Rainforest giants with rare autumn displays: there’s a lot more to Australia’s red cedar than timber


Peter Woodard/Wikimedia

Gregory Moore, The University of MelbourneNative deciduous trees are rare in Australia, which means many of the red, yellow and brown leaves we associate with autumn come from introduced species, such as maples, oaks and elms.

One native tree, however, stands out for its leaves with soft autumnal hues that drop in March and April: Australia’s red cedar. Don’t be fooled by its common name — red cedar is not a cedar at all, but naturally grows in rainforests throughout Southeast Asia and Australia.

You may be more familiar with its timber, which I’ve been acquainted with all of my life. My grandmothers had cedar chests of drawers they had inherited from their mothers or grandmothers, and I had assumed they were made from one of the Northern hemisphere cedar species. The wood still smelled of cedar after all this time in family homes – a scent I associate with grandparents and country homes.

By the time I was given one of these chests to restore, I knew much more about the tree and valued the chest of drawers all the more. So, with autumn putting a spotlight on Australian red cedars, let’s look at this species in more detail.

Majestic giants of the rainforest

I first encountered red cedar trees in the sub-tropical rainforests of Queensland and New South Wales in the 1980s. Then, its scientific name was called Cedrela toona and later Toona australis. Now, it’s recognised as Toona ciliata.

The various names reflect a taxonomic history in which the Australian species was once regarded as being separate from its Asian relatives, but all are now considered one.

Two red cedars in a rainforest
Native red cedar trees can grow up to 60m tall.
Shutterstock

The trees are awe-inspiring. Under the right conditions, it can grow to 60 metres tall (occasionally more) with a trunk diameter of up to 7m.

After losing its foliage in autumn, the new foliage in spring often has an attractive reddish tinge. In late spring it has small (5 milimetres) white or pale pink flowers, but they usually go unnoticed in the rainforest because of their height or the density of other tree canopies growing beneath.

Older red cedars have wonderful buttresses at the base of their trunk, a characteristic shared by many tall tropical trees. These buttresses have long been considered an advantage for species that can emerge above the canopy of a rainforest where winds are much stronger, with the buttresses and expanded root systems providing greater strength and resistance to the wind.

These buttresses also greatly increase the surface area of the base of the trees exposed to air, which facilitates the uptake of extra oxygen as the activity of micro-organisms in the soil can leave it oxygen-depleted.

White flowers against the leaves of red cedar
Tiny white flowers are hard to see from the ground in a rainforest.
Forest and Kim Starr/Wikimedia, CC BY-SA

Logged to near extinction

With a wide distribution throughout Asia and Australia, its uses in ancient times were many and varied. In traditional medicine, bark was used or digestive remedies as well as wound dressing and its resin was used for treating skin conditions.

Dyes, oils and tannins used for preparing leather could also be extracted by boiling various plant parts. Today the wood is used for culturing shiitake mushrooms, which are much in demand in restaurants.

But the recent history of red cedar is a typically sad colonial tale. The species belongs to the same family as mahogany (Meliaceae) and, not surprisingly, was exploited for its timber from the early days of colonisation.

Red cedar bannister
You can find red cedar timber in many public buildings across Australia.
denisbin/Flickr, CC BY-ND

The timber is durable, lightweight and suitable for naval use and so was very heavily logged, right along the east coast of Australia from the early 1800s until the early 20th century.

The rich deep red colour of its timber and the fact it was soft and easily worked meant it was used for furniture, ornate carvings in public buildings, town halls and parliaments, such as the State Library in Melbourne. It was also used for implements and handles, and for sailing and racing boats.




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You’ve probably had a close encounter with the lovely red banisters on some of these old buildings that were made of red cedar, often darkened under the patina of so many hands.

The once common and widespread species was logged almost to extinction along the east coast by the mid-1900s, and to the point of practical commercial extinction with little timber available to industry by the 1960s.

