Native forest logging makes bushfires worse – and to say otherwise ignores the facts


Philip Zylstra, University of Wollongong; Grant Wardell-Johnson, Curtin University; James Watson, The University of Queensland, and Michelle Ward, The University of QueenslandThe Black Summer bushfires burned far more temperate forest than any other fire season recorded in Australia. The disaster was clearly a climate change event; however, other human activities also had consequences.

Taking timber from forests dramatically changes their structure, making them more vulnerable to bushfires. And, crucially for the Black Summer bushfires, logged forests are more likely to burn out of control.

Naturally, the drivers of the fires were widely debated during and after the disaster. Research published earlier this month, for example, claimed native forest logging did not make the fires worse.

We believe these findings are too narrowly focused and in fact, misleading. They overlook a vast body of evidence that crown fire – the most extreme type of bushfire behaviour, in which tree canopies burn – is more likely in logged native forests.

Logged forest
The authors say logging increases the risk of intense crown fires.
Australian National University

Crown fires vs scorch

The Black Summer fires occurred in the 2019-20 bushfire season and burned vast swathes of Australia’s southeast. In some cases, fire spread through forests with no recorded fire, including some of the last remnants of ancient Gondwanan rainforests.

Tragically, the fires directly killed 33 people, while an estimated 417 died due to the effects of smoke inhalation. A possible three billion vertebrate animals perished and the risk of species extinctions dramatically increased.

Much of the forest that burned during Black Summer experienced crown fires. These fires burn through the canopies of trees, as well as the undergrowth. They are the most extreme form of fire behaviour and are virtually impossible to control.

Crown fires pulse with such intense heat they can form thunderstorms which generate lightning and destructive winds. This sends burning bark streamers tens of kilometres ahead of the fire, spreading it further. The Black Summer bushfires included at least 18 such storms.

Various forest industry reports have recognised logging makes bushfires harder to control.

And to our knowledge, every empirical analysis so far shows logging eucalypt forests makes them far more likely to experience crown fire. The studies include:

  • A 2009 paper suggesting changes in forest structure and moisture make severe fire more likely in logging regrowth compared to undisturbed forest
  • 2012 research concluding the probability of crown fires was higher in recently logged areas than in areas logged decades before
  • A 2013 study that showed the likelihood of crown fire halved as forests aged after a certain point
  • 2014 findings that crown fire in the Black Saturday fires likely peaked in regrowth and fell in mature forests
  • 2018 research into the 2003 Australian Alps fires, which found the same increase in the likelihood of crown fire during regrowth as was measured following logging.

The findings of these studies are represented in the image below. The lines a, b and c refer to the 2013, 2014 and 2018 studies respectively.

Graph showing the likelihood of crown fire relative to years since logging or fire

Author supplied

Crown fires take lives

The presence of crown fire is a key consideration in fire supression, because crown fires are very hard to control.

However, the study released last week – which argued that logging did not worsen the Black Summer fires – focused on crown “scorch”. Crown scorch is very different to crown fire. It is not a measure of how difficult it is to contain the fire, because even quite small flames can scorch a drought-stressed canopy.

Forestry studies tend to focus more on crown scorch, which damages timber and is far more common than crown fires.

But the question of whether logging made crown scorch worse is not relevant to whether a fire was uncontrollable, and thus was able to destroy homes and lives.

Importantly, when the study said logging had a very small influence on scorch, this was referring to the average scorch over the whole fire area, not just places that had been logged. That’s like asking how a drought in the small town of Mudgee affects the national rainfall total: it may not play a large role overall, but it’s pretty important to Mudgee.

The study examined trees in previously logged areas, or areas that had been logged and burned by fires of any source. It found they were as likely to scorch on the mildest bushfire days as trees in undisturbed forests on bad days. These results simply add to the body of evidence that logging increases fire damage.




Read more:
I’m searching firegrounds for surviving Kangaroo Island Micro-trapdoor spiders. 6 months on, I’m yet to find any


Timber plantation after fire
Forestry industry studies tend to focus on crown scorch.
Richard Wainwright/AAP

Managing forests for all

Research shows forests became dramatically less likely to burn when they mature after a few decades. Mature forests are also less likely to carry fire into the tree tops.

For example during the Black Saturday fires in 2009, the Kilmore East fire north of Melbourne consumed all before it as a crown fire. Then it reached the old, unlogged mountain ash forests on Mount Disappointment and dropped to the ground, spreading as a slow surface fire.

The trees were scorched. But they were too tall to ignite, and instead blocked the high winds and slowed the fire down. Meanwhile, logged ash forests drove flames high into the canopy.

Despite decades of opportunity to show otherwise, the only story for eucalypt forests remains this: logging increases the impact of bushfires. This fact should inform forest management decisions on how to reduce future fire risk.

We need timber, but it must be produced in ways that don’t endanger human lives or the environment.




Read more:
‘We know our community better than they do’: why local knowledge is key to disaster recovery in Gippsland


The Conversation


Philip Zylstra, Adjunct Associate Professor at Curtin University, Honorary Fellow at University of Wollongong, University of Wollongong; Grant Wardell-Johnson, Associate Professor, Environmental Biology, Curtin University; James Watson, Professor, The University of Queensland, and Michelle Ward, PhD Candidate, The University of Queensland

This article is republished from The Conversation under a Creative Commons license. Read the original article.

A staggering 1.8 million hectares burned in ‘high-severity’ fires during Australia’s Black Summer


Shutterstock

Ross Bradstock, University of Wollongong; Hamish Clarke, University of Wollongong; Luke Collins, La Trobe University; Michael Clarke, La Trobe University; Rachael Helene Nolan, Western Sydney University, and Trent Penman, The University of MelbourneIn the aftermath of Australia’s devastating Black Summer fires, research has begun to clarify the role of climate change.

We already know climate change contributed to the record-breaking drought and fire weather conditions, leading to the bushfires’ unprecedented range across Australia.

Our new research looks at whether bushfires are becoming more “severe” (an indicator of how intensely the vegetation burned) as a result of climate change.

