Photo by Stephanie Reif.

The cry of ‘timber’ and the crashing of rainforest trees evokes a romanticised ideal of rugged, bearded men hacking their way through an impenetrable ‘jungle’ with their bullock teams and of loneliness, hardship and deprivation in their search for timber.

In the pioneering days of Australia, the ‘Cedar Cutters’ frequently preceded more permanent settlers and were often responsible for the ‘opening-up’ of new areas for the ever-expanding European arrivals. Unfortunately, it also resulted in the sad over exploitation of our rainforests with the most precious of rainforest trees, the legendary Red Cedar (Toona ciliata), or ‘Red Gold’ as it was known, being cut to commercial extinction by the beginning of the 20th century.

As early as 1802 (only 14 years after European arrival), Governor King issued restrictions on the felling of Red Cedar without authority. This didn’t stop the decimation of these magnificent trees and they were systematically felled wherever they were found. Consequently, apart from the occasional magnificent specimen that was spared the axe and those in the most inaccessible of locations, the Red Cedar you find growing today were either flawed, too small to be felled at the time, are recent regrowth or have been planted. It will be another couple of human generations before these leftovers attain the awe-inspiring status of their forebears. In exceptional circumstances these trees attained heights of 60 metres, but more typically grew to 45 metres.

Looking at my Grandfather’s Red Cedar table, it’s not difficult to see why this wood was so prized as a cabinet timber and veneer. The wood is a magnificent, deep, rich red and you can almost lose yourself staring into its depths. The colour of the wood alone makes it a wood worker’s dream, but Red Cedar has a couple of other attributes that made it so desirable. The wood is soft, making it easy to work and is pest and water-resistant.

The most accessible of the trees grew in fertile, deep, well-drained basalt soils east of the Great Dividing Range, primarily along rivers and creeks from southern NSW to northern Queensland. This allowed the cedar cutters to take advantage of one of its other attributes – it floated. The transport of cut logs was greatly simplified as they were rafted down these ready-made water highways.

Photo by Pete the Poet, Flickr.

Just as the timber from the related Mahogany’s of Africa and India were becoming scarce due to over exploitation, Red Cedar was able to fill the void in nineteenth century England. This trend continued in colonial Australia, so even as Red Cedar was being shipped back to England in the holds of convict ships, it was also being increasingly used in Australia to build and adorn the ever-growing number of houses and public buildings.

Red Cedar is one of the few deciduous native trees in Australia and even this fact works against it. In the intact rainforest, Red Cedar was able to disappear into the background, but come spring, having earlier shed its leaves to see out the dry winter, their flush of beautiful coppery-red leaves (see image below) made them stand out like signposts to the cedar cutters. This new growth of compound leaves, with a distinctive asymmetrical base then turned bright green to fuel the growth of this rainforest giant.

To help stabilise the immense size of these trees, most large Red Cedars are flanged or buttressed. At this time their trunk heads for the heights of the rainforest canopy with the first branches finally emerging high above the ground. The bark of older cedar is a scaly grey or brown and is often shed in oblong pieces giving the trunk a distinctive plated appearance.

The final twist of the knife in the story of the Red Cedar is the reason why so few of those trees found today will mirror their forebear’s spectacular growth. It is also the reason why Red Cedar, despite being easily propagated, fast growing and quite hardy once established, is not being grown to any extent as a timber tree in Australia. The tree has a little understood relationship with a rather non-descript brown moth, the Cedar Tip Moth or Shoot-borer (Hypsipyla robusta) in Australasia and Asia, whose larvae attack the growing tip of the plant. In young Red Cedar this invariably includes the dominant growing stem tip (the apical meristem) that is responsible for stem elongation. Many centimetres of new growth can be destroyed as the larvae munch into the succulent sapwood. The destruction of this dominant growing tip triggers otherwise dormant lateral (axillary) buds to grow, resulting in a twisted and sometimes multi-stemmed tree developing.

Planted Red Cedars, such as this one at Mapleton, are rarely straight-boled due primarily to insect attack. Photo by Stephanie Reif.

Borer attack of young trees rarely causes tree death, but it does result in deformed trunks that are of no commercial value. Interestingly, Red Cedar gives off a chemical attractant that the female moths are able to home in on from many kilometres away. It is also believed that a combination of the destruction and disruption of the natural ecosystem, coupled with the extra light that seedlings are exposed to when grown in disturbed forest, revegetation areas or forestry plots, results in the moth being able to single out young cedar.

The beautiful flowers of Red Cedar. Photo by Paul Donatiu.

In an intact forest, the majority of young Red Cedar are able to escape the moth until such time that they are too large for moth attack to make an impact on trunk growth. At this much later stage of cedar growth, the moth’s larvae voraciously attack inflorescences, soft developing fruits, unexpanded leaves and growing branch shoots. So, due to a quirk of nature, only a fraction of these ‘new’ Red Cedars will mature into the straight-boled giants of the past. Do you have one on your property?

 

References & Further Reading

Bygrave FL & Bygrave P (2005) Growing Australian red cedar: and other Meliaceae species in plantation. Rural Industries Research and Development Corporation & Joint Venture Agroforestry Program.

Griffiths M (2001) The biology and ecology of Hypsipyla shoot borers. In Hypsipyla Shoot Borers in Meliaceae. ACIAR Proceedings No. 97, eds. R.B. Floyd and C. Hauxwell, pp. 74–80. ACIAR.

https://poi-australia.com.au/australian-red-cedar-toona-ciliata-var-australis/

www.planthealthaustralia.com.au/wp-content/uploads/2015/07/Shoot-borer-FS.pdf

www.smh.com.au/national/saving-grace-of-the-tall-timber-20040517-gdixt6.html

 

Article by Tony Mlynarik
Conservation Partnerships Officer
Brisbane City Council

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