In Samana, we also need to measure the pre-existing biomass (baseline) on a sample, as was done in Damaro in 2025. We should have taken these measurements in 2024, the year the plots were seeded. Measuring these trees two years too late means that their biomass will contain two years of growth and therefore two years of carbon that belongs to the project but that we will have to deduct (since, as we remember, the project cannot account for pre-existing carbon on the land prior to project activities).
Measuring pre-existing biomass requires several steps:
EcoAct calculates the sample size, performs stratification, and randomly identifies the sample plots and GPS coordinates of the measurement point on each plot.
We update the standard operating procedure and train GUIDRE
For each of the 40 plots, GUIDRE’s measurement teams must
find the plot in the given village
mark the perimeter of the 600 m² circular plot with barrier tape
identify all existing trees, measure their diameter at breast height and height, and identify the species of each tree
send the data via the Kobo-Collect form
The results show that stratification, based on satellite images, is validated by the reality on the ground. It can also be seen that the number of pre-existing trees per plot is reflected in the NDVI value during the dry season (NDVI measures vegetation health via satellite). NDVI is therefore a relatively robust indicator of pre-existing biomass.
On average, we will need to deduct 30 tonnes of biomass from existing trees from our subsequent measurements.
Our reforestation project removes CO2 from the atmosphere, but what is the carbon footprint of arboRise’s activities? How much CO2 do the project’s activities emit into the atmosphere?
This carbon footprint is based on the Bilan Carbone™ methodology and lists all GHG emissions from arboRise and GUIDRE activities in Switzerland and Guinea for the two regions (Linko-Damaro-Konsankoro and Samana-Diassodou-Sokourala-Koumandou) during the 30-year and 20-year certification periods, respectively.
Summary of results:
This carbon footprint of 1,100 t CO2e will enable the absorption of 2,400,000 t CO2e thanks to the reforestation activities carried out by arboRise and GUIDRE in two regions (Linko-Damaro-Konsankoro and Samana-Diassodou-Sokourala-Koumandou) over a period of 20 and 30 years respectively. The project’s emissions therefore represent only 0.5% of the CO2 that the project will remove from the atmosphere.
Comments and potential for improvement:
The travel of GUIDRE teams in the field is, of course, the main source of CO2 emissions. In the long term, the use of electric vehicles will need to be considered and tested.
Air travel (project leader, auditors, partners, business visitors) accounts for 18% of the total (196 t CO2e). If all non-employees (auditors, partners, business visitors) were represented by only one person instead of two, this would save 72 t CO2e. This requires a change in standards and practices. When the Transguinéen railway is available, we will be able to replace internal flights with train travel.
Half of the input footprint is made up of meals for GUIDRE teams in the field, which are difficult to reduce unless they become vegetarian (meat footprint: 123 t CO2e). Other inputs with a significant footprint are fencing and tarpaulins for seed families.
A historic day in the sub-prefecture of Samana on 13 December 2025: Samana’s first cooperative, bringing together the 248 farming families of Samana, was founded in the presence of local authorities.
The 248 cooperative members were invited to gather at the Youth Centre in the commune’s capital. Such an event is exceptional in the region: most of the participants were very surprised to receive two good meals during the day as well as a daily allowance.
The Samana authorities were invited and the sub-prefect of Samana gave a very inspiring speech, which we recorded and broadcast on local radio. The main theme of the day was to explain ‘why create this cooperative’ (to better manage the reforested plots that are the common property of all families) and to prepare for the elections of the cooperative’s governing bodies at the next general meeting in March 2026.
The Samana Cooperative is already the second, following the creation of the Linko Cooperative in 2023.
201 participants gathered at the Samana Youth Centre. The building was just large enough to accommodate the assembly.
CGC trainings follow the “train the trainer” approach. To provide immediate support to seed families and field families in each village, the project sets up a Community Management Committee. This committee is made up of 10 to 20 prominent members of the village, who are often already responsible for specific issues (women’s groups, youth, health and hygiene, etc.).
In our project, the CGCs are responsible for
Supporting seed families and field families. The CMC coordinates collective activities (seed collection, sowing, etc.) and organizes peer learning activities.
Identifying best practices. The CGC identifies the plots of land in its village where trees have grown best and seeks to understand why, in order to recognize best practices.
Disseminating best practices within the village and between villages. The CGC passes on good ideas from seed families to other seed families in the village and does the same for field families. The CGC shares good examples from its village with other CGCs. The CGC is the driving force behind mutual aid.
Training. The project trains CGCs so that they can train families in the village.
Identifying equipment and infrastructure that is useful to the community. The CGC organizes discussions between seed families and land families to decide together what equipment and infrastructure are needed.
