Climate explained: is New Zealand losing or gaining native forests?


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Sebastian Leuzinger, Auckland University of Technology


CC BY-ND

Climate explained is a collaboration between The Conversation, Stuff and the New Zealand Science Media Centre to answer your questions about climate change.

If you have a question you’d like an expert to answer, please send it to climate.change@stuff.co.nz


In recent decades, has New Zealand lost forest (both native and exotic) or gained it, courtesy of the One Billion Trees programme? What about natural habitats like wetlands?

Apart from wetlands, land above the treeline, coastal dunes and a few other exceptions, New Zealand was once covered in forests from Cape Reinga to Bluff.

So was Europe, which basically consisted of a single forest from Sicily in southern Italy to the North Cape in Norway, before human intervention.

But since people arrived in New Zealand some 850 years ago, about three quarters of the country’s native forest area has been lost. About half of the loss happened before Europeans arrived, mostly through burning to clear large areas of native bush.

Most of New Zealand was once covered in native forest.
Shutterstock/Latitude Creative

In recent decades, the loss of native forest has slowed down. For example, in the first decade of the 21st century, we lost roughly 16,000 hectares of native forest, which translates to a loss of about 0.2% of the remaining total area covered in native forest (about 7.5 million hectares). The error associated with such estimates is considerable, though, because land cover is complex and highly fragmented.




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A billion trees

According to Global Forest Watch, the drivers behind the more recent losses of native forests include exotic plantation forests, urban developments and wildfires. Indeed, the total land area dedicated to exotic plantation forests increased by about 200,000 hectares per decade between 1990 and 2017.

Commercial plantations of exotic pines have replaces native forests.
Shutterstock/Cloudia Spinner

So what has the One Billion Trees Programme achieved in comparison to these changes?

The project’s aim is to double the current planting rate and plant one billion trees between 2018 and 2028. The latest report shows about a quarter of this goal has been achieved in terms of the number of trees planted. In regards to forest area, 25,557 hectares have been reforested, about half of it with natives.

This is a remarkable achievement in light of the losses cited above and the short duration of the programme.

About a quarter of a billion trees have been planted so far, half of it native species.
Shutterstock/Kira Volkov

Saving remaining peat bogs

We think of forests as our guardians of carbon — and indeed, an aged New Zealand forest can hold about 350 tonnes of carbon per hectare. But intact peat bogs, such as the Kopuatai dome in the Waikato region, can hold up to 1,400 tonnes of carbon per hectare.

But peat bogs only store carbon if they remain wet. Once drained, they begin to emit carbon dioxide. Almost half of New Zealand’s peatlands are in the Waikato, but of a total of 89,000 hectares only 19,400 hectares remain in a natural state.

Aerial view of the Kopuatai bog.
The Kopuatai dome is New Zealand’s largest intact peat bog.
Georgie Glover-Clark, CC BY-SA

The Kopuatai bog itself is surrounded by dairy farms operating on drained peat. Collectively, the Waikato’s drained peatlands produce 10-33 tonnes of CO₂-equivalent emissions per hectare each year.

The draining of peatlands in the Waikato region did far more damage, in terms of carbon emissions, than a small loss of forest area.




Read more:
Peat bogs: restoring them could slow climate change – and revive a forgotten world


But nevertheless, planting trees and increasing our forest area is an important and necessary contribution to climate mitigation, and often comes with a myriad of other benefits, far beyond carbon sequestration.

Sometimes it’s as easy as planting your own fruit trees around your house. They will capture carbon for years to come, and keep you from buying fruit that has been transported thousands of kilometres.

They might even motivate you to reduce food waste. Globally, about 25-30% of food goes to waste. If we reduced food waste, we could save agricultural land multiple times the size of New Zealand and plant trees there instead.The Conversation

Sebastian Leuzinger, Professor, Auckland University of Technology

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

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.




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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.




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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.

