Validation audit

audit de validation

We’ve been able to carry out the validation audit of our project 😊 For the South Pole technical team, Nicolò, Tosca and Nele, this is the culmination of a lot of hard work and effort. They are the ones who drew up the Project Description Document submitted to Gold Standard and audited in the field over the last few days. This document describes how our project meets all the requirements of the certification standard.
Before starting the audit, we spent a few days preparing with our partners from South Pole and GUIDRE. Our aim was to make the auditors’ work as easy as possible by planning activities with the villages and preparing the necessary documents. Of course, as before an exam, it was an opportunity to rehearse together the strong points of our project and to anticipate any ‘trick’ questions. But as we all know, it’s not just before an exam that you have to learn: you have to plan well in advance, as we have been doing, conscientiously, for the last three years.

approche à pied  approche en moto
The plots were randomly selected and not very accessible, so the approach was by motorbike and on foot.
a proximité d'un village  le centre d'une placette de mesure
The goal was always the measurement plot, at the centre of a radius of 14.11 m (625 m2) [40 plots for 500 ha].

The two auditors, Kuldeep and Manish, from Earthood, accompanied by their interpreter, arrived in Linko on the evening of Tuesday 10 December and the audit itself took place from the 11th to the 16th. They had previously asked to check 48 project documents, such as lists of training participants, minutes of the stakeholder consultation, etc. On site, Kuldeep, the auditor responsible for forestry aspects, visited 15 randomly selected plots to check the baseline measurements.

On site, Kuldeep, the auditor responsible for forestry aspects, visited 15 randomly selected sites to check the baseline measurements. Manish, responsible for social aspects, interviewed over 50 people (seed families, field families, GSCs, authorities, etc.) in eight villages. Of course, coming from India, he had to translate and answer their countless questions.

Diagnostic de la placette  Audit de la placette
 Mesure de la hauteur au clinomètre
Ama Diallo measures the circumference at chest height and Benoît Lelano measures the height with the clinometer.
 
Both GUIDRE and South Pole have acrobats to measure height with the graduated pole 🙂
 
All interviews with beneficiaries follow a rigorous protocol and are documented.
Together we also presented the project to the authorities of the Damaro sub-prefecture, where we will be expanding our activities from 2025:
Présentation du projet aux chefs de village de Damaro
At the beginning our relationships were relatively formal, but as the stay progressed we were able to create more personal links. It has to be said that we were all living with each other 24 hours a day in a small space, with few moments alone. There was never any tension despite our different origins, languages, religions and genders 😊
 
On the left, our living environment for 5 days. Right: Nicolò and Edouard scale the fish.

So what? Did we pass the exam? Our impression of this validation audit is good. Manish and Kuldeep have reported only minor improvements. We’ll know the result in the next few months. The auditors and Gold Standard have the opportunity to conduct three ‘rounds’ of questions and answers, each lasting around 2 months. The final verdict will therefore come in June at the latest, with very likely requests for improvements to be made to the project between now and the next audits. The purpose of these audits will be to check that the project continues to comply with the rules of the standard and that the dendrometric measurements are carried out in accordance with the state of the art.

But for now, the whole project team deserves a big thank you and a welcome rest.

Create the monitoring plots

Visualiser le centre de la placette

The second half of the year is mainly devoted to establishing monitoring plots on a representative sample of land. These plots will be used to measure tree growth over a 20-year period. Each plot is a circle 14.11 metres in diameter, the center of which must be fixed and the circumference marked out.

fixer le centre de la placette Un rayon de 14,11 mètres

To guarantee representativeness, we estimate that 40 monitoring plots per 500 ha stratum will be sufficient to reduce the uncertainty interval below the target values defined by the standard. The final sample size will be determined according to the heterogeneity of the vegetation in the field. Our partner South Pole randomly determines the location of the plots (on which plots and where in the field). South Pole has also created a digital form that allows the GUIDRE team to send measurement results directly to South Pole.

Coordonnées des placettes Formulaire Kobo

…because it’s not just a question of establishing the plot, but also of carrying out a precise survey (species, circumference, height) of all the existing trees on the plot before we start our activities in 2021.

