Trees and water: don’t underestimate the connection

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By: Douglas Sheil, Norwegian University of Life Sciences
This blog was originally posted in CIFOR Forest News

Read this blog in Spanish: Los-arboles-tienen-poderes-extraodinariosDownload

Trees have extraordinary powers, especially when it comes to water. But such powers must be wielded with care.

  Lake Bam, in the Centre-Nord region a hundred kilometers from Ouagadougou, is undergoing enormous environmental challenges such as silting, drastic reduction of aquatic life and conflicts of interest the 28,000 people living from this lake see their livelihoods threatened, Burkina Faso. Photo by Ollivier Girard/CIFOR

Trees have extraordinary powers. They provide shade, cool the local climate, draw carbon dioxide from the air, and can repair and replicate themselves while running on little more than sunlight and rainwater (PokornĂœ 2018). They also contribute numerous goods and services like fruit, wood and soil improvement with a wide choice of species and varieties suitable for different needs and conditions. But such powers should be wielded with care.

On the 5th of July 2019 Science published an article by Jean-François Bastin and colleagues titled “The global tree restoration potential”. In it, they explain how, without displacing agriculture or settlements, there is enough space to expand the world’s tree cover by one-third or around one billion hectares. Such increased forest would eventually reduce atmospheric carbon by about a quarter. A lot could be said about this proposition, much of it supportive. But in a brief comment piece just published in Science, colleagues and I highlight some reservations along with some even bigger opportunities. We focus on water.

The idea that the protection and restoration of tree cover could improve the climate while providing other benefits is well established. Indeed, there have been numerous international programs based on this including REDD â€œReducing Emissions from Deforestation and Degradation”, the Bonn Challenge, which seeks to reforest and restore degraded land, as well as various related programs.

So what is new here?

Well, what Bastin et al. have done is estimate the scale of this opportunity and the contribution that restoring tree cover could make. For example, they list such estimates country by country as a “scientific evaluation” with relation to restoration targets specified under the Bonn Challenge. Under these targets, and those specified by the New York Declaration on Forests, an impressive list of countries (59) have undertaken to end deforestation and to restore 350 million hectares of land by 2030. They note that several of these countries have committed to restoring an area that “exceeds the total area that is available for restoration”. They note how these results “reinforce the need for better country-level forest accounting”.

Yet there is a paradox lurking within these claims. The authors state that their estimates are not â€œfuture projections of potential forest extent”. So what are they?

Aerial view of the Amazon rainforest and river, near Manaus, the capital of the Brazilian state of Amazonas. Brazil. Photo by Neil Palmer/CIAT

In brief, their assessment represents an estimate of potential tree cover assuming current environmental conditions and no influence or modifications arising from the trees themselves. But large-scale changes in tree cover would modify these conditions.

Trees and forests influence the availability of water and water influences the degree to which a landscape can support trees. While current tree cover reflects current conditions, any assessment of the prospects for large-scale changes in tree cover must account for how these changes will influence those conditions. Potential tree cover should reflect the conditions that would exist with that tree cover.

This may seem esoteric, which may explain why it was not raised in the extensive media coverage, but these details matter. They matter a lot.

Access to adequate fresh water is a key development challenge and is central to the United Nations Sustainable Development Goals. Around half a billion people suffer insufficient fresh water year-round while many more face seasonal scarcity. Such shortages cause hardship and are widely believed to play an increasing role in the complex of issues that increase the likelihood of conflict and migration. With relatively fixed fresh water resources and a growing population, the global fresh water resources per person are declining.

As we highlight in our comment, trees influence the availability of water both locally and regionally. Neglecting these influences undermines the value of the estimates and renders them near meaningless. This affects both the technical aspects of the estimates—the variables used to predict tree cover would change, and more importantly, the wider implications for people and life on the planet.

Tree cover influences water availability through a range of processes and mechanisms. Only some of these are well understood. But we know enough to know there will be impacts.

Impacts can be negative. Where trees use a lot of water this can accentuate local water scarcity. There are many examples where dense plantations have caused a decline in local stream flows and depleted groundwater when compared to open lands. This is crucial, but far from being the whole story.

Impacts can also be positive. This has been shown by studies in Burkina Faso where landscapes with some tree cover captured several times more water than otherwise comparable tree-free landscapes. In this case, the costs of increased water use are more than compensated by the increased soil infiltration and moisture storage. Trees and forest also provide water vapour and condensation nuclei (the particles that promote cloud formation) that can contribute to rainfall elsewhere. Thus, it is clear that tree cover supports rainfall downwind—and many people depend on such rainfall.