New research finds native forest logging did not worsen the Black Summer bushfires


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David Bowman, University of TasmaniaThe Black Summer bushfires shocked the world and generated enormous global media interest. Fire scientists like myself found themselves filling a role not unlike sport commentators, explaining the unfolding drama in real time.

Scientists who engaged with the media during the crisis straddled two competing imperatives. First was their duty to share their knowledge with the community while knowing their understanding is imperfect. Second was the ethical obligation to rigorously test hypotheses against data analysis and peer review – the results of which could only be known long after the fires were out.

One area where this tension emerged was around the influential idea that logging exacerbated the bushfire disaster. During the fire crisis and in the months afterwards, some scientists suggested logging profoundly affected the fires’ severity and frequency. There were associated calls to cease native forestry and shift wood production to plantations.

But there is no scientific consensus about the possible effects of logging on fire risk. In fact, research by myself and colleagues, published in Nature Ecology and Evolution today, shows logging had little if any effect on the Black Summer bushfires. Rather, the disaster’s huge extent and severity were more likely due to unprecedented drought and sustained hot, windy weather.

These findings are significant for several reasons. Getting to the bottom of the bushfires’ cause is essential for sustainable forest management. And, more importantly, our research confirms the devastating role climate change played in the Black Summer fires.

Firefighters recover after battling blazes at Kangaroo Island on 10 January 2019.
David Mariuz/AAP

Looking for patterns

Our research focused on 7 million hectares of mostly eucalyptus forests, from the subtropics to temperate zones, which burned between August 2019 and March 2020.

There is some evidence to suggest logged areas are more flammable that unlogged forests. Proponents of this view say logging regimes make the remaining forests hotter and drier, and leave debris on the ground that increases the fuel load.

In our research, we wanted to determine:

  • the relative roles logging and other factors such as climate played in fires that destroyed or completely scorched forest canopies
  • whether plantations are more vulnerable to canopy scorch than native forests.

To do so, we used landscape ecology techniques that could compare very large areas with different patterns of land use and fire severity. We sampled 32% of the area burnt in three regions spanning the geographic range of the fires.




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firefighters run past fire
The research used landscape ecology techniques to compare large areas.
Shutterstock

What we found

Fire intensity is classified according to the vertical layer of vegetation burnt. A scorched tree canopy suggests the most intense type of fire, where the heat extended from the ground to the treetops.

We found several predictors of canopy damage. First, completely scorched canopy, or canopy consumed by fire, typically occurred across connected swathes of bushland. This most likely reflected instances where the fire made a “run”, driven by localised winds.

Extreme weather fire conditions were the next most important predictor of canopy damage. The drought had created vast areas of tinder-dry forests. Temperatures during the fire season were hot and westerly winds were strong.

Southeast Australia’s climate has changed, making such extreme fire weather more frequent, prolonged and severe.

Logging activity in the last 25 years consistently ranked “low” as a driver of fire severity. This makes sense for several reasons.

As noted above, fire conditions were extraordinarily extreme. And there was mismatch between the massive area burnt and the comparatively small areas commercially logged in the last 25 years (4.5% in eastern Victoria, 5.3% in southern NSW and 7.8% in northern NSW).

Fire severity is also related to landscape features: fire on ridges is generally worse than in sheltered valleys.

Our research also found timber plantations were as prone to severe fire as native forestry areas. In NSW (the worst-affected state) one-quarter of plantations burned – than 70% severely. This counteracts the suggestion using plantations, rather than logging native forest, can avoid purported fire hazards.




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plantation forest divided by road
Plantation forests were found to be highly flammable.
Shutterstock

A challenge awaits

Our findings are deeply concerning. They signal there is no quick fix to the ongoing fire crisis afflicting Australia and other flammable landscapes.

The crisis is being driven by relentless climate change. Terrifyingly, it has the potential to turn forests from critical stores of carbon into volatile sources of carbon emissions released when vegetation burns.

Under a rapidly warming and drying climate, fuel loads are likely to become less important in determining fire extent and severity. This will make it increasingly difficult, if not impossible, to lower fuel loads in a way that will limit bushfire severity.