Numérotation des arbres  Marquage des arbres

In September and until mid-October, the team had to contend with unusually strong thunderstorms for this time of year (confirmed by weather reports and the media: https://quoideneuf.info/article/cote-divoire-les-plus-fortes-quantites-de-pluies-en-aout-ont-ete-enregistrees-a-korhogo-odienne-et-man-sodexam

Motos dans l'eau

How to share the revenues ?

partager les revenus carbone

One of the aims of the Cooperative, and the main role of the Cooperative Committee, is to draw up a key for distributing the carbon revenues. It is certainly not up to arboRise to define how this income will be shared among the cooperative members. This choice must be made by those primarily concerned, in accordance with local traditions and customs.

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

Rather than discuss these criteria in the abstract, we opted for serious games, which are more effective. In practical terms, we used pre-printed tarpaulins with a number of scenarios on them, as in this case, where the aim was to distribute income according to the hazards suffered by the landowners:

bâche préimprimée

Each member of the cooperative committee was given 20 (symbolic) coins representing the project’s carbon revenues and was tasked with dividing them between the 10 situations presented on the tarpaulin, then commenting on his or her choice in front of his or her peers.

le comité coopératif  répartition - verteilung - sharing

As the day progressed, a consensus quickly emerged on the principles for distributing carbon income, for example:

  • Compliance with the cooperative’s rules by each member should be rewarded in proportion to the effort required to comply with each rule. For example, certain ‘costly’ rules (such as the installation of firewalls around the pitches) should be better rewarded than simple rules (such as the installation of tape to mark the pitches).
  • Of course, those who do a great deal to encourage the growth of trees on their plots should be rewarded, but the ‘undeserving’ should also be given a little, otherwise they risk leaving the project.
  • The reward should (very clearly) be for the result (the density and height of the trees on the land) and not for the effort required to achieve this result.
  • External factors (infertility of the land, fires, etc.) should not be regarded as inevitable: it is the responsibility of the landowning family if it has chosen an unfavourable plot of land or if its land has been affected by fires.

Over the following days, we repeated the same exercise in the 26 villages, 2 villages a day, with all the land families in the village and in the presence of the 2 members of the village cooperative committee. The idea was to show the farmer-families the complexity of the Cooperative Committee’s task, and it also made it possible to express out loud what everyone else is thinking: in the end, it will be those who achieve results who receive the most carbon income. Another reassuring lesson is that there are no real differences between the villages: the distribution choices are fairly homogenous.

At the very end of the tarpaulin exercise, we asked each village ‘how much of your carbon revenue would you be prepared to share freely with your village? Most of the participants said they would be willing to share around 10% of their carbon revenue with their community. This would enable the villages to develop their infrastructure (wells, market gardening, health post, school, etc.).

We also spoke to the land families about their opportunity costs. Indeed, if these farmers lend land to be reforested, they are potentially giving up income from their crops. We therefore immersed ourselves with them in the details of hillside rice cultivation to understand every aspect (yields, expenditure, length of crops, fallow periods, etc.).

partage des revenus  qui récompenser

In all, 255 people in the 26 villages, or 88% of all the family plots, took part in this deliberative process. For arboRise, participatory reforestation is not an empty word. It’s essential that everyone has their say so that everyone takes ownership of the project.

Thank you to the Somaha Foundation for helping to make this consultation possible.

fondation Somaha

In our experience, leaders are one of the levers of change in any organisation or social group. And our process also aims to facilitate the emergence of new leaders, legitimised by transparent elections in their village, then at sub-prefectoral level, within the Cooperative. Of course, the current political leaders (sub-prefect, mayor of Linko, village chiefs) are involved in the process. They are delighted with 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.

Elections at the Cooperative

élections - Wahlen - votations

In October last year we founded the Cooperative of the field-families in Linko to manage the new arboRise forests as a common asset (see our report here), and on 9 July 2024 the Cooperative’s General Meeting was held. This year it was a question of electing the organs of the cooperative:

organes de la coopérative de Linko

In preparation for the election of the 26 members of the Comité Coopératif, each village had previously elected two representatives, one man and one woman. At the General Assembly, we simply used a hat in which 14 women’s tickets and 12 men’s tickets were placed. Each village drew a ticket at random and that’s how we ended up with a Cooperative Committee made up of a majority of women, all recognised in their village, and therefore visible at sub-prefecture level.

