Sparking debate over fire use on agricultural land in Indonesia

Sparking debate over fire use on agricultural land in Indonesia


New peatlands research center aims to reshape conservation efforts

Indonesia “I can keep my land fertile and I’m able to work regardless of the season, but my neighbor who uses the burning method has difficulties during the rains because their land becomes a swamp,” said Akhmad (Taman) Tamanuruddin, addressing delegates at the launch of a new peatland research center in Indonesia.

Taman is a farmer in Palangka Raya, the capital of Indonesia’s province of Central Kalimantan on the island of Borneo. He rejects the traditional local practice of using fire to clear residue from the fertile peatlands before planting his crops.

Instead, he applies herbicides and lets the old vegetation die off and decompose, allowing it to become a natural fertilizer.

Traditional burning practices are under scrutiny by scientists and policymakers because peatlands are effective carbon sinks. They are made up of layers of decomposed organic material built up over thousands of years. When they burn, warming gases are released into the atmosphere exacerbating climate change. Fires often burn out of control, damaging vast areas and drying out the land, rendering it useless for farming.

In 2015, the impact of wildfires was far-reaching. Fire destroyed more than 2.6 million hectares of land — an area 4.5 times the size of the Indonesian island of Bali, according to the World Bank. The price tag for the damage was more than $16 billion, the bank said.

Indonesia has since boosted efforts to ban the use of fire to clear forested peatlands to plant oil palms, maize or rice by establishing the Peatland Restoration Agency in 2016.

Legislation banning fire use to clear land was introduced in 2009 and 2014.

Research compiled in Riau province by Indonesia’s Forestry and Environment Research, Development and Innovation Agency (FOERDIA) of the Ministry of Environment and Forestry (MOEF) shows that land prepared by burning vegetation before planting is more productive. They examined peatlands cultivated for oil palm, rubber, corn, rice, and other food crops.

Oil palm yield in burned peatlands was found to be almost 30 percent greater than in those that were not, producing yields of about 13.3 tons per hectare a year. In peatlands that were not burned, yield was only 9.4 tons per hectare a year. Rubber tree yields were found to decrease on average by 46 percent if the land was not burned. Corn yield disparities were even more extreme.

Burning resulted in higher soil fertility in the peatlands. It also reduced acidity, contributing to the higher yields.

Aware of the yield benefits, many farmers involved in the study disregarded prohibitive legislation and burned off their fields. Of the study participants, only 49.3 percent stopped the practice, while 45.2 percent of respondents continued and 5.5 percent said they would give up on farming as they did not see any alternative to burning.

“Some farmers are unwilling to cultivate corn without burning since the yield will drop sharply and produce only a third or a quarter,” said Murniati, a scientist with FOERDIA.

“They were afraid to use the burning techniques but they don’t have enough money to finance the no-burning techniques,” Murniati added, explaining that farmers are scared of incurring penalties for violating anti-burning laws but feel they have no choice but to face the risk.


Since he got involved in sustainable agriculture, Taman has trained hundreds of farmers.  He adds fertile soil, dolomite, and manure to his land and plants a variety of crops, including corn, chili, and vegetables.

Initially, the cost of farming in this manner may seem more expensive, but over the long term it saves him money, Taman said, explaining the environmental benefits.

Although burning more resistant vegetation is a less expensive and easier solution, it can strip nutrient levels in the soil and spoil the peatlands in the long run.

As farmers, we need more support for infrastructure to lower costs, Taman said.

“We at least need proper roads and bridges in our village to cut distribution expenses,” he added. “It can help us big time.”

Currently, poor infrastructure causes high costs for herbicides and harvested crops. Farmers are forced to rent cars to cover a short 250-meter distance because trucks cannot fit into narrow roadways.

Finding other livelihood options might be key for helping local communities thrive while conserving peatlands, according to Dede Rohadi and Herry Purnomo, scientists with the Center for International Forestry Research (CIFOR) currently working with MOEF and several partners.

The Haze Free Sustainable Livelihoods project led by CIFOR, MOEF and the University of Lancang in Riau aims to find alternatives for farmers who cultivate crops in the province.

“We try to empower communities so they can maximize the existing livelihood potentials in their village,” said Rohadi, who leads the project.

Some villages already cultivate honey, develop fisheries and grow food crops such as chili peppers and pineapples.

In addition to the Haze-free Sustainable Livelihood project, CIFOR is currently coordinating the Community-based Fire Prevention and Peatland Restoration project with Riau University, local government, communities, and the private sector.