Our findings were unexpected, as we learned the proportion of high-severity fires generally hasn’t increased in recent decades. However, the sheer breadth of the Black Summer fires meant an unprecedented 1.8 million hectares across southeast Australia were exposed to high-severity fires. This has dire consequences for the people and wildlife who call the forests home.

What is fire severity?

Two measurements in fire science are pertinent to our research: fire severity and fire intensity.

Fire severity refers to how high the flames and the plume of hot air reach, as measured by the resulting damage to vegetation (vertical profile of scorch and consumption of leaves and twigs). Fire intensity refers to the energy released from the fire — how hot and destructive the flames are.

Scientists can estimate severity using using satellite imagery, by contrasting differences in the cover and condition of vegetation before and after fires.

In forests, “high-severity” fires occur when the crowns of dominant trees are fully burnt or scorched. High-severity fires are lethal to tree-dwelling mammals in forests, such as possums, gliders and koalas. They also pose a big risk to nearby homes and buildings.

“Low-severity” fires, on the other hand, may be confined to the leaf litter and ground cover plants beneath the forest canopy, and can even leave entirely unburnt patches in forests.

Are high severity fires becoming more common?

To determine if high-severity bushfires are becoming more common, we looked at satellite data for bushfires from 1988 to 2020. The data covered more than 130,000 square kilometres of forest, woodland and shrubland ecosystems in southeast Australia.

If fires were becoming more intense in recent decades, we would have expected the proportion of vegetation subjected to high-severity fire to have increased.

Instead, we found the average proportion of high-severity wildfire remained constant in dry forest — the dominant vegetation across this region. There was, however, evidence of an increase in the average proportion of high-severity fire in wet forests and rainforests, along with woodlands.




Read more:
5 remarkable stories of flora and fauna in the aftermath of Australia’s horror bushfire season


Nonetheless, the main conclusion was clear: across the bulk of the study area, the average proportion of high-severity fires has not changed in recent decades, despite an increase in the area burned during the Black Summer bushfires.

Why the Black Summer bushfires were exceptional

While the proportion of high-severity fires hasn’t changed, the enormous range of the 2019-2020 bushfires meant 44% of the total area burned by high-severity fire since 1988 occurred in that one summer alone.

This means 1.8 million hectares of the forest and woodland regions of southeastern Australia — an enormous proportion — was exposed to intense and severe fire. In this regard, the Black Summer bushfires were exceptional.

As Australians remember all too clearly, this had a devastating effect on the environment. An estimated three billion animals were killed or displaced, vulnerable rainforests burned and 3,000 homes were destroyed.

A firefighter runs through a burning forest
Firestorms could become more common under a changing climate.
AAP Image/Dean Lewins

The 2019-20 fire season also involved a record number of “firestorms”, particularly during the latter part of the season in January and early February. This occurs when fires create their own weather.

These fires can burn at exceptional intensity. And research from 2019 indicates such firestorms could become more common under climate change.

This means we can’t rule out a future change in the proportion of bushfires that burn at the highest levels of intensity and severity.

Ecosystems in jeopardy

The results of our study underline one of the likely consequences of future climate change.

The sheer scale of the area burned in the 2019-20 fire season exceeded not only historical records for forested ecosystems of southern Australia, but also outstripped projections for the late 21st century under strong scenarios of climate change.




Read more:
3 billion animals were in the bushfires’ path. Here’s what the royal commission said (and should’ve said) about them


As bushfires become larger in the future, the area exposed to intense and severe fires is likely to increase commensurately. As a result, the future of our wetter forest types, which have not evolved to cope with frequent and severe fires, is in jeopardy.

So, as the area exposed to intense fires is likely to increase in the future, we’ll see major challenges to the long-term viability of our forested ecosystems, the services they provide and the people who reside in and around them.The Conversation

Ross Bradstock, Emeritus professor, University of Wollongong; Hamish Clarke, Research Fellow, University of Wollongong; Luke Collins, Research scientist, La Trobe University; Michael Clarke, Emeritus professor, La Trobe University; Rachael Helene Nolan, Postdoctoral research fellow, Western Sydney University, and Trent Penman, Professor, The University of Melbourne

This article is republished from The Conversation under a Creative Commons license. Read the original article.

5 remarkable stories of flora and fauna in the aftermath of Australia’s horror bushfire season



hamiltonphillipa/iNaturalist, CC BY-NC-SA

Will Cornwell, UNSW; Casey Kirchhoff, UNSW, and Mark Ooi, UNSW

Around one year ago, Australia’s Black Summer bushfire season ended, leaving more than 8 million hectares across south-east Australia a mix of charcoal, ash and smoke. An estimated three billion animals were killed or displaced, not including invertebrates.

The impact of the fires on biodiversity was too vast for professional scientists alone to collect data. So in the face of this massive challenge, we set up a community (citizen) science project through the iNaturalist website to help paint a more complete picture of which species are bouncing back — and which are not.

Almost 400 community scientists living near or travelling across the firegrounds have recorded their observations of flora and fauna in the aftermath, from finding fresh wombat droppings in blackened forests, to hearing the croaks of healthy tree frogs in a dam choked with debris and ash.

Each observation is a story of survival against the odds, or of tragedy. Here are five we consider particularly remarkable.

Greater gliders after Australia’s largest ever fire

The Gospers Mountain fire in New South Wales was the biggest forest fire in Australian history, razing an area seven times the size of Singapore. This meant there nothing in history scientists could draw from to predict the animals’ response.

So it came as a huge surprise when a community scientist observed greater gliders deep within the heart of the Gospers Mountain firegrounds in Wollemi National Park, far from unburned habitat. Greater gliders are listed as “vulnerable” under national environment law. They’re nocturnal and live in hollow-bearing trees.

A greater glider with shining eyes at night
A citizen scientist snapped this photo of a greater glider in the heart of the the Gospers Mountain firegrounds.
Mike Letnic/iNaturalist, CC BY-NC

How gliders survived the fire is still unknown. Could they have hidden in deep hollows of trees where the temperature is relatively cooler while the fire front passed? And what would they have eaten afterwards? Greater gliders usually feed on young leaves and flowers, but these foods are very rare in the post-fire environment.