The power of such recycling suggests that if tree cover in drylands can be expanded in the right manner, it can generate increased rainfall, thus opening the opportunity to increase regional moisture and land able to support trees and forests. In addition, an exciting new theory, the Biotic Pump, suggests that forest cover plays a fundamental role in generating the winds that carry moisture into continents. This theory conforms with observations in the Amazon region concerning how rainfall relates to changes in air pressure, and how forest derived moisture controls the monsoon. In effect, we could develop a system that waters itself and thereby regreens the world’s deserts. We could, for example, imagine returning a much wetter climate to the Sahel of Africa or to Western Australia.

So how can we avoid the negatives and promote the positives of increased tree cover? We don’t yet know the optimal way. Likely we may not even agree what “optimal” implies. My personal view is that, if we emphasise the protection, expansion and restoration of natural vegetation that can regenerate and maintain itself (rather than industrial plantations), the positives are generally more likely. The rationale is that nature has evolved effective systems for distributing and maintaining water. These are the systems that kept the world green and productive long before people got involved. (Such restoration is what Bastin and colleagues are suggesting, though much of the media attention discussed “tree planting” more generally as if this is equivalent—it isn’t).

 General View of the Brazilian Amazon. Photo by Neil Palmer/CIAT

But there are plenty of good reasons to promote tree cover even in productive landscapes and to identify how we might green large areas of our planet. The potential to bring more water into currently arid regions seems a real opportunity. We can also look for ways to ensure that plantations, where justified, are developed without wider environmental costs. Natural systems can provide both template and inspiration.

But it remains true that negative impacts can still result, especially as what may be optimal at a continental scale may not be ideal at more restricted scales, and patches of regenerating forest may deplete local water even if it boosts rain downwind. When tree cover does boost groundwater in arid regions there can be additional challenges if this raises salt within the soil profile.

Looking beyond water there is no shortage of additional concerns. For example, we need to ensure people benefit, we need to protect key grasslands and we need to ask why the tree cover was depleted in the first place.

There are many good reasons to protect and restore tree cover and other natural vegetation—wherever and to the degree that that is possible. There are also plenty of good reasons to promote agroforestry and to encourage even scattered tree cover where that is possible within productive landscapes.

Our point is that there will be wider impacts than those on atmospheric carbon alone. Many impacts are likely to be positive, increasing greenness, stabilising rainfall, and reducing biodiversity losses. But widespread tree planting can also cause harm, displacing people and biodiversity and contributing to water scarcity.

The power of trees is often underestimated—it is a transformative power with capacity to achieve great good and great harm. Please use it wisely.

Original Science Article:

Bastin, J.F. et al. 2019. â€œThe global tree restoration potential”, Science, Vol. 365, Issue 6448, pp. 76-79, DOI: 10.1126/science.aax0848 

Comment letter to Bastin et al.:

Sheil, D. et al. 2019. â€œForest restoration: Transformative trees”, Science, Vol. 366, Issue 6463, pp. 316-317, DOI: 10.1126/science.aay7309 

Bastin et al. response:

Bastin, J.F. et al. 2019. â€œForest restoration: Transformative trees-Response”, Science, Vol. 366, Issue 6463, pp. 317, DOI: 10.1126/science.aaz2148 

Drips of hope for Brazilian forests

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By: Rosa Goodman, Associate Senior Lecturer at the Department of Forest Ecology and Management; Tropical Forestry and Land Use Management Unit at SLU.

In May 2019, I went to Brazil to see if we (the Swedish Forest Agency, Stockholm Water Institute, and SLU), could set up a cooperation with SĂŁo Paulo Secretariat for Infrastructure and Environment (SIMA) to work on issues surrounding forests. This was my first time being part of a delegation and this is my first blog.

I have lived, worked, studied, and traveled extensively in 28 countries and have realized that I have an underlying life motto that “I cannot say no to a new country”. Every time I travel, I learn something new, something sad and something beautiful. Plus, as a tropical forest researcher, Brazil and its vast share of the world’s tropical forests are of peak importance to me. Many Brazilians, like the rest of us, are worried about the new government and eager to start an official cooperations with outsiders. This is what hooked me. If there is any chance to protect and even restore the world’s largest tropical forest, I am in.

Jair Bolsonaro is the Brazilian Donald Trump — on the far, far right, defends dictatorship and torture, and belittles women, minorities, and homosexuals. He was elected with the agenda to promote agri-corporation and exploit the country’s natural resources (which include a quarter of the world’s remaining tropical forests) and weaken environmental enforcement. He initially planned to merge the Ministries of Agriculture and Environment (presumable to weaken the Ministry of Environment’s autonomy and authority), but even agribusinesses opposed this citing unworkable differences.

In São Paulo, infrastructure and environment (two classically conflicting entities) were merged into a single ministry, SIMA. Fortunately, the members of the three institutes we met are striving to make this merger work to their advantage. In a time of uncertain and frightening political regimes and corruption, it was certainly a breath of fresh air to meet government officials with such dedication and sincerity — and with a mission aligned with mine.