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In some circles, there is a great deal of self-pity about the condition of African women. For our part, we have observed tangible signs of their influence, which contradict this image of weakness. In one village in the sub-prefecture, for example, the women deposed the village chief, who was reluctant for the village to join the project! Another example: it’s a woman from the village of Booko who heads the brotherhood of hunters for the whole sub-prefecture, an extremely powerful position that implies significant customary powers. Third clue: the fact that a majority of women were required to sit on the cooperative committee was never contested or even debated. To close this parenthesis, here’s some inspiring reading on the subject: L’autre langue des femmes von Léonora Miano.

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…Then we moved on to the election of the 5 members of the Administration. The cooperators from each village first chose the candidate from their village, then the whole room voted by a show of hands for each candidate, and the 5 with the most votes were elected. We are very pleased that Imam Bangaly Condé has been elected Director of Administration. He is well educated, has lived in Côte d’Ivoire for a long time and has been involved in the project in an exemplary way right from the start.

Assemblée Générale de la Coopérative Saidou Marega

The day after the General Meeting, we organised a training session for the 5 members of the administration and the 26 members of the Co-operative Committee and their substitutes to prepare them for their role and responsibilities.

  • For the Administration, it’s simple: they have to manage the budget and organise the next General Meeting (and thus relieve our partner GUIDRE, who has been doing this until now).
  • For the Cooperative Committee, it’s more difficult: they have to mandate the measuring machines to visit and evaluate each plot of land, and then, on the basis of their report, work out a key for distributing the carbon income. It is certainly not up to arboRise to define the criteria for distributing this income. This choice must be made by the people concerned, based on local traditions and customs.

But what criteria should be used to distribute carbon revenues? Find out here.

Dendrometric measurements

Mesure du DBH

How much CO2 does a forest absorb per year in the project area? This is the key question that all reforestation projects must answer in order to obtain certification and attract donors.

The simplest solution is to rely on scientific studies that have measured biomass growth in similar forests. The problem: very few articles on African forests have been published on this subject. Fortunately, the Hérault et al. research team has quantified the growth of several of our project’s tree species in the Korhogo region of Côte d’Ivoire, 400km from our project, over 30 years (The long-term performance of 35 tree species of sudanian West Africa in pure and mixed plantings).

Another, more precise approach is to measure the biomass of mature forests in the project area, and then deduce annual growth. This is what we have done with our partner EcoAct.

Before we can begin, we need to accurately identify the age of the forests to be measured. The objective is to know the average biomass growth per year and per hectare. To do this, EcoAct identified all the 20-year-old forests and all the 10-year-old forests in the Samana sub-prefecture. We then applied a number of additional selection criteria to obtain forests with little degradation and easy access.

sélection des forêts

Thanks to this pre-selection, we were able to identify the GPS points of 5 forests of 10 years and 5 forests of 20 years (knowing that we would only have time to measure four of each category).

On site, it’s not advisable to go into a forest alone, especially if you’re a foreigner. It is more respectful and prudent to make yourself known to the authorities in the nearest village, to explain your intention, receive advice and be accompanied. These discussions can be time-consuming, as there are also many questions about the project, but it’s well worth the effort. The support of the village is crucial.

Then it’s off to the forest. This often requires long approach walks, either in the bush or in the forest. The machete is essential for progress, and it’s best not to have forgotten anything in the vehicle (measuring equipment, raincoat, boots, water, etc.).

Once the GPS point had been reached, we marked out a 30m x 30m perimeter in each forest with tape, so that we knew exactly which trees to include in the measurements and which to exclude because they were outside the 900 m2 perimeter.