Finding these gliders shows how there’s still so much to learn about the resilience of species in the face of even the most devastating fires, especially as bushfires are forecast to become more frequent.

Rare pink flowers burnishing the firegrounds

The giant scale of the 2019-20 fires means post-fire flowering is on display in grand and gorgeous fashion. This is a feature of many native plant species which need fire to stimulate growth.

Excitingly, community scientists recorded a long-dormant species, the pink flannel flower (Actinotus forsythii), that’s now turning vast areas of the Blue Mountains pink.

Pink flannel flowers are bushfire ephemerals, which means their seeds only germinate after fire.
Margaret Sky/iNaturalist, CC BY-NC

Pink flannel flowers are not considered threatened, but they are very rarely seen.

Individuals of this species spend most of their life as a seed in the soil. Seeds require a chemical found in bushfire smoke, and the right seasonal temperatures, to germinate.

Rediscovering the midge orchid

Much of Australia’s amazing biodiversity is extremely local. Some species, particularly plants, exist only in a single valley or ridge. The Black Summer fires destroyed the entire range of 100 Australian plant species, incinerating the above-ground parts of every individual. How well a species regenerates after fire determines whether it recovers, or is rendered extinct.

The midge orchid.
Nick Lambert/iNaturalist, CC BY-NC

One of these is a species of midge orchid, which grows in a small area of Gibraltar Range National Park, NSW.

All of the midge orchid’s known sites are thought to have burned in late 2019. The species fate was unknown until two separate community scientists photographed it at five sites in January 2021, showing its recovery.

Like many of Australia’s terrestrial orchids, this species has an underground tuber (storage organ) which may have helped part of it avoid the flames’ lethal heat.




Read more:
After last summer’s fires, the bell tolls for Australia’s endangered mountain bells


Don’t forget about insects

Despite their incredible diversity and tremendous value to society, insects tend to be the forgotten victims of bushfires and other environmental disasters.

Many trillions of invertebrates would have been killed in the fires of last summer. A common sight during and after the bushfire season was a deposit of dead insects washed ashore. Some died from the flames and heat, while others died having drowned trying to escape.

Dead insects washed up on the beach was a common sight in the fire aftermath.
BlueBowerStudio/iNaturalist, CC BY-NC

One dead insect deposit — one of hundreds that washed up near Bermagui, NSW on Christmas Eve — included a range of species that have critical interactions with other organisms.

This includes orchid dupe wasps (Lissopimpla excelsa), the only known pollinator of the orchid genus Cryptostylis. Transverse ladybirds (Coccinella transversalis), an important predator of agricultural pests such as aphids, also washed up. As did metallic shield bugs (Scutiphora pedicellata), spectacular iridescent jewel bugs that come in green and blue hues.

Some insects died from the flames and heat, while others died having drowned trying to escape the flames.
BlueBowerStudio/iNaturalist, CC BY-NC

The unlikely survival of the Kaputar slug

Creatures such as kangaroos or birds have a chance to flee bushfires, but smaller, less mobile species such as native slugs and snails have a much tougher time of surviving.

The 2019-2020 bushfire season significantly threatened the brilliantly coloured Mount Kaputar pink slug, found only on the slopes of Mount Kaputar, NSW. When fires ripped through the national park in October and November 2019, conservationists feared the slug may have been entirely wiped out.




Read more:
Photos from the field: zooming in on Australia’s hidden world of exquisite mites, snails and beetles


But park ranger surveys in January 2020 found at least 60 individuals managed to survive, likely by sheltering in damp rock crevices. Community scientists have spotted more individuals since then, such as the one pictured here found in September 2020.

But the slug isn’t out of the woods yet, and more monitoring is required to ensure the population is not declining.

Bright pink slug
A community scientist spotted this rare slug in firegrounds.
Taylor/iNaturalist, CC BY-NC

Continuing this work

While community scientists have been documenting amazing stories of recovery all across Australia, there are still many species which haven’t been observed since the fires. Many more have been observed only at a single site.

The Snowy River westringia (Westringia cremnophila), for instance, is a rare flowering shrub found on cliffs in Snowy River National Park, Victoria. No one has reported observing it since the fire.

So far these community scientist observations have contributed to one scientific paper, and three more documenting the ability for species to recover post-fire are in process.

Recovery from Black Summer is likely to take decades, and preparing a body of scientific data on post-fire recovery is vital to inform conservation efforts after this and future fires. We need more observations to continue this important work.




Read more:
Summer bushfires: how are the plant and animal survivors 6 months on? We mapped their recovery


The Conversation


Will Cornwell, Associate Professor in Ecology and Evolution, UNSW; Casey Kirchhoff, PhD Candidate, UNSW, and Mark Ooi, Senior Research Fellow, UNSW

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Fires bring home climate-driven urgency of rethinking where we live – and how


Barbara Norman, University of Canberra; Peter Newman, Curtin University, and Will Steffen, Australian National University

As we were still recovering from last summer’s fires in southeast Australia, the southwest fires brought in 2021. Both were far more intense fires than seen before, driven by deep drying, extreme heat and powerful winds. It’s a harsh reminder that climate change is going to bounce us up and down with increased frequency.

We have published a new research paper in the journal Nature, titled Apocalypse Now: Australian Bushfires and the Future of Urban Settlements. It was put together as the fires were raging in the east, and comes out as Perth residents are still reeling from the devastating fires in the west this month.

Both sides of Australia have now learnt hard lessons.




Read more:
As Perth’s suburbs burn, the rest of Australia watches and learns


What have we learned?

1. Bushfires have become more frequent and more intense

The 2019-2020 Black Summer bushfires were unprecedented in their scale and were fuelled by unprecedented climatic conditions.

The fires burned about 21% of eastern Australia’s temperate broad-leafed (mainly eucalypt) forests. That’s more than ten times the annual average of about 2%, even in extreme fire seasons.

Individual fires were also massive in size. For example, the Gospers Mountain fire near Sydney burned more than 500,000 hectares. This made it the largest individual fire ever recorded in Australia.