On the first day, we met at the SIMA office in SĂŁo Paulo. They wowed us with impressive large-scale restoration initiatives, data collection and management, geospatial analyses and landuse change detection, and complicated and complex socioeconomic-geopolitical-biophysical modelling. Brazil is quite unique among tropical countries in terms of excellent education, advanced technology, and producing many very impressive scientists and practitioners.

We also learned that the state of São Paulo is unique. It occupies less than 3% of the land and produces over a third of the country’s GDP. São Paulo State often leads Brazil in policy-making, as other states often adopt policies set in São Paulo. This is comforting because São Paulo seems to be quite progressive. The downside is that São Paulo state does not contain any of the Amazon basin forest.

In fact, São Paulo hosts the Atlantic forest ― one of the most threatened ecosystems on Earth. They are far more into protection and restoration than extractive management, and it is illegal to harvest or sell timber from native species (unless you planted it or are from an officially recognized traditional community). I certainly don’t blame them — there isn’t much Atlantic forest left and a lot can go wrong when timber harvesting is allowed.

We are thus stuck in the endless debate: Do we try to do the best thing for biodiversity and ecosystem services and strictly protect and restore the remaining natural forests — which all cost money and often perversely incentivize land conversion (aka, deforestation) to alleviate the responsibility of forest protection? Or do we try to be realists and encourage management of natural forests since it is the only business model that encourages the maintenance of natural forests? On the other hand, this strategy is also quite idealistic because it relies on both high technical capacity (to plan and carry out sustainable forest management) and honesty (ie, lack of corruption and bending of the rules). The forest industry seems to be forever plagued with corruption — as activities take place in remote locations, are so difficult to track, and require time scales much longer than our current economy and political systems accommodate. In any case, water and the connections between forests and water, are high on their minds after years of barely eking though a nearly catastrophic drought.

We spent the next day at Serra do Mar State Park with people from the Forest Foundation talking about just this. The Forest Foundation is full of do-gooders and nature lovers. They focus on protected areas and have developed a model to quantify the water ecosystem services provided by State’s protected areas and conservation units. Together the protected areas, conservation units, and Green Belt Biosphere Reserve provide a whopping 60% of the city’s water supply, and adding a fee to protect these water-providing areas would cost the average household a mere 0.50 USD each month. Everyone surveyed said they would be happy to pay this extra fee for water use — except that they don’t trust this money would actually be used for this.

In all my experience in countries across the globe, I have identified corruption as the biggest barrier to progress. There are so many good ideas and good people wanting to implement them, but nothing works with corruption in the equation. Funds disappear, regulations are prohibitive (especially against those trying to do things legitimately), people get frustrated and give up — or decide they are much better off participating. As the drug lords have taught us: plata o plomo (silver or lead). You would have to have a superhuman moral conviction and nonattachment to your own life to choose a bullet over a bribe. So corruption spreads and thrives like the most infectious disease and holds us in this global epidemic.

The notable lack of corruption, and instead a great sense of working together and following the rules (because that’s how you maintain a functioning society), is one of the things I love most about Sweden. Americans (I am an American) tend to fear that countries with such a strong social welfare system cannot survive: “If the State just takes care of everybody in need, how can they afford that? And why would anyone even bother working?” What I have figured out is that when you take corruption out of the equation, there is plenty to go around. It’s a beautiful way to run a country.

While in the state park, we got to take a gorgeous walk on Pirapitinga trail and visit the ParaĂ­ba river. We spent ample time on the misty rocks enjoying the power and beauty of the waterfalls crashing and flowing all around us. Water is life. Oxygen is life. Life is life. It is always good to reconnect with the reason I dedicate my life to conservation and sustainable management of our precious natural resources.

The ParaĂ­ba river inspires conversation. Photo: R. Goodman.

We had feijoada for lunch — a delicious meal of beans and rice and veges, and there was even a vegetarian version. Most people at Forest Foundation joined me in eating the meat free version, which makes me quite happy because I really respect authenticity and applying what we know to our own lives. I personally can’t talk about reducing deforestation and eat cows. But I will admit that I still fly around talking about mitigating climate change. I don’t take flying lightly, but I also haven’t found a proper alternative to real, in-person connection with other people and places. This a real conundrum. Traveling has made me a far more aware, compassionate, open-minded, and dedicated global citizen. It also leaves a huge carbon footprint.

I had an excellent conversation with Gerd, president of the Forest Foundation, about modeling, complicatedness, and complexity plus personal resilience. He builds hugely complicated models with input data from every sector and discipline and then injects them with complexity (e.g., a new president) to see how a new policy might play out across Brazil. I asked him how accurate his predictions have been. Gerd responded that the point is not about predicting the future but telling a story that changes things now. Human brains love stories, but I think that biologists, foresters, and climate change scientist are pretty slow to catch on.

