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Showing posts with label carbon emissions. Show all posts
Showing posts with label carbon emissions. Show all posts

Saturday, 3 July 2010

Tall trees

A century ago, Gippsland settlers stand proudly round a giant tree they have ringbarked.

In 2008, in Tasmania’s southern forests, surveyors found the tallest known tree in Australia today. Standing 101 metres high, it is a magnificent find – higher than any tree we have known about for many decades. It is not, as some reports have suggested, the second tallest tree in the world - there are 16 trees in the US over 110 m in height, let alone 101. But Australia once had much taller trees.

On 21st February 1872, Victorian government surveyor and Inspector of State Forests William Ferguson reported to Mr Clement Hodgkinson, Assistant Commissioner of State Forests, on his inspection of “areas that had not been penetrated by the timber splitter or the woodcutter”: 


Some places, where the trees are fewer and at a lower altitude, the timber is much larger in diameter, averaging from 6 to 10 feet and frequently trees to 15 feet in diameter are met with on alluvial flats near the river. These trees average about ten per acre: their size, sometimes, is enormous. Many of the trees that have fallen by decay and by bush fires measure 350 feet in length, with girth in proportion. In one instance I measured with the tape line one huge specimen that lay prostrate across a tributary of the Watts and found it to be 435 feet from the roots to the top of its trunk. At 5 feet from the ground it measures 18 feet in diameter. At the extreme end where it has broken in its fall, it (the trunk) is 3 feet in diameter. This tree has been much burnt by fire, and I fully believe that before it fell it must have been more than 500 feet high. As it now lies it forms a complete bridge across a narrow ravine.

In other words, Ferguson measured the tree (in an area near Healesville) from its base to the point where it had broken off in its fall to be 435 feet (133 m) and did not measure its crown. Even at 435 feet, there is no tree on Earth known ever to have surpassed it. However, the information that the tree was still 3 feet in diameter at this point supports the estimate that the tree had been over 500 feet (152 m) high. This tree has become known as “the Ferguson tree”.

The tree found in Tasmania, like the Ferguson tree, is a mountain ash, although in that State they use the less impressive name “swamp gum”. Mountain ash (Eucalyptus regnans – monarch of the eucalypts) is still today the world’s tallest hardwood and the world’s tallest flowering plant, but there were several nineteenth century trees any one of which, if alive today, would be the tallest tree in the world, and the largest of all was the Ferguson tree - listed in the Guinness Book of Records as the tallest recorded tree.

The tallest Californian redwood currently standing is the newly-discovered ‘Hyperion’ of the Redwood State Park, standing 115.55 m tall (379 feet). The tallest North American tree ever known was a Douglas fir (Pseudotsuga menziesii) measured at 400 feet (122 m). Unlike Australia’s Ferguson Tree, the giant Douglas fir was not professionally measured, so must remain a tantalizing anecdote.

Other Australian trees of which we have reliable records from the nineteenth century are: 


  • A tree at Mt Baw Baw measured by surveyor G W Robinson prior to 1889 to be 470 feet (143 m). 

  • The Centennial Exhibition Tree from the Menzies Creek area, which was measured after felling at 400 feet (122 m). This tree was felled so that its spectacular trunk could be dismantled and then reassembled to form a display in the 1888 centennial exhibition in Melbourne. 
There are good photographs of this tree in the State Library of Victoria.
  • Fallen tree in the Dandenong ranges measured by surveyor David Boyle in 1862 to be 392 feet (119 m). Again the tree had broken in its fall, and Boyle estimated that the top would be another 30 feet, giving a total height of about 420 feet (128 m).

Trees which were huge but which would not top the highest remaining trees in North America are: 


  • Thorpdale tree in South Gippsland, felled in 1880 and then accurately measured by surveyor G Cornthwaite to be 375 feet high (114 m) 

  • Olongolah tree near Beech Forest in the Otways, which was measured by an unnamed Colac Shire Engineer on an unknown date prior to 1900 to be 347 feet (106 m). 

  • The “Neerim Giant” was measured by a government surveyor to be 325 feet (99 m). It had a broken top, however, and must once have been considerably taller. It was destroyed by fire early in the 20th century.

In 1939 in Toorongo Forest, Noojee, another fallen tree was measured by Inspector of Forests, F G Gerraty to be 348 feet (106 m).

It is a source of shame for Australians that our forefathers destroyed giant trees which, if they were living today, would be wonders of the world. Many huge trees were destroyed, and for many there are no measurements. In some cases, the trees were cut down and simply burnt, often in places so inaccessible that they would never be useful for grazing.

Trees were hunted down, and the challenge of destroying these ancient giants was taken on with gusto. Old photographs of people in the forest almost always show an axe present. It was as if this was a statement of manhood against the uncivilised immensity of the forest.

What does it take to have tall trees grow? One factor is time. Hundreds of years are needed for the trees to grow, but this is after millennia of nutrients building up as trees grow and decay. Another factor is a large area of forest. Trees grow upwards when competing for light, and can grow very tall when protected from wind and storm by a large number of other tall trees.

Might there be still taller trees out there? Perhaps the tallest tree in the world? Who knows? In the past few years we have discovered several new species of trees in East Gippsland, the Wollemi Pine in the Blue Mountains, and the world’s oldest known tree on Mt Read in Tasmania. And now we have found a tree which tops any tree found in Australia for many decades. We are still finding things in the Australian bush that we do not expect.

