Logging is due to start in fire-ravaged forests this week. It’s the last thing our wildlife needs


David Lindenmayer, Australian National University and Doug Robinson, La Trobe University

New South Wales’ Forestry Corporation will this week start “selective timber harvesting” from two state forests ravaged by bushfire on the state’s south coast.

The state-owned company says the operations will be “strictly managed” and produce timber for power poles, bridges, flooring and decking.

Similarly, the Victorian government’s logging company VicForests recently celebrated the removal of sawlogs from burnt forests in East Gippsland.

VicForests says it did not cut down the trees – they were cut or pushed over by the army, firefighters or road crews because they blocked the rood or were dangerous. The company said it simply removed the logs to put them “to good use”.

However the science on the impacts of post-fire logging is clear: it can significantly impair the recovery of burned ecosystems, badly affect wildlife and, for some animal species, prevent recovery.

We acknowledge that for safety reasons, some standing and fallen burnt trees must be removed after a fire. But wherever possible, they should remain in place.

Damaging effects

Hollows in fire-damaged trees and logs provide critical habitat for animal species trying to survive in, or recolonise, burned forests.

Detailed studies around the world over the past 20 years, including in Australia, have demonstrated the damage caused by post-fire logging.

Indeed, the research shows post-fire logging is the most damaging form of logging. Logging large old trees after a fire may make the forests unsuitable habitat for many wildlife species for up to 200 years.




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Buzz off honey industry, our national parks shouldn’t be milked for money


Long-term monitoring data from extensive field surveys shows hollow-dependent mammals, such as the vulnerable greater glider, generally do not survive in areas burned and then logged. Research by the lead author, soon to be published, shows populations are declining rapidly in landscapes dominated by wood production.

Forests logged after a fire have the lowest bird biodiversity relative to other forests, including those that burned at high severity (but which remain unlogged). Critical plants such as tree ferns are all but eradicated from forests that have been burned and then logged.

Soils remain extensively altered for many decades after post-fire logging. This is a major concern because runoff into rivers and streams damages aquatic ecosystems and kills organisms such as fish.

A double disturbance

Fire badly disrupts forest ecosystems. Animals and plants then begin recovering, but most forests and the biota they support simply cannot deal with the second intense disturbance of logging so soon after a first one.

For example, young germinating plants are highly vulnerable to being flattened and destroyed by heavy logging machinery. And in an Australian context, post-fire logging makes no sense in the majority of eucalypt-dominated ecosystems where many tree species naturally resprout. This is an essential part of forest recovery.

Logs provide shade, moisture and shelter for plants, and rotting timber is food for insects – which in turn provide food for mammals and birds.




Read more:
Logged native forests mostly end up in landfill, not in buildings and furniture


Living and dead trees are also important for fungi — a food source for many animals, including bandicoots and potoroos which have been heavily impacted by the fires.

Similarly on burnt private land, removing damaged and fallen trees will only hinder natural recovery by removing important animal habitat and disturbing the soil. If left, fallen trees will provide refuge for surviving wildlife and enable the natural recovery of forests.

While the sight of burnt timber can be disheartening, landholders should resist the urge to “clean up”.

It doesn’t add up

Research in North America suggests debris such as tree heads, branches and other vegetation left by post-fire logging not only hinders forest regeneration, but can make forests more prone to fire.

And the economics of logging, particular after a fire, is dubious at best. Many native forest logging operations, such as in Victoria’s East Gippsland, are unprofitable, losing millions of taxpayer dollars annually.




Read more:
Yes, the Australian bush is recovering from bushfires – but it may never be the same


Timber is predominantly sold cheaply for use as woodchips and paper pulp and fire-damaged timber is of particularly poor quality. Even before the fires, 87% of all native forest logged in Victoria was for woodchips and paper pulp.

Post-fire logging certainly has no place in national parks. But for the reasons we’ve outlined, it should be avoided even in state forests and on private land. Million hectares of vegetation in Australia was damaged or destroyed this fire season. The last thing our forests need is yet more disturbance.