There are actually so many good stories. We visited a farm in SĂŁo JosĂ©, owned by Mr. Pedro Magno. Our hosts laid out a lovely fika (very culturally appropriate) and enthusiastically showed us their restoration site — over 25 hectares of land (mostly hilltops) have been planted with Atlantic Forests species. Mr. Magno’s father fenced off a few hectares a decade ago, and now it is a dense secondary forest (see photo). Mr. Magno himself was inspired by this and volunteered his land to a local NGO, Ecological Corridor, for restoration. He is a lawyer and would prefer to leave the land in better shape than he inherited it. At the same time, he wants to show his neighbors that restoration does not mean giving up all tradition and income, so he keeps some cattle that roam and graze on the abundant green grasses.

Mr. Magno points out the area that his father fenced off a few hectares a decade ago, which has regenerated naturally and regrown. Photo: Rosa Goodman.

We also visited the Coruputuba Farm in Pindamonhangaba. It is a beautiful agroforestry system and an even more beautiful story. Someone from the government asked Patrick if he had ever heard of agroforestry. Patrick had not, so he did a Ph.D. on the topic (on this own land) and practices agroforestry to this day. His love and enthusiasm for life and his land was abundant and inspiring. Patrick produces high quality products, but it is difficult to market because of scale. He cannot provide an entire industry with a steady supply of timber, fruit, or vegetables, and cooperation and coordination among a bunch of farms in the region is hard to put together and operate.

I am a natural scientists, and the more I learn about markets and economics, the more I wonder how the world works. I have seen a lot of struggling corn fields and acacia plantations — and zero goji berry or ginger plantations — so it seems like magic all these products are supplied to global markets.

Patrick smiling and showing us his agroforestry farm. Photo: R. Goodman.

During the day, someone commented that only rich people who inherit their land can do this kind of thing — grow niche vegetables on prime land. In a time when the richest 1% of people control over half of the world’s wealth, I think it is something to encourage. If the ultra rich want to do something, it happens. And we don’t need to be anywhere near the top 1% to start doing good things with the assets we have — land, money, time, effort — or forgoing further accumulation of assets. How to be satisfied with “enough” is another area where Swedes have a lot to teach the world (see “lagom”).

After years of declining deforestation rates in Brazil (since 2004), there has now been a huge spike — to which environmental organizations have responded in outcry and the President Bolsonaro responded by undermining the data and monitoring system and blaming environmental NGOs. The German and Norwegian governments then suspended donations to the Amazon Fund (a REDD+ mechanism to protect the Brazilian Amazonian forests and monitor deforestation), and Mr. Bolsonaro closed the steering committee. The situation looks grim. But as Mr. Rogers’s mother told him, “Look for the helpers. You will always find people who are helping”. I was personally amazed and inspired by all the ‘helpers’ we met at SIMA. I have never met and traveled with government officials before, and I had no idea how dedicated and sincere these people remain in the face of great challenges.

This loops back to the age-old question of why we Westerners work in tropical countries. I am reminded of a very honest meeting I had with a top forestry official in Malaysia. He was frustrated with all the corruption in his country and became a proponent for international agreements. He said the outside eyes really help combat the rampant “hanky panky” that goes on within forest management. This is exactly where Sweden is a shining star of nearly impeccable honesty and rule-following (mind you, I say this as an American who has lived here for 2.6 years). I commend SIMA for reaching out and believe that we (Swedish Forest Agency, SLU, and other Swedish actors) can and should do what we can to support them through this cooperation.  

Is there any hope left amongst the flames?

With all the new reports of the Amazon on fire!, I have had to take several deep breaths and re-evaluate whether there is any room for hope left. Over 70,000 fires are burning; indigenous groups and other activists are being murdered, and so on. I spoke with a friend last month who said that the insider info is even worse: “Between the intentional fires and the drought fires (intentional fires out of control), we basically hit the point of no return yesterday — a tipping point where the forested areas are no longer substantial enough to facilitate the humidity necessary to maintain. In terms of global climate processes, this could be a big deal — currents and trade winds big deal. Flora and fauna are losing their refugia so fast they have nowhere to run. Brazilian organizations have been cut off at the knees. Brazil has a ‘burn baby burn’ motto and environmental and indigenous activists have been getting murdered left and right. Everyone in Brazil is scared.” Devastating.

I checked the news to see how much has burned so far. I found one report that said 500 million hectares in 16 days. This is pretty impossible considering the country is than 852 million ha, and only 472 million hectares had tree cover in 2018 (about 303 million hectares in the Brazilian Amazon). Other reports say that about 345,000 hectares have been burned between January and early August.