So valued was the timber that in the late 1970s, a plan was hatched to remove red cedar from Queensland National Park rainforests using helicopters. Luckily, the idea did not fly and so some great trees persist. The species has a conservation status of concern, but is not considered to be endangered at present.

Leaves of the Toona ciliata
The leaves of red cedar begin to fall in late March.
Peter Woodard/Wikimedia

A terrible pest

The fact they are deciduous makes them potentially very interesting and useful for horticultural use, but that potential remains largely unrealised. And given the value and quality of its timber, you may be wondering why it’s not being grown in plantations across the continent.

The reason is a native moth called the cedar tip moth (Hypsipyla robusta), which lays its eggs on the main growing shoot of the tree. When the eggs hatch the larvae bore down the shoot, which not only results in shoot dieback but also causes the trees to develop multiple stems and branches which reduce its timber value.




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Despite this, they are still planted as a quick-growing ornamental tree for their shade in other parts of the world, such Hawaii and Zimbabwe.

The moths are attracted to the scent of the tree, so they’re very difficult to control. The moth does not attack the tree in South America, for instance, because the moth has not established there, so there are large plantations of red cedar in Brazil.

It’s an interesting reminder: often it’s the little things in ecology that can affect success, or failure. When we humans meddle without knowledge, things don’t necessarily go to plan, usually to our cost.




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The Conversation


Gregory Moore, Doctor of Botany, The University of Melbourne

This article is republished from The Conversation under a Creative Commons license. Read the original article.

When it comes to climate change, Australia’s mining giants are an accessory to the crime



Australia’s major mining companies are significant contributors to global emissions.
Global Warming Images

Jeremy Moss, UNSW

There are many reasons for Australia’s absence from the podium of the the United Nations Climate Action Summit this week. No doubt it would send a poor message if emission reduction laggards such as Australia had taken centre stage.

But Australia is also the world’s largest exporter of coal and liquified natural gas. And by providing fossil fuel subsidies and exploration rights, the Australia federal government encourages its major mining companies to export more. This situation is now profoundly hostile to action on climate change.




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The emissions produced from the fossil fuels extracted by Australia’s major gas, coal and oil producing companies – our “carbon majors” – such as BHP, Glencore and Yancoal, are now larger than all Australia’s domestic emissions.

While these companies, and Australia itself, have no legal responsibility for these “exported” emissions, morally it is comparable to selling uranium to a failed state or dumping medical waste unsafely. We understand the harm our exports cause, and are therefore at least partially culpable for the harms they cause.

We think in nations, not companies

Why aren’t Australian carbon majors considered to be responsible for addressing their emissions and their consequences? One reason is when we think about reducing emissions, we typically focus on the role of nations.

After all, it is nations that negotiate climate agreements, and their policies are substantially responsible for the contribution their citizens make to the problem of climate change.

But the impact of carbon majors is now so large, we must make the case for holding them responsible for the consequences.

In 2018 alone, BHP’s global fossil fuel production led to the emissions of the equivalent of 596 megatonnes (Mt) of CO₂-equivalent . Over the last 15 years BHP’s Australian coal operations have produced 1,863Mt of CO₂-e.

These figures would be significantly higher still if we included the remainder of the emissions since 1990, when the first major report from the Intergovernmental Panel on Climate Change revealed the risks of climate change and the consequences of emissions.

To put that in perspective, in 2018 BHP’s emissions from its global fossil fuel operations alone were more than the whole of Australia’s domestic emissions (534Mt CO₂-e) for 2018. If BHP were a country, the products it produces would cause emissions greater than those emitted by 25 million Australians.

As well as their current levels of production, many of the carbon majors hold vast reserves to be extracted in the future as well as new fossil fuel projects. Glencore, the largest coal mining company in Australia, reported in 2018 that they have 6,765Mt of measured metallurgic coal resources, and 1,565Mt of thermal coal in proved marketable reserves. Together, that’s the equivalent of 18,202Mt of CO₂, more than 34 times Australia’s 2018 carbon emissions.