VicForests response: VicForests told The Conversation that timber currently being removed by VicForests, at the direction of the Chief Fire Officer, is from hazardous trees that were cut or knocked over to enable the Princes Highway to be re-opened.

It said the timber would be used for fence restoration, firewood and to support local mills “protecting jobs, incomes and families. It would otherwise be left in piles on the side of the highway”.

“Any further post-fire recovery harvesting will occur in consultation with government including biodiversity specialists and the conservation regulator, following careful assessment and protection of high conservation values,” VicForests said.

The company said post-fire recovery harvesting, particularly of fire-killed trees, does not increase fire risk.

“Sensitive harvesting including the retention of habitat trees and active re-seeding is more likely to result in a successfully regenerated forest and a supportive environment for threatened species. This regenerating forest will have the same fire risk as natural regeneration following bushfire.”


Forestry Corporation of NSW response: Forestry Corporation of NSW said in a statement that small-scale selective timber harvesting operation will begin on the south coast this week.

The company’s senior planning manager Dean Kearney said the Environment Protection Authority, with the input of scientific experts “has provided Forestry Corporation with site-specific conditions for selective timber harvesting operations in designated parts of Mogo and South Brooman State Forests. These areas were previously set aside for timber production this year but have now been impacted by fire.”

“Strictly-managed selective timber harvesting will help prevent the loss of some high-quality timber damaged by fire, including material that will be in high demand for rebuilding, while ensuring the right protections are in place for key environmental values, particularly wildlife habitat, as these forests begin regenerating,” he said.

“The harvesting conditions augment the already strict rule set in place for forest operations and include requirements to leave all unburnt forest untouched and establish even more stringent conditions to protect water quality, hollow-bearing trees and wildlife habitat.”The Conversation

David Lindenmayer, Professor, The Fenner School of Environment and Society, Australian National University and Doug Robinson, Honorary Visiting Fellow, Department of Ecology, Environment and Evolution, La Trobe University

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

Researchers allege native logging breaches that threaten the water we drink



Researchers have uncovered what appears to be widespread logging of steep slopes in Victoria, which has the potential to damage critical water supplies.
Chris Taylor, Author provided

David Lindenmayer, Australian National University and Chris Taylor, Australian National University

The Victorian government’s logging business is cutting native forests on steep slopes, in an apparent rule breach that threatens water supplies to Melbourne and rural communities.

Our research indicates that across vital water catchments in the Central Highlands of Victoria, state-owned VicForests is logging native forest on slopes steeper than is allowed under the code of practice. Logging also appears to be occurring in other areas supposedly excluded from harvesting.

Logging operations are prohibited from taking trees from slopes steeper than a certain gradient, because it can lead to soil damage which compromises water supplies. There are far better commercial alternatives to this apparent contravention of the rules, which must immediately cease.

A steep slope recently logged measuring 33 degrees on site near Mount Matlock in the Upper Goulburn Catchment.
Chris Taylor

Logging on steep slopes matters

Water catchments are areas where the landscape collects water. They are defined by natural features such as mountain ridgelines and valleys. Rain drains into rivers and streams, which supply water to reservoirs.

Forest cover protects the soil in water catchments by preventing erosion and other damage which can pollute water.

Areas that provide water for drinking, agriculture and irrigation are known in Victoria as special water supply catchments. Under the state’s Code of Forest Practice, logging in these catchments is prohibited on slopes steeper than 30 degrees (or 25 degrees in some catchments). VicForests claims it does not log trees on such slopes.

Sobering evidence

Water in some affected catchments ends up in Melbourne’s drinking water supply.

We analysed slopes across multiple special water supply catchments. We first examined the relationships between slope and logging disturbance using data from the Victorian government, Geoscience Australia, and the European Space Agency. To confirm the results, we visited multiple sites in the Upper Goulburn catchment, which supplies water to Eildon Reservoir, to measure the slopes ourselves.

