News and Activities

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

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

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.  

We have known that the soil has a significant influence on the growth of our trees since Ines and Aurèle’s Design Project 2024. We wanted to find out more as part of a new Design Project with EPFL. Camille Perrin and Alena Vasilyeva analysed soil samples taken from 19 sites: 10 sites where our trees are growing strongly according to our dendrometric measurements, and 9 sites where our trees are not growing well. Alena and Camille show that two groups of factors explain our trees’ growth and that pH is a key determinant. The more acidic the soil, the less accessible the nutrients present in it are to plants (paradoxically, there is more phosphorus in the soil of the underperforming plots, as this phosphorus cannot be absorbed by the trees because it is more strongly bound to other atoms). In temperate zones, liming is used to make the soil more

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.

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

The end of March was spent preparing for the verification audit. Around thirty plots were initially selected at random. Of these, the auditors check half, generally based on the stratum. For example, three plots sown in 2021, four from 2022, three from 2023, and so on. To ensure the site visit programme can be completed within a few days, it is also important to check that each plot is accessible. On the selected plots, our partners at South Pole insisted that the GUIDRE teams repeat the tree measurements taken in November, to be absolutely certain of avoiding any unpleasant surprises. The tree measurements taken in the presence of the auditors must correspond exactly to those taken before the audit. There is no room for error. Yet surprises cannot be ruled out: traces of past fires or livestock grazing, a baseline tree that has been ‘overlooked’ or ‘added’… several issues that