To put this in perspective, almost 3 million hectares were cleared in 1995 and about 2.75 million in 2004. Then, deforestation rates in Brazil dropped to around half a million hectares from 2012–2014. Since Brazil is home to roughly a quarter of the world’s remaining tropical forests, what happens in Brazil is globally significant. Global deforestation rates dropped, and the perceived threat and attention to tropical forests also dropped. Since 2015, deforestation rates in Brazil have risen to about 0.8 million (800,000) hectares in 2018.

To be clear, clearing forest, primarily though burning takes place absolutely every year. Cattle ranching is responsible for over 2/3rds of this and agriculture is responsible for at least a quarter. Skies are often clouded by smoke in the dry season, which is now. Also, non-forested lands are burned repeatedly, so not every hectare that burns means a hectare of forest lost. That said, many Amazonian states are reporting major spikes in fires. Of course, every loss is still loss.

Thus, as the world watches in horror, Global Forest Watch seems remarkable calm. So far, we only have a 39% increase in fires compared to last year. However, they point out that over 60% of fires take place from September through December, so what happens next is important.

What I have seen so far is incredible. This is the most global attention, outrage, and pressure I have ever seen over an environmental issue. Trade deals are up in the air, the Finnish minister might ban beef imports from Brazil, and the far right-wing president went from blaming NGOs to deploying warplanes to dump water on the burning Amazonian forests in Rondonia. Nearly every article refers to the Amazon as the “lungs of the planet” and many include “the cradle of biodiversity” and references to enormous carbon stocks held in these forests. The value of forests are broadly recognized, and this is great news. What we are destroying is bad news, but at least it’s big news. Many articles even point out that cattle ranching is the main driver of deforestation, and if you are bothered by destruction of the Amazon you can stop eating beef.

Even declining deforestation rates mean more deforestation every year. Perhaps this rapid spike is just what we need to wake up and take action before critical tipping points are reached. Though I am alarmed and partially terrified by the rise in right wing, “pro-business” governments, I am inspired by the increasing awareness and participation to create a more just and sustainable world. Complacency is no longer an option. It’s time to take action, and we are.

We are really all in this together. It’s not business vs. environmentalists. We are all humans who depend on the sky to deliver water, the air to carry enough oxygen, the climate to be stable enough to continue growing food, and all the species to fulfill their functions. For all of us to survive, we need functioning ecosystems. Let us take united and coordinate action to build sustainable economies and livelihoods and a healthy planet.

Chefs spill the beans, but where are the farmers? Reflections from the EAT Forum 2019 in Stockholm

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By: Aniek Hebinck, Communicator and Researcher at SLU Global & Environmental Change Institute. Aniek holds a Ph.D. in Sustainability Science from the Stockholm Resilience Centre and wrote her thesis on Shaping Sustainable Food Systems.

The EAT Forum carnival is back in town and it’s as ambitious as ever! This year’s edition is themed ‘The Science is Clear: It’s time to Act’.

During two days in June Stockholm becomes the temporary hive for many ‘foodies’ coming from business, policy, academia and civil society. The forum kicked off with messages bouncing from hopeful, thanks to the environmental movement created by the youth, to fearful of the current social and ecological challenges. Gunhild Stordalen, founder and executive chair of EAT, set the tone for the 2019 edition of the Forum by calling on all of us to be a bit more like Greta Thunberg.

‘Academic rock stars’ Jessica Fanzo and Johan Rockström emphasized that “the science is clear”. By this, they mainly refer to the EAT-Lancet report, which argues for a drastic protein shift to plant-based foods, particularly in high-income societies. After having set out the main points of the dense EAT-Lancet report, they urged governments and business to embrace science-based evidence and use it for setting the targets for sustainable diets.  

Fanzo and Rockström also highlighted some of the aspects that this report has not covered. These include translation of what the ‘planetary health diet’ means for a national setting or the analysis of trade-offs between the potential winners and losers of the transition. It’s here where EAT invites the forum’ attendees to fill in those gaps, invoking higher participation from the civil society, contrary to earlier years.

One group that is keen to contribute to solving this puzzle are the chefs. The ‘planetary health diet’ may have been scrutinized by academics for its overgeneralization and the lack of adaptation to national contexts, but the chefs happily tackle this challenge. Lorna Maseko, a celebrity chef from South Africa, and a Nigerian chef Michael Elegbede emphasized that it is crucial to increase the diversity of what we eat and what we grow for the intake of micronutrients and biodiversity in general, but also to learn from other cultures through their food. 

Photo: Aniek Hebinck

This message echoes through as a collective of chefs, united behind the ‘Chefs Manifesto’, enters the Kitchen Stage. Doing what they do best – cooking. The audience eagerly munched on the ‘turtle bean’ dish that the Kenyan Instagram celebrity Chef Ali Mandhry was handing out. Meanwhile, Chef Chantelle Nicholson from New Zealand stressed that chefs could inspire both professional and home cooks to prepare meals based on the ‘planetary health diet’. Indeed, this merry bunch has clearly demonstrated how Lancet’ scientific targets can be translated into recipes for sustainable, healthy and tasty daily home cooking.