The collective equipment obtained through arboRise is managed by the CGCs. The CGC establishes a plan for using the equipment according to the needs of the seed families and landowners. After use by the families, they return the equipment to the CGC, which ensures that it is in good condition and carries out maintenance.
The CGCs coordinate health and safety measures. The CGC documents emergencies, accidents, incidents, and injuries related to the project reported by families. In case of an emergency, the CGC organizes immediate transportation to the Health Center.
Identification of disputes or grievances related to the project. Each CGC assesses the project’s impact on the community. It can express families’ expectations of the project and advise on measures to be taken.
Each year, the project organizes trainings for CGC delegates from each village. In December, the CGCs from the 20 villages in Damaro received their first training covering topics such as “climate change,” “carbon markets,” “brush fire prevention,” “the roles of CGCs,” “the grievance mechanism,” etc. The CGC delegates from the villages were very attentive, and the mayor visited the participants during the training to emphasize the importance of the project for Damaro and the communities and to urge the participants to listen carefully and learn as much as possible.
These training sessions are, of course, also an opportunity to listen to and discuss the participants’ concerns. This dialogue helps to adapt the project to any specific situations that may arise.
The training took place in the new town hall, and we had the honor of receiving a visit from the Mayor of Damaro.
As in Damaro, the CGCs in Samana and Diassodou received initial training. In Samana, as we are now in the second year of the planting cycle, we explained the role of the Cooperative and analyzed the contents of the agreements in detail, as this issue had been raised by the auditors during the validation audit.
The participants were very attentive and asked some very good questions.
As we have seen, manually measuring trees for verification purposes is very time-consuming. Furthermore, biomass is estimated using an allometric equation that only takes into account diameter and height.
What about biomass in branches? Is it sufficiently taken into account by equations, which are often not based on forest measurements, regardless of species?
Other dendrometric measurement methods exist, which generally use scanners (TLS: terrestrial laser scanner).
Numerous studies show that the accuracy of the measurement and the time required are similar to manual measurements, but this equipment is very expensive (CHF 60,000).
Since 2021, most iPhones and iPads have included a lidar (laser) scanner, and specific applications for tree measurement have appeared in the App Store. The cost is much lower than TLS equipment, and the mobility allows for the resolution of occlusion problems faced by fixed TLS. We wanted to test this approach.
There is already a wealth of scientific literature on the subject:
Based on these studies, we selected two applications to test. Unfortunately, ForestScanner andArboreal Forest only measure diameter (but they do so very well) and create a digital terrain model. We would have liked to see real 3D images of each tree.
We then tested two 3D modelling applications (3D Scanner app andPolycam), but the results were inconclusive: scanning a tree from all sides takes several minutes and it is still impossible to scan the tree from above, so the 3D image of the branches and crown is incomplete. Furthermore, when the undergrowth is dense, with lots of foliage (which moves in the wind), the scanner has difficulty working properly.
Conclusion: manual measurements are still more advantageous in terms of speed, cost and accuracy. But thank you to all the application developers who provide very useful tools for measuring monocultures.
With project validation almost complete, we can now begin the project tree measurement as main part of the initial verification process. As you may recall, we established a representative sample of 116 monitoring plots from among the 840 plots reforested between 2021 and 2024. Now we must measure all the trees present on the 116 plots covering 625 m², or 72,500 m² in total. This operation requires several steps:
Update the standard operating procedure and train GUIDRE via videoconference
For each of the 116 plots, the GUIDRE measurement teams must
find the plot in the given village
refresh the yellow paint in the centre of the plot
mark the 625 m² perimeter of the circular plot with barrier tape
identify each tree over 2 metres tall, mark it with a piece of coloured string so as not to measure it twice, measure its diameter at breast height and identify the species of each tree. This is a daunting task, given that there are around 100 trees in each perimeter.
send the data via the Kobo-Collect form
In the first two villages (Linko and Kala), the teams also had to count all trees taller than one metre and measure the height of each tree taller than two metres.
Based on our experience in Samana, we know that this activity is demanding because it requires concentration and precision in a difficult environment (rain, dense trees and bushes). Although we want to stick to our schedule, we do not put too much pressure on the teams in order to guarantee the quality of the measurements. After a period of adjustment, both teams are making very good progress.
It is difficult to define the perimeter of the plot 14.1 metres from the centre due to dense vegetation.
All 290 field-families in Linko received their “carbon revenues” for the first time, according to the distribution key proposed by the cooperative committee and approved by the Cooperative’s General Assembly. It should be noted that this is virtual carbon income, as the project has not yet generated any carbon credits. The amount distributed to beneficiaries is drawn from the project’s pre-financing.