Read more:
Asking people to prepare for fire is pointless if they can’t afford to do it. It’s time we subsidised fire prevention


2. Climate change is creating unprecedented conditions

The preceding climatic conditions were also unprecedented. 2019 was Australia’s hottest year on record. The average maximum temperature was 2.09°C above the baseline and 0.5°C higher than the previous record.

Australia also experienced its driest year on record in 2019. Rainfall was about 40% below average across the continent.

Climate change played a strong role in driving these weather records.




Read more:
Cities could get more than 4°C hotter by 2100. To keep cool in Australia, we urgently need a national planning policy


3. It’s a global problem

Modelling by the Intergovernmental Panel on Climate Change (IPCC) shows if the world goes past the 2°C rise on average and moves towards 3°C, the world is likely to lose most of the forests in dry climate areas like ours.

The southwestern region of Australia has been drying for 40 years, linked to climate change. In recent years, the Perth region has depended on desalinating seawater for about half of the water supply to more than 2 million residents.

perth desalination plant
Perth’s rainfall has fallen dramatically for decades and the city now relies very heavily on desalination for its water supply.
Callistemon/Wikimedia Commons, CC BY-SA



Read more:
Cities turn to desalination for water security, but at what cost?


The bushfires have become more intense over the past decade. Similar patterns are found in California and other areas with a Mediterranean climate.

4. The global community is watching

State and federal governments must commit to net-zero emissions targets. These would signal to industry and communities that there is a diminishing future for fossil fuels and encourage investment in a renewable future.

The fires strikingly remind people that we remain a global climate laggard. This will soon spread to our trade discussions and ability to raise finance for nation-building infrastructure and major projects.




Read more:
All eyes on Australia as World Urban Forum urges climate action


5. Our settlements will need to change

The most vulnerable parts of our cities are in the urban fringes where there is substantial scattered development set in bush. Such homes are going to be increasingly vulnerable. As a result, owners will find insurance harder to secure.

Consolidating the city will need to start by reviewing such lifestyle zonings to reduce risk to communities. Rural areas and coastal settlements also will need a new model based on new green technology infrastructure, new building materials and new ways of living together rather than living in forest hideaways.




Read more:
Disaster season is here — do you have a Resilience Action Plan? Here’s how the small town of Tarnagulla built theirs


6. Indigenous fire management needs to be applied to all bush

Indigenous fire techniques are beginning to be developed and adapted with local communities after the fires last summer. These are needed around our cities and in urban bushland, as well as in forests and rangelands across our country.

If we don’t begin to adopt such “cool burn” approaches, then we face the prospect of losing our forests, even those in and around our cities.




Read more:
Australia, you have unfinished business. It’s time to let our ‘fire people’ care for this land


What must we do to make this happen?

Key elements include:

  • regional urban centres make the transition to renewable energy

  • urban design becomes responsive to climate through retrofitting programs and consolidating settlements

  • settlements retreat from areas of high climate risk, working with affected communities to identify options

  • community climate action plans get funded, including climate change adaption, climate-sensitive urban design and heat reduction though urban green spaces

  • embed action on climate change (mitigation and adaptation) through a national investment program, in partnership with the states, to review urban planning processes.

This is a crisis that needs strong leadership of the type shown in the COVID response. That means working together, fostering innovation and investing in creating and building more climate-adapted communities.


This article is part of a series The Conversation is running on the nexus between disaster, disadvantage and resilience. You can read the rest of the series here.The Conversation

Barbara Norman, Chair of Urban & Regional Planning and Director of Canberra Urban & Regional Futures, University of Canberra; Peter Newman, Professor of Sustainability, Curtin University, and Will Steffen, Emeritus Professor, Fenner School of Environment & Society, Australian National University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Asking people to prepare for fire is pointless if they can’t afford to do it. It’s time we subsidised fire prevention



Shutterstock

David Bowman, University of Tasmania

Once again, Australia is on fire. This year it’s the turn of Western Australia and South Australia, where bushfires are threatening homes and lives. In the south of Tasmania, conditions are dry and the region is entering a period of peak fire danger.

In the lead up to every bushfire season, the mantra is the same each year: prepare, prepare, prepare. Remove the fuel load. Clean out the gutters. Mow lawns, tidy gardens, create a burnbreak between bushland and your house. Identify your strengths and weaknesses. Have a plan.

After 40 years studying the interaction between humans and fire, I have seen this mantra rolled out every year — and watched, every year, as it is comprehensively ignored by large numbers of people. Why? Because they are bad or lazy? No.

The fact is asking people to prepare for fire is pointless if they can’t afford to do it. If you don’t have time or money (or both), it doesn’t matter how many times authorities tell you to prepare. It’s not going to happen. What if we had a system, like Medicare, where the cost of these fire prevention measures was subsidised by the public system?




Read more:
Friday essay: living with fire and facing our fears


We know the current system doesn’t work

Institutions such as local fire authorities, councils or governments can say “we have done our bit and we expect the community to do their part and manage their risk, their property, their bushfire plan”.

But it’s just passing the problem along to the next person, without considering whether they’re able to actually take up that advice.

For years, authorities have essentially handed people a very formidable and expensive checklist of things to do, right up to the level of retrofitting your house to be compliant with modern building standards. These are significant time and financial investments.

The cost of failing to prepare is huge. Bushfire often spreads by embers landing in a series of unprepared properties. If your neighbours don’t make their home defendable, chances are it may cause your house to burn down.

There are many reasons people don’t prepare, and a key one is affordability. If you’re not physically able to get up a ladder to clean your gutters or mow around your property and remove fuel load — and you can’t afford to pay someone to do it — what are you supposed to do?

You might think, “Well, if people choose to live in a bushfire prone area then that’s their problem. Why should they get subsidies?” But there are many reasons people might not be able to prepare, including poverty, old age, and health issues.

And if they don’t prepare, it won’t just affect them; it could create a vector for the fire to spread to other properties. Research suggests disasters, including fires, are more likely to occur in low socioeconomic areas.

