Sending Leadbeater’s Possum down the road to extinction
14 December 2012, 2.28pm AEST
An alternative pathway is to reform (and significantly reduce) the loss-making pulpwood and timber industries, capitalise on the massive financial carbon values of these forests, maintain and then improve the water catchment values for Melbourne, and, in doing so, protect the globally endangered Leadbeater’s Possum.
It’s our choice.
Thirty years of work in Victorian ash forests
I first began working in Victorian Mountain Ash forests in mid-1983. Nearly 30 years later, my research team and I still work in these stunningly beautiful forests – located just two hours from the MCG.
One of the target species of our work is Leadbeater’s Possum, one of Victoria’s two faunal emblems. (The other – the Helmeted Honeyeater – is also highly endangered.) We have worked on this highly endangered possum and its habitat, especially the effects of fire and logging on the dynamics and structure of the forest in which it lives.
These forests are the tallest flowering plants on earth (some trees approach 100 metres tall and even taller specimens have been documented). Mountain Ash forests are also the world’s most carbon-dense forests and produce most of the water for the city of Melbourne.
Our research has clearly demonstrated that a key part of the habitat of Leadbeater’s Possum is access to large old trees. They are typically 190 years old (and often much older).
Recent articles in Science and PLOS One have shown there is a rapid and catastrophic decline in populations of large old trees throughout Mountain Ash forests. This is occurring because of past recurrent logging, fire, post-fire salvage logging; and logged and regenerated forests are more fire prone for about 70+ years after harvesting.
These drivers are creating a severe shortage of suitable nesting and denning sites; a shortage that will last until 2067 – the time when the existing 73-year forest will first begin to develop hollows for use by arboreal marsupials.
Around 42% of Leadbeater’s Possum’s habitat was burned in the 2009 wildfires and our repeated surveys at long-term sites since then have indicated that the species does not occur on burned sites – even those subject to moderate or low severity fire. Large areas of intact forest are critically important for the survival of Leadbeater’s Possum.
Logging and Leadbeater’s Possum
Logging is a major form of human disturbance. It is damaging the habitat of Leadbeater’s Possum and leading to the rapid demise of the species.
Logging has a range of detrimental effects. Clear-felling is the conventional form of logging in Mountain Ash forests. Under the Victorian Government’s Timber Release Plan, 412 coupes- or 17,640 ha of Mountain Ash – will be logged to 2016. This is out of around 38,000 ha of 1939-regrowth-aged Mountain Ash forest that is available for logging.
Clear-felled areas do not support viable populations of large old trees. These trees are typically destroyed in logging operations or, if retained, they die or collapse soon after logging. Logging areas therefore do not support habitat for Leadbeater’s Possum.
Based on work we published in 1993, we have found that changes in landscapes arising from a series of closely juxtaposed logged areas renders such landscapes unsuitable for Leadbeater’s Possum.
Third, and very importantly, logging changes fire regimes in wet forests such as Mountain Ash forests. It makes them both more fire prone) and more likely to burn at high severity. Such changes, in turn, have devastating effects, both directly on Leadbeater’s Possum (the species is absent from burned sites) and on populations of large old trees on which the species depends.
Leadbeater’s Possum as a test of ecologically sustainable forest management
Forest management practices cannot be claimed to ecologically sustainable unless there are viable populations of Leadbeater’s Possum maintained in the wild and in perpetuity.
However, all existing data gathered over the past four to five years clearly indicates that Leadbeater’s Possum is heading for extinction. Some urgent and radical reforms must take place in Mountain Ash forests:
- Set aside an expanded national park that incorporates additional large and intact areas of forest. Why not give this new park an evocative name like the Giant Trees National Park? Make the world’s tallest flowering plants something that all Victorians, Australians, and overseas travellers want to come and see.
- Reduce sustained yield of pulpwood and timber logged from Victorian ash forests by 50-75%. Despite the loss of tens of thousands of hectares of forest in the 2009 fires, sustained yields have not been re-assessed. This means the reduced area of green forest is being cut much faster than it was before the fire! This industry reform must be socially just.
- Stop logging all areas of 1939-regrowth that support some large, living trees. These areas have considerable current and future habitat value and logging such places significantly increases the risk that critically important large trees will die and collapse.
- If logging continues, retain islands on logged coupes. In partnership with the Department of Sustainability and Environment and VicForests, we have trialled Variable Retention Harvesting Systems and shown they can work. Yet, the approach has not been implemented in Victorian ash forests. Notably, Variable Retention Harvesting Systems are now widely adopted across Tasmania – leaving Victoria well behind on issues to do with the ecologically sustainable management of its forests.
Worth more standing up
The Victorian Government must recognise the carbon value of its native forests and the truly massive financial benefits that can be generated – just as has happened in the peace deal for Tasmanian forests.
Mountain Ash forests are the most carbon-dense in the world. The carbon offset value is worth tens of billions of dollars to Victorians – if Mountain Ash and Alpine Ash forests remain unlogged.
Right now, millions of dollars are being lost annually through forest logging in Victoria – there is effectively a government loss-making subsidy to cut down forest. Imagine how the Victorian Government could use such new sources of funds to fix problems with shortages of doctors, nurses, hospital beds, teachers, school infrastructure, transport systems and so on.
This approach will require people in the forest to manage this important resource. And maintaining and increasing the carbon storage value of forest will be compatible with other values like water production and biodiversity conservation (including the conservation of Leadbeater’s Possum).
Public natural resources should always be managed for the maximum public benefit. The current loss-making approach clearly fails where an alternative carbon value approach can succeed.
The future pathways are clear in Victoria. We can chose a 1950s pathway: clear fell forests in ways that lose large amounts of money, degrade the forest, erode water catchment yields, increase fire risks, and drive the state’s faunal emblem to extinction.
Or we can reform (and significantly reduce) the loss-making pulpwood and timber industries, capitalise on the massive financial values of maintaining carbon in these forests, improve the water catchment values for Melbourne and protect the globally endangered Leadbeater’s Possum.
If Leadbeater’s Possum goes extinct, it will not be because we did not have the science. It will be because we chose the wrong path.