We then proceed methodically to make sure we don’t miss any trees. Specifically, one person measures the diameter at breast height, one person measures the height, one person indicates the species and marks the tree, to avoid re-measuring it a second time, and one person records this information. To recognize species, we need to rely on local expertise.

dendrométrie

In the end, we measured over 1,500 trees in six days on 13 plots of land (in addition to the 4 10- and 20-year-old forests, we also measured trees on land to be reforested by arboRise in 2021 and 2022). It’s tedious work and not without risks, sometimes in the rain and in overgrown vegetation, but it’s essential work that will enable us to accurately calculate the biomass, and therefore the carbon, and therefore the potential income from the project, and therefore the possible expenditure.

Thank you Stéphane, thank you Julia for your strong engagement in the field under difficult conditions

This initial overview of the forests has given us some tentative indications:

  • Species diversity depends on the soil: some 20-year-old forests were almost monospecific, with Uapaca Somon dominating, like beech in temperate forests, at the expense of all other species. This should encourage us to carry out targeted thinning to maintain biodiversity.
  • On the sites reforested in 2021 and 2022, there is great variability in terms of density: it can reach more than 4,500 stems per hectare, but some parts of the plots are still bare 2 years after seeding. This is due to the soil.
  • The same 10-15 pioneer species are almost always found, and we can assume that natural regeneration is effective. This should encourage us to focus seed collection on the rare species on our list of 40 species.

Once the data has been collected, the analysis work can begin. Silviculturists and forestry specialists long ago learned how to estimate the volume of a log (a delimbed trunk) when Europe was being deforested to build ships. Basically, it’s a matter of calculating the volume of a cylinder: Pi x radius2 x height. In reality, a trunk is not really cylindrical, but rather conical. And the proportions between diameter and height vary depending on the type of forest (temperate, tropical, boreal, dry, humid, rainforest, etc.). This is why numerous studies have attempted to find the allometric equation that most closely approximates a given forest type. Some even try to include branch volume in the equation. It should be remembered that these equations are fairly reliable for monospecific cash tree plantations, but in natural forests made up of several species this quickly becomes approximate and generally underestimates the forest’s biomass volume.

With our partner EcoAct (thanks Margarita! ), we tested seven allometric equations, specific to tropical forests, and selected the equation whose correlation with the NDVI value of the GPS point was maximum: the equation of Djomo et al. (2010)* which considers diameter and wood density (as we couldn’t measure the height of all trees): B = exp(-1,8623 + 2,4023 ln(D) – 0,3414 ln(p))

* Adrien N. Djomo, Adamou Ibrahima, Joachim Saborowski, Gode Gravenhorst: Allometric equations for biomass estimations in Cameroon and pan moist tropical equations including biomass data from Africa, Forest Ecology and Management 260 (2010) 1873–1885, 2010

équations allométriques

These values indicate the weight of dry biomass. Then remove the weight of all non-carbon atoms (x 0.47), and add the weight of the two oxygen atoms (x 3.67) to obtain the weight of CO2 in the trunks of each hectare. To this, by convention, we add 20% to account for subterranean CO2, present in the roots.

We can thus say that, in the project area, the trees of a forest have absorbed 325 tonnes of CO2 per hectare after 20 years, i.e. 16 tonnes per year.

Since we have values for forests of 2, 3, 10 and 20 years, we can even estimate the growth curve:

courbe de croissance de la biomasse

It should be remembered that we’re dealing here with naturally regenerating forests, some of which have probably been degraded (for example, the biomass of one of the 10-year-old forests is significantly lower than that of the others). However, our garden forest approach should generate more diversified, denser and less degraded stands, with a greater quantity of biomass as a result.

We’ll talk more about this in a few years’ time, when we take the first dendrometric measurements of our forests. And in this regard, perhaps some of you can help us find Terrestrial Laser Scanning equipment, which will enable us to measure exactly the whole of a tree (not just the diameter at chest height and the height), so that we can include the CO2 absorbed by the branches, without going through an allometric equation. Thanks for your help !