While their importance is frequently mentioned, a group that hasn’t been very visible at the forum, are farmers. Early on in the day, Wiebe Draijer (Rabobank) urged to make farmers the heroes of change. After all, they are crucial in making a transition to a ‘planetary health diet’. However, this has proven to be easier said than done.

The last panel of the first day titled â€˜Transforming Agriculture: restoring hope”, represented by international institutions and large businesses, made an attempt to capture the voice of farmers as it was. Assan N’gombe (AGRA) underscored the crucial role of small-scale farmers, highlighting the challenges farmers face when adopting climate-smart agriculture and that there is a need to engage with farmers directly and to build trust. Mariana Vasconcelos (Agrosmart and farmer’s daughter) continued by stressing that being a farmer is not an easy job and requires, daily decision-making and risk management. Lastly, Eric Souberain (Danone) acknowledged that food has become a commodity and that farmers are not fairly rewarded for what they bring to the table. At the end of this session, very little was said about the implications of a shift to a ‘planetary health diet’ for the many small-scale farmers worldwide.

Day one of the forum highlighted many insights regarding technological innovations and uptake of science, but also underscored the continued challenge to establish an inclusive dialogue and action to foster food system change.

This blog post was originally published at SIANI.

The spread of African swine fever is a serious threat to Asian pig farmers

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By: Gunilla Ström Hallenberg, SLU Researcher at the Department of Clinical Sciences;
Division of Reproduction 

The current outbreak of African swine fever in several Asian countries is causing severe impacts on the pig industry. Since the disease has a very high mortality rate of up to 100%, it is associated with substantial losses for pig farmers and may lead to trade restrictions and ban on exports of pigs and pork from affected countries.

Destruction of dead pigs during an outbreak of African swine fever in a Cambodian village. Photo: Kristina Osbjer, FAO.

It was in August 2018 that the first outbreak was reported in China. Previously, African swine fever had only occurred in Africa, although with recent spread to Russia and parts of Europe. The emergence of the disease in China is highly worrisome, given that the country harbours around 50% of the world pig population (around 430 million pigs). Since the first reported outbreak, the disease has spread throughout eastern China, with a recent outbreak in the western province of Xinjiang. To date, it has been estimated that around one million pigs have died or been culled as a results of African swine fever in the country. 

As a consequence of the ongoing outbreaks in China, neighbouring countries have put in a lot of efforts in order to stop the disease from spreading into their countries. Despite these efforts, African swine fever was reported in Mongolia in January 2019. In Mongolia, the disease has so far led to that more than 10% of the country’s (although quite small) pig population have died or been culled.

On 19 February 2019, the first outbreak was reported in Vietnam, a country with more than 10 million pigs, of which the majority are still raised by smallholders. Initially, outbreaks were concentrated to the northern regions around Hanoi but the disease was recently reported in central Vietnam as well.

The most recent report on African swine fever is from Cambodia, where disease symptoms were first noticed on 22 March 2019 on a small-scale farm in Ratanakiri province, bordering Vietnam. The disease is believed to have been spread through contaminated food products imported from Vietnam. Since then, more outbreaks have been reported in neighbouring districts in Cambodia.

Map illustrating the outbreaks of African swine fever in Asian countries, from August 2018 to May 9, 2019. Source: FAO, “ASF situation in Asia update”.

The disease

African swine fever is caused by a virus of the Asfarviridae family. It affects both domestic pigs and the wild boar population. The disease is usually deadly, especially among domestic pigs. Wild boars appear to be less severely affected by the disease but may still carry the virus and infect other pigs. Infected pigs typically show symptoms like fever, loss of appetite, lack of energy and internal bleeding. Reddening of the ears and flanks is also a common symptom. Pigs infected with the virus usually die within ten days, sometimes before even showing any symptoms. The African swine fever virus does not cause disease in humans.

Sampling for African swine fever detection in a Cambodian village. Photo: Kristina Osbjer, FAO.

To date there are no vaccine available against African swine fever, which makes controlling the disease challenging. Early detection and good biosecurity are the main tools used to control the spread of the virus. As biosecurity measures are often poorer in backyard or non-commercial farms, those farms are often the ones first affected by the disease. With the exception of China, all outbreaks in Asia have so far occurred in backyard pig farms.

Transmission and spread

The African swine fever virus affects both domestic pigs and wild boars. Healthy pigs usually become infected through direct contact with infected animals, both domestic and wild boar, or if they are fed meat products from infected animals, for example from kitchen waste or through swill feeding. The virus is very heat resistant which means that infected products must be properly heated to eliminate the virus. According to FAO, the majority of the first 21 outbreaks of the disease in China were related to swill feeding, leading to updated feed restrictions and the banning of swill feeding to pigs.

