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What is biochar and why is it important? In Guinea, due to the low fertility of tropical soils, farmers face low yields and are forced to practise extensive farming over large areas. This is why they practise shifting cultivation (slash-and-burn). After being cultivated for around five years, the land loses its fertility and must be left fallow for about ten years to regenerate. When the farmer sees that the land is fertile again, he burns the vegetation (shrubs, young trees) that has grown up on the old fallow land. The ashes are mixed into the soil during ploughing, before sowing (usually with upland rice), provided they have not been washed away by the rain beforehand.

Why are tropical soils not very fertile? They have a low organic carbon content, as decomposition proceeds very rapidly under hot and humid conditions. This limits the soil’s ability to store nutrients. Furthermore, tropical soils are heavily leached due to heavy rainfall. This leads to the loss of soluble nutrients such as nitrogen, calcium, potassium and magnesium. Many tropical soils are acidic, which reduces the availability of certain nutrients to plants.

This process generates significant CO₂ emissions. The practice of slash-and-burn farming (‘shifting agriculture’) is the main cause of deforestation (loss of biodiversity) and CO₂ emissions in Guinea (Report on the preliminary estimate of greenhouse gas (GHG) emissions and removals from the forestry sector in Guinea, World Bank 2024) and indeed across Africa as a whole:

To summarise: Guinean farmers must regularly clear (= cut down trees) on their long-fallow land in order to cultivate it. At present, they burn the vegetation and use the ash as fertiliser, but this is washed away by the rain and, more importantly, this process releases a huge amount of CO₂ into the atmosphere.

What if we helped this farmer turn this wood into biochar, which could then be worked into the soil whilst ploughing? This would boost soil fertility using a natural, free substrate, whilst avoiding CO₂ emissions. Let’s dream a little: perhaps this farmer could then cultivate his field for longer and thus delay the next time he has to clear the land… Turning fallow crop residues into biochar could therefore be a way of reducing deforestation… Imagine the impact if 130 million farmers changed their practices!

We thought to ourselves: it’s worth a try.

All the more so because, as this process enables carbon to be sequestered in the soil whilst avoiding CO₂ emissions, it is possible to generate income from carbon credits. There are several carbon certification standards for biochar, generally involving the conversion of crop residues (rice straw, maize or sugarcane stalks, coffee husks, cocoa pods, etc.) into biochar. We have opted for the Global Artisan C-Sink methodology from Carbon Standard International, which is designed for small-scale biochar producers, such as our farming families. This standard sets out numerous requirements, such as:

• Ensuring the traceability of the sourced biomass: it must be ensured that the producer does not cut down trees indiscriminately, but that their biomass comes from fallow land which they had in any case intended to clear.
• The fallow land must not be more than 10 years old (no old trees)
• The pyrolysis process must comply with quality standards to minimise CO₂ and methane emissions and achieve a high carbon content: the wood must be completely dry; combustion must not emit smoke or produce ash, and must reach a temperature of 700°–800°
• The fire must go out very quickly
• The volume of biochar produced must be measured accurately
• The ratio of volume to dry weight must be measured in a laboratory
• The project must demonstrate that all the biochar has been incorporated into the soil
• The carbon content of the biochar must be measured in a laboratory

To document this, our supervisors are equipped with a specialised app, developed for us by Circonomy :

Digging pits of 14 m³ (on 2 ha of fallow land there is a great deal of wood: the Kontiki kilns would have been too small and production would have been very complicated)

At the same time, we also wanted to give a role (and an income) to the seed-families, so as to include women in this activity as well. Enriching biochar with nitrogen-rich materials further enhances its fertilising power. That is why we asked the women’s groups in the four villages to collect manure, which will be mixed with the biochar before it is incorporated into the soil.

The actual production of biochar took place under difficult conditions, mainly due to the late timing of the activities (a decision dictated by the availability of the CERES CERT auditor and the availability of the Circonomy documentation tool). Producing the biochar competed with other agricultural work, and the supervisors had to put in a great deal of effort to convince the farmers to honour the agreement they had signed. This is a valuable lesson for next year.