A massive challenge awaits. We must find socially and environmentally acceptable ways to make forests more resilient to fire while the also produce sustainable timber products, store carbon, provide water and protect biodiversity.

The next step is a real-world evaluation of management options. One idea worth exploring is whether the fire resistance of native forests can be improved in specific areas by altering tree density, vegetation structure or fuel loads, while sustaining biodiversity and amenity.

Commercial forestry could potentially do this, with significant innovation and willingness to let go of current practices.

Through collective effort, I’m confident we can sustainably manage of forests and fire. Our study is but a small step in a much bigger, zig-zagging journey of discovery.




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The Conversation


forest regenerating after fire
Forests must become fire-resilient while performing other functions.
Shutterstock

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.

Are young trees or old forests more important for slowing climate change?



Jeremy Kieran/Unsplash, CC BY-SA

Tom Pugh, University of Birmingham

Forests are thought to be crucial in the fight against climate change – and with good reason. We’ve known for a long time that the extra CO₂ humans are putting in the atmosphere makes trees grow faster, taking a large portion of that CO₂ back out of the atmosphere and storing it in wood and soils.

But a recent finding that the world’s forests are on average getting “shorter and younger” could imply that the opposite is happening. Adding further confusion, another study recently found that young forests take up more CO₂ globally than older forests, perhaps suggesting that new trees planted today could offset our carbon sins more effectively than ancient woodland.

How does a world in which forests are getting younger and shorter fit with one where they are also growing faster and taking up more CO₂? Are old or young forests more important for slowing climate change? We can answer these questions by thinking about the lifecycle of forest patches, the proportion of them of different ages and how they all respond to a changing environment.




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The forest carbon budget

Let’s start by imagining the world before humans began clearing forests and burning fossil fuels.

In this world, trees that begin growing on open patches of ground grow relatively rapidly for their first several decades. The less successful trees are crowded out and die, but there’s much more growth than death overall, so there is a net removal of CO₂ from the atmosphere, locked away in new wood.

As trees get large two things generally happen. One, they become more vulnerable to other causes of death, such as storms, drought or lightning. Two, they may start to run out of nutrients or get too tall to transport water efficiently. As a result, their net uptake of CO₂ slows down and can approach zero.

Eventually, our patch of trees is disturbed by some big event, like a landslide or fire, killing the trees and opening space for the whole process to start again. The carbon in the dead trees is gradually returned to the atmosphere as they decompose.

The vast majority of the carbon is held in the patches of big, old trees. But in this pre-industrial world, the ability of these patches to continue taking up more carbon is weak. Most of the ongoing uptake is concentrated in the younger patches and is balanced by CO₂ losses from disturbed patches. The forest is carbon neutral.

A misty forest scene.
New trees absorb lots of carbon, old trees store more overall and dead trees shed their carbon to the atmosphere.
Greg Rosenke/Unsplash, CC BY-SA

Now enter humans. The world today has a greater area of young patches of forest than we would naturally expect because historically, we have harvested forests for wood, or converted them to farmland, before allowing them to revert back to forest. Those clearances and harvests of old forests released a lot of CO₂, but when they are allowed to regrow, the resulting young and relatively short forest will continue to remove CO₂ from the atmosphere until it regains its neutral state. In effect, we forced the forest to lend some CO₂ to the atmosphere and the atmosphere will eventually repay that debt, but not a molecule more.

But adding extra CO₂ into the atmosphere, as humans have done so recklessly since the dawn of the industrial revolution, changes the total amount of capital in the system.

And the forest has been taking its share of that capital. We know from controlled experiments that higher atmospheric CO₂ levels enable trees to grow faster. The extent to which the full effect is realised in real forests varies. But computer models and observations agree that faster tree growth due to elevated CO₂ in the atmosphere is currently causing a large carbon uptake. So, more CO₂ in the atmosphere is causing both young and old patches of forest to take up CO₂, and this uptake is larger than that caused by previously felled forests regrowing.