Terrestrial Laser Scanning

 

 

Collaboration with the EPFL

I

Which natural and anthropogenic factors influence tree growth on land reforested by arboRise? To find out, we were lucky enough to have our research project selected by EPFL as part of the Design Projects course. In this compulsory course, master’s students in the ENAC department are responsible for providing scientific answers to problems posed by companies, local authorities and others. This applied research represents around 500 hours of work for each pair, so it’s a real scientific analysis, supervised by EPFL professors.

Ines and Aurèle were immediately interested in our project, and we were lucky enough to benefit from their expertise for several months (around 2 days a week for 15 weeks). Thank you Ines, thank you Aurèle! Both are geoscientists, so they know all the tools of satellite analysis inside out. They were supervised by Professor Devis Tuia. Ines and Aurèle’s report is a mine of information. It can be consulted in detail here: 240607_EPFL Design Project – Final Report.

First, they had to divide the land we reforested from 2021 to 2023 into several categories (basically “good” and “bad” land) based on biomass growth since the seeding date and compared to reference “neutral” land. The data comes from the Sentinel 2 satellite, which arboRise has frequently used for its own analyses. Our two researchers chose to focus the analyses on the month of February (2021, 2022, 2023, 2024), at the height of the dry season, to avoid as far as possible the influence of herbaceous plants on the data.

In a second stage, the baseline (the trees present on the land prior to reforestation) was removed from the data, again to avoid any external influence on the project.

arbres matures

Thirdly, a large number of other data – all potential anthropogenic or natural influencing factors – were collected via various satellites: slope, exposure, altitude, soil type, distance to the nearest village, roads, watercourses, bush fires, etc. The correlations between these potential influencing factors enable us to formulate numerous hypotheses and gain a better understanding of our perimeter’s geography. Correlations between these potential influencing factors allow us to formulate numerous hypotheses and better understand the geography of our perimeter. For example:

  • There is a correlation between longitude (West-East) and altitude, and this is normal: the Simandou chain of hills that borders our perimeter to the West is higher than the bed of the Dion River that borders our region to the East, so our region “leans” towards the East.
  • The average slope of our land is therefore logically steeper to the west, close to the Simandou, which is more rugged. It’s therefore normal that the distance between our plots is greater there than in the flatter areas to the east, where it’s easy to group plots together. Logically, roads tend to lie to the east, so the proximity of our lots to roads is greater to the east of the perimeter.
  • We can also see that the nature of the soil changes according to altitude: soils are more clayey in the West and sandier in the East, since runoff flows from West to East.
  • There are also strong, logical correlations between all the factors linked to soil type: nitrogen and organic carbon levels, soil ph, size of fractions and so on.

corrélations

Finally, fourthly, Aurele and Ines statistically measured the degree of influence of each factor on the growth of terrain categories (e.g.: do all “good” terrains rise in altitude more than all “bad” terrains?). Here, only statistically significant influences are presented:

  • First, there’s the influence of soil type. Sandy soils with a ph close to neutral are more conducive to growth. Surprisingly, we would have expected soils richer in clay, which retain water better, to be more favorable. Also surprising is the fact that nitrogen and organic carbon richness tend to be found in “bad” soils, even though these factors generally favor plant growth.
  • Slope clearly has a negative impact on growth, certainly due to rainwater runoff (water stays on the ground for less time, taking nutrients with it), especially on low baseline sites (baseline: the vegetation existing on the site at the time of seeding). This seems logical: vegetation on the site slows down water runoff. It may also be explained by the fact that grazing fires are lit at the bottom of the slopes, which are more likely to climb the slopes than flat terrain.
  • South-facing land is favorable, since the sunlight favors photosynthesis.
  • Proximity to watercourses and fires is negative. Interestingly, only recent fires (2024) have had a visible impact. Fires in 2021, 2022 and 2023 do not stand out as an influencing factor, probably because trees regenerate quickly after being hit by a fire. It is grazing fires in particular (which stimulate the germination of young grass shoots that livestock are fond of), set in the vicinity of watercourses, that sometimes affect reforested land.
  • Interestingly, distance from the nearest village or distance from tracks and paths had no influence on biomass growth.
  • The year of planting also has an impact. This may be due to the arboRise methods, which have been perfected over time, or to the rainfall, which varies from year to year.
  • There seems to be better growth in plots whose seeds are harvested and sown just before the rainy season. Whether this is linked to the species sown in this group or to the wetter period remains unclear.
  • Finally, it seems that young trees grow better where the “baseline” is low. This may be an effect of natural competition: existing vegetation occupies the land, absorbing water and reducing sunlight.