Another lesson is the complexity of the production process: to meet all the standard’s requirements, a great many resources need to be co-ordinated and synchronised (having enough wood to fuel the fire, having sufficient water to extinguish the pit, obtaining manure from women’s groups, arranging for oxen to plough, etc.) and perhaps we have overestimated the farmers’ management capacity. We will optimise this aspect in 2027.

Producing biochar requires the coordination of several resources: labour, wood, water, tricycles, manure, oxen, etc. Synchronising these resources is a challenge.

The biochar audit was intensive, as we visited 20 producers in three days so that the auditor from Burkina Faso could check all aspects of the project across a representative sample of producers. He was particularly thorough in his feedback, going into the finest details (for example: how to angle the ploughshare so that the biofertiliser can be easily incorporated and the furrow closed up on the next pass of the plough). We therefore came away with plenty of ideas for improvement for 2027.

Every auditor has their own areas of focus. For our auditor, these were the quality of the ignition, the mixing of biochar with manure, the incorporation of the biofertiliser into the soil, and the representativeness of the sampling.

In the end, 1,445 270-litre bags were produced across 127 production ‘batches’. This represents 300 tonnes of CO₂ (bearing in mind that the average Swiss person generates 15 tonnes of CO₂ per year). This production is currently being verified, and the 300 carbon credits should be issued before the end of this year. This is another major advantage of biochar: carbon revenues are generated immediately.

The rainy season is drawing to a close, and in a few weeks’ time we will also know what effect the biochar has had on the agricultural yield of the rice sown by the farmers. One of them has already spontaneously expressed his great satisfaction with his harvest.

We would like to take this opportunity to extend our sincere thanks to REPIC, a joint initiative of SECO, the SDC, the FOEN and the SFOE to promote renewable energy, energy efficiency and resource efficiency in developing and transition countries, which placed its trust in us by funding this pilot project, impressed by our two objectives:

1. To increase agricultural yields using biochar-based biofertiliser
2. To utilise plant waste (fallow land residues) through carbon credits

On Thursday 15 August, communities in the Linko sub-prefecture, within the Kérouané prefecture, received the second round of payments for carbon credits generated by their efforts to reforest and maintain forest areas.

The ceremony was attended by representatives from the beneficiary villages, the administrative and local authorities of Kérouané and Linko, as well as the project managers and their partners.

Taking the floor, the Executive Director of the NGO GUIDRE reiterated the project’s objectives and emphasised the importance of transparency in the payment process, particularly through the partnership with Crédit Rural de Guinée. He explained that this is the second time that beneficiary families have received financial rewards for their efforts in reforestation and forest maintenance, the first payment having been made in October 2025.

A total of 1.1 billion Guinean francs will be distributed amongst the beneficiaries concerned. The Executive Director also called on communities to remain vigilant against bushfires, in order to safeguard the project’s achievements.

For their part, the beneficiaries reaffirmed their commitment to continuing forest restoration and conservation activities, whilst adhering to the project’s recommendations.

Presiding over the ceremony, the Sub-Prefect of Linko encouraged the communities to become more involved in the fight against climate change and the conservation of natural resources, before proceeding to launch the payment scheme.

Through this campaign, arboRise and its local partner GUIDRE are strengthening their participatory approach by enabling communities to benefit directly from the economic benefits generated by their forest conservation and restoration efforts.

In July, just before the rainy season, it is time to sow the fields. It is also the time to sow the forest seeds harvested by the ‘seed families’ of the arboRise project. This is a collective activity, with the group dividing into those who dig the holes with their hoes and those who place a seed in each hole.

Predicting land clearing is important for our project. That is why, once again this year, we have collaborated with EPFL as part of a Design Project.

Feryel El Phil and Camille Dupré Tabti first demonstrated that the first derivative of NDVI values is a good method for identifying when land is being cleared.

This enables them to calculate the crop rotation cycle for each plot of land. As can be seen below, this varies considerably: some plots have a rotation cycle of 7 years (roughly 2 years of cultivation, 5 years of fallow), whilst others can be as long as 25 years:

Building on these findings, they then produced a map showing the probability of land clearing in Linko and Samana and concluded that the risk of our plots being cleared increases if the land is easily accessible to farmers (close to the village) and if it is naturally fertile. We can therefore predict which land-owning families would be most likely to reconsider their participation in the project if they are not satisfied with the carbon payments they receive.