The effect of climate change

But the implications of climate change are quite different. All else being equal, warming tends to increase the likelihood of death among trees, from drought, wildfire or insect outbreaks. This will lower the average age of trees as we move into the future. But, in this case, that younger age does not have a loan-like effect on CO₂. Those young patches of trees may take up CO₂ more strongly than the older patches they replace, but this is more than countered by the increased rate of death. The capacity of the forest to store carbon has been reduced. Rather than the forest loaning CO₂ to the atmosphere, it’s been forced to make a donation.

So increased tree growth from CO₂ and increased death from warming are in competition. In the tropics at least, increased growth is still outstripping increased mortality, meaning that these forests continue to take up huge amounts of carbon. But the gap is narrowing. If that uptake continues to slow, it would mean more of our CO₂ emissions stay in the atmosphere, accelerating climate change.

Overall, both young and old forests play important roles in slowing climate change. Both are taking up CO₂, primarily because there is more CO₂ about. Young forests take up a bit more, but this is largely an accident of history. The extra carbon uptake we get from having a relatively youthful forest will diminish as that forest ages. We can plant new forests to try to generate further uptake, but space is limited.

But it’s important to separate the question of uptake from that of storage. The world’s big, old forests store an enormous amount of carbon, keeping it out of the atmosphere, and will continue to do so, even if their net CO₂ uptake decreases. So long as they are not cut down or burned to ashes, that is.The Conversation

Tom Pugh, Reader in Biosphere-Atmosphere Exchange, University of Birmingham

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

Animals are disappearing from forests, with grave consequences for the fight against climate breakdown – new research



A toucan eating a fruit in the tropical wetlands of the Pantanal, Brazil.
Uwe Bergwitz/Shutterstock

Charlie Gardner, University of Kent; Jake Bicknell, University of Kent; Matthew Struebig, University of Kent, and Zoe Davies, University of Kent

It’s tempting to think that our forests would be fine if we could simply stop trees being felled or burnt. But forests – particularly tropical ones – are more than just trees. They’re also the animals that skulk and swoop among them.

Worryingly, these furry and feathered companions are rapidly disappearing – and our new research indicates that this will have grave repercussions for the role forests play in combating climate breakdown.

Healthy tropical forests swarm with life. Beyond myriad invertebrates there are seed-eating rodents, a range of leaf eaters, birds of all kinds, and often primates. However, many forests have already lost most of their largest animals, mainly as a result of hunting to supply a growing bushmeat trade.

Hunting isn’t the only reason. Thanks to deforestation for farmland and logging, many forests today are highly fragmented. The small, unconnected patches that remain aren’t big enough to support populations of the largest species, which tend to need more space.

The disappearance of animals from otherwise intact habitats is known as defaunation, and it is leading to a growing number of empty forests not just in tropical countries, but around the world. The UK has already lost most of its largest species (think lynx, wolf, and wisent), while woodland bird numbers have declined by a quarter since 1970.




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The impacts of this defaunation have attracted the attention of the world’s conservation scientists, but studies to date have usually been carried out at single locations. Consequently, we lack a worldwide picture that takes into account different types of forest and the diversity of animals that are disappearing.

To fill this gap, we worked with William Baldwin-Cantello, chief adviser on forests at the World Wide Fund for Nature UK, to gather together all the existing research and perform a meta-analysis – an analysis of analyses – on the available data.

Forest flora need flourishing fauna

Our findings reveal a worrying trend. The loss of animals compromises the ability of forests to reproduce. This effect is particularly severe when primates and birds disappear, because of the key role they play in seed dispersal. Trees make fruit to entice animals to transport their seeds, because they are more likely to germinate and grow successfully if they fall further from their parent tree. So when fruit-eating animals disappear, fewer seeds are dispersed and the trees struggle to reproduce.

A black howler monkey eating a juicy cashew fruit.
akramer/Shutterstock

This animal absence will slowly change how forests look. Most tropical forests today are dominated by trees whose seeds are dispersed by animals. Over time, they are likely to be gradually replaced by trees that use the wind to reproduce. Naturally, these usually have small seeds, and therefore produce smaller trees that store less carbon for the same area of forest. As a result, forests will store less and less carbon, even if we completely halt deforestation.