Besides being heat resistant, the virus may also survive in cold or frozen meat products for several months. Importing meat products from affected countries may therefore involve a risk of introducing the virus to other countries. The virus may also be spread between farms and animals through contaminated material, such as clothing, vehicles and other equipment. This appears to be an important route in the transmission and spread of the virus in China. Thorough cleaning of any material or clothing in contact with infected animals or meat products is therefore of great importance. However, such practices might not be properly implemented in lower-income countries and on backyard farms, which facilitates the spread of the disease.

Contaminated meat products may be a source of transmission of the African swine fever virus. Photo: Gunilla Ström Hallenberg, SLU.

Impacts on the Asian pig production

The spread of African swine fever in Asia will seriously affect the pig production in the region. Besides the obvious effects the disease will have on animal health and welfare, the high mortality and the culling of pigs on positive farms will lead to substantial economic losses for the farmers. Since it is to a large extent small-scale backyard farms that have been affected, this will likely have extensive impact on the income and livelihoods of the farmers and their families. Consequently, these farmers will likely run out of business and there are projections that there will be a shift towards more large-scale pig farms that can afford better biosecurity measures.

The pig industry in affected countries will also suffer the consequences, not only through direct economic losses from deceased pigs, but also through stricter legislation on trade and export of pigs and pork. For example, the pig industry in Vietnam is of great economic importance for the country’s economy and depends to a large extent on the export of products to China and other countries in the region. However, not all changes will be bad. For example, the prospective ban on long-distance transport of live pigs, replaced by refrigerated transportation of pork, will be a step towards better animal welfare. Also, the necessary improvements in biosecurity will likely lead to reduced incidence of diseases and better animal health and productivity.

It is not only the pig industry that is affected by the spread of African swine fever. The decreased supply and availability of pork may lead to increased prices on those products, thereby affecting consumers and retailers. There have been some reports on increased prices on both the European and U.S. markets as well, resulting from the increased demand for pork in China.

Containment of African swine fever might be difficult, especially on small-scale backyard farms with low biosecurity. Photo: Gunilla Ström Hallenberg, SLU.

Containing African swine fever in Asia might be an impossible task, given the high density of pig farms in many parts of the region and the high proportion of small-scale backyard farms with low biosecurity. Despite this, governmental authorities and different organisations are working hard to control and prevent the disease from spreading further. If they will be successful remains to be seen. However, one can definitely state that it has been a tough start for the Year of the Pig in Asia.

Read more about African swine fever and a SLU research project in Uganda

Restoring degraded tropical landscapes with trees

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By: Aida Bargues Tobella, Postdoctor at the Department of Forest Ecology and Management; Tropical Forestry and Land Use Management Unit 

Land degradation is a major problem in the tropics. Such degradation entails a decline in the capacity of the land to produce and provide ecosystem goods and services, with negative impacts for human livelihoods, food security and the environment at large. 

Land degradation is a widespread phenomenon across the tropics. The Nyando River Basin (Western Kenya) is a regional erosion hotspot and one of the main sources of sediment and phosphorous into Lake Victoria. Photo: Aida Bargues Tobella

The establishment of trees on degraded lands is considered a fundamental tool in landscape restoration. Establishing trees is about more than just planting trees, and can include assisted natural regeneration (ANR) of forests, farmer-managed natural regeneration or direct seeding among other techniques. Similarly, the concept of landscape restoration is not limited to re-establishing lost forests and should be seen on a broader perspective, taking into consideration, for instance, the incorporation of trees into farming systems (agroforestry).

Faidherbia albida is a popular agroforestry tree which generates numerous provisioning and regulating ecosystem services. Photo: Aida Bargues Tobella

The potential benefits from tree-based restoration include enhanced water quality, biodiversity, carbon sequestration, soil fertility, and food and nutrition security. But, how much do we know about tree-based restoration? What are the trade-offs and synergies among ecosystem services from trees? What management practices and tree traits contribute most to promote specific ecosystem services? As we enter the UN Decade on Ecosystem Restoration, answering such questions is pressing. 

Sesbania sesban improved fallows have a great potential to restore soil fertility and increase crop yields. Photo: Aida Bargues Tobella

In the research group on Tropical Forestry and Land Use Management at the Department of Forest Ecology and Management in SLU, we work towards advancing our understanding of tree-based restoration of degraded landscapes in the tropics. Currently, we have projects in six countries across the global tropics: Malaysia, Thailand, Kenya, Burkina Faso, Tanzania and Mozambique.