To ensure secure payment, the project offered each of the 290 members of the Linko CR Land Family Cooperative the opportunity to open a bank account with Crédit Rural de Guinée. The project financed the administrative costs of opening these accounts through the CRG’s Kérouané branch.
The payment process went smoothly despite some technical difficulties encountered by Crédit Rural de Guinée (delayed payment from the Central Bank to CRG and IT problems related to the software used to distribute funds to individual accounts).
The Crédit Rural de Guinée team has set up a mobile office in Linko to reduce the distance for beneficiaries.
The share allocated to the villages, as voted at the cooperative’s last general meeting, will be handed over to the authorities of each village very soon in order to promote public utility projects.
After demarcating and seeding plots 2025 during the first half of the year, we need to measure the baseline on a sample, which is done during the second half of the year. This requires several steps:
South Pole calculates the sample size and randomly identifies GPS coordinates
We update the standard operating procedure and train GUIDRE
For each of the 45 plots, GUIDRE’s measurement teams must
find the plot in the given village
install a metal pole in the middle of the plot and secure it with stones
mark this centre with yellow paint
mark the perimeter of the 625 m² circular plot with marking tape
identify all existing trees, mark them with a nail (so they can be found during future measurements), measure their diameter at breast height and their height, and
identify the species of each tree
send the data via the kobo-collect form
The aim of this activity will be, in the future, to deduct this biomass, which is not due to the project, from the biomass generated by the project. Indeed, the project cannot take credit for planting these trees since they were already there. However, from now on, the project must protect these trees, because if they were to disappear, we would have to remove the lost biomass from the tonnes of carbon generated by the project.
This activity began in mid-September and was made difficult by heavy rains.
It is difficult to measure the height of trees due to the density of the vegetation. As it is not possible to use a clinometer, we use a pole combined with a tape measure.
The validation audit in Samana took place from 27 July to 4 August, without any logistical problems and avoiding the increasingly frequent rain showers during this period. It had to be postponed from mid-June to the end of July due to Schneider Electric’s acquisition of EcoAct: Verra had requested changes to the project documents before opening the public consultation period prior to any audit (here are the documents: https://registry.verra.org/app/projectDetail/VCS/4870)
The mission involved 14 people:
The two auditors from Earthood and their interpreter
The two consultants from our partner EcoAct
The Executive Director of GUIDRE and his right-hand man
The director of arboRise
Two drivers
The GUIDRE field team consisting of four supervisors and one forester
Nepolion and Manish, the two auditors from Earthood, visited 15 randomly selected plots in seven villages and interviewed more than 30 people: plot families, seed families, village chief, CGC, president of women’s groups, youth representatives, imam, etc.
Interviews in the villages of Ballacondedou, Kamandou, Sogboro et Sokourala:
The field visits raised few questions: the baseline was deemed acceptable and the growth of the young shoots (sown in 2024) plausible. However, the sometimes implausible responses of those interviewed sparked more discussion. Some beneficiaries, so overwhelmed by this unfamiliar situation, literally panicked as if they were taking an exam. Others had not yet internalised all aspects of the project, which is perfectly normal since we have only been in Samana for 18 months. These hesitant responses may generate as many ‘findings’ on the part of the auditors, but this is the human aspect of any community project.
On a plot of land in Farawanidou with the owner, the GUIDRE team and Margarita from EcoAct:
Due to funding uncertainties, we had to postpone the date of the General Assembly of the Linko Family Land Cooperative from June to the end of July. During this period, Crédit Rural de Guinée visited each of the 290 land-owning families in their respective villages to open bank accounts into which arboRise will pay the first ‘carbon credits’. Unfortunately, the opening of these accounts has raised expectations, and some land-owning families have even gone into debt in anticipation of this payment (without knowing the amount…).
The General Assembly finally took place on 31 July with a high participation, as all the cooperative members were eager to receive their first payment. Their disappointment was as great as their expectations when it had to be explained to them that the payment could not be made immediately after the Assembly, as planned, due to funding delays beyond our control.
A second critical point further exacerbated the irritation: we had agreed with the Cooperative Administration to transfer to them the responsibilities and budget for organising the Assembly, which was not done due to a lack of communication.
This strong collective emotion was justified and predictable. To avoid it, we could have postponed the Assembly a second time and moved it to October after receiving the funding. But we felt it was more trustworthy to personally face the disappointment of our beneficiaries and explain to them in person the reasons for the delay in payment.
Following these lively exchanges, we were able to resume the presentation and calmly explain to everyone how the income would be distributed. The Cooperative Committee’s proposals were unanimously accepted.
We then settled with the five members of the Administration how the 2026 Assembly would be managed.