This is particularly concerning because roughly 20% of the carbon dioxide we emit is absorbed by the world’s vegetation and soils, and half of this is due to tropical forests alone.

Rethinking forest health

Conserving forests is essential for the fight against climate breakdown – and, we do have a global tool at our disposal to help. Known as Reducing Emissions from Deforestation and forest Degradation, or REDD+ for short, it allows wealthy countries with large carbon footprints to pay poorer, tropical countries to protect their forests.

Of course, REDD+ is only an effective tool if the forests countries pay to protect continue to store the same amount of carbon. We usually monitor this by taking satellite images of the quantity of forest canopy remaining. But what satellite imagery can’t do is measure aspects of forest quality beneath the canopy.

Our research strongly suggests that one aspect of forest quality – defaunation – is a vital early warning sign of future losses in the carbon storing capacity of forests. In light of this, policies for managing forest carbon around the world may need a rethink.

We need to pay more attention to what’s going on beneath global forest canopies through research on the ground, though this will be difficult in remote areas. More importantly, we must make sure we’re doing all we can to conserve the full complement of animal species that live in our forests. For example, we need to heavily invest in conservation actions that help communities accustomed to hunting bushmeat to meet their dietary protein needs without harming wildlife. We must also enforce existing rules better, such as those that outlaw hunting within parks and reserves.

Preventing defaunation in forests won’t be easy. But given what we know about the critical role forest animals play, doing so will be essential if we hope to retain diverse and carbon-rich forests in the tropics and around the world. If the beauty and wonder of the forest’s animals wasn’t enough reason to protect them, we now have another: by conserving wildlife, we will be helping to save ourselves from the catastrophic effects of climate breakdown.


Click here to subscribe to our climate action newsletter. Climate change is inevitable. Our response to it isn’t.The Conversation

Charlie Gardner, Lecturer in Conservation Biology, University of Kent; Jake Bicknell, Lecturer in Conservation Biology, University of Kent; Matthew Struebig, Senior Lecturer in Biological Conservation, University of Kent, and Zoe Davies, Professor of Biodiversity Conservation, University of Kent

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

‘Edible forests’ can fight land clearing and world hunger at the same time



A Nepalese woman collects mushroom in a forest.
Jagannath Adhikari, Author provided

Jagannath Adhikari, UNSW

Reducing emissions from deforestation and farming is an urgent global priority if we want to control climate change. However, like many climate change problems, the solution is complicated. Cutting down forests to plant edible crops feeds some of the world’s hungriest people.




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More than 820 million people suffer from hunger, and about 2 billion people face moderate food insecurity – meaning they do not always know when their next meal will come.

After a decade of slow decline, climate change is driving this number up again, particularly in Africa and Asia, where competition over land for both farming and forest conservation is acute.

But villagers in the Himalayas are turning to a traditional practice that can slow land clearing and feed people: growing and collecting food from the forests.

Mushrooms, as well as honey, roots and other edible plants are harvested by locals as an important food source.
Jagannath Adhikari, Author provided

Food in the forest

My research in the Himalayan region, where high population density means farmland is very scarce, investigated how people used their forests as a food source.

An “edible forest” is one in which people have planted trees and crops that can produce food in the forest, as well as harvesting what naturally grows. In fact, this is a traditional practice in the Himalayan region. A farmer I interviewed in Siding village, at the base of Mardi Himal – one of the peaks in Annapurna Himalayan range – told me:

I go to [the] forest when food is scarce at home. I collect vegetables, fruits, nuts, medicinal herbs, spices, roots and tubers. Sometimes I also collect wild honey, bamboo shoots and mushroom, which is consumed at home and also sold in the market. Occasionally, we also get wild meat.

Traditionally, these villagers see forest and farms as an extension of each other rather than distinct categories, and manage them so they support each other.

