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Invitation to the consultation

For arboRise it is essential to understand the local impact of our reforestation activities. This is why we regularly carry out field surveys (example 1, example 2, example 3). As the Gold Standard carbon certification process shares this concern, we organised a very broad stakeholder consultation in February 2023. This consultation aims to

• Inform about the details of the project and receive feedback from anyone potentially affected by the project
• Exchange views and concerns in a free and transparent manner
• Discuss the benefits, impacts and risks of the project
• Establish a mechanism for ongoing communication and conflict resolution
• Create the basis for close and sustainable collaboration

ArboRise and its partners South Pole and GUIDRE identified the following stakeholders:

• The 250 seed families and 250 land families of the 26 villages participating in the first reforestation cycle
• The authorities and the entire population of the 26 villages, and the members of the Community Management Committee created in each village
• Prefectural authorities (Prefect, Secretary General, Prefectural Director of the Environment, Head of the Water and Forests section, Head of the OGUIB branch)
• Sub-prefectural authorities (Sub-prefect, Mayor of the Linko Rural Commune, Vice-Mayors, Secretary General, District President, Imam of Linko, Sotikomo of Linko, Chief of the Linko Forestry Unit)
• The national authorities of the Ministry of the Environment and Sustainable Development (Minister, Advisor in charge of sustainable development, Guinea National Designated Authority – Green Climate Fund, National Director of Water and Forests (DNEF), Head of Land Use Planning, DNEF)
• Employees of our partner GUIDRE
• Experts and consultancies: International Union for Conservation of Nature (IUCN), WWF, FairTrade Africa, Biotope Guinée

To enable all interested people to participate, more than 700 personalised invitation letters were sent out 30 days before the start of the consultation, with essential logistical support from our partner GUIDRE. To include illiterate people as well, the invitation was broadcast on the local radio in Kérouané for five days in the morning and evening.

In order for each guest to be prepared, the invitation contained

• a description of the project
• the Sustainable Development Goals targeted by the project
  • SDG 4: Quality education
  • SDG 8: Decent work
  • SDG 13: Climate action
  • SDG 15: Life on earth (biodiversity)
• all potential risks of the project according to the Gold Standard principles, as well as the measures planned to mitigate each specific risk:
  • Principle 1. Human rights
  • Principle 2. Equality between men and women
  • Principle 3. Health, safety and working conditions of the community
  • Principle 4.1 Cultural and historical heritage sites
  • Principle 4.2. Forced evictions and displacement
  • Principle 4.3 Land tenure and other rights
  • Principle 4.4 Indigenous Peoples
  • Principle 5. Corruption
  • Principle 6.1 Labour rights
  • Principle 6.2 Negative Economic Consequences
  • Principle 7.1 Emissions
  • Principle 7.2 Energy supply
  • Principle 8.1 Impact on natural water patterns/flows
  • Principle 8.2 Erosion and/or instability of water bodies
  • Principle 9.1 Landscape and Soil Modification
  • Principle 9.10 Areas of High Conservation Value and Critical Habitats
  • Principle 9.11 Endangered Species
  • Principle 9.2 Vulnerability to natural disasters
  • Principle 9.3 Genetic Resources
  • Principle 9.4 Discharge of Pollutants
  • Principle 9.5 Hazardous and Non-Hazardous Waste
  • Principle 9.6 Pesticides and fertilizers
  • Principle 9.7 Harvesting of forests
  • Principle 9.8 Food
    Principle 9.9 Livestock

The correct receipt of invitations was confirmed by tallying:

ArboRise is proud to announce a strategic partnership with South Pole, a global leader in carbon reduction projects and strategies. South Pole develops and finances climate projects around the world (over 700 projects to date) to reduce carbon emissions, protect biodiversity and help the most vulnerable local communities adapt to climate change.

Under the Emission Reduction Partnership Agreement signed with South Pole, arboRise will benefit from

• South Pole’s technical expertise to obtain carbon certification of our approach
• South Pole’s resources to market the carbon credits generated by our reforestation campaigns
• Pre-financing in the form of a loan to cover the costs of the planting phase

As a reminder, arboRise and the field-families make a mutual commitment over a 20-year period. Only the income from carbon credits will guarantee a fair remuneration for these families who commit their land to our project.