Generally speaking, with the exception of recent fires, it seems that it’s mainly natural factors that influence tree growth. Of course, it is possible to identify villages on whose land trees grow better than in other villages, but this is probably due more to natural factors (soil type, slope, exposure, etc.), as the “unsuitable” villages tend to be located to the west in a hilly area.

These results are therefore very useful in determining the choice of future sites, where slopes should be avoided, especially along watercourses, and land with a lot of existing vegetation should be avoided.

A huge THANK YOU to Aurèle and Ines, who were truly passionate about the subject, and to Devis Tuia, who was kind enough to choose our research project. As with ETHZ, thanks also to EPFL for providing high-quality scientific expertise to organizations such as arboRise.

Mycorrhizae to help our trees

champignons à mycorhizes

In addition to its mission of participative and sustainable reforestation, the arboRise foundation has the statutory objective of “experimenting with natural reforestation methods that enhance biodiversity“. That’s why we asked ourselves how we could use mushrooms to make our trees grow.

We’ve known for several years that trees and fungi interact. In a nutshell:

  • Some fungi link up with tree roots via their mycelium to help each other.
  • Trees provide sugar to fungi in exchange for water and mineral salts
  • Trees that benefit from this grow better

mycorhizes

There are three types of fungi:

Saprophytes

  • Saprophytic (or saprophagous) fungi feed on dead or decomposing organic matter. They play an essential role in the decomposition of dead organic matter, such as leaves, branches and plant debris. By breaking down complex organic matter into simpler compounds, they release nutrients into the soil.
  • Although direct interactions between saprophytic fungi and mycorrhizal fungi are limited, saprophytic fungi contribute to the availability of nutrients, which can benefit mycorrhizal fungi by providing organic substrates. Since saprophytes feed on dead matter, they are not known to attack the seeds of living trees directly.
  • Generally speaking, in cultivated soils, 20% of saprophytes and 80% of bacteria remain. When the field is left fallow, the saprophytic fungi grow and the pathogens disappear. So these saprophytic fungi play an important role in revitalising soil that has been impoverished by cultivation.

Endomycorrhizal fungi

arbres à endomycorhizes

  • Endomycorrhizae generally do not produce sporocarps (what are commonly known as “mushrooms”, visible on the surface, which contain the spores needed for reproduction) and are therefore only present in the soil, around the roots of host plants. To collect inoculum, part of the root of the host tree must be removed.
  • Endomycorrhizal fungi reproduce mainly asexually, producing spores inside the roots of the plants with which they form a symbiosis. These spores, known as arbuscules, are specialised structures that enable the fungus to propagate within the root cells of the host plant.

Natural inoculum is the simplest and least expensive way of achieving mycorrhization, and there is a very simple technique :

  • A few weeks before the start of the rains, fill a sock with rice and bury it under a mature tree of the Parkia, Pterocarpus, Khaya, Prosopis, Erythrophelum, Daniellia, Anogeissus or Adansonia species (there is a high probability that this tree harbours endomycorrhizal fungi in its roots).
  • Dig up the soil after a few weeks: the rice is full of mycorrhizae (white filaments). But be careful: the hyphae of the mycelium are fragile and must not be cut. A hypha isolated from the mycelial network will not survive. So remove the sock and the soil around it
  • Bury this soil sock in the most humid part of the soil in the reforested area, close to the sown seeds. As soon as the seeds germinate, they will bind with the mycelium of the fungus, which will help them to grow.