We found logging in many areas steeper than 30 degrees. In larger catchments such as the Upper Goulburn, around 44% of logged areas contained slopes exceeding this gradient. In many instances, logged slopes were far steeper than 30 degrees and some breaches covered many hectares.

In the Thomson, Melbourne’s largest water supply catchment, 35% of logged areas contained slopes steeper than 30 degrees.

We also found areas that should have been formally excluded from logging but where the forest had been cut. Many of these exclusion zones were around steep slopes. In the Upper Goulburn catchment, nearly 80% of logged areas contained exclusion zones that should not have been cut.

Recently logged areas near Mount Matlock in the Upper Goulburn Water Catchment. The top map shows where we detected slopes exceeding 30 degrees in logged areas (red). The bottom map shows areas designated by the Victorian government as exclusion zones (magenta).
DELWP 2019, ESA 2019, Gallant et al. 2011

Why is this happening?

Last week, VicForests rejected our allegations of slope breaches. VicForests claimed it was complying with a rule under which 10% of an area logged can exceed 30 degrees. This rule applies to general logging areas; our interpretation is this exemption does not apply to the special water supply catchments.

Forest on steep and rugged terrain is economically marginal for wood production because the trees are relatively short and widely spaced. Almost all timber from these areas is pulpwood for making paper.

So why are such areas being logged at the risk of compromising the water catchments that supplies Melbourne and regional Victoria?

We suspect pressure to log steep terrain is tied to the Victorian government’s legal obligation to provide large quantities of pulp logs for making paper until the year 2030 (coincidentally the year the government plans to phase out native forest logging).

This pressure is reflected in recent reductions in log yields. Some commentators have blamed efforts to protect the critically endangered Leadbeater’s possum for this trend. However, only 0.17% of the 1.82 million hectares of forest allocated to VicForests for logging has been taken out of production to protect this species.

In our view, other possibilities for declining yields are past over-cutting and bushfires. VicForests failed to take into account the effects of fire on its estimates of sustained timber yield – despite some of Victoria’s forests being some of the world’s most fire-prone environments.

There are alternatives

Pulp logs sourced from native forests is not a commercial necessity; there are viable alternatives. Victorian hardwood plantations produced 3.9 million cubic metres of pulp logs last year. Most of this was exported.

If just some of these logs were processed in Victoria, it would be enough to replace the pulpwood logged from native forests several times over. Plantation wood is better for making paper than native forest logs, and processing the logs in Victoria would boost regional employment.

Degrading soil and water by logging steep terrain is not worth the short-term, marginal gain of meeting log supply commitments, especially when there are viable alternatives. The Victorian government must halt the widespread breaches of its own rules.


In a statement, VicForests said it “strongly rejects” the allegations raised by the authors.

In addition to the refutations included in this article, the company said:

  • Any concerns about its practices should be referred to the Office of the Conservation Regulator

  • VicForests does very little harvesting in catchments, where restrictions are in place

  • In the Thompson catchment, VicForests only harvests on average 150ha a year out of about 44,000ha in the catchment – which is 0.3%, or around 3 trees in 1000

  • VicForests only asks contractors to harvest on slopes if it complies with regulation.The Conversation

David Lindenmayer, Professor, The Fenner School of Environment and Society, Australian National University and Chris Taylor, Research Fellow, Fenner School of Environment and Society, Australian National University

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

Message to the EU: you have the chance to stop fuelling devastation in the Amazon



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Deforestation in the Amazon has accelerated since Brazilian president Bolsonaro scrapped environmental laws.
Shutterstock

Claire F.R. Wordley, University of Cambridge and Laura Kehoe, University of Oxford

The effects of European consumption are being felt in Brazil, driving disastrous deforestation and violence.

But the destruction can end if the European Union demands higher environmental standards on Brazilian goods. Hundreds of scientists and Indigenous leaders agree: the time to act is now, before it’s too late.