We currently have on-going research projects in six different countries across the global tropics

Rainforest degradation and restoration

The group has been doing research on rainforest degradation and restoration in Borneo for over 35 years. The INIKEA Sow-a-Seed rainforest restoration project in the Malaysian state of Sabah is a collaboration between the Sabah Foundation, SLU and the Swedish furniture company IKEA andit is unique in that it is one of the largest and most successful tropical rainforest restoration projects in the world. Since the startof the project in 1998, we have planted more than three millionseedlings, consisting of ca. 80 different indigenous tree species, and roughly14,000 ha of forest have been restored with assisted natural regeneration and enrichment plantings. 

In connection with the project, we have established a number of scientific experiments: 

  • In the SUAS experiment, established already in 1992, we aim to develop silvicultural methods that make management of natural forests environmentally and economically sustainable.
  •  In our three different species/genetic common gardens we seek to advance the present lack of knowledge on the economic and environmental values of indigenous species. Here we also study the importance of genetic variation in traits within and among species.
  •  In the Rainforest Restoration Experiment,we have established 84 plots in various forest types to evaluate where each of our four different approaches of restoration is most appropriate; 1) Passive protection; 2) ANR; 3) ANR with line planting and 4) ANR with gap-cluster planting.
  • In our permanent sampling plots inside the restoration area and surrounding landscape of large-scale oil palm and industrial tree plantations as well as undisturbed protected forests, we are evaluating ecosystem values, such as economic value, carbon sequestration, water quality and biodiversity among these land-use systems. 

These long-term forest management experiments in northern Borneo provide many opportunities for research. In the project Balancing production and ecosystem services from degraded tropical rainforests to aid the transition to a more sustainable bio-based economy, we are using data from these experiments to quantifybiomass production and a range of ecosystem services across multiple spatial and temporal scales. Using a multi-disciplinary approach, including aspects of economics, social science, silviculture, plant ecophysiology, ecology, human health,and biogeochemistry, we aim to identify sustainable management practices that can maximize the production of raw materials while at the same time minimizing adverseenvironmental impacts. Using this holistic approach, the overall objective is to obtain and communicate novel information to scientists, private, and government stakeholders about trade-offs between biomass production and ecosystem services to aid the transition to a sustainable bio-based economy.

Rainforest vulnerability to climatic water stress

The frequency and intensity of drought events are predicted to increase in tropical monsoon forests of Southeast Asia, ecosystems that are known to be biodiversity hotspots and a persistent carbon sink in the global carbon cycle. Such increases could drive rapid and large-scale shifts in forest structure and species composition as well as cause dramatic decreases in the amount of carbon stored by these tropical forests. We have recently started a research project thatbrings together scientists from Thailand, France,and Sweden, to assess the vulnerability of mature and secondary forests to climatic water stress. Such information is crucial to more accurately predicted how future climate change wouldaffect the cycling of carbon and water in tropical forested ecosystems. 

Trees and water in African tropical drylands

Another leading research topic of the group is how we can use trees to improve soil and water resources in African tropical drylands. Our previous research in the seasonally dry tropics indicates that an intermediate tree cover can maximize groundwater recharge, which is contrary to the predominant scientific view that more trees always lead to less water. But, under what specific conditions can more trees improve groundwater recharge? Together with scientists from the World Agroforestry Centre (ICRAF), the Norwegian University of Life Sciences and Wageningen University, we are evaluating the extent of the optimum tree cover theoryacross African tropical drylands. To do this, we are primarily using data from the network of Land Degradation Surveillance Framework (LDSF) sites, which is hosted at ICRAF. To date, the LDSF has been employed in over 200 sites across the global tropics and therefore constitutes a unique dataset to test this theory. The overall aim of the project is to provide evidence to inform better land-use policies in African tropical drylands and identify management options that can increase groundwater resources. 

LDSF field campaing in Embu county, Kenya. Photo: Aida Bargues Tobella
LDSF field campaing in Makueni county, Kenya. Photo: Aida Bargues Tobella

Courses

Are you interested in these questios and want to learn more about tropical forestry and land-use management? At the moment we offer two courses within this field:

This year’s MSc course on Sustainable Forestry and Land-se Management in the tropics included a one- week field trip to Mozambique. Photo: Rosa Goodman
Participants of the course “Forest Management Forest Management, Land Use Change and Ecosystem Services in Degraded Tropical Landscapes” had the opportunity to visit the INIKEA Sow-a-Seed restoration project in northern Borneo. Photo: Niles Hasselquist

Who we are

Ulrik Ilstedt, associate professor; ulrik.ilstedt@slu.se
Gert Nyberg, associate professor; gert.nyberg@slu.se
Niles Hasselquist, associate professor; niles.hasselquist@slu.se
Rosa Goodman,associate senior lecturer; rosa.goodman@slu.se
Aida Bargues Tobella, postdoc;  aida.bargues.tobella@slu.se
Daniel Lussetti, postdoc; daniel.lusetti@slu.se