The latest commitment from the governments of Indonesia, the Democratic Republic of the Congo and Republic of the Congo, to establish the International Tropical Peatland Center (ITPC) promise for peatland preservation efforts. ITPC is currently based at CIFOR in Bogor, near Indonesia’s capital Jakarta.

It provides valuable opportunities for cooperation in the global south to ensure policymakers, practitioners, and communities have access to trustworthy information, analyses, and the tools needed to conserve and sustainably manage tropical peatlands.

Although peatlands extend over only 3 percent of the world’s land mass, they contain as much carbon as all terrestrial biomass and twice as much as all forest biomass.

About 15 percent of known peatlands have already been destroyed or degraded.

Could El Niño and climate change spell the end for tropical forests?

Could El Niño and climate change spell the end for tropical forests?

by  on 25 June 2018

In summer 2014, governments across tropical Asia readied for a looming weather and political emergency – potential droughts, crop failures, and food shortages that could stress developing world nations and challenge their ability to respond. According to weather observatories, the chance of an El Niño event occurring before the year’s end was high. The central and eastern equatorial Pacific Ocean was warming up, a predictive precursor of El Niño, a temporary increase in global temperature that at its worst can generate a worldwide cascade of catastrophic changes to weather patterns.

It was a false alarm. But the following year El Niño materialized with a vengeance. Boosted by the earlier warmth in the Pacific, the 2015-16 El Niño turned out to be one of the strongest events on record. Intense droughts affected almost 40 million people in southern Africa; flooding swept South American countries, displacing 150,000 people; and coral reefs experienced the most significant bleaching event scientists have ever seen, with nearly all corals in some parts of the Great Barrier Reef dying due to the high temperatures.

In space, a new NASA satellite, launched on 2 July 2014, allowed scientists to study the El Niño’s rise and fall, and its effects on the global carbon cycle in greater detail than ever before. The Orbiting Carbon Observatory-2 (OCO-2) was equipped with sensitive instruments able to measure atmospheric CO2 concentrations ten times more accurately than previous methods.

Overall, the 2015-16 El Niño led to the fastest rise in atmospheric COon record, and helped push CO2 concentrations above 400 ppm for a full year for the first time in modern history. The OCO-2 findings went deeper. They revealed that the sudden surge in CO2 was greatly enhanced by emissions coming from the tropical forests of South America, Africa, and Southeast Asia – all responding to the El Niño by temporarily shifting from carbon sink to source. However, there were striking regional differences in each forest’s response.

Because El Niño conditions, with their elevated temperatures, may reflect what tropical climates will look like in the future as climate change escalates, such events “represent a massive experiment where we can get a glimpse of how these ecosystems” might respond, said Anders Ahlström, a scientist at Stanford Woods Institute for the Environment.

And with tropical forests storing almost 250 billion tons of carbon, their fate has major implications for the earth’s atmosphere – and life on earth.

“[T]his research shows that [El Niño] is truly a global phenomenon, impacting all the world’s tropical regions and beyond,” said William Laurance, of James Cook University, Australia, and a Mongabay board member. The “region-specific effects on forests and ecosystems” were intriguing, he said, “reflecting nuances of the global climate that we hadn’t appreciated previously.”

A glimpse of our climate change future

OCO-2 continues to record 100,000 to 200,000 measurements a day as it orbits the earth, documenting CO2 concentrations in regions where terrestrial measurement stations are few and far between. As such, it allows for the pinpointing of carbon sources and sinks in places like the Congo, Amazon and Indonesian rainforests.

Using this data to make large-scale inferences about the global carbon cycle was hailed as “an important milestone,” by Emanuel Gloor, of the University of Leeds. It gets “us closer to near-real-time monitoring of ecosystem function and carbon cycle dynamics,” said Trevor Keenan, of the University of California, Berkeley.

“Previously, limited data in the tropics greatly limited our ability to determine key processes, or even to pin down which regions of the tropics were responding most strongly,” to El Niño events, explained Junjie Liu of the Jet Propulsion Laboratory, California Institute of Technology, who led the research.

Liu’s team found that during the 2015-16 El Niño, extreme drought meant trees stopped absorbing CO2 in South America. In Southeast Asia, forest fires raged in extremely dry conditions, quickly releasing stored carbon. And in tropical Africa, high temperatures resulted in increased ecosystem respiration.

Together, the three regions emitted 2.5 gigatons more carbon during the 2015-16 El Niño than during the opposing phase of the cycle, known as La Niña, in 2011, with emissions split roughly evenly between the three forest regions. That’s comparable to “about a third of all the emissions from fossil fuel burning,” commented OCO-2 science team member Scott Denning when the research was published – but it wasn’t the scale of the emissions that surprised Liu.

