• Removal of canopy and understorey leads to large amounts of topsoil being washed away (erosion in the short term) and deposited into waterways (sedimentation). Sedimentation can have serious consequences and implications for the health of waterways.
• Poses risks to human health. Pathogens like giardia can breed in depressions left by logging machinery and can then be washed into waterways.
• Microclimatic effects can lead to drying in the forests that are adjacent to coupes this might result in greater susceptibility to fires and changes in vegetation types if a fire does occur. Rainforests and riparian vegeation are particularly susceptible to these effects.
• Opening forest canopy can lead to windthrow and wind shear (damage to canopies from wind) which also results in microclimatic effects.
  Central Highlands

  

  Before modern industrial logging practices loggers would selectively harvest the forest. This method is self explanatory in that loggers would choose the trees they wanted in a given area and leave everything else. Provided an area was not logged too intensively, the forest would remain very similar to untouched forest. There would be young trees, old trees, undergrowth, habitat trees. The forest would sustain the same number and density of species and quantity and volumes of water.

  DSE now argues that this method does not allow for adequate regeneration. Oddly enough, some of the areas that were selectively harvested in the past have been deemed important and spectacular enough to include in National Parks but untouched biodiverse old growth forest outside parks needs to be cleared to make way for "healthy" forest.

  The real problem with native forests from a forester's perspective is that they don't provide enough timber and fibre to keep up with the society's capacity to consume timber and fibre products. This puts pressure on forest managers to use the cheapest and fastest means of extracting timber regardless of the ecological sustainability of the methods. The dilemma for society is, do we determine the level of logging based on our capacity to consume, or by forests capacity to supply without compromising its ability to perform all the environmental services we take for granted?

  The benefits of the old logging methods in terms of their ability to preserve biodiversity are self-evident. Leaving trees behind to senesce (grow old ) and form hollows creates places for birds and animals to live. This is important as all the species that make up a forest such as plants, animals birds, insects, microbes etc. contribute to its health and function. Managing forests only for timber and fibre production alienates all other values. In selectively logged mixed species forests, trees of all ages grow alongside giant old growth trees.

  Selective logging is not without some risks. Species with higher commercial value can be targeted for extraction leading to changes in proportional representation of species in a forests composition. Another risk is related to a higher proportion of the better shaped trees, i.e. trees with nice straight trunks that are better suited to sawmilling, being taken out of the forest. Some people suggest that this would lead to trees with a genetic prediposition to being warped or twisted etc., becoming over-represented in forests. There is some question as to whether the environment or genetics of a tree are responsible for its shape. These issues do represent insurmountable hurdles and could be accounted for by harvesting prescriptions and coupe level management.

  The clearfell method of logging has proven to be a disaster for the environment as some coupes have failed to regenerate at all after logging and have had to be replanted by hand with non-local species or in some cases they are not replanted at all . DSE continues to anticipate 100% regeneration in logged areas even though their own figures show as little as 30% regeneration in the Central Highlands and near total failure in other regions. This type of failure by DSE has had a disasterous effect on the timber industry and local communities.

  N.E. Victoria

  It is abundantly clear that the real motive behind clearfelling is commercial and political expedience. "The 'mosaic' of forests of different ages" that DSE espouses are no more than a system of monocultural woodlots of different ages. They bear no resemblance to the original ecological mosaic. As regenerated clearfell coupes will be harvested in short rotation (< 80 yrs) they are never allowed to fulfill their biological potential and are becoming, in effect, biological deserts. DSE’s commitment to “ecological sustainability” is barely a token gesture when it comes to the areas it manges for timber production.

  The problems with cleafelled forests are not only short term either:

  • a large area of regrowth can attract animals that want to feed on seedlings. In Tasmania they lay 1080 poison baits to kill Wallabies that are attracted to the area

  • regrowth forest use lots of water when they are growing and deprives adjacent forests and waterways of enviromental flows (see graph at right)

  • the density and structure of regrwoth forest makes them more susceptible to fire. This in turn also impacts on adjacent areas. Rainforest and riparian strips can be killed or severely impacted by fire.