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Jair Bolsonaro can be stopped from trashing the Amazon – here’s how


In an open letter published today in the journal Science, more than 600 scientists from every country in the European Union (EU) and 300 Brazilian Indigenous groups asked the EU to demand tougher standards for Brazilian imports.

The letter calls on the EU to ensure a trade deal with Brazil respects human rights and the natural world.

Crucially, this can be done without harming Brazil’s agriculture, if already cleared land is used to its full potential. Indeed, in the long term, farming in the region depends on the rains brought by healthy forests.

Destruction of the Amazon under Bolsonaro

Brazil’s Indigenous people and the forests they protect are facing annihilation.

Controversial president Jair Bolsonaro is opening the Amazon rainforest to business and threatening Indigenous people who stand in the way. In his first hours in office, Bolsonaro gave power over Indigenous land to the Ministry of Agriculture, which is widely seen to be controlled by corporate lobbyists.




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In the months since, he has axed environmental roles in the government and planned three major building projects in the Amazon, including a bridge over the river itself.

As Bolsonaro scraps environmental laws, forests are being cut down faster than they have been in years. And the EU is helping drive this carnage: more than a football field of Brazilian rainforest is cut down every hour to produce livestock feed and meat for Europe.




Read more:
Amazon deforestation, already rising, may spike under Bolsonaro


Although the situation may seem dire for the Amazon and its inhabitants, ongoing trade talks provide a chance to act.

Billions of euros flow to Brazil from business with the EU, its second-largest trade partner. Goods flowing in the other direction include environmentally and socially destructive livestock feed (usually soy grown on deforested land) which enters the EU on a tariff-free basis. Right now, European consumers have no way of knowing how much blood is actually in their hamburger. The ongoing EU-Brazil trade talks are therefore a powerful opportunity to curb Bolsonaro’s appetite for destruction.

With a side order of indigenous human rights abuse.
Laura Kehoe and Sara Lucena, Author provided

It is hard to overstate the case for strong action from Europe. People in Brazil – especially Indigenous and local communities – are being violently repressed when trying to defend their land against agricultural and mining companies.

Brutal repression and environmental catastrophe

This violence has reached record levels under Bolsonaro, with at least nine people murdered so far in April 2019. And genocide is a real possibility if nothing is done to protect Indigenous people and their land.

Alarmingly, Bolsonaro has even said:

It’s a shame that the Brazilian cavalry hasn’t been as efficient as the Americans, who exterminated the Indians.

On top of the horrifying assault on Brazil’s original inhabitants, demolishing the country’s forests, savannas and wetlands would have devastating consequences for the world.

If the Amazon rainforest alone is destroyed, the resulting carbon emissions could make it extremely difficult to limit global warming to less than two degrees. Burning fossil fuels is often seen as the only culprit in climate breakdown, but tropical deforestation is the second-largest source of carbon emissions in the world.

Brazil’s forest loss 2001-2013 shown in red. Indigenous lands outlined.
Mike Clark/GlobalForestWatch.org, Author provided

Even losing part of the Amazon could cause a tipping point where the forests no longer create enough rain to sustain themselves. This would cause droughts that would drive many species to extinction, devastate farming in the region and likely cause further violence.

We must act now

We are not just at an ecological tipping point, but a social one, too. The world is waking up to the risks posed by destroying our climate and natural world. Climate change is considered the number one security threat by Brazilian people and by many European nations.

Deforestation could affect the Amazon’s diverse animal population, such as squirrel monkeys.
Ryan Anderton/flickr, CC BY-NC-ND

Europeans believe neither their country nor the EU is doing enough to protect our planet’s life support systems. As protests flare up in Europe over environmental crises, climate change will be a key issue in the upcoming European elections.




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As scientists, we use emotive words carefully. But our open letter calls on the EU to take urgent action because we are terrified of the consequences of Brazilian deforestation, both locally and globally.

We beg the EU to stand up for its citizens’ values and our shared future by making sure trade with Brazil protects, rather than destroys, the natural world on which we all depend.