“I was more surprised by the complexity of the Earth’s carbon-climate system,” she said.

Worsening Amazon drought and tree death

The 2015-16 El Niño brought record-breaking temperatures and the third major droughtin a decade to the Amazon, affecting an area 20 percent greater than ever previously observed.

At first, drought causes trees to absorb less CO2 as they slow their photosynthesis rate, or stop photosynthesizing completely, to conserve water. But if conditions become extremely dry, hydraulic failure may occur: air bubbles form in the trees’ xylem – the channels that carry water from the roots to the canopy, resulting in tree death.

“Once a tree dies it will slowly decompose, releasing all the carbon it had stored in its leaves, stems and roots back up to the atmosphere,” explained Lucy Rowland, of the University of Exeter.

Many species of tree are already near their limit of drought tolerance due to climate change, according to a 2012 study. Even a small shift to drier conditions could lead to hydraulic failure for 70 percent of 226 forest species, the research found. “[R]apid forest collapse as a result of drought could convert the world’s tropical forests from [CO2] sink to source during this century,” the scientists reported.

Climate models predict that Amazon droughts will become more common in the future, said Juan Carlos Jiménez-Muñoz, of the University of Valencia, which could result in an intensifying positive feedback loop. “In simple terms, more warming [leads to] more severe droughts, and maybe [to] more extreme El Niño events, which in turn leads to more severe droughts linked to El Niño conditions.”

Paulo Brando, of the Woods Hole Research Center in Massachusetts, U.S., said that some resilience to droughts is to be expected, because the Amazon rainforest “has adapted to periodic droughts over millions of years.” But when multiple droughts hit in quick succession – as seen in 2005 and 2010, and again with the intense 2015-16 event – there is limited time for recovery, Jiménez-Muñoz said. This reduces forest resilience, increasing the chances of degradation “with implications [for] carbon uptake.”

“A major ‘unknown’ is whether Amazon forests are resilient enough to cope with [the] intensification of drought regimes,” that’s predicted to accompany future climate and land use change, explained Brando. A better understanding of the recovery capacity of forests is needed in order to know “how much is too much” for Amazon forests, he said.

The Amazon also saw a peak in fire activity during the 2015-16 event, Brando added. “A major concern is that with mega-droughts becoming more common in the near future, fires could burn forested areas that are currently too moist to carry a fire.” Wildfires dump the stored carbon in trees all at once into the atmosphere.

Southeast Asia: forests on fire

By late 2015, parts of Indonesia, Malaysia, Singapore and Thailand were without clear sight of the sun, as smoke clouded the sky. Indonesia’s forest fire crisis engulfed the region in a toxic haze which was later shown to have affected 69 million people; over 100,000 likely died as a result.

In total, 2.6 million hectares (more than 10,000 square miles) of land burned. At their peak, daily greenhouse gas emissions from the fires exceeded those of the USA, according to research by Guido van der Werf of the University of Amsterdam.

“What makes Indonesia special [compared with other tropical forest regions] is that a substantial part of the tropical forest is on peatland, and that the human factor is much more important,” van der Werf explained. “If you look at a map with forest loss over the past decades, there is hardly anything untouched.”

Peatlands are especially carbon-rich, accumulating organic material over thousands of years. Draining the peatlands “lowers the water table so the land can be worked on [for agriculture], but it also means the peat starts to decompose,” said van der Werf. “During an El Niño, dry conditions lead to even lower water tables which makes both the forests and peat vulnerable to fire, and humans take advantage of these drought conditions to burn the forests,” in order to clear more croplands, especially for oil palm production.

Fires frequently burn out of control, said David Gaveau of the Center for International Forestry Research (CIFOR), destroying larger areas of forest than originally intended. “Once the forest has burned, one would expect the forest to recover,” he said, but an increased risk of subsequent fires “leads many forests to cycles of repeated burns.”

“Such cycles have converted millions of hectares of old-growth and selectively logged forest to fire-prone low vegetation: scrublands and fern fields. Once the land has reached that state, it is nearly impossible for the forest to grow back,” he said.

“The drought-fire mechanism in peatland depends on the [level] of [the] groundwater table [in relation] to the surface, that maintains [the] water content of [the] upper peat layer,” explained Muh Taufik of Wageningen University.

If the groundwater level becomes depleted, this is known as hydrological drought. Taufik’s research has shown that in years of hydrological drought, fires burned ten times the area of forest as in non-drought years. Taufik also found that there has been a general drying trend in Borneo’s groundwater over the last century, making the forests ever more susceptible to fire.