And only a carbon certification will guarantee to our donors

• that the reforestation has actually been implemented (real)
• that the reforestation would not have taken place without the project (additional)
• that real biomass growth can be measured against a baseline, taking into account uncertainties and risks of leakage (e.g. if the project induces deforestation in other locations) (measurable)
• that an external auditor from an accredited organisation has audited the project (verifiable)
• that the sequestered carbon will be retained for 100 years (permanent)
• That the sequestered carbon is only counted once (unique)

The agreement with South Pole is an essential step in making the project sustainable and ensuring its long-term economic viability.

A major step in the arboRise adventure was taken yesterday evening, 12 December, at the extraordinary general meeting of our association. following the committee’s proposal, the general assembly voted unanimously the dissolution of the association and transform it into an arboRise foundation.

Why ?

Reforestation is an activity that naturally takes time. Consequently, arboRise is committed to long-term partnerships:

1. In particular with the field families, the agreements extend over a period of 20 years. Following our on-site surveys, we are convinced that only the income from carbon credits will guarantee a fair remuneration for the Guinean families who commit their land to our project.
2. For our donors, only a carbon certification will guarantee them
   • that the reforestation has actually been implemented (real)
   • that the reforestation would not have taken place without the project (additional)
   • that real biomass growth can be measured against a baseline (initial measurement), taking into account uncertainties and risks of leakage (e.g. if the project induces deforestation in other locations) (measurable)
   • that an external auditor from an accredited organisation has audited the project (verifiable)
   • that the sequestered carbon will be retained for 100 years (permanent)
   • That the sequestered carbon is only counted once (unique)
3. The agreement with the company that will accompany us in the certification process will have a minimum duration of 10 years

How can we ensure the sustainability of our partnerships?

Stability is needed to work in continuity. Experience shows that associations are generally more fragile than other structures, such as foundations, whose statutes and governance are more stable. This is why the committee proposed yesterday to the extraordinary general assembly of 12 December 2022 to transform arboRise into a public utility foundation. This implies the dissolution of the association and the transfer of its assets to an arboRise Foundation, with the same statutory objectives as the association.

In all likelihood arboRise will have to manage large amounts of money, so it is necessary to ensure that these resources are used wisely. The Federal Supervisory Authority for Foundations will provide this security by checking that the funds are used in accordance with the statutory purposes. Such control is not mandatory for an association.

Finally, a foundation is a guarantee of seriousness that will facilitate fundraising.

The formal vote necessary for the dissolution of the association and its transformation into a foundation was submitted yesterday evening to the General Assembly, which unanimously approved the committee’s proposal by the 15 members present. The committee has been mandated to implement this transformation, planned for the beginning of 2023.

Our warmest thanks to all members for the trust you have placed in us and for your faithful support during these 27 months of associative life. Together we have achieved strong results. And this is only the beginning!

As it is extremely time-consuming to visit each of the 650 hectares restored by arboRise to assess the health of the new forests, we sought to measure tree growth remotely. But how to do this? NDVI sentinel 2 is the answer!

The European Union’s Sentinel II satellite takes an infrared photograph of the earth’s soil every 5 days with a resolution of 10m (1 pixel: 10m x 10m = 100m2). The data provide many indications about a region, such as humidity/aridity, the presence of fires, and also the nature of the vegetation. An important advantage is that the data is available free of charge (see Sentinel Playground).

The value we are interested in is the “NDVI” (Normalized Difference Vegetation Index) which corresponds to the rate of vegetation cover on the ground, a good index of the quantity of biomass, therefore an index of the quantity of trees (forests appear clearly on the maps with a darker shade of green).

