'Saving' Australia’s forests for carbon - valid science or 'green' activism?

A recent Australian Government study of 115 key industries found that only the forestry sector was net carbon-positive. Yet, a major Wilderness Society campaign is advocating the closure of Australian timber industries to help mitigate climate change.

Their campaign revolves around research by scientists from the Australian National University Fenner School of Environment and Society who have found that large amounts of carbon reside in some Australian “old growth” forests. Environmental activists have shoe-horned this finding into their over-arching 40-year campaign to completely evict timber production from all Australian forests. Their rationale is that a total absence of timber harvesting will allow all forests to become “old growth” which will store maximum amounts of carbon.

This raises several important issues. First, closing a carbon-positive industry that is based on a renewable resource is hardly likely to reduce carbon emissions. Second, the capability of most forests to attain “old growth” is reliant on fire, irrespective of timber harvesting. And third, there is concern about the integrity of the Wilderness Society’s campaign and the key participatory role of several ANU scientists.

It is hardly a surprise that large trees store more carbon than small trees. Yet this is essentially the finding of the ANU research which the Wilderness Society has loudly trumpeted as an exciting new development since it was released via two academic papers published during the past 10 months.

The first paper entitled Green Carbon - the Role of Native Forests in Carbon Storage - Part 1, by ANU scientists Professor Brendan Mackey, Dr Heather Keith, Sandra Berry, and Professor David Lindenmayer, was published in August 2008. This is now supported by a follow-up paper published just days ago (in late June 2009) - entitled Re-evaluation of forest biomass carbon stocks and lessons from the world’s most carbon dense forests, by Keith, Mackey, and Lindenmayer.

Much of the research underpinning these papers has focused on mountain ash (Eucalyptus regnans) forests in Victoria’s Central Highlands. Prior to February 2009, the majority of these ash forests were classed as advanced regrowth derived from the 1939 and 1926 bushfires. Only about 1.5 per cent of their area was classed as “old growth”.

February’s “Black Saturday” fires changed this quite significantly by killing a large area of ash regrowth and most of the “old growth” ash. Ash forests depend on fire for renewal and these burnt areas will regenerate as new young stands. The period between stand replacement fires is variable, but may be sufficiently infrequent to allow some forests to grow for hundreds of years to attain “old growth” status. However, as we have seen over the past century, more frequent fires can kill huge areas before they grow old and thereby maintain much of the forest in a regrowth state.

Anti-logging activism is typically silent on matters of scale and proportion as it is far easier to foster community outrage by implying that all forests are threatened. However, this is far from the reality. In Victoria, less than 10 per cent of public forests are available and suitable for timber production: the national figure is 6 per cent. Within these available forests, harvesting and regeneration occurs on a sustainable cycle that aims to supply timber and fibre in perpetuity.

Despite being Victoria’s most productive forest type, about two-thirds of the state’s mountain ash forests are in parks and reserves where timber production is excluded. Where permitted, timber production is restricted to regrowth ash forest mostly emanating from the 1939 bushfires. While, the ANU research and associated environmental campaign have built a perception that central Victoria’s “old growth” ash forests are threatened by logging, all were protected in parks and reserves, or by management prescription.

The exclusion of timber production from the vast majority of Australia’s forests means that most already have the potential to grow their carbon stocks towards their maximum carrying capacity. However, it is drawing an extremely long bow to expect all Australian forests to attain “old growth” given the prevalence of fire in the landscape; and an even greater leap of faith to expect that closing down a timber industry which operates in only a minor part of the forest, to be a catalyst for maximising forest carbon storage.

On the contrary, it is highly likely that closing Australia’s hardwood timber industry would exacerbate climate change. This is because it would encourage greater importation of hardwoods from developing countries whose forests are not sustainably managed; and increase the substitution of renewable wood products with non-renewable alternatives, such as steel and aluminium, which embody massive carbon emissions in their manufacture.

Furthermore, the forced removal of economic activity from Australia’s forests in response to political activism is already acknowledged as a significant factor in declining capability to manage forest fire. Total removal of industry and associated government workforces would only exacerbate this problem and thereby further reduce the chances of forests growing old before they are burnt.