Lan Qie, of Imperial College London, highlights a second major threat to Borneo’s forests: fragmentation. This is a “persistent and progressive threat,” said Qie, whose research has shown that forest fragment edges, adjacent to fields or oil palm plantations, are significant sources of carbon emissions because trees are more likely to die if they are near an edge.

A fragment needs to be larger than 300 hectares (about one square mile) in order for carbon uptake to outweigh carbon loss, Qie and colleagues reported.

But even where intact forests remain, extreme El Niño events can knock those forests off balance. Qie’s study also found that the 1997-98 El Niño, which was more pronounced in the region than the 2015-16 event, caused so much tree mortality due to drought that Borneo’s intact forests tipped from carbon sink to source.

The good news: these forests recovered quickly, suggesting that intact forests have a degree of resilience to even strong droughts, Qie said. Southeast Asia’s Dipterocarp forests have evolved “under a climate regime including El Niño-driven supra-annual droughts,” she added, with periodic, synchronized mass-seeding being an adaptation to these conditions. But, as has been seen in the Amazon, “it is possible that the resilience of the Borneo [carbon] sink may also be challenged in the future,” Qie concluded.

Again, it is a matter of “how much is too much,” but no one currently knows where the tipping point may be, beyond which climate stressed tropical forests won’t be able to recover.

Congo discovery

Until recently, Indonesia’s peatlands were thought to be the largest tropical peatlands in the world. But in January 2017, scientists published confirmation of a discovery: peat forests in the Congo basin covering 145,500 square kilometers (56,177 square miles) knocked Indonesia’s peatlands into second place.

With the Congo peatlands containing 30 billion tons of carbon, the future of tropical African forests is even more critical for the global carbon cycle than scientists realized at the time of the OCO-2 launch in 2014.

The OCO-2 research revealed that tropical African forests did not dry out during the 2015-16 El Niño event: instead, rainfall levels remained normal. But temperatures did rise, driving increased ecosystem respiration, which resulted in heightened CO2emissions.

However, with on-the-ground weather data so limited across tropical Africa, the OCO-2 scientists reported that it was “challenging to verify” the link between temperature and carbon emissions that their remote-sensing data and models identified

This lack of data is also a hindrance when looking ahead. “[T]here are still many uncertainties as to how the climate will change across Central Africa in response to increased greenhouse gas emission,” said Greta Dargie, who led the Congo peatland research, and there is “little consensus amongst the climate models for projections of precipitation patterns across the region.”

The Congo peatlands “appear to be strongly dependent on rainfall for the maintenance of their water tables,” said Dargie, of the University of St. Andrews. A reduction in rainfall, or an increase in evapotranspiration – the movement of water from the soil, up through a tree’s trunk and leaves, into the atmosphere – which could occur if temperatures increase, “could lead to the peatlands becoming drier and therefore result in an increase in carbon dioxide emissions,” she said. But more research is needed to fully understand these mechanisms.

Future feedbacks: could tropical forests collapse?

What can these diverse responses to El Niño tell us about the climate future of tropical forests?

“Predicting the exact responses of tropical forests to climate change is tricky,” said Rowland. “We know they are likely to suffer as a result of rising temperatures and increasing droughts, but […] some of this damage may be partially off-set by increasing CO2 concentrations which will allow them to photosynthesise more.”

However, even without knowing how big the effect will be, “the response of tropical forests to climate change will almost certainly be negative,” Rowland concluded.

If climate change mirrors El Niño conditions “it may result in more carbon dioxide released from tropical forests, and more carbon dioxide remaining in the atmosphere, further warming our planet,” said Liu. A warmer planet could see more frequent extreme El Niño events, resulting in further detrimental interactions between cyclical El Niños, tropical forests, carbon emissions and worsening climate change.

The emissions from El Niño events also have a long-term cumulative effect: “global [atmospheric] CO2 levels have permanently ratchet[ed] up a notch [as a result of] the strong 2015-2016 El Niño event,” Liu explained.

But the magnitude of the most recent El Niño’s carbon emissions may be smaller than one might expect, considering the event’s near record intensity, said Gloor, which is some good news for forest resilience. “Interestingly, and maybe surprisingly, the global atmospheric concentration record does not show any signs that carbon release during the 2015/16 El Niño was anomalously large compared to other El Niño [events] in the past,” once fossil fuel emissions are taken into account, he said.