   

  • suppress competing species thereby altering forest composition (logging in short rotations prevents forest from developing mature structural charcteristics e.g. diverse understorey).

   

  • are not suitable habitat for many species as they are in a perpetual state of arrested development. Species that rely on mature forest cannot live in forests that are locked into an 80 year logging cycle.

     

  From The AGE

  Clear-felling: a big, burning issue

  By Claire Miller

  May 13 2002

  If a picture speaks a thousand words, then the image of a freshly clear-felled coupe, blackened and smoking, tells a confusing story. For conservationists, it is an image of wanton destruction to feed a voracious export woodchip market. But for the state's forest managers and the timber industry, clear-felling is about renewal. Sure, it is not pretty to start with, but within a few short years, a better forest is growing back. In principle, the practice is ''natural" because it mimics the effects of wildfires. Certainly the aftermath of clear-felling and wildfires look pretty much the same at first glance, except that a fire generally leaves far more trees standing and alive.

  Clearfell logging in Melbournes water catchment.

  But such subtle differences tell another story - that clear-felling may be changing native forests in ways anything but natural. Peer-reviewed scientific research here and overseas suggests clear-felling has serious, long-term and negative ecological effects. Such concerns have led to clear-felling being reviewed, modified, and in some cases, abandoned in developed countries such as the United States and Canada. In view of such concerns, Environment and Conservation Minister Sherryl Garbutt has commissioned a review by Melbourne University's Forest Science Centre. Centre director Mark Adams says the review of the scientific literature would highlight how different forest types respond to logging and other disturbances, natural and man-made.

  A spokesman for Garbutt says logging practices generate much community debate and the government has a responsibility to obtain the best and most accurate information. "We would be negligent if we didn't do it." He says the findings of the review would be "an important tool in developing future forestry policies". About 30 per cent of Victoria's forests with commercial potential are open to logging after taking out reserves, stream buffer zones, and other constraints, according to Forestry Victoria general manager Peter Rutherford. About half the 12,000 hectares logged each year is clear-felled. Forestry Victoria operations manager Peter Ford says clear-felling is the way to get a healthy, growing forest. Often in the past the best trees and species were selectively removed so that forests were no longer representative of their natural state. Starting over meant the original mix could be regenerated. "We try to mimic nature and get the product out at the same time," he says. But Simon Birrell of the Otway Range Environment Network says clear-felling changes biodiverse forests into an artificial environment. "It is no longer natural, it is something of human creation," he says. Humans have already transformed so much of the landscape through agriculture and plantations that what little natural land is left should be protected.

  Clear-felling has strong industry and union support. Victorian Association of Forest Industries public affairs director Pat Wilson says clear-felling is not appropriate in every case, but it is safer for workers and seems to promote better regeneration. He says the industry would need to be convinced alternatives were safer and promoted better-quality trees. Clear-felling is also more economic than selective logging. Trees destined for woodchipping are removed at the same time as logs for value-adding in sawmills, adding to contractors' incomes. In the Otways, for example, cutting and transporting woodchip logs accounts for 60 per cent of the loggers' income, according to Freedom of Information documents. However, forest ecology experts say the suitability of clear-felling depends on whether the forest is managed primarily for timber production or not. They say clear-felling, particularly on the short 60-80 year rotations practised in Victoria, is reducing the overall diversity and abundance of wildlife and plant species, lowering water run-off, and, arguably, making forests more vulnerable to fire.

  In 1998, the Cooperative Research Centre for Catchment Hydrology reported that run-off from a clear-felled coupe in a mountain ash forest halves over the first 40 years and does not recover until the regrowth is more than 150 years old. This means an extra 17,000 megalitres of water a year would flow into Melbourne's Thomson Dam if the forest was left to grow old, according to a government-appointed committee discussion paper on meeting future water needs. The $147 million value of the extra water compares with the $1.43 million a year the government earns from the logging.