A man cleans leaf litter out of gutters.
Many people are not physically able to get up a ladder to clean gutters and can’t afford to pay someone to do it.
Shutterstock

It’s time to look at preventative fire measures the same way we look at preventative healthcare.

Our taxes fund Medicare and public health measures because Australian society recognises it’s cheaper in the long run. It’s cheaper than allowing low-level health problems to fester until they become so threatening they have to be dealt with in the mind-bogglingly expensive emergency department.

In the same way, subsidies for household bushfire preparation would help prevent the vast taxpayer expense incurred for emergency fire-fighting when fire strikes.

What might the system look like?

The system could take many forms.

State governments already give vouchers to citizens to incentivise spending in one area. Think of the NSW government’s Active Kids or Creative Kids voucher systems, or its planned dining and entertainment voucher system.

So why not give vouchers you can use to pay someone to clear your gutters, mow your lawn or clear dry grass and other fuel loads?

Insurers could offer lower premiums to people who take action to reduce fire risk around their home by ember-proofing or installing gutter-guard, for example (in the same way there are insurance benefits if you make your house more resistant to being broken into).

A burnt out house.
Insurers could offer lower premiums to people who take action to reduce fire risk around their home.
Shutterstock

Perhaps councils could offer lower rates for low-income people who, in exchange, pay for measures to reduce their fuel load.

Or we could have a bulk-billing system, where you can ask a service provider to assess your home’s risk and do basic fire load reduction, and it’s charged to a Medicare-style system.

To me, these ideas make a lot more sense than more punitive measures being considered in some places, where authorities could clear a fire risk around a house themselves and simply send the bill to the occupant or land owner.

The punitive system just puts more pressure on people who may not be able to afford to reduce their home’s fire risk, much less deal with going to court to dispute a bill they’ve been sent. It also means people are less likely to trust and cooperate with fire authorities.

That sounds expensive

Yes, I know these ideas are expensive. So is Medicare. So is the pension system. So is the public health response that helped Australia drive the COVID-19 epidemic into submission. But they’re worth it, aren’t they?

And do you know what else is expensive? Doing the same thing every year, even though it doesn’t work.

We have just been through an enormously expensive bushfire royal commission. And as fire expert Kevin Tolhurst points out here, we’ve had 57 formal public inquiries, reviews and royal commissions related to bushfires and fire management since 1939. A huge expense to taxpayers.

We know the cost of the Black Summer fires ran into the billions, with costs to the health system, individuals, businesses and emergency services.

Aerial fire suppression aircraft are expensive. Having 100-day firefighting campaign is an extraordinary drain on the public purse — and that’s before you even start counting the cost of economic disruption that comes with it.




Read more:
As bushfire and holiday seasons converge, it may be time to say goodbye to the typical Australian summer holiday


It sounds a bit radical

I know! But radical change is what’s needed — and it’s possible. In early 2020, I wrote it was time to re-arrange the Australian school calendar around fire seasons and people said this was crazy. But then a few months later we completely rearranged schooling around the pandemic — an idea that, in January, would have seemed completely unworkable.

It turns out radical change is possible when push comes to shove. And for climate change-related fire risk, push really has come to shove.

Our current system involves telling people to create “a defendable space” around your house. I’ve been on Google Earth to look to at how that’s played out in many bushland suburbs; you don’t need to be a genius to work out there they are not defendable spaces.

Climate change adaptation does feel radical, but it’s also necessary.

If we are sitting round going into a hotter, drier, more fire-prone world, what are we doing if we are not enabling people to adapt?


This story is part of a series The Conversation is running on the nexus between disaster, disadvantage and resilience. You can read the rest of the stories here.The Conversation

David Bowman, Professor of Pyrogeography and Fire Science, University of Tasmania

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Open data shows lightning, not arson, was the likely cause of most Victorian bushfires last summer



Tracy Nearmy/AAP

Dianne Cook, Monash University

As last summer’s horrific bushfires raged, so too did debate about what caused them. Despite the prolonged drought and ever worsening climate change, some people sought to blame the fires largely on arson.

Federal Coalition MPs were among those pushing the arsonist claim. And on Twitter, a fierce hashtag war broke out: “#ClimateEmergency” vs “#ArsonEmergency”.

Fire authorities rejected the arson claims, saying most fires were thought to be caused by lightning.

We dug into open data resources to learn more about the causes of last summer’s bushfires in Victoria, and further test the arson claim. Our analysis suggests 82% of the fires can be attributed to lightning, 14% to accidents and 1% to burning off. Only 4% can be attributed to arson.

Lightning in the sky
Lightning, not arson, caused most Victorian bushfires last summer.
Twitter

What we did

We started with hotspots data taken from the Himawari-8 satellite, which shows heat source locations over time and space, in almost real time. We omitted hotspots unlikely to be bushfires, and used a type of data mining called “spatiotemporal clustering” – where time dimension is introduced to geographic data – to estimate ignition time and location.

We supplemented this with data from other sources: temperature, moisture, rainfall, wind, sun exposure, fuel load, as well as distance to camp sites, roads and Country Fire Authority (CFA) stations.




Read more:
Bushfires, bots and arson claims: Australia flung in the global disinformation spotlight


Victoria’s Department of Environment, Land, Water and Planning (DELWP) holds historical data on bushfire ignition from 2000 to the 2018-19 summer. The forensic research required to determine fire cause is laborious, and remotely sensed data from satellites may be useful and more immediate.

By training our model on the historical data, we can more immediately predict causes of last summer’s fires detected from satellite data. (Note: even though we were analysing events in the past, we use the term “predict” because authorities have not released official data.)

DELWP’s data attributes 41% of fires to lightning, 17% to arson, 34% to accidents and 7% to hazard reduction or back burning which escaped containment lines (which our analysis refers to as burning off).

Causes of fires from 2000-2019. Lightning is most common cause. The number of fires is increasing, and this is mostly due to accidents.
Own work

To make predictions for the 2019-20 bushfires, we needed an accurate model for causes in the historical data. We trained the model to predict one of four causes – lightning, accident, arson, burning off – using a machine learning algorithm.