“Thus, so far, tropical forests seem to be able to cope with the steadily increasing temperatures, even when further enhanced during El Niño phases,” he concluded. However, “the very rapid increase in temperatures is unprecedented. My guess is that if [peak dry season] temperatures move towards 45-50 degrees [Celsius, 113-122 degrees Fahrenheit] then forests may not be able to cope.”

If tropical forests cannot cope, then this globally important carbon store and sink could be at stake.

The possibility of a looming tipping point — when the world’s tropical forests cease to act as a sink, and become a permanent source of carbon — is an active area of research. “Some models project tropical forests will change from a sink to a source for carbon later in this century,” said Keenan, although “there is large disagreement between model projections.”

“[O]ur satellite record isn’t long enough yet to distinguish between” those varying model predictions, Liu explained. To get a better handle on if and when tipping points may occur, “we need a longer data record that [is] sensitive to changes of tropical forest carbon fluxes, such as [that provided by] OCO-2 type satellites, as well as field studies and experiments that can push tropical systems artificially into new conditions,” she said.

Human activity key

Irrespective of the timing of any climate-induced tipping point, human activity changing the face of the world’s tropical forests may ultimately prove to be more critical.

“Currently the biggest threat to tropical forests remains, in my opinion, sadly, still human destruction,” said Gloor.

Taking the impact of deforestation and degradation into account, tropical forest regions are already making a substantial contribution to annual anthropogenic greenhouse gas emissions. A recent study concluded that, overall, all tropical forest regions are net carbon sources already.

“[G]iven that both fires and peat oxidation are so substantial, it is unlikely that the Indonesian forests as a whole are sinks,” concluded van der Werf. In a drained peatland, “carbon goes out much faster than it went in.”

For the Amazon, Ahlström anticipates that three factors will determine whether the forest will be resilient in the long-term: “future changes in rainfall; the ecosystems’ ability to adapt to new, warmer and more extreme climates that have no present analogue; and deforestation.”

Tropical biologist Tom Lovejoy and climate scientist Carlos Nobre agree that deforestation may help spell the end of the Amazon rainforest. In a recent commentary piece, the two researchers argue that “negative synergies between deforestation, climate change, and widespread use of fire indicate a tipping point for the Amazon system to flip to non-forest ecosystems in eastern, southern and central Amazonia at 20-25 percent deforestation.” Lovejoy previously told Mongabay that he saw the major droughts since 2005 as the “first flickerings” of this process.

Given the large uncertainties surrounding how tropical forests will respond as the climate warms, taking action to keep forests standing and healthy may offer the single best hope for mitigating negative impacts. Annual greenhouse gas emissions could be reduced by up to 30 percent if tropical deforestation was halted, and forests were allowed to recover.

In the meantime, more research is needed “in order to understand the likely future trajectory of the tropical carbon sink” and “directly inform policy” said Keenan. Liu agrees to the need for more tropical data, coupled with the right tools “to piece those data [sets] together into a complete picture” and “improve our understanding of how the earth system works.”

Laurance concludes, “[c]learly, we still have a lot to learn about Earth’s climate, and how it affects life and ecosystems.” The big unknowns: are dangerous climate and deforestation tipping points approaching faster than we can understand and respond to them?


Liu, J., Bowman, K. W., Schimel, D. S. et al. (2017) Contrasting carbon cycle responses of the tropical continents to the 2015–2016 El Niño. Science 358: eaam5690

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Physics theory explains patterns of deforestation in the tropics

Physics theory explains patterns of deforestation in the tropics

Scientists get a handle on sizes of forest fragments using percolation theory

Predicting rising numbers is usually good news in ecology, but not if they are forest fragments. Current rates of deforestation could cause a 33-fold increase in forest fragments over the next 50 years, shows a study published in Nature.

Deforestation, fuelled by factors including habitat conversion and timber production, causes fragmentation. As large forests are cut into pieces, biodiversity suffers and carbon is also lost. To study patterns of tropical forest fragmentation, scientists at the Helmholtz Centre for Environmental Research (Germany) used remotely-sensed images to map more than 130 million forest fragments across 427 million hectares in the Americas, Asia, Africa and Australia.

They found that fragment sizes in three continents followed similar frequency distributions. The number of forest fragments smaller than 10,000 hectares, for instance, is similar in Central and South America (11.2 %), Africa (9.9 %) and south-east Asia (9.2 %).

“This is surprising because land use noticeably differs from continent to continent,” said mathematician and lead author Franziska Taubert in a press release. While habitat conversion is what plagues the Amazon, it is logging of commercially-important forest trees in south-east Asia.

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