Visit EUBrazilTrade.org for more information – including a list of parliamentary members standing in the European election who support this initiative. Register to vote in the EU elections here.The Conversation

Claire F.R. Wordley, Research Associate in Conservation Evidence, University of Cambridge and Laura Kehoe, Researcher in Conservation Decision Science and Land Use, University of Oxford

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

Logged native forests mostly end up in landfill, not in buildings and furniture



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Almost all native forest logging in Victoria is for woodchips, pulp and pallets, which have short lifespans before going to landfill.
Janelle Lugge/Shutterstock

Chris Taylor, Australian National University and David Lindenmayer, Australian National University

Victoria has some of the most carbon-dense native forests in the world. Advocates for logging these forests often argue that wood products in buildings and furniture become long-term storage for carbon.

However, these claims are misleading. Most native trees cut down in Victoria become woodchips, pulp and pallets, which have short lifespans before going to landfill. In landfill, the wood breaks down and releases carbon back into the atmosphere.

On the other hand, our evolving carbon market means Australia’s native forests are extremely valuable as long-term carbon stores. It’s time to recognise logging for short-lived wood products is a poor use of native forests.




Read more:
Logging must stop in Melbourne’s biggest water supply catchment


The problem with logging native forests

Victoria has about 7.6 million hectares of native forests. The most carbon-dense areas are in ash forests, consisting of mountain ash, alpine ash and shining gum trees.

These forests can store up to 1,140 tonnes of carbon per hectare for centuries.

Only 14% of logs cut from Victorian native forests end up as timber products used in buildings and furniture.
Shutterstock

But around 1.82 million hectares of Victorian native forests are allocated to the government’s logging business, VicForests.

VicForests claims logging is the only market for the large area of native forest allocated to it. In other words, its forests are exclusively valued as timber asset, in the same way a wheat crop would be exclusively valued for wheat grain production.

In Victorian native forests, industrial scale clearfell logging removes around 40% of the forest biomass for logs fit for sale.

The remaining 60% is debris, which is either burned off or decomposes – becoming a major source of greenhouse gas emission.




Read more:
Logging burns conceal industrial pollution in the name of ‘community safety’


Myth one: storing carbon in wood products

The first myth we want to address is logging native forests is beneficial because the carbon is stored in wood products. This argument depends on the proportion of forest biomass ending up in wood products, and how long they last before ending up in landfill.

On average, logs suitable to be sawn into timber make up only an average 35% of total logs cut from Victorian native forests.

Of this 35%, sawmills convert less than 40% into sawn timber for building and furniture. Offcuts are woodchipped and pulped for paper manufacturing, along with sawdust sold to chicken broiler sheds for bedding.

Sawn timber equates to 14% of log volume cut from the forest. The remaining 84% of logs cut are used in short-lived and often disposable products like copy paper and pallets.




Read more:
Forest soil needs decades or centuries to recover from fires and logging


The lifespan of paper products is assumed to be three years. Although around 75% of paper and cardboard is recovered, recycling is growing more uncertain with recovered paper being sent to landfill.

The maximum lifespan of a timber pallet is seven years. At the end of their service, timber pallets are sent to landfill, chipped for particleboard, reused for landscape mulch or burnt for energy generation.

Longer-lived wood products, such as the small proportion of native timber used in building and furniture, have a lifespan of around 90 years. These wood products are used to justify logging native forests.

But at the end of their service life, the majority of these wood products also end up in landfill.

In fact, for the 500,000 tonnes of wood waste generated annually from building, demolition and other related commercial processes in Victoria, over two thirds end up in landfill, according to a Sustainability Victoria report.

Myth two: the need to log South East Asian rainforests

A second myth is using logs from Victorian native forests will prevent logging and degradation of rainforests across South East Asia, particularly for paper production.

This is patently absurd. The wood from the Victorian plantation sector – essentially timber farms, rather than trees growing “wild” in native forests – could replace native forest logs used for paper manufacturing in Victoria several times over.