Moral responsibility

But why should we hold the companies themselves responsible for these emissions? After all, except for the emissions created during the extraction process, they don’t themselves directly produce these emissions. For the most part, carbon majors contribute by being producers and suppliers of fossil fuels.

Like nations, carbon majors are seen as having responsibility only for emissions they have produced directly in operating a mine or transporting their commodities to port. This is the “territorial” model of emissions attribution.

Yet the responsibility of carbon majors is much greater than this territorial model suggests. To see how this might be the case, it is useful to draw on some basic moral and legal theory.




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For example, a murderer or thief is directly responsible for the harm they cause their victim. They pulled a trigger or absconded with the money, and no-one else shares that direct blame.

But in the case where a person intends to shoot another person and I announce that I will sell them a gun — knowing full well what it will be used for — the responsibility for the murder no longer falls solely on the person who pulls the trigger. Given I sold the gun knowing that someone would be harmed, I am now an accomplice to the crime and should share at least some of the blame.

In this case, there is a relationship between my actions and the murder that ought to make me at least partially responsible.

In the case of carbon majors, by producing and selling fossil fuels which are, in turn, consumed in another country, they are complicit in the harm directly caused by their customer: the releasing of greenhouse gas into the atmosphere by consuming the fuel.

Australia’s carbon majors are accessories to the wrongful harm of climate change.

Shared blame

These companies of course point out they are not wholly responsible – other companies and people actually use the fossil fuels overseas, where the emissions count towards another country’s tally. But accepting even some fault for the effect of their exports is a huge increase in a company’s moral responsibility over what they currently admit.

What does this mean in practice? First of all, it means that they have a strong moral reason to stop contributing to the harm by appropriately cutting their fossil fuel operations in line with IPCC timeframes and take a fair share of their climate-related liabilities. They should also stop seeking support for fossil fuels through lobbyists, politicians, “think tanks” and industry groups.

It will be argued that such actions will be costly to the carbon majors. But unless we are willing to concede that it is acceptable to harm others without sanction or an end it sight, this is not a convincing response.




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However as citizens, we also need to move beyond reducing our domestic emissions. As voters, investors and consumers, we share a responsibility for our exported emissions. Ending state and institutional support for carbon majors should now be a major focus of climate action.The Conversation

Jeremy Moss, Professor of Political Philosophy, UNSW

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Comic explainer: forest giants house thousands of animals (so why do we keep cutting them down?)



File 20181129 170241 np8k0s.png?ixlib=rb 1.1

Wes Mountain/The Conversation, CC BY-ND

Madeleine De Gabriele, The Conversation and Wes Mountain, The Conversation

Giant eucalypts play an irreplaceable part in many of Australia’s ecosystems. These towering elders develop hollows, which make them nature’s high-rises, housing everything from endangered squirrel-gliders to lace monitors. Over 300 species of vertebrates in Australia depend on hollows in large old trees.

These “skyscraper trees” can take more than 190 years to grow big enough to play this nesting and denning role, yet developers are cutting them down at an astounding speed. In other places, such as Victoria’s Central Highlands Mountain Ash forests, the history of logging and fire mean that less than 1.2% of the original old-growth forest remains (that supports the highest density of large old hollow trees). And it’s not much better in other parts of our country.

David Lindenmayer explains how these trees form, the role they play – and how very hard they are to replace.




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Wes Mountain/The Conversation, CC BY-ND



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Sign up to Beating Around the Bush, a series that profiles native plants: part gardening column, part dispatches from country, entirely Australian.The Conversation

Madeleine De Gabriele, Deputy Editor: Energy + Environment, The Conversation and Wes Mountain, Multimedia Editor, The Conversation

This article is republished from The Conversation under a Creative Commons license. Read the original article.