  Similarly, according to a 2001 Sinclair Knight Mertz report for the government, run-off would rise 10 per cent and 26 per cent by 2080 for Geelong and Warrnambool respectively if clear-felling stopped in their Otways catchments. The report also says there is a rapid drop in water yield in the event of a severe wildfire. But Adelaide University paleo-ecologist Peter Gell says there is a critical difference. Charcoal records suggest that, in prehistoric times, severe wildfires comparable in effects to clear-felling swept through Victoria's tall, wet forests perhaps only once every 300 years. This compares with clear-felling every few decades. But Gell says the frequency and intensity of fires has increased dramatically since white settlement and has changed the character of the forests. Clear-felling has continued that pattern of human-induced change.

  The CSIRO's Malcolm Gill, an expert in fire ecology, says if forest managers are interested only in timber values, then clear-felling could be similar to wildfire in terms of boosting the regeneration of certain trees, like the commercially valuable mountain ash. But he says clear-felling and wildfires have different impacts if other concerns are taken into account. For example, trees take at least 150 years to form hollows, upon which a third of native fauna species rely for breeding, shelter and prey. ''If you are cutting the trees at 60 years and it takes hollows 150 years to form, then anything dependent on the hollows is doomed," Gill says.

  Australian National University biologist David Lindenmayer has spent almost 20 years studying the ecology of Victoria's mountain ash forests. He says wildfires leave a centuries-old biological and structural legacy. Clear-felling, on the other hand, removes almost all vegetation, so that a quite different, botanically simplified and even-aged forest grows back. Lindenmayer says clear-felling leaves too few trees to sustain species relying on hollows. Victoria's endangered faunal emblem, the Leadbeaters possum, for example, suffers because it needs multiaged forests where short-lived, fire-loving forage trees stand under a canopy of old, hollow-bearing giants that have survived a series of mild and moderate blazes over the centuries. He says logging should be varied according to natural landscape variations. He says other countries such as Sweden are adjusting methods to resemble local patterns of natural disturbance. This means, for example, that a patch with little natural fire history would never be logged. ''We are behind the world in best practice and we have some work to do to catch up now," he says.

• "The mosaic of forests of different ages"...?

• Consultant ecologist and former head of the Natural Resources and Environment Department's forest flora unit, Steve Mueck, says clear-felling is a long-term fire hazard because the forest that grows back contains a mix of species typical of drier forest types. It is therefore at risk of burning more frequently with greater intensity and speed. Mueck says clear-felling dramatically reduces the abundance of long-lived plants like tree ferns that otherwise recover quickly from wildfires and help suppress blazes by keeping the forest floor damp. Dense regrowth of saplings also creates an oil-rich canopy closer to the ground, making it easier for flames to jump into the tree-tops and race away. "In a situation where wetter (plant) components have been eliminated, the forest is drier and structurally there is a great opportunity for fires to start, so we are building a potential firebomb. "This is not to say it wasn't flammable to start with, but we are making the situation worse from a fire perspective." Principal fellow at Melbourne University's School of Botany, Peter Attiwell, says while there is evidence that species typical of drier forests do invade after clear-felling, no studies have been done to establish if there is a missing link leading to more flammable forests.

  Forests are complex. It is difficult to generalise across different types, topography and climatic conditions. It is possible to find botanically diverse regrowth forests, and old growth forests as botanically diverse as clear-felled areas. Since any forest would burn under the right sorts of conditions, he says it is a matter of degree whether, overall, they burn more or less in the decades after clear-felling. Attiwell says it would be difficult to show conclusively that clear-felling really tipped the balance towards a more flammable kind of forest.

  Head of geospatial science at RMIT University in Melbourne, Tony Norton, says it is not true that clear-felling mimics the ecological effects of wildfires. "There are plenty of scientific journal articles written in the last 15 years indicating how the impacts of clear-felling actually do not mimic natural disturbances in these forests - but we haven't moved too far to reflect that in our forest management."

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