The full analysis report is available here: DP_Leakage_final_report

As we recall, in 2025 the land-owning families had agreed to allocate 10 per cent of their ‘carbon income’ to their village. The amount was distributed in proportion to the number of land-owning families and the area of land reforested by each village. Thus, Forono, the largest village, received around CHF 800, whilst Kala, the smallest village, received CHF 50. As these sums were insufficient for genuine infrastructure works, they were spent without any lasting impact.

We wanted to change this and proposed that the cooperative’s committee consider the matter. The idea was to no longer distribute the annual CHF 10,000 from the ‘villages’ share’ amongst all 26 villages, but only to two villages each year. The amounts would then be sufficient to build sustainable infrastructure. The cooperative committee approved the idea and put it forward to the Cooperative’s General Assembly, suggesting that the two beneficiary villages be chosen by lot from among those that do not yet have a borehole (as access to water is the most critical piece of infrastructure for a village). The General Assembly accepted the cooperative committee’s proposal, and the villages of Mamouroudou and Diaradouni were chosen at random.

How were the two villages chosen? It’s quite simple: by drawing lots!

Mariame Condé has been a ‘seed family’ in the village of Kofilakoro since January 2022. She harvests the Carapa procera (Kobi) species. Let’s hear her describe her experiences in her mother tongue, Konianke, translated by Sékouba Condé, one of the supervisors at our partner organisation GUIDRE:

My name is Mariame Condé, a seed family. This project has changed my life. In 2022, I was pregnant and collected 20,000 seeds. The project paid me 1,000,000 GNF, which was a relief. At the time, my husband had gone to Sigiri, a mining area, to search for gold, and our harvest was almost gone. I used the money from Arborise to buy food and clothes for my son.

In 2023, I received 1,000,000 GNF and bought two sheep. I also got a large tarp that makes collecting seeds easier. After the seed harvest, I used the tarp to dry my rice and for my children to sleep on.

In 2024, I received another 1,000,000 GNF from Arborise and increased my sheep count. I’m happy with this project because it helps us and fights poverty. I now have 7 sheep, which are savings for my children.

Our seed harvest is done, but I profit from my sheep, and we women have formed a group (CGC SABOUGNOUMA DE KOFILAKORO). Each year, we produce lots of peppers, okra, and peanuts. It’s thanks to this mega Arborise-Guidre project that our lives have changed.

I’ve never seen a project like this that gives so much money to our husbands (land families) and us, while helping create forests that bring water to our streams. Mr. Condé, you know that from 2021–2023, the stream you once crossed dry now has water year-round.

I love this project because it keeps its promises. We’ve always received everything in the agreement—and more, like fencing, tarps, machetes, plows… always on time.

One of the Cooperative’s objectives, and the main role of the Cooperative Committee, is to develop a carbon revenue sharing formula. Indeed, it is certainly not up to arboRise to define how these revenues will be shared among the cooperative members. This choice must be made by those most directly concerned, based on local traditions and customs.

But what will these criteria be? And how should they be weighted? Should effort and merit be taken into account, or should revenues be distributed evenly? Can fate be invoked to justify certain disappointing results? Etc.

Rather than discussing these criteria in the abstract, we opted for serious games, which are more effective. In concrete terms, we used pre-printed tarpaulins showing several scenarios, such as this one, where the aim was to distribute income according to the hazards suffered by landowners:

Each member of the cooperative committee had 20 (symbolic) coins representing the project’s carbon revenues and was tasked with distributing them among the 10 situations presented on the tarpaulin, then commenting on their choice in front of their peers.

Over the course of the day, a consensus quickly emerged on the principles of carbon revenue distribution, for example:

• Compliance with the cooperative’s rules by each member must be rewarded in proportion to the effort required to comply with each rule. For example, certain ‘costly’ rules (installing firebreaks around plots) must be better remunerated than simple rules (installing barrier tape to mark plots).
• Of course, those who make a significant commitment to promoting tree growth on their land should be rewarded, but it is also necessary to give a little to those who are ‘undeserving’ because otherwise they may leave the project.
• It is necessary to (very clearly) reward the result (the density and height of the trees on the land) and not the effort that was necessary to achieve this result.
• External factors (soil infertility, fires, etc.) should not be considered inevitable: it is the responsibility of the land family if they have chosen unsuitable land or if their land has been affected by fires.