In fact, in 2016-17 89% of logs used to make wood pulp (pulplogs) for paper production in Victoria came from plantation trees, with the majority of hardwood logs exported.

And Australia is a net exporter by volume of lower-value unprocessed logs and woodchips.




Read more:
Native forests can help hit emissions targets – if we leave them alone


Processing pulplogs from well managed plantations in Victoria instead of exporting them would give a much needed jobs boost for local economies.

With most of these plantations established on previously cleared farmland, they offer one of the most robust ways for the land use sector to off-set greenhouse gas emissions.

Next steps

The time is right for Australian governments to develop a long-term carbon storage plan that includes intact native forests.

Logging results in at least 94% of a forest’s stored carbon ending up in the atmosphere. A maximum of 6% of its carbon remains in sawn timber, for up to 90 years (but typically much shorter). This is patently counterproductive from a carbon-storage point of view.




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State-owned forest management companies, such as VicForests, can transition away from the timber business and begin managing forests for carbon storage. Such a concept is not new – the federal government has already approved a way to value the carbon storage of plantations.

The same must now be developed to better protect native forests and the large amounts of carbon they can store.The Conversation

Chris Taylor, Research Fellow, Fenner School of Environment and Society, Australian National University and David Lindenmayer, Professor, The Fenner School of Environment and Society, Australian National University

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

Forest soil needs decades or centuries to recover from fires and logging



File 20190121 100288 15v1q9i.jpg?ixlib=rb 1.1

David Blair, Author provided

Elle Bowd, Australian National University and David Lindenmayer, Australian National University

The 2009 Black Saturday fires burned 437,000 hectares of Victoria, including tens of thousands of hectares of Mountain Ash forest.

As we approach the tenth anniversary of these fires, we are reminded of their legacy by the thousands of tall Mountain ash “skeletons” still standing across the landscape. Most of them are scattered amid a mosaic of regenerating forest, including areas regrowing after logging.




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But while we can track the obvious visible destruction of fire and logging, we know very little about what’s happening beneath the ground.

In a new study published in Nature Geoscience, we investigated how forest soils were impacted by fire and logging. To our surprise, we found it can take up to 80 years for soils to recover.

Logging among the charred remains of Mountain ash after the 2009 fires.
David Blair, Author provided

Decades of damage

Soils have crucial roles in forests. They are the basis for almost all terrestrial life and influence plant growth and survival, communities of beneficial fungi and bacteria, and cycles of key nutrients (including storing massive amounts of carbon).

To test the influence of severe and intensive disturbances like fire and logging, we compared key soil measures (such as the nutrients that plants need for growth) in forests with different histories. This included old forests that have been undisturbed since the 1850s, forests burned by major fires in 1939, 1983 and 2009, forests that were clearfell-logged in the 1980s or 2009-10, or salvage-logged in 2009-10 after being burned in the Black Saturday fires.

We found major impacts on forest soils, with pronounced reductions of key soil nutrients like available phosphorus and nitrate.

A shock finding was how long these impacts lasted: at least 80 years after fire, and at least 30 years after clearfell logging (which removes all vegetation in an area using heavy machinery).

However, the effects of disturbance on soils may persist for much longer than 80 years. During a fire, soil temperatures can exceed 500℃, which can result in soil nutrient loss and long-lasting structural changes to the soil.

We found the frequency of fires was also a key factor. For instance, forests that have burned twice since 1850 had significantly lower measures of organic carbon, available phosphorus, sulfur and nitrate, relative to forests that had been burned once.

Sites subject to clearfell logging also had significantly lower levels of organic carbon, nitrate and available phosphorus, relative to unlogged areas. Clearfell logging involves removing all commercially valuable trees from a site – most of which are used to make paper. The debris remaining after logging (tree heads, lateral branches, understorey trees) is then burned and the cut site is aerially sewn with Mountain Ash seed to start the process of regeneration.