For each reforested area, the NDVI value (= shade of green) of each pixel is extracted and the median value, the biomass of the area, is calculated:

For each reforested plot, we then calculate the median NDVI value of the “background”, an area of 2km side around the plot (by subtracting the NDVI of the plots present in the background):

On the basis of the Sentinell II cloud cover index, we then eliminate all values with a probable cloud cover of more than 90% (the purple spots on the image below):

For each available day of data (75 per year) and for each plot, we obtain

• The median NDVI of the plot
• The cloud cover over the plot for that day
• The median NDVI of the background
• The background cloud cover for that day

…44815 lines for the period from January 1, 2021 to November 22, 2022…

The graph below represents the NDVI values for 2021 and 2022 over a year. The values of the days where the median background cloudiness on one or more fields was above 90% have been removed:

It can be seen that the NDVI in 2022 is lower than the NDVI 2021 (yellow and green lines below the red and blue lines). At this stage three hypotheses are possible:

1. It may be a change in the calibration of the satellite or the measurement (but this is unlikely) and this change should then apply uniformly to all 2022 measurements, but the NDVI of the Background decreases significantly more (-0.19) than the NDVI of the Polygons (-0.16)
2. 2022 may have been drier than 2021, but this is not confirmed by the local population, who say that 2022 was rainier
3. There were more fires and deforestation in 2022…

The reason for this change needs to be investigated. For the time being, annual comparisons should be interpreted with caution.

On the other hand, the effect of the rainy season can be clearly seen:

• A progressive increase in biomass from February to August
• A significant cloud cover between June and October (less data for this period because of clouds)

Great news: In 2021 the polygons (arboRise plots) have an average NDVI 5.2% lower than the background NDVI (normal, arboRise reforests bare land), but in 2022 the NDVI of the polygons is 3% higher than the background NDVI! And there is a positive growth in the difference between the biomass of the reforested plots and the biomass of the background, which means that the biomass on the arboRise plots is growing faster than in the surrounding area:

For the reforested areas in 2021, two years of data are available and can be compared: NDVI sentinel 2

The visualization on this graph allows to identify the “good plots” (top right) from the “bad plots” (bottom left):

It can be seen that the majority of the plots are located in the upper right part of the graph, which is excellent news!

But how well does this satellite analysis match reality? We went to see on the spot what it was like for plots ID03 and ID09.

For the “bad” field n°3, we observe a depleted soil following several years of cultivation. Situated between two hills, it is probably an area where cattle used to transhumance towards a watering place (visible dung). The trampling makes it difficult for the vegetation to grow. However, small shrubs of 1.5m are visible and 4 remnants of trees are completely dry. No sign of fire. This low biomass in the field validates the satellite measurement of NDVI

As for plot 9, it is impossible to enter without a machete because the vegetation is so dense, especially the 3m high grasses. We can see several shrubs of about 2m and 3-4 trees of 8m. The land has obviously not been grazed or burnt. This higher biomass in the field validates the satellite NDVI measurement.

In conclusion, the field observations are consistent with the satellite measurements of biomass. It will of course be necessary to confirm this correlation with other examples.

With the help of these indices provided by the Sentinel II satellite, we will be able to target our visits to areas of high growth, to learn from them and to share these good practices with the owners of the land, whose satellite images indicate that they are less wooded. This will serve as case studies for the training of land families and Community Management Committees.

We also hope to inspire other reforestation projects to use this same technique to assess biomass growth on their plots and become more efficient.

A huge THANK YOU to Sergiy for his expertise in GIS and NDVI sentinel 2 data analysis and his valuable advice!

What a pleasure to celebrate with Natascha, Thaís, Tiago and Faisal the presentation of their “When Forests Meet Finance” case study to the Executive MBA (IMD EMBA) management of the ‘Institut for Management Development in Lausanne! All four of them are following this very demanding management course and have become passionate about arboRise’s activities in recent months.

Karl Schmedders, Professor of Finance at IMD, was interested in the situation of arboRise, which is fascinating from an economic point of view. How can an NGO active in reforestation be made profitable? What are the stakes in the carbon markets? How to reconcile the interests of investors and those of the Guinean families who make their land available for reforestation?

Convinced of the pedagogical potential of this case study, Karl proposed to our four students to make it the subject of their Strategic Consulting Project. This is an in-depth analysis of the context of a client – arboRise – to recommend one or more strategic options to ensure its future success.