Over the following days, we repeated the same tarpaulin exercise in the 18 villages, visiting two villages per day, with all the field families in the village and in the presence of the two members of the village cooperative committee. The idea was to show the field families the complexity of the Cooperative Committee’s task, and it also allowed everyone to express aloud what they were all thinking: in the end, it will be those who achieve results who will receive the most carbon revenue. Another reassuring lesson is that there are no real differences between the villages: the distribution choices are fairly consistent.

At the very end of the tarpaulin exercise, we asked each village, ‘How much of your carbon income would you be willing to share freely with your village?’ Most participants indicated that they were willing to share about 10% of their carbon income with their community. With this, the villages will be able to develop their infrastructure (wells, market gardens, health posts, schools, etc.).

We also discussed opportunity costs with the families involved. By lending their land for reforestation, these farmers are potentially foregoing income from their crops. We therefore worked with them to examine the details of hillside rice cultivation in order to understand all aspects of it (yields, expenses, crop duration, fallow periods, etc.).

In total, 186 people from 18 villages, representing 72% of all the families involved, took part in this deliberation process. For arboRise, participatory reforestation is not just an empty phrase. It is essential that everyone has a say so that they can all take ownership of the project.

In our experience, one of the drivers of change in any organisation or social group is its leaders. Our process also aims to facilitate the emergence of new leaders, legitimised by transparent elections in their villages and then at sub-prefectural level within the Cooperative. Of course, current political leaders (sub-district chief, mayor of Linko, village chiefs) are involved in the process. They welcome the momentum generated by the project in the region. Indeed, we are convinced that it is the networking of leaders (old and new!) that will be decisive.

In December 2025, we founded the Samana Family Land Cooperative to properly manage the common good that is the new arboRise forests (see our report here), and on 1 February 2026, a new General Assembly was held to elect the cooperative’s governing bodies:

In preparation for the election of the 18 members of the Cooperative Committee, each village had previously elected two representatives, one man and one woman. At the general meeting, we simply used a hat in which we placed 10 ‘Woman’ tickets and 8 ‘Man’ tickets. Each village drew a slip at random, and that is how we ended up with a Cooperative Committee made up mostly of women, all of whom are well known in their villages and therefore visible at the sub-prefecture level.

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In this regard, some circles readily express sympathy for the plight of African women. For our part, we see tangible signs of their influence that contradict this image of weakness. For example, in a village in the sub-district, the women deposed the village chief who was reluctant to have the village join the project! Another example: a woman from the village of Booko heads the hunters’ guild for the entire sub-prefecture, an extremely powerful position that carries significant customary powers. A third indication is that the requirement for a majority of women on the cooperative committee has never been challenged or even debated. To conclude this digression, here is an inspiring read on the subject: L’autre langue des femmes (The Other Language of Women) by Léonora Miano.

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…We then moved on to electing the five members of the administration. The cooperative members from each village first chose their village’s candidate, then the entire room voted by a show of hands for each candidate, and the five with the most votes were elected. We are very pleased with the election of Mr Mamady Kourouma, from the village of Farawanidou, as Director of Administration, and that Ms Mariam Sidibé from Sokourala will represent women within the Cooperative’s Administration.

Each candidate first introduced themselves to the Assembly, then the five members of the administration were democratically elected.

The day after the General Meeting, we organised a training session for the five members of the administration and the 18 members of the Cooperative Committee and their deputies to prepare them for their roles and responsibilities.

• For the Administration, it’s simple: they have to manage the budget and organise the next General Meeting (thus relieving our partner GUIDRE, which had been responsible for this until now).
• For the Cooperative Committee, it is more tricky: they must appoint surveyors to visit and assess each plot of land and then, based on their report, develop a carbon revenue distribution key. Indeed, it is certainly not up to arboRise to define the criteria for distributing this revenue. This choice must be made by those most directly concerned, based on local traditions and customs.

But what criteria should be used to distribute carbon revenue? You can find out here.