The model performed well on the historical data: 75% overall accuracy, 90% accurate on lightning, 78% for accidents, and 54% for arson (which was mostly confused with accident, as would make sense).

The most important contributors to distinguishing between lightning and arson (or accident) ignition were distance to CFA stations, roads and camp sites, and average wind speed.

As might be expected, smaller distances to CFA stations, roads and camp sites, and higher than average winds, meant the fire was most likely the result of arson or accident. In the case of longer distances, where bush would have been largely inaccessible to the public, lightning was predicted to be the cause.

Spatial distribution of causes of fires from 2000-2019, and predictions for 2019-2020 season.
Own work

What we found

Our model predicted that 82% of Victoria’s fires in the summer of 2019-2020 were due to lightning. Most fires were located in densely vegetated areas inaccessible by road – similar to the historical locations. (The percentage is double that in the historical data, though, probably because the satellite hotspot data can see fire ignitions in locations inaccessible to fire experts).

All fires in February 2020 were predicted to be due to lightning. Accident and arson were commonly predicted causes in March, and early in the season. Reassuringly, ignition due to burning off was predicted primarily in October 2019, prior to the fire restrictions.

Spatio-temporal distribution of cause predictions for 2019-2020 season. Reassuringly, fires due to burning off primarily occurred in October, prior to fire restrictions. February fires were all predicted to be due to lightning.
Own work

Quicker fire ignition information

Our analysis used open-data and open-source software, and could be applied to fires elsewhere in Australia.

This analysis shows how we can quickly predict causes of bushfires, using satellite data combined with other information. It could reduce the work of fire forensics teams, and provide more complete fire ignition data in future.

The code used for the analysis can be found here. Explore the historical fire data, predictions for 2019-2020 fires, and a fire risk map for Victoria using this app.


This analysis is based on thesis research by Monash University Honours student Weihao Li. She was supervised by the author, and former Principal Inventive Scientist at AT&T Labs Research, Emily Dodwell. The Australian Centre of Excellence for Mathematical and Statistical Frontiers supported Emily’s travel to Australia to start this project. The full analysis is available here.

The Conversation

Dianne Cook, Professor of Business Analytics, Monash University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Before and after: 4 new graphics show the recovery from last summer’s bushfire devastation



Airborne Research Australia, Author provided

Jorg Michael Hacker, Flinders University

Two days before Christmas last year, a fire reached our heritage-protected bush property in the Adelaide Hills, and destroyed our neighbour’s house. For the next two weeks we were on constant alert to keep the fire in check.

Green shoots of grass trees after bushfire
Grass trees are some of the first plants to regrow after a bushfire.
Wikimedia, CC BY

A few weeks later, I flew over fire-affected areas in the Adelaide Hills and had my first aerial view of the devastation. Fighting fires around my home, and what I saw on this flight, convinced me to get involved with helping recovery in the aftermath of the fires.

In the past year, I’ve taken high-resolution aerial data to monitor the recovery of fire-affected areas and help with post-fire efforts. This work includes clearing access tracks into burnt forests, locating unburnt areas within burnt forests to serve as refuges for wildlife, or simply documenting the degree of destruction.

I now have a unique dataset – a combination of very high-resolution and detail from three sensors: aerial photography, airborne Lidar (a way to measure distances with laser light) and hyperspectral imaging (looking at the landscape and vegetation with hundreds of narrow wavelengths).

Flying at just 250 metres above the ground, it’s possible to generate complete three-dimensional views and animations of the landscape and its features at resolutions in the 10cm-range.

Usually such airborne data is only available to government agencies, industry and sometimes researchers, but rarely to the general public. So we decided to make the data publicly available, so anyone can download it. It will help you appreciate the level of destruction, and how it varied for different landscapes.

My property, for example, is showing strong regrowth, but most of our neighbour’s block burnt so intensely that even now, after nearly one year, there’s very little regrowth even in terms of ground cover.

Here are a few examples of the landscape’s recovery around Kangaroo Island, generated from our data.



Bushfires decimated almost half of Kangaroo Island. The image sequence above shows a small area on Kangaroo Island before the fires and about one, three and nine months afterwards.

Before the fires, the landscape was dominated by dense bushland, which the fires nearly completely destroyed. The first signs of regrowth were visible after three months, and even more so after nine months.

The imagery is so detailed you can inspect the regrowth even for individual trees and scrubs. And in the slider below, you can more clearly compare how well the bushland regrew between February and October this year.

@media only screen and (max-width: 450px) {
iframe.juxtapose { height: 180px; width: 100%; }
}
@media only screen and (min-width: 451px) and (max-width: 1460px) {
iframe.juxtapose { height: 300px; width: 100%; }
}


Much of Australia’s native flora have evolved to cope with fire. Grass trees are among the first species to recover, and the Lidar data below demonstrates just how dramatic this recovery is.

Thousands of grass trees (“yuccas”) on Kangaroo Island grew up to seven metre-high flowers in the months after the fires. This is a typical phenomenon for this species after fire, and we were lucky enough to see this first hand on our bushland property, too.


@media only screen and (max-width: 450px) {
iframe.juxtapose2 { height: 270px; width: 100%; }
}
@media only screen and (min-width: 451px) and (max-width: 1460px) {
iframe.juxtapose2 { height: 430px; width: 100%; }
}


The video below shows the regrowth in and around a tree plantation on Kangaroo Island, directly after the fires and then after nine months. You can clearly see the intense regrowth on the ground and near the bottom of the burnt trees.

Usually firegrounds are observed via satellite imagery, imagery captured from high-flying survey aircraft and, more recently, using unmanned aerial vehicles (drones). None of these observations can map the landscape at the exceptionally high detail over large areas and with the combination of sensors as we have flown.

High-resolution aerial photographs at pixel sizes as small as five centimetres can be put together in a mosaic, covering many square kilometres. Combined with Lidar, and the hyperspectral scanner, we get detailed animations, such as those in the video, which can zero in on various intricate aspects, such as vegetation health.



How these datasets can help bushfire recovery

With a some moderate funding, we can continue these regular mapping flights next year and beyond to learn how these areas develop. We can put this into context with other factors, such as burn severity, soil structure and vegetation type.

