Last week the Australian National University released a report** on “Green Carbon” claiming that un-logged native forests store three times more carbon than previously reported and this prompted a demand by The Wilderness Society for an urgent end to logging of the carbon dense native forests in New South Wales, Victoria and Tasmania.
Alan Ashbarry, a Tasmanian with an interest in the social and economic benefit of value adding native forest timber from sustainable forestry and a member of Timber Communities Australia, has sent me his critique of the report.
The report was funded by the Wilderness Society as part of its campaigns against the harvesting of native forest of high political value. This campaign includes opposing Tasmania’s approved pulp mill as it will use pulp wood from native forests at a time when the Wilderness society claims that their “carbon storage is critically important to combat climate change”.
So is it not surprising that the report recommends the banning of all industrial logging in Australia’s south eastern native forests.
This means closing down the native forest timber industry in Tasmania, Victoria and Southern New South Wales and stopping the pulp mill.
In the ultimate irony, if the industry is shut down, it is likely that Australia will import timber and paper products from tropical forests in developing counties as alternatives for the wood products created by sustainable forestry in these areas.
It is these tropical forests that are most at risk and are the target of the United Nation’s REDD program. This program aims to reduce emissions from deforestation or degradation of forests in the developing world.
According to data from the United Nations the REDD program does not target sustainable forestry in Australia.
All official statistics and reports show that deforestation has virtually stopped in Australia and all forest harvesting/ management is undertaken and measured against international criteria for sustainable management.
Unlike the Wilderness Society, the UN’s Intergovernmental panel of Climate Change (IPCC) recognises the value of our forest sector explaining:
“In the long term, a sustainable forest management strategy aimed at maintaining or increasing forest carbon stocks, while producing an annual sustained yield of timber, fibre or energy from the forest, will generate the largest sustained mitigation benefit”
But what about the new report published by the ANU and funded by the Wilderness Society? How robust is the claim that un-logged native forests store three times more carbon than previously stated in Australian government reports and by internal climate change experts?
The report itself states: “A technical paper that details the source data, the methods used and the full results is being prepared for a scientific journal.”
In the absence of this data, I checked their maths and found the report also failed the common sense test.
The ANU report has used a new model to estimate the carbon in our forests, a model that is completely at odds with studies undertaken by the Australian Greenhouse Office, Professor Peter Attiwill, Forestry Tasmania, MBAC, and the Cooperative Research Centre for Greenhouse accounting and they have significantly higher results than modelling by the Australian National University in 2003 and 2006.
The report’s lead author, Professor Brendan Mackey, who is a Wilderness Society volunteer on their Wild Country panel, last year in The Age demanded logging must be stopped to solve the global warming problem.
In The Age article he claimed “One hectare of mature, tall, wet forest can store the equivalent of 5500 tonnes of carbon dioxide” this is the equivalent of the large figure of total 1500 tonnes Carbon per hectare stored in the biomass and the soil [The conversion factor used for C/CO2 is 12/44 (0.273)].
Now this new ANU report in which he is lead author claims that forests “can store three times more carbon than scientists previously thought.”
The model used in the ANU report somewhat quaintly colour codes the carbon throughout the World: black is for charcoal, grey from fossil fuel, green is carbon stored in the biosphere, brown is carbon in “industrialised forests” and blue is carbon in the atmosphere and oceans. As green carbon is defined by the report as carbon sequestered through photosynthesis and stored in natural forests, the report can then ignore all that carbon that is stored in timber products from managed forests. This is extraordinary given that the carbon in managed forests is also manufactured through photosynthesis, yes even the carbon stored in the “brown” trees!
The ANU report selects only 14.5 million hectares from Australia’s forest estate of over 147 million hectares.
The new model created for this report relies on data of the ‘gross primary productivity’ and the report states: “The value of GPP used was the maximum annual value for the period from 1 July 2000 to 30 June 2005 (the maximum was used in order to exclude periods of major disturbance such as the 2003 bushfires).” This statement begs the question of why would you want to exclude bush fires surely this is “green” carbon.
Thus the model is all about potential not reality, and states on page 7:
“The difference in carbon stocks between our estimates and the IPCC default values is the result of us using local data collected from natural forests not disturbed by logging. Our estimates therefore reflect the carbon carrying capacity of the natural forests.”
The ANU report argues that “If logging in native eucalypt forests was halted, the carbon stored in the intact forests would be protected and the degraded forests would be able to regrow their carbon stocks to their natural carbon carrying capacity.”
Until this report it has mostly just been the forest sector that has stated the forest re-grows after harvest and can maintain both biological diversity and carbon carrying capacity.
The report authors then make a series of assumptions to determine the carbon sequestration potential of the logged forest area.
The report claims that an average carbon carrying potential of 360 t C ha-1 of biomass carbon (living plus dead biomass above the ground). It also claims the highest biomass carbon stocks, with an average of more than 1200 t C ha-1 and maximum of over 2,000 t C ha-1 are in the mountain ash (Eucalyptus regnans) forest in the Central Highlands of Victoria and Tasmania.
These are the areas of highest political value and have constantly been in the middle of the debate about forest management for the last decade or two.
It is these figures that clearly demonstrate that the model fails basic maths and common sense. If the carbon volumes are converted to the actual volume of trees, it means that there would be trees growing on trees!
Carbon density of eucalypt wood is about 0.325 t C/ m3, this means at 2,000 t C ha-1, this is 6,153.84 m3 of wood, say 6,150 m3 per ha. If only half of this could be considered the timber available to the forest sector(exclude branches, litter, rotting wood, stumps), then this wood equates to a volume of logs of about 3,000m3/ha.
Therefore in an average coupe of 50 ha this represents 150,000m3 of log, it means based on the model that two average size coupes will produce over 300,000 m3 of log.
To compare just how big a figure this is, Forestry Tasmania has a legislated requirement to supply the whole of Tasmania’s saw milling industry 300,000 m3 of saw logs each year from the 1.5 million hectares it sustainably manages!
In 2006-07 Forestry Tasmania harvested over 11,500 ha of native forest for a harvest of 301,526 m3 of sawlog, 283,880 m3 veneer and peeler hardwood and 2,136,687 tonnes of pulpwood. By approximating a tonne of pulp to 1.5 cubic metre this would be about 330 m3 per ha or 16,500 m3 per average coupe.
Even The Wilderness Society used a completely different figure of only 225 tonnes pulp wood per hectare, when calculating the impact of the approved pulp mill on Native forests. Even allowing for harvesting residues this is a tiny fraction of the new model’s figures.
The report fails the common sense test but it was published by a reputable university and has been given all the credibility of an independent scientific report by the mainstream media including the ABC.
The Wilderness Society and the ANU chose to release the report to the media rather than first publish it in a scientific journal subject to peer review. Now the report is likely to be used to lobby the United Nation committee that current forest practices degrade the forest. This lobbying attempt is just after their failure to convince UNESCO over wild allegations about the Tasmanian World Heritage Area.
Until the data and the calculations supporting this report have been subject to full independent scrutiny, the reports status must be considered just another claim in the ‘war of words’ on forestry.
** The report’s title is rather long: Green Carbon: The role of natural forests in carbon storage
Part 1. A green carbon account of Australia’s south-eastern Eucalypt forests, and policy implications
Authors are: Brendan G. Mackey, Heather Keith, Sandra L. Berry and David B. Lindenmayer
Published by: The Fenner School of Environment & Society, The Australian National University
And you can download it from: http://epress.anu.edu.au/green_carbon/pdf_instructions.html