Ectomycorrhizal fungi

  • Ectomycorrhizal fungi are capable of mobilising and transferring to the host plant nutrients trapped in the soil’s organic matter (carbon, but also nitrogen, particularly that found in chitin). They regulate the balance between CO2 in the atmosphere and the amount of nitrogen in the soil by accelerating or reducing photosynthesis. They inhibit respiration in the soil by micro-organisms, reducing the outflow of carbon from ecosystems. Finally, the litter from ectomycorrhizal trees decomposes slowly due to the presence of secondary compounds that slow down the degradation of organic matter, helping to sequester carbon in the soil. These ectomycorrhizal symbioses therefore play a key role in climate regulation. Ectomycorrhizae also play a major role in the absorption of minerals such as phosphorus and potassium.
  • Ectomycorrhizal fungi are rarer. They tend to be found in the tropical rainforests of the Guinean zone, where they associate with tree species such as Afzelia, Isoberlinia and Uapaca. This is particularly true of Isoberlinia and Uapaca, which grow on poor, leathery soils.
  • In Guinea Forestière, ectomycorrhizal fungi are most often found in the Russula, Amanita and Lactarius genera. Ectomycorrhizal fungi have sporocarps (the fungi visible on the surface of the soil), so it’s easier to harvest their spores!
  • The particular advantage of ectomycorrhizal fungi is their ability to supply organic nitrogen from the soil to the tree.

How can ectomycorrhizal fungi be used?

  • Natural inoculum is the simplest and least expensive way of achieving mycorrhization. It can take the form of soil and humus from old plantations containing ectomycorrhizae, crushed sporophore, spores or excised roots. Inoculation of nurseries with spores has been the most common practice due to the number of spores available from fungi that fruit abundantly in forests and plantations.
  • In practice, roots can be praline-coated with a spore suspension or sprinkled with dry spores. Seeds can also be coated with spores just before sowing.
    • Harvest mature ectomycorrhizal fungi from Afzelia, Isoberlinia or Uapaca forests around May.
    • Look for a dark place, away from light
    • Place 10 mushrooms in each 10-litre bucket of water
    • Crush and mix until you obtain a liquid purée of mushroom flesh full of spores
    • Leave to infuse for 24 hours
    • Add a spoonful of sugar to the solution and stir
    • Soak the tree seeds in the mushroom purée and mix
    • Sow the praline seeds

An interesting observation: Among the 40 species of arboRise trees, the early season species are more likely to use mycorrhizae:

mycorhizes et espèces d'arbres

This is not surprising: January-February is the dry season and March is the hottest month. So it’s very useful for these tree species, which suffer from the climate, to be able to associate with fungi underground that provide them with water in exchange for sugars.

What are we going to test in 2024?

  • The NGO AGIDE in Togo, headed by Mr Kossi Agbalenyo, is a specialist in the use of mycorrhizae in agriculture and reforestation. MYCOTRI, a 100% natural product marketed by AGIDE, contains spores of saprophytic fungi, which we will use to coat our tree seeds. These fungi will decompose the organic matter present in the reforested land and reduce the quantity of bacteria in soil that has been impoverished by cultivation. This will encourage the arrival of ectomycorrhizal and endomycorrhizal fungi, which will promote the growth of our trees.
  • We are going to encourage a few interested land families to test both methods on their fields:
    • grow endomycorrhizal fungi using the sock method
    • grow ectomycorrhizal fungi to make spore mash and soak the seeds in it

mycotri et graines

To find out more :

A book: The ectomycorrhizal fungi of forest trees in West Africa, Amadou Bâ, Robin Duponnois, Moussa Diabaté and Bernard Dreyfus, 2017.

Watch lectures by Marc-André Selosse, a soil microbiologist specialising in mycorrhizae:

Biological Functioning of Soils: https://www.youtube.com/watch?v=DAOdifyrfp4

  • Mycorrhizae and mycorrhizal networks : From 4’47’20 to 5’35’30 (ectomycorrhizae: 4’56”30)
  • Tropical forest diversity and succession: from 5’43’57 to 5’51’46
  • Mycorrhizae and competition between species: 5’53’52 to 6’07’35 (depending on the mix of tree species per village, the results will differ with Mycotri because it will favour certain species which will take advantage over others).
  • Mushrooms are also in the leaves! : 6’24’27 à 6’29’00