Such detailed datasets would assist researchers assessing flammability and fuel load (dried vegetation) which, in turn, would help prevent and even fight future fires.




Read more:
Fire-ravaged Kangaroo Island is teeming with feral cats. It’s bad news for this little marsupial


Flammability and fuel load, alongside the slope of the landscape, are key parameters in computer simulations of fire behaviour. High resolution datasets depicting landscapes before and after bushfire can verify the simulation results, and help to improve the performance of the models.

Our datasets can also be useful for people needing to access areas directly after the fires, such as identifying where burnt trees have fallen, or are just about to do so.

For our own bushland block in the Adelaide Hills, these detailed imagery and datasets means we can study the regrowth from the Cudlee Creek Fire almost a year ago, as well as from previous fires. For example, some areas were burnt in the 2015 Sampson Flat Fire and had already regrown over the four years — only to be burnt again.

Continuing such flights would require a comparatively low amount of funding. However, this is currently not available in the standard government grant system. You can download data from the mapping flights over Adelaide Hills and Kangaroo Island.




Read more:
Yes, native plants can flourish after bushfire. But there’s only so much hardship they can take


The Conversation


Jorg Michael Hacker, Chief Scientist at Airborne Research Australia (ARA); and Professor, Flinders University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

How the size and shape of dried leaves can turn small flames into colossal bushfires


Shutterstock

Jamie Burton, University of Melbourne; Alexander Filkov, University of Melbourne, and Jane Cawson, University of Melbourne

The 2020-21 fire season is well underway, and we’ve watched in horror as places like K’gari (Fraser Island) burn uncontrollably, threatening people and their homes and devastating the environment.




Read more:
The K’gari-Fraser Island bushfire is causing catastrophic damage. What can we expect when it’s all over?


To lessen the impact of fires, we need to know when they are likely to burn and how intensely. Central to this is the flammability of litter beds — the layer of dead leaves, needles, twigs and bark on the forest floor.

Every large fire begins as a small fire, igniting and initially spreading through the litter bed, but what makes some litter beds more flammable than others?

Aerated litter beds fuel bigger fires

Over the past few years, fire scientists across the world have been busy tackling this burning question. In tropical forests in the Amazon, oak forests in North America and eucalypt woodlands in Australia, they have been collecting leaf litter beds and burning them in the laboratory to understand why litter beds from some plant species burn differently to others.

Each of these studies focused on leaf litter beds made up of a single species, and each identified a range of drivers of flammability. These drivers relate to both the characteristics of the individual litter particle (leaf, needle or branch) and the litter bed itself.




Read more:
Not all blackened landscapes are bad. We must learn to love the right kind


Our new research sought to consolidate these studies to find the common drivers of flammability between different single-species litter beds from different parts of the world.

From our meta-analysis, we found “litter packing” and “litter bulk density” were key factors in litter bed flammability.

Litter packing is a measure of how many gaps are between the dried leaves, needles and branches, and is important for determining how much air is available for burning. Likewise, litter bulk density is a measure of how much litter there is, and is important for determining how quickly and how long litter burns.

Oak tree litter bed
The litter bed from oak trees. The curly leaves create air gaps throughout the litter bed, which lead to bigger fires.
Jamie Burton, Author provided

We found loosely packed litter beds spread fire faster, burned for shorter periods of time and were more consumed by the flames. Importantly, we found this was universal across different types of litter beds.

We also identified the characteristics of leaves, needles and branches that cause variations in litter packing and litter bulk density.

For example, if the litter particles are “curly” and have a high surface area to volume ratio, then they’ll form litter beds with low packing ratios which burn faster and have higher consumption. Examples include leaves from some oak (Quercus) species.




Read more:
Tree ferns are older than dinosaurs. And that’s not even the most interesting thing about them


At the opposite end, small and less curly leaves form densely packed litter beds which are less aerated. Examples include coast tea tree (Leptospermum laevigatum) and conifers with small needles such as Larix and Picea. This results in slower moving fires, which do not consume all the litter.

For eucalypt litter beds, things are a little more complicated. Some species have thick and flat leaves which pack densely, so fire spreads more slowly and less litter is consumed. Other species, such as the southern blue gum (Eucalyptus globulus), have larger leaves which tend to pack less densely, so fires burn more quickly with taller flames.

Eucalyptus litter bed
The litter bed of eucalyptus trees.
Jamie Burton, Author provided

How can this information help us manage fires?

Of course, under extreme fire weather conditions, any litter bed will burn. However, at the beginning of a fire or under mild conditions, differences in litter characteristics may strongly influence how that fire spreads. Research on this can be useful for many aspects of fire management and planning.

For example, if we know which plants produce less flammable litter, we can select them for planting around houses, landscaping in fire-prone areas and also use them as green firebreaks to reduce the risk to people and homes. If a fire was to start, it may spread less quickly and be less intense, making it easier to contain and put out.

_Allocasuarina_ needle litter
Allocasuarina species with long thin needles tend to pack loosely, leading to faster flame spread and shorter burning times.
Jamie Burton, Author provided

But also it may not be that straightforward. When deciding which species to plant, the flammability of living plants needs to be considered, as well. Some plants that have less flammable litter may actually be highly flammable as a living plant. For example, although coast tea tree may form densely packed litter beds, the high oil content in the leaves makes it highly flammable as a living plant.

Our findings could also be used for predicting fire behaviour. For example, our results could be integrated into fire behaviour models, such as the Forest Flammability Model, which uses information on the composition and structure of the plant community to predict fire behaviour.

Next steps

Our study provides information on what leaf and litter characteristics affect flammability in litter beds composed of a single species. But in many forests, litter beds are made up of a variety of plant species, and more research is needed to understand what happens to litter packing and flammability in these multi-species litter beds.

Sydney red gum
The bark of the Sydney red gum tends to take longer to ignite, but burns for longer than its leaves.
Shutterstock

Besides different species, litter beds also contain different components such as twigs and bark. For example, in a mature wet eucalypt forest, bark and twigs can make up to 44% of the litter bed.

And for some eucalypt species, we already know bark burns differently to leaves. For example, the flaky bark of the Sydney red gum (Angophora costata) tends to take longer to ignite, but burns for a longer time compared to its leaves.

With fires becoming more frequent and fire seasons becoming longer, research into litter bed flammability has never been more needed.




Read more:
‘I felt immense grief’: one year on from the bushfires, scientists need mental health support


The Conversation


Jamie Burton, PhD Candidate, University of Melbourne; Alexander Filkov, Senior research fellow, University of Melbourne, and Jane Cawson, Research Fellow in Bushfire Behaviour and Management, University of Melbourne

This article is republished from The Conversation under a Creative Commons license. Read the original article.

The K’gari-Fraser Island bushfire is causing catastrophic damage. What can we expect when it’s all over?


Gabriel Conroy, University of the Sunshine Coast

K’gari (Fraser Island) has been burning for more than seven weeks and, so far, the fires have razed half of the World Heritage-listed island off the coast of Queensland. The devastation will become more pronounced in coming weeks, despite overnight rain.

Much of the commentary on these fires has focused on how these landscapes are “meant to burn”, and that (luckily) there have been no major fires in the fire-sensitive, rainforest-style ecosystems in the island’s centre.

However, the fact remains that a fire of this magnitude will alter the ecological balance on the island. Let’s explore why.

An uphill battle

K’gari is an incredibly biodiverse place, with more than 30 mammal species, 354 types of birds, 60 reptiles and 17 types of frogs.

For thousands of years, the Butchulla traditional owners maintained the island’s ecosystems with patch mosaic burning. The general principle behind patch mosaic burning is that by burning regularly and strategically, you create habitat niches that cater for a wide variety of generalist and specialist species, which favours biodiversity.




Read more:
Australia, you have unfinished business. It’s time to let our ‘fire people’ care for this land


With an absence of this mode of burning during 130 years of logging on the island (ending in 1991), today’s environmental managers have faced an uphill battle to claw back the balance.

This — alongside tinder-dry conditions and large swathes of relatively inaccessible wilderness in the north — is why we unfortunately find ourselves in the situation where an incredibly widespread, intense fire has occurred.

These types of fires can irrevocably alter the nature of even fire-adapted ecosystems (like in the northern half of K’gari) and are likely to become more commonplace in our changing climate.

Let’s take two of K’gari’s rare plant species — the tiny wattle (Acacia baueri) and the much-loved Christmas bells (Blandfordia grandiflora) — as examples of why the Australian landscape’s need for fire isn’t straightforward, and requires patch burning.

Christmas bells
Christmas bells flower for one to three years after a fire, and then disappear underground.
Shutterstock

These species rely on low intensity fire occurring every three to five years to regenerate and avoid local extinction.

However, other fire-adapted species that grow alongside them, such as Banksia robur, would struggle to withstand burning this frequently. Some may not even be able to reach reproductive maturity during that kind of time span.

Invertebrates: the island’s unheralded heroes

K’gari is famous for its wild population of dingoes, which undoubtedly will have suffered in these fires. We won’t know the full impact for these and many other species until the dust has settled.




Read more:
Dingoes and humans were once friends. Separating them could be why they attack


But one of my greatest concerns is for the largely forgotten species propping up ecosystems: invertebrates. In normal circumstances, the island is teeming with highly abundant and diverse invertebrate life if you bother to look for it — and will undoubtedly bite you or keep you awake at night even if you don’t.

Herbivorous species, including insects, are the unheralded heroes that transfer a lot of the the energy generated by plants up through the food chain, for example, by providing food for predators like dingoes.

With 50% (and counting) of the island’s ecosystems already burnt in this fire, the amount of food available for herbivores has reduced. This means significantly less energy can be fed back up the food chain, affecting the entire ecosystem.

A dingo on the beach
Wild dingoes are an important feature of the World Heritage-listed island.
Shutterstock

When there’s nowhere to escape

On mainland Australia, birds, bugs and fast-moving animals like dingoes and wallabies often flee to safe habitats when fires occur, and then later recolonise fire-affected regions.

Although relatively close to the mainland, K’gari is a very long and narrow island, and because the entire northern end of the island has burnt, most terrestrial species have only a narrow interface through the central part of the island to try to escape. These lack of escape routes will likely exacerbate death rates of native fauna.




Read more:
Click through the tragic stories of 119 species still struggling after Black Summer in this interactive (and how to help)


To make matters worse, the ecosystems to the north are markedly different to those in the centre of the island. So while we wait to see how the northern regions regenerate, the species that depend on them may have moved further south to find equivalent ecosystems.

Effectively, only 50% of the island now provides habitat and food sources for the entire island’s wildlife, and the remaining habitat is not always a like-for-like replacement.

How will it look when it ‘bounces back’?

When the fires have extinguished and plants begin to regenerate, a sea of green may convince people the ecosystems have bounced back marvellously from the fires. But in actual fact, they may have been irrevocably changed.

Certain species will flourish in the post-fire environment, but because of the fire’s widespread nature, it’s possible the composition of the vegetation will change.




Read more:
Yes, native plants can flourish after bushfire. But there’s only so much hardship they can take


Weeds, for example, love bare ground, and even native species can become “weedy” in nature and can dominate in disturbed areas. In ongoing research, our team has observed this in areas of the island impacted by sand mining in the 1970s, where there’s an overabundance of immature Acacia and Casuarina species.

My greatest hope is that the future of K’gari includes patch mosaic burning (and cultural burns) at a landscape scale.

If we want to ensure K’gari bounces back as much as possible, then we need to use these devastating bushfires as an opportunity to work collaboratively towards a common conservation goal.

The intent from key stakeholders is evident, with productive conversations already occurring between our team at the University of the Sunshine Coast, Queensland Parks and Wildlife Service and the Butchulla Aboriginal Corporation. For this to come to fruition, on-ground efforts will need to be well-resourced and supported by ongoing monitoring and research.The Conversation

Gabriel Conroy, Environmental Management Program Coordinator, University of the Sunshine Coast

This article is republished from The Conversation under a Creative Commons license. Read the original article.