Fire is important to natural growth cycles in our forests, but it changes the soil composition.
David Lindenmayer, Author provided

Logging compounds the damage

The impacts of logging on forest soils differs from that of fire because of the high-intensity combination of clearing the forest with machinery and post-logging “slash” burning of debris left on the ground. This can expose the forest floor, compact the soil, deplete soil nutrients, and release large amounts of carbon dioxide into the atmosphere.

Predicted future increases in the number, frequency, intensity and extent of fires in Mountain Ash forests, coupled with ongoing logging, will likely result in further declines in soil nutrients in the long term. These kinds of effects on soils matter in Mountain Ash forests because 98.8% of the forest have already been burned or logged and are 80 years old or younger.

To maintain the vital roles that soils play in ecosystems, such as carbon storage and supporting plant growth, land managers must consider the repercussions of current and future disturbances on forest soils when planning how to use or protect land. Indeed, a critical part of long-term sustainable forest management must be to create more undisturbed areas, to conserve soil conditions.




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New modelling on bushfires shows how they really burn through an area


Specifically, clearfell logging should be limited wherever possible, especially in areas that have been subject to previous fire and logging.

Ecologically vital, large old trees in Mountain Ash forests may take over a century to recover from fire or logging. Our new findings indicate that forest soils may take a similar amount of time to recover.The Conversation

Elle Bowd, PhD scholar, Australian National University and David Lindenmayer, Professor, The Fenner School of Environment and Society, Australian National University

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

Comic explainer: forest giants house thousands of animals (so why do we keep cutting them down?)



File 20181129 170241 np8k0s.png?ixlib=rb 1.1

Wes Mountain/The Conversation, CC BY-ND

Madeleine De Gabriele, The Conversation and Wes Mountain, The Conversation

Giant eucalypts play an irreplaceable part in many of Australia’s ecosystems. These towering elders develop hollows, which make them nature’s high-rises, housing everything from endangered squirrel-gliders to lace monitors. Over 300 species of vertebrates in Australia depend on hollows in large old trees.

These “skyscraper trees” can take more than 190 years to grow big enough to play this nesting and denning role, yet developers are cutting them down at an astounding speed. In other places, such as Victoria’s Central Highlands Mountain Ash forests, the history of logging and fire mean that less than 1.2% of the original old-growth forest remains (that supports the highest density of large old hollow trees). And it’s not much better in other parts of our country.

David Lindenmayer explains how these trees form, the role they play – and how very hard they are to replace.




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Mountain ash has a regal presence: the tallest flowering plant in the world



Wes Mountain/The Conversation, CC BY-ND



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The plan to protect wildlife displaced by the Hume Highway has failed



Sign up to Beating Around the Bush, a series that profiles native plants: part gardening column, part dispatches from country, entirely Australian.The Conversation

Madeleine De Gabriele, Deputy Editor: Energy + Environment, The Conversation and Wes Mountain, Multimedia Editor, The Conversation

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

Logging must stop in Melbourne’s biggest water supply catchment


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Clearfell logging in the Thomson Catchment with the Thomson Reservoir in the background.
Chris Taylor

David Lindenmayer, Australian National University and Chris Taylor, Australian National University

Continued logging in Melbourne’s water catchments could reduce the city’s water supply by the equivalent of 600,000 people’s annual water use every year by 2050, according to our analysis.

We calculated water lost due to logging in the Thomson Catchment, which is the city’s largest and most important water supply catchment. Around 60% of Melbourne’s water is stored here.

Since the 1940s, 45% of the catchment’s ash forests (including mountain and alpine ash forest) have been logged. There are plans to log up to a further 17% of these forests under the VicForest’s existing logging plan.

Past logging in the ash forests has reduced the Thomson Catchment’s water yield, which is the amount of water that flows through the catchment, by 15,000 megalitres (a megalitre is a million litres) each year. This equates to around 9% of water yield from ash forests across the catchment.

By 2050, continued logging in these forests at the current rates could increase this loss to 35,000 megalitres each year, or 20% of water yield. This will be equal to the water use of around 600,000 people every year, based on estimated water use of 161 litres per person each day.