Generally, people plant trees useful for households – for their wood, for example, or fruit – in the forest close to the villages, and preserve those grown naturally.

The community itself protects the forest, in the past even pooling grains and cash to hire a guard if needed.

This forest food is supplementary, becoming more important in scarce times and as a buffer during famine. Taking wood for fuel or timber is strictly regulated, but there are no restrictions on gathering food, to the great benefit of the poorest.

Collecting food is mainly the work of women, who gather a few things whenever they go into the forest for firewood or animal fodder. They have a great deal of knowledge about edible plants. Men take part by hunting for honey and wild animals. Children, too, go to the forest in their free time to gather berries and tubers.

Sometimes villagers collect these foods to sell in nearby markets as a seasonal source of cash.

A woman sells bamboo shoot in Pokhara, Nepal. These bamboo shoots are collected in forests at high altitude, 2,200-2,600 meters above sea level.
Jagannath Adhikari

Modern bureaucracy

The centralised forest management and curtailment of traditional rights of the communities that came with modern forest bureaucracy in the Himalayan region distanced people from the forest. This also led to rapid deforestation between the mid-1960s to 1980s.

This trend was reversed in the early 1990s, when community rights came to the forefront and communally managed forestry gained a strong foothold. This helped reduce poverty. Yet it is still hard for locals to grow food in the forests as they once did. One farmer told me,

We do not destroy forest when collecting these things, but conservation regulation is making this collection difficult.

We need power to move from centralised governments to local stewardship and local knowledge. Government oversight would still be required to protect the local interests, but any new mechanism needs to be developed in consultation with local communities. Research institutions could play a role in finding better ways to meet the interest of local communities when they manage their forest.

A new category of land use

Edible forests are a departure from standard schemes to reduce emissions from deforestation and land degradation, in which developed countries pay less developed countries to preserve or replant their forests.




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If people are actively planting and harvesting in a forest, it may not qualify as protected or conserved land. Conversely, if a local community depends on their forest for food, they may hesitate to register for a formal scheme, for fear they will lose a valuable resource.

If reforestation schemes can be expanded to take into account planting that doesn’t compromise tree coverage, we can encourage rapid growth of edible forests and speed up our response to climate change. It will help meet goals like food security, mitigation and adaptation to climate change, and reducing desertification and land degradation that the United Nations’ Intergovernmental Panel on Climate Change has recommended for sustainable land management in the light of climate change.

Climate migration

Climate change and food insecurity are the main drivers of migration away from rural areas in developing countries, which brings its own challenges for sustainable land management.

Wages sent home by those who move away is a huge part of food security and reducing poverty for many people. In 2018 about US$530 billion was transferred to low- and middle-income countries between family members, compared with US$162 billion in development aid.




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This flow of money means families with marginal land – like farmland on hill slopes in Nepal’s case – can afford to slowly convert it to plantations or forests. Migration and remittances – which contribute some 28% of Nepal’s gross domestic product – helps increase forest coverage, especially in marginal lands vulnerable to erosion and landslides.

There is an opportunity to increase planting in these lands, which have been abandoned for farming. If official reforestation policies can acknowledge and support edible forests, we could see the Himalayan region lead the pack on a new way of thinking about forests and food.The Conversation

Jagannath Adhikari, Sessional Lecturer, UNSW

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

Want to beat climate change? Protect our natural forests



Natural forest systems are far better at adapting to change conditions than young, degraded or plantation forests.
Shutterstock

Kate Dooley, University of Melbourne and Brendan Mackey, Griffith University

Tomorrow a special report on how land use affects climate change will be released by the Intergovernmental Panel on Climate Change.

Land degradation, deforestation, and the expansion of our deserts, along with agriculture and the other ways people shape land, are all major contributors to global climate change.

Conversely, trees remove carbon dioxide and store it safely in their trunks, roots and branches. Research published in July estimated that planting a trillion trees could be a powerful tool against climate change.




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However, planting new trees as a climate action pales in comparison to protecting existing forests. Restoring degraded forests and expanding them by 350 million hectares will store a comparable amount of carbon as 900 million hectares of new trees.

