Biochar as an Alternative to slash and burn farming

Saving lungs with heart

Air is a very precious element, which as we know, is vital for us to continue living. In spite of this, routine poisoning of the air continues all around the globe.  One of the major contributors to this is slash and burn farming. As I explored in one of my previous articles ‘Hazy Suggestions’, in many places in South East Asia, the smoke caused by the fires that are used in slash and burn farming, as well as forest clearance for monoculture plantations, is so thick that during the ‘smoky season’, the sun is invisible for weeks at a time, hidden behind a veil of grey haze. Children cough, eyes are red and itchy, the smoke clouds your head making it difficult to think let alone breath.

Many groups around the world are working to provide alternatives to the burning practices involved with creating so much pollution. One such alternative being applied in Thailand is the production of biochar.


How to encourage cleaner air?

The seasonal practice of slash and burn farming in Northern Thailand means that for two or three months every year, the towns and cities of this normally pristine area are among the most polluted in the world. Chiang Mai for example, was ahead of Kathmandu, Beijing and New Delhi this year.  It was reported as having the most polluted air in the world for a few weeks in March. In order to address this issue, it’s important to engage with those doing the burning in the first place.  They need encouraging to use alternative methods. This is exactly what charity organisation Warm Heart aims to achieve in rural communities in Northern Thailand.


What is Warm Heart?

Warm Heart, is a charitable organisation. Evelind Schecter and Michael Shafer are the founders and they are engaged in a range of social and environmental campaigns.  One of their objectives is to bring positive change to the poor community of Phrao, a district in the north eastern part of the Chiang Mai provence.  This year, they launched their ‘Stop the Smoke Campaign’, which is aimed at engaging communities to change their current farming and land management methods, with the main focus being the switch from slash-and-burn to biochar production.


What are farmers doing now?

This summer, I got the chance to speak with Warm Heart volunteer, Ben Shread-Hewitt, about the “Stop the Smoke Campaign”. He has been working within rural communities at two different sites.  One in Phrao district to the North-East of Chiang Mai city. The other at Mae Chaem, a remote village to the South-West of Chiang Mai city, in the foothills of Thailand’s tallest mountain, Doi Inthanon (6).

Ben pointed out, the main reason why farmers are engaged in slash and burn farming in the first place.  In recent years, the farmers began growing corn (Zea Mays) using intensive monocultural farming methods. This creates more organic mater than rice or perennial crops (6). There are many problems (other than the pollution caused by the slash-and-burn) with corn as a crop in this area.  For example, being more water intensive, increasing deforestation, and soil erosion.  This all directly leads to further pollution because there are less trees and less water held in the soil, as such the burning creates more damage.

All these are part of the much wider issues of human-environmental relationships. From Shread-Hewitt’s experience of living and working closely with rural communities, one problem he can see, is that the farmers no longer feel connected to the land. Today, the farmers are banned from hunting or foraging in the jungle. Traditionally this is exactly how they would have obtained a lot of their food.  It’s one reason why they feel compelled to engage in intensive farming in the first place.


How biochar can help?

Ben says, “it would be better for them to stop growing corn completely”(6)  and to stop burning completely.  Warm Heart’s log-term goal is to encourage perennial farming of tree species intercropped with others.  For example, “perennial bamboo and coffee”, as well as replanting “new forest” (5).

To show farmers that such an alternative can be viable, Warm Heart first need to be able to demonstrate it. Biochar is an effective short-term solution because the farmers still burn the organic matter from the fields at the end of the harvest, as such they can adapt quite easily because it is not such a big change.

The production of the biochar produces far less smoke than simply burning the crops (6,7).  This is because biochar is produced in an enclosed space at high temperatures.  Therefore it is healthier for the farmers involved and for everyone who lives in the nearby area who also has to breathe the air. Biochar increases soil fertility more than simple burnt plant matter (7). Even if the farmers continue with monocultural farming methods, they have to use less chemical fertiliser.  This makes it cheaper for the farmers and healthier for the land and water. It also empowers the farmers to have less reliance on the large agribusiness corporations which produce the fertilisers(6).

Photo by Marcia O’Connor (image cropped) with licence: CC BY-NC 2.0

Long-term regeneration

Warm Heart buys the biochar which is produced from the farmers directly, giving them an instant financial incentive, and currently re-sells it, mainly to farmers already engaged in organic or natural production methods (6). As Shread-Hewitt points out, biochar also has a range of other uses, from medicine for cows and pigs to water filtration. It can even be used as an alternative to concrete, though since it is quite flammable, using it as a building material could also be risky (6).

In the long-term, Warm Heart plan to use the biochar on a 5,000 rai (around 2000 acre) demonstration site, in order to provide soil fertility for the new perennial crops (5). Warm Heart are currently raising funds for the site so it seems that the demonstration has not yet begun. But the long-term goal is clearly a regenerative solution.


How is the biochar produced?

The method which Warm Heart are promoting is very simple.  As Shread-Hewitt says “all you need is two barrels” (6): a smaller one for the inside and a larger one outside. The organic matter is placed within the smaller barrel, which has several holes drilled in it, this allows oxygen inside. It is then set on fire and left to burn for many hours, in a similar way to charcoal production. The enclosed space means that it burns much more completely and at a higher temperature than if it was just burned in the field.  It produces less smoke as well as a pure charcoal end-product (6).

One key point about this production method is that in order for the burning process to begin, it is not usually enough to just set fire to the crop matter.  A small amount of dead wood is added at the beginning to make sure that the fire catches and burns hot enough. This could create a demand for wood which may encourage further deforestation. In order to prevent this, Warm Heart has banned the farmers involved in producing the biochar from cutting down trees (6).


The risks of relying on biochar

As an alternative to slash and burn farming, biochar creates less air pollution and can increase soil fertility further. However, as I have explored in previous articles, biochar production also comes with some risks. The first of which is that, although the burning is safer than just setting fire to the fields, the production still involves burning, so there is still a demand for materials to burn. While these materials are already being produced as ‘waste’ it seems effective to convert them to biochar.  However, as George Monbiot pointed out in his “woodchips with everything” article a few years ago, if biochar products become too popular, there is the potential of big businesses to start biochar ‘plantations’. This would entirely defeat the point of it.


Next steps

Therefore, it seems of great importance to see biochar production as a short-term solution only, with long-term goals being to engage in perennial crop production and effective land management in order to stabilise water catchment and prevent erosion. Warm Heart also helps farmers with achieving these long-term goals. Shread-Hewitt was recently involved, in a water-stabilisation project in Mae Chaem. This project entailed planting a tough species of grass around the edges of reservoirs (6).

At the moment, perhaps, the changes are small, but communities can only alter their behaviour and methods at the speed at which the members of the community decide that they need an alternative. One reason I feel that Warm Heart’s work is effective is that they offer not only practical solutions, but actually go into the communities. They encourage the farmers and others involved to create their own solutions. As Shread-Hewitt pointed out, those farmers who become interested in biochar production “can do it better than we can now” (6).


Coming home to the forest

Inhabitants of rural communities are feeling a lack of connection, which in many cases is due to the laws. Laws which are supposedly aimed at protecting nature.  However, these laws are actually alienating those best-placed to engage in holistic environmental practices.  Surely this is something that needs to be addressed in the long-term. While the forest is off-limits to hunters and gatherers, but fair game for agricultural clearance, there seems little incentive for humans to want to protect it. Therefore, regenerative practices need to be part of a wider conversation with government, policy-makers, and members of effected communities.

This inclusion of the social permaculture aspect seems essential in encouraging any real regenerative change in production methods. Groups are already engaged in helping to build community empowerment in order to encourage change created by those most affected.  Good examples are Permaculture For Refugees (P4R)’s  who work with people in refugee camps, or Resilience Now, who encourage community empowerment in various locations in Africa, and who have a number of useful online resources, such as their workshop on ‘Psychology of Change’.

I hope the work of Warm Heart and others around the world, can provide inspiration for encouraging regenerative agricultural practices within your own communities, and cleaner air everywhere.



  1. Ashwanden, C, 2019. ‘Hazy Suggestions’. Permaculture News, 10/6/19. – retrieved 1/9/19
  2. Wipatayotin, A, 2019. ‘Chiang Mai air pollution the worst in the world’. Bangkok Post, 13/3/19. – retrieved 1/9/19
  3. Warm Heart, 2019. ‘Warm Heart’. – retrieved 1/9/19
  4. Warm Heart, 2019. ‘Warm Heart Founders’. – retrieved 1/9/19
  5. Warm Heart, 2019. ‘Stop the Smoke 2019’. – retrieved 1/9/19
  6. Ashwanden, C, 2019. Interview with Ben Shread-Hewitt, 23/7/19.
  7. Steiner, C, 2006. ‘Slash and Char as Alternative to Slash and Burn – soil charcoal amendments maintain soil fertility and establish a carbon sink’. Research Gate, 1/1/06.
  8. Monbiot, G, 2009. ‘Woodchips with Everything’. Permaculture News, 25/3/09. – retrieved 1/9/19
  9. Ashwanden, C, 2017. ‘Gardening with Woodchips: What, Why, How and Who?’ Permaculture News, 6/4/17. – retrieved 1/9/19
  10. Permaculture For Refugees, 2019. ‘About Us – Values and Mission’. – retrieved 1/9/19
  11. Resilience Now, 2019. ‘Our Mission’. – retrieved 1/9/19
  12. Resilience Now, 2019. ‘Crash Course: Psychology of Change’. Available as a PDF here: – retrieved 1/9/19

Charlotte Ashwanden

Charlotte Ashwanden (nee Haworth). Born in London, I am very interested in peace and community and have a degree in Peace Studies. I got my Permaculture Design Certificate in 2011, from Treeyo at Permaship in Bulgaria, and my Permaculture Teaching Certificate in 2018 at Aranya in India. For me, permaculture is about so much more than garden design; I am mainly interested in applying ‘human permaculture’ as a complement to peace practices. In particular, I like to look at how human permaculture can be applied through psychology, communication and education techniques. In 2015 I got married in a pagan ceremony in a field to David Ashwanden and changed my surname to Ashwanden. With my husband, I’ve travelled a lot in Europe and Asia and encountered many permaculture and community projects. I have lived in various situations, from squatted land to intentional communities, as well as more ‘normal’ places, in the UK, Spain, Italy, Thailand and Vietnam. A professional dancer, I do fire and hula dance and sometimes run dance meditation workshops. Currently, I live in the Andalucian mountains.

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