The exchange with Natascha, Thaís, Tiago and Faisal was fascinating. None of them knew anything about reforestation, the rules of the carbon markets, let alone the situation of Guinean farmers. They learned a lot and applied IMD’s methods to modelize arboRise economic situation. From arboRise’s point of view, their questions and suggestions also contributed greatly to our understanding of the subject.

In the end, their recommendations are in line with our intention to finance our reforestation efforts on the carbon markets, either by offering carbon credits directly to companies or through a reseller. We also agree that these revenues should mainly benefit Guinean families who decide to reforest some of their plots.

It seems that this analysis even has the potential to become a real case study, taught at IMD.

Thanks to Natascha, Thaís, Tiago and Faisal for their great commitment and our friendly exchange (and good luck with their IMD EMBA!) and thanks to Karl Schmedders and IMD for this great opportunity to make the challenges of arboRise visible!

Final results of the field experiment

As a reminder (see publications of 15 August and 15 September), our scientific experiment, funded by the Research Challenge of ETH for Development, aimed to measure the impact of seed coating on the germination rate. What were our findings?

Out of 40 selected forest species, seeds of 26 species could be harvested. The remaining 14 species could not be identified in time. A first shoot count took place in mid-July. This was followed by a second verification count in mid-August. These counts were made difficult by the abundance of weeds present in the field. This explains certain inconsistencies, indicated in red in the table below:

Of the 26 species in the experiment, 17 (65%) had already germinated two months, respectively three months, after sowing. The correlation between the maximum germination rate per species obtained in the experiment and the theoretical germination rate according to scientific sources is 68%. On average the maximum germination rate per species in the experiment reaches 54%, while their theoretical germination rate is 69%.

Before analysing the impact of the seedballs technique we wanted to understand why eight species have a germination rate at least 30% lower than the theoretical rate. What could be the reasons for this?

• Parkia biglobosa (68% vs 99%): the physical dormancy of its seeds is important and it is possible that our pre-treatment was not sufficient to lift this dormancy or that germination is simply slower for this species.
• Carapa procera (35% vs. 80%): the seeds of this species are recalcitrant. It is likely that some have dried out before sowing and thus lost their germination capacity.
• Syzygium guinéense spp (0% vs. 80%): The seeds, also recalcitrant, should be sown immediately after harvesting the fruit according to Prota4U, as they may spoil within 24 hours of storage. In this case too, the seeds may have waited too long before being sown.
• Prosopis africana (0% vs. 70%): “The results show a high production of seeds, most of which are either attacked or rotten. Despite the existence of integumentary dormancy, Prosopis africana seeds are able to germinate in situ in the absence of fire and livestock, but with a fairly long lag time”[1]. To avoid seed rotting under the seed tree, harvesting on tarpaulin might have been necessary.
• Pterocarpus erinaceus (0% vs. 50%): Physiological dormancy is low and it is surprising that the treatment was not sufficient to lift it, especially as germination should start 6-10 days after sowing according to Prota4U. Perhaps the seed quality was poor?
• Tectona grandis (0% vs 30%): According to Prota4U: “The teak ‘seed’ is actually a fruit that can contain up to four true seeds. […] Generally, there are one to two viable seeds per fruit, but sometimes the fruits are sterile. Germination of the same batch of seeds can start after about ten days and end after several years; the optimum germination time is about 35-45 days. Dormancy is difficult to lift and no really reliable technique has been developed. [To promote germination, the seeds should not be completely buried and should not be shaded. It is possible that the seeds were sown too deep in the soil and that the pelleting impaired germination.
• Vitex doniana (0% vs. 34%): According to Prota4U, untreated fruit can take a long time to germinate and it is possible that fire accelerates germination. Indeed, physiological dormancy is important and the intensity of treatment we applied was probably not sufficient.
• Terminalia Glaucescens (0% vs. 30%): It is possible that the seeds of this species are recalcitrant. In addition its physiological dormancy is important.

This short analysis allