LOGGING MAKES FOREST FIRES WORSE : EXPERTS
So much has happened this year. If you weren't directly affected it almost takes an effort to think back before Covid-19 and the Black Summer of bushfires that raged from September to March through our forests and communities.
Air quality was at hazardous levels for months, 18.6 million hectares burned, 3,121 buildings and 2,779 homes lost, 34 people killed, an estimated One billion animals are thought to have died and endangered species may have been driven to extinction. The economic recovery was only just being tallied before the virus hit.
An edge of Wet Eucalyptus viminalis forest in Loongana.
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With evidence between the links of logging and bushfire mounting, will the proposed transmission easement through Loongana be one fire risk too far? Having been warned, will the proponents face culpable negligence lawsuits in the future? |
Loongana Valley already has high fire risks, and the proposed transmission line easement risks drying out our wet forests even further. The transmission line could push our community beyond acceptable risk, and we are worried about the consequences.
Loongana is one of many small communities that have lost their fire appliance and brigade due to the restructuring of resources. We are working on a community fire resilience plan but to date our regional fire service has been unable to identify a Place of Last Resort for our safety and point of evacuation. That leaves each resident fending for themselves which is a frightening thought when communication during a forest fire is paramount and we have no mobile coverage here. A large part of a good fire plan is organising your house and property well and this extends to your local environment.
The Loongana Valley runs west to east and so too does the prevailing wind. There is one winding road in and out over bridges with wooden foundations. A fire from the west will arrive on our doorsteps quickly and a fire from the east will have us trapped. So when experts who study catastrophic fire events and conclude that logging native forests is a dangerous practice, we sit up and take notice.
Loongana is one of many small communities that have lost their fire appliance and brigade due to the restructuring of resources. We are working on a community fire resilience plan but to date our regional fire service has been unable to identify a Place of Last Resort for our safety and point of evacuation. That leaves each resident fending for themselves which is a frightening thought when communication during a forest fire is paramount and we have no mobile coverage here. A large part of a good fire plan is organising your house and property well and this extends to your local environment.
The Loongana Valley runs west to east and so too does the prevailing wind. There is one winding road in and out over bridges with wooden foundations. A fire from the west will arrive on our doorsteps quickly and a fire from the east will have us trapped. So when experts who study catastrophic fire events and conclude that logging native forests is a dangerous practice, we sit up and take notice.
New Research from Tasmania Shows That Logging Makes Fires More Severe
by Dr. Jen Sanger
17 May 2020
New research from the University of Tasmania has found that logging causes bushfires to be worse. In a scientific paper published in the Journal ‘Fire’, the researchers found that logging regrowth and plantations burned at a higher severity than old-growth forests. The study examined the area in the Huon Valley, Tasmania that was impacted by the Riveaux Road Fire in January 2019.
Satellite images of the area taken before and after the fire allowed the researchers to examine where the fire burned, its severity, and the types of forest that were impacted. Old growth, mature forest and plantation tended to burn less than regrowth forest: but the most notable differences were in fire severity. More severe fires occurred in logging-regrowth and plantation forests (about 60% crown death each) while fires were less severe in mature forests (30% crown death), and old-growth forests (12%).
Satellite images of the area taken before and after the fire allowed the researchers to examine where the fire burned, its severity, and the types of forest that were impacted. Old growth, mature forest and plantation tended to burn less than regrowth forest: but the most notable differences were in fire severity. More severe fires occurred in logging-regrowth and plantation forests (about 60% crown death each) while fires were less severe in mature forests (30% crown death), and old-growth forests (12%).
Area of wet forest scheduled for clearfell and regeneration at Loongana
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The lower flammability of older forests, and their importance as an increasing store of carbon, suggests that a cessation of logging outside plantations might have considerable benefits. |
Old-growth wet-eucalypt forests, which are the most commonly logged forest type in Tasmania, are naturally more resilient to fire than younger forests. This is because they often contain shady, wet understoreys of non-flammable rainforest plants which helps to slow down fires. In contrast, younger forests and plantations have a much higher density of young eucalypts and a much drier understory, causing them to be much more flammable. The flames can also easily reach into the canopy, creating very intense fires which tend to spread quickly and are difficult to control.
One of the paper’s co-authors, Dr Jennifer Sanger, said the finding of this research were significant. ‘Regrowth from logging and plantations often form the interface between untouched forests and our communities. We really need to take this into consideration when planning on how we make our communities safer from wildfire’.
‘There have been calls from the forestry industry after the recent bushfires to use logging as a way to reduce the fire risk. This is extremely misleading as our research has shown that logging can make forests more fire prone,’ Dr Sanger said.
One of the paper’s co-authors, Dr Jennifer Sanger, said the finding of this research were significant. ‘Regrowth from logging and plantations often form the interface between untouched forests and our communities. We really need to take this into consideration when planning on how we make our communities safer from wildfire’.
‘There have been calls from the forestry industry after the recent bushfires to use logging as a way to reduce the fire risk. This is extremely misleading as our research has shown that logging can make forests more fire prone,’ Dr Sanger said.
An area of wet forest area in Loongana scheduled for clearfell logging.
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Our results show a clear relationship between disturbance history and fire incidence and severity under moderate fire weather conditions. |
Propensities of Old Growth, Mature and Regrowth Wet Eucalypt Forest, and Eucalyptus nitens Plantation, to Burn During Wildfire and Suffer Fire-Induced Crown Death
ABSTRACT:
There are conflicting conclusions on how the flammability of wet eucalypt forests changes in the time after disturbances such as logging or wildfire. Some conclude that forests are most flammable in the decades following disturbance, while others conclude that disturbance has no effect on flammability. The comparative flammability of Eucalyptus nitens plantations in the same environment as wet eucalypt forest is not known. We determined fire incidence and fire severity in regrowth, mature and old growth wet eucalypt forest, and E. nitens plantation, in the Huon Valley, Tasmania after the January–February 2019 wildfire. To control for topographic variation and fire weather, we randomly selected sites within the fire footprint, then randomly located a paired site for each in different forest types in the same topographic environment within 3 km. Each pair of sites was burned on the same day. Old growth forest and plantations were the least likely to burn. Old growth and mature forest exhibited scorched eucalypt crowns to a much lesser degree than regrowth forests. In a comparison of paired sites, plantation forest was less likely to burn than combined mature and old growth forests, but in all cases of detected ignition the canopy of plantation was scorched. The lower flammability of older forests, and their importance as an increasing store of carbon, suggests that a cessation of logging outside plantations might have considerable benefits.
CONCLUSION:
Our results show a clear relationship between disturbance history and fire incidence and severity under moderate fire weather conditions. Fire severity is related to intensity, which is important for ease of suppression. Thus, the retention of older forests across the landscape may decrease fire risk. Allowing eucalypt forests to mature further than the normal cycles of 40 to 90 years could help reduce fire hazards. This is especially pertinent around built assets and vegetation types vulnerable to fire. Our results are consistent with the ‘landscape trap’ theory.
In addition to providing a valuable damper on fire incidence and severity, old growth Eucalyptus regnans wet forests store the highest density of carbon of any forests in the world. Carbon continues to be captured in the aging old growth forests, rather than reaching an asymptote. Soil carbon in wet eucalypt forest is a substantial store, its magnitude related to the above ground biomass of the forest. The slow release of carbon from the soil as a result of previous conversion from primary forest to production forest, can only be prevented by allowing forest regrowth to continue to old age.
To refine our understanding of the relationship between disturbance history and fire we need to ask: how localised is the effect of patches of more flammable regrowth in a landscape—does a patchwork of forest types make a whole region more susceptible to fire; at what point after clearfell logging does a forest become less flammable; and, is there a way to manage the forest up to this point to reduce fire hazards while maintaining natural values?
A study with similar findings was published in the leading international journal Nature only two weeks ago by researchers from Australian National University.
In addition to providing a valuable damper on fire incidence and severity, old growth Eucalyptus regnans wet forests store the highest density of carbon of any forests in the world. Carbon continues to be captured in the aging old growth forests, rather than reaching an asymptote. Soil carbon in wet eucalypt forest is a substantial store, its magnitude related to the above ground biomass of the forest. The slow release of carbon from the soil as a result of previous conversion from primary forest to production forest, can only be prevented by allowing forest regrowth to continue to old age.
To refine our understanding of the relationship between disturbance history and fire we need to ask: how localised is the effect of patches of more flammable regrowth in a landscape—does a patchwork of forest types make a whole region more susceptible to fire; at what point after clearfell logging does a forest become less flammable; and, is there a way to manage the forest up to this point to reduce fire hazards while maintaining natural values?
A study with similar findings was published in the leading international journal Nature only two weeks ago by researchers from Australian National University.