But we have lost so much already. In the nineteenth century people knew no better, but we know otherwise now. We know that logging causes a loss of water yield for up to 150 years, we know that there are very few people employed by the industry, we know that the industry enjoys substantial public subsidies, we know that endangered species are killed by logging. And we know, following studies by Professor Brendan Mackey and his team at ANU that for each hectare we log we lose an average of 1000 tonnes of carbon into the atmosphere – after taking replanting into account. We know there are ready and viable alternatives, including the use of plantation timber. We know that the alienation of our nation from its land is causing immense environmental and personal damage, with logging providing the most dramatic illustration.

It is time to stop.


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Friday, 25 June 2010

Dirty deals

Mining brown coal in the Latrobe Valley

In 1840 Count Paul de Strzelecki travelled through the ranges that now bear his name in South Gippsland. So dense was the forest cover that his party was reduced to felling trees and walking along the fallen trunks - far above the ground on a tangle of vegetation. They reached Westernport Bay a month late, with almost no equipment left, and starving.

Most of that forest was cleared in the 19th and 20th centuries, but there are a few magical patches left - especially in the Tarra-Bulga National Park, where I spent some holidays as a child.

20 million years ago, the forests covering what is now the Latrobe Valley were very similar to the forests through which Strzelecki struggled. As trees died and plant material compacted, they slowly formed brown coal. The layers of brown coal there are up to 400 metres thick. In places it is possible to see entire tree trunks in the upper layers where digging machines are cutting away at the deep seam.

The brown coal layer forms an insulation blanket, and research is under way to see whether the much higher temperatures below that blanket can be used to provide geothermal energy: if so, it will be important to keep the brown coal in place, so we don't let the heat dissipate.

But this week Victorian company Environmental Clean Technologies (don't you just love that name?) has signed the first deal to export Victorian brown coal. The company will send up to 20 million tonnes of processed brown coal to Vietnam every year. (ECT has also been involved in the oxymoronic "clean coal" business.)

Last year the Victorian Government stopped a similar export deal. But they have been studiously silent about this one.

Gillard government Trade Minister Simon Crean - who could veto the export - said that the export of brown coal was good for the economy.

He probably won't be around when we are dealing with the jobs lost from the Great Barrier Reef tourism industry - or the countless other benign industries which will be ruined by climate change.

Starting a new industry of shipping our dirty brown coal into third world countries to burn for fuel is crazy policy.

The signs of the climate crisis are in our face, and yet we are acting as though it is only a question of the money we can make now.

We've just seen a change of national leadership because of a failure to act on the climate crisis. This is a test of our new leadership.

Thursday, 10 June 2010

The Year Without a Summer

Eyjafjallajökull in Iceland - in eruption this year

On 11 April 1815 the British ship Benares was in port at Makassar in the southern Celebes, when the officers and crew heard a growing fusillade of loud cannon fire. She sailed south to investigate.

It was the time of the Napoleonic Wars, and unbeknown to those in the East Indies, Napoleon had been restored to power in France a few weeks earlier for what would be known as the Hundred Days.

The Benares could find nothing, and returned to port, but on 19 April the explosions resumed with such intensity that they shook houses and ships.

The captain of the Benares again sailed south, under a sky dark with ash, and with cinders raining down onto the deck of his ship.

On the northern tip of the island of Sumbawa (two islands to the east of Bali) stood the volcano Mount Tambora, and it had erupted.

Once the eruption was over, Mount Tambora was fully 1,300 metres shorter than it had been previously.

Sir Thomas Stamford Raffles - Lieutenant Governor of Java - wrote:
The area over which tremulous noises and other volcanic effects extended was one thousand English miles [ie 1,600 kilometres] in circumference, including the whole of the Molucca Islands, Java, a considerable portion of Celebes, Sumatra, and Borneo. ... Violent whirlwinds carried men, horses, cattle, and whatever came within their influence, into the air.
Tens of thousands died, both from the blast itself and from famine caused by the rain of ash which buried crops.

The discharge from the Mount Tambora eruption was far greater than that from Krakatoa in 1883, and over one hundred times greater than that from the Mount St Helens eruption of 1980. The Mount Tambora eruption remains the most powerful in recorded history.

Following the eruption of Tambora, volcanic dust at high altitudes provided a shield from solar radiation, and led to much lower surface temperatures around the globe.

The following year, 1816, has been known ever since as "the year without a summer". In the bitter cold, crops failed and many died in Europe and the Americas. Percy Shelley entertained house guests in Geneva, and the weather remained so bitter that they could not go out. To amuse them Mary Shelley composed her masterpiece "Frankenstein" - the first work of science fiction.

This year we have seen the eruption of the Iceland volcano with the almost unpronounceable name Eyjafjallajökull. Ash clouds from the eruption have affected air travel, and they have no doubt prevented some of the sun's warmth reaching the Earth - which should reduce global warming for a time.

Those who want to make a killing from the climate crisis have been spruiking a geoengineering solution - mimicking the action of volcanoes by injecting millions of tonnes of sulphur dioxide into the atmosphere.

This scary option has been identified as having many dangers - including interference with major weather patterns such as the Indian monsoon. It would also mean we would not see a blue sky during the years when these aerosols linger in the atmosphere.

Playing around with this expensive and risky option is one way to avoid taking real action to attenuate carbon emissions and live sustainably.

This year Victoria's Brumby government was the sole sponsor of an invitation-only conference of geoengineers and venture capitalists in California to discuss this Frankenstein solution to the climate crisis.

A further "debriefing" from the conference is planned in Melbourne shortly.
The Victorian government already has a shameful dirty brown coal legacy: when Hazelwood (the developed world's dirtiest power station) was due to close in 2005, the government extended its life to 2031. Spending money on geoengineering strategies takes us further backwards: it is not only dangerous, it leads Victoria away from a carbon-free, sustainable future.

There are enough natural disasters in the world without making our own.

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