larvae hide out-of-site inside the stem where they are hard to kill.
Growers have tried a range of insecticides which, if applied regularly, may help achieve a useful butt log. Once the main stem is established the economic impact of the tip moth is greatly reduced. Whilst any subsequent attack might affect the canopy itself it will not affect the shape of the main trunk. As the crown develops the lower branches on the stem can be removed to increase the value of the butt log. Once stem pruning is complete the trees can be left to grow on for twenty or thirty years without any need for further worry about insect attack.
My own farm is in southern Victoria, well away from any native Red Cedar or any planted trees of susceptible species. My young Red Cedar trees are growing well and showing no signs of tip moth attack... yet. In the Burnley gardens in Melbourne there is a young Red Cedar that appears to have grown a single healthy stem up to about 3 metres after which it is a mess suggesting the Tip Moth may have eventually found it!
How my Red Cedar will cope with our dry summers I’m not sure. The photos were taken in August and my young trees are already in full leaf and growing strongly. In a warming world I’m looking north for new species to grow for valuable timber. Red Cedar is an obvious choice.
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