Thomson Catchment showing the extent of ash forest, with historic and planned logging (left) and annual rainfall distribution (right).
DELWP, 2018; Xu and Hutchinson 2018; DSE 2007.



Read more:
Ashes to ashes: logging and fires have left Victoria’s magnificent forests in tatters


Why forests are important for water supply

The city of Melbourne has some of the best quality water in the world. A key reason for this is that the city’s first water infrastructure planners closed many of the key water catchments to intensive human disturbance, such as logging.

But there also can be competition for water between different land uses in catchments that are not closed and open to logging. Indeed, it has long been known that logging can significantly reduce the amount of water produced from forests, especially those close to Melbourne.

Research on forest hydrology shows that the amount of water yielded from ash forests is related to forest age. Catchments covered with old-growth ash forests yield almost twice the amount of water each year as those covered with young forests aged 25 years. This is because evapotranspiration, the process by which trees transpire water into the atmosphere as well as evaporation from the surrounding land surface, is higher in young forests compared with older forests.

Up to 200,000 trees per hectare germinate following logging or an intense fire which burns the whole stand. Intense competition between young trees results in rapid growth rates along with increased evapotranspiration. As the forest matures, the trees thin out, and after 200 years, an ash forest can have less than 50 trees per hectare. These older ash forests release more water back into the catchment.




Read more:
Mountain ash has a regal presence: the tallest flowering plant in the world


With logging occurring every 60-120 years, large areas of ash forest are kept in a high evapotranspiration stage of growth, therefore releasing less water back into the catchment.

Perhaps the losses in water yield could be justified if the value of the timber and pulpwood produced from logging exceeded the value of water. However, previous research has shown that the water in these areas is 25.5 times more valuable than the timber and pulpwood from ash forests.

What can the Victorian government do?

The ash forests in the Thomson Catchment are logged primarily for paper manufacturing. Under the Forest (Wood Pulp Agreement) Act 1996, the Victorian government is bound to supply Australia’s largest pulp and paper mills at Maryvale, owned by the Nippon Paper Group, with at least 350,000 cubic metres of native forest logs each year. The Thomson Water Supply Catchment is allocated for logging under this Act.

If logging was stopped in the catchment, what is the alternative for these paper mills? The answer is to source wood from current plantations. In 2017, Victoria produced 3.9 million cubic metres of logs from plantations. This could supply the pulp and paper mills at Maryvale several times over.

A challenge facing Victoria’s forest industry is the loss of jobs. One major factor in this is out-of-state processing. Australia tends to import lower volumes
of more processed and higher value wood products, including printing and writing paper. By contrast, higher volumes of less processed and lower value wood products, such as woodchips and unprocessed logs – largely from plantations, are exported.

Redirecting plantation sourced logs and woodchips from export markets to domestic processing can address some of these problems. In fact, detailed analysis suggests doing this would have an overall positive economic impact for Victoria.

Stopping logging in the Thomson Catchment and sourcing instead from well managed plantations could both boost water supply and create more jobs. Of course, some jobs would be lost for people who log from the catchment, but this would be more than compensated for by employment in the plantation processing sector.

The first Wood Pulp Agreement Act of 1936, which legislated supply of pulplogs from Victorian state forest to earlier paper manufacturers in Maryvale, featured a clause stating logging was to cease following the designation of the Thomson Catchment in 1967. This has clearly not occurred. In fact 63% of logging in the ash forests across the catchment has occurred since 1967.

The Thomson Catchment is the only one of Melbourne’s large water supply catchments open to logging. Given the critical importance of the Thomson Catchment, our work clearly indicates the Victorian government needs to cease logging and prioritise the supply of water to the people of Melbourne.The Conversation

David Lindenmayer, Professor, The Fenner School of Environment and Society, Australian National University and Chris Taylor, Research Fellow, Fenner School of Environment and Society, Australian National University

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