Natural climate solutions

Using ecological mechanisms for reducing and storing carbon is a growing field of study. Broadly known as “natural climate solutions”, carbon can be stored in wetlands, grasslands, natural forests and agriculture.

This is called “sequestration”, and the more diverse and longer-lived the ecosystem, the more it helps mitigate the effect of climate change.

Allowing trees to regenerate naturally is a more effective, immediate and low-cost method of removing and storing atmospheric carbon than planting new trees.
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Research has estimated these natural carbon sinks can provide 37% of the CO₂ reduction needed to keep the rise in global temperatures below 2℃.

But this research can be wrongly interpreted to imply that the priority is to plant young trees. In fact, the major climate solution is the protection and recovery of carbon-rich and long-lived ecosystems, especially natural forests.




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With the imminent release of the new IPCC report, now is a good time to prioritise the protection and recovery of existing ecosystems over planting trees.

Forest ecosystems (including the soil) store more carbon than the atmosphere. Their loss would trigger emissions that would exceed the remaining carbon budget for limiting global warming to less than the 2℃ above pre-industrial levels, let alone 1.5℃, threshold.




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Natural forest systems, with their rich and complex biodiversity, the product of ecological and evolutionary processes, are stable, resilient, far better at adapting to changing conditions and store more carbon than young, degraded or plantation forests.

Protect existing trees

Forest degradation is caused by selective logging, temporary clearing, and other human land use. In some areas, emissions from degradation can exceed those of deforestation. Once damaged, natural ecosystems are more vulnerable to drought, fires and climate change.

Recently published research found helping natural forest regrow can have a globally significant effect on carbon dioxide levels. This approach – called proforestation – is a more effective, immediate and low-cost method for removing and storing atmospheric carbon in the long-term than tree planting. And it can be used across many different kinds of forests around the world.

Avoiding further loss and degradation of primary forests and intact forest landscapes, and allowing degraded forests to naturally regrow, would reduce global carbon emissions.
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Avoiding further loss and degradation of primary forests and intact forest landscapes, and allowing degraded forests to naturally regrow, would reduce global carbon emissions annually by about 1 gigatonnes (Gt), and reduce another 2-4 Gt of carbon emissions just through natural regrowth.




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Research has predicted that protecting primary forests while allowing degraded forests to recover, along with limited expansion of natural forests, would remove 153 billion tonnes of carbon from the atmosphere between now and 2150.

Every country with forests can contribute to this effort. In fact, research shows that community land management is the best way to improve natural forests and help trees recover from degradation.

By the numbers

Tree planting carries more limited climate benefits. The recent Science paper focused on mapping and quantifying increases in tree canopy cover in areas that naturally support trees. However, increasing canopy cover through natural forest regeneration can sequester 40 times more carbon over the course of the century than establishing new plantations.




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We need to think very carefully about how we use land that has already been cleared: land is a finite resource, and we need to grow food and resources for a global population set to hit 9 billion by 2050.

We need to understand land as a finite resource and accomodate for a global population set to hit 9 billion by 2050.
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Any expansion of natural forest area is best achieved through allowing degraded forests to naturally recover. Allowing trees to regenerate naturally, using nearby remnants of primary forests and seed banks in the soil of recently cleared forests, is more likely to result in a resilient and diverse forest than planting massive numbers of seedlings.

Instead of planting entirely new areas, we should prioritise reconnecting forested areas and restoring the edges of forest, to protect their mature core. This means our carbon-storing forests will be more resilient and longer-lasting.




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For forests to effectively help avert dangerous climate change, global and regional policies are needed to protect, restore and regenerate natural forests, alongside a carbon-zero energy economy.


A version of this article was co-published with Pursuit.The Conversation

Kate Dooley, Research Fellow, Climate and Energy College, University of Melbourne and Brendan Mackey, Director of the Griffith Climate Change Response Program, Griffith University

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.




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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.
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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.




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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.




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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.




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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.