Mycorrhization – Mycorrhizae

  • Ectomycorrhizae https://www.youtube.com/watch?v=pmjWysrPyJI
  • Contribution of non-organic minerals by ectomycorrhizae: https://www.youtube.com/watch?v=6KbnCzU9yRM
    • 4’20”: some ectomycorrhizae can provide the tree with mineral resources
    • 8’37”: inoculation difficult only with spores… “mycorrhizal fungi are often found in dead wood because dead wood stores the water that the fungi seek”, “in tropical zones decomposition is strong and endomycorrhizal fungi are sufficient”).
  • Applications https://www.youtube.com/watch?v=pJPze25Vods 6’12” renaturation of agricultural land: reforesting land cultivated with artificial fertilisers is difficult because there are no mycorrhizae left. Mycorrhizae must be added to nursery plants.

Harvesting tree seeds

Récolte de graines avec le bambou

Seed harvesting began in the villages in the second group (you’ll recall that the 26 villages are divided into three groups corresponding to the ripening period of the trees: the first group of villages harvests seeds from trees ripening in January-February, the second group harvests seeds from trees ripening in March-April and the third group harvests seeds from trees ripening in May-June).

The harvesting technique differs depending on the tree species. Here, on the Uapaca Somon, the women use long, light bamboos at the end of which they attach blades to pluck the clusters of seeds from the top of the tree.

Préparation du bambou de récolte Récolte de graines avec le bambou arrachage des grappes de graines de uapaca somon

For other species, the women collect the seeds that have fallen to the ground:

ramassage des graines

All the seed families have been fitted with large tarpaulins to make it easier to collect the seeds (see news item ‘Equipment for the families’). In these images, the harvesters are not using them.

The seeds will then be dried before being taken to the village for counting and mixing.

Equipments for families

équipements

The Guinean families involved in the project are extremely poor. They lack clothes and tools, even for their usual farming activities. In the first year of the project, the participants had asked for a distinctive sign that they belonged to the project, which we provided, although we were sceptical about its real usefulness. In the second year, we provided tarpaulins for the seed families and boots for the field families:

  • The large ARBORISE-GUIDRE tarpaulins are placed under the seed tree to collect the seeds, for the duration of the harvest phase.
    • The tarpaulin makes the seeds clearly visible and facilitates harvesting.
    • Above all, it protects against animals that might hide in the grass or branches under the trees.
    • It also protects against abrasions caused by thorny grasses.
  • ARBORISE-GUIDRE boots protect the lower legs of land families as they move around and work on sowing, clearing and establishing protective strips.

In 2023, following the local stakeholder consultation, we opted for a more detailed approach: each family was given the opportunity, by means of a questionnaire, to choose the individual equipments that would be most useful to them. As you can see below, the choices were mainly for tarpaulins, mackintoshes and boots:

Equipements individuels individual equipments

To foster collaboration and solidarity, we also proposed collective equipments in each village. The seed families, mostly women, opted for fences and the field families, mostly men, chose ploughs:

Equipements collectifs shared equipments

But why did the women choose fences? In most villages, the women work together to set up market-gardening areas where they grow vegetables (onions, aubergines, etc.), each on a small plot, rather like allotments. These market garden areas need to be protected from livestock and wild animals, usually by wooden fences. In tropical regions, this dead wood decomposes very quickly because of the humidity in the rainy season and because of insects. The women therefore have to continually fetch wood to maintain the fence, and this takes up a lot of their time, on top of all the other tasks they have to perform. It’s easy to see why mesh is useful: it’s more durable and saves a lot of time.

Transporting 326 tarpaulins, 160 mackintoshes, 57 pairs of boots, 104 rolls of netting and 25 ploughs is no mean feat, especially on Guinean roads. But the small bus, packed to the rafters, fulfilled its mission perfectly:

chargement des équipements

The equipments arrived in Linko, where it was divided into 26 batches (one for each village):

Déa

In the end, each Community Management Committee received the collective equipment in its village, and each family received the individual equipment it had ordered. We could verify this in the villages of Linko, Kala, Sékamadou and Koyola during our field visit in March.

All in all, our project is helping to make work in the communities safer and less arduous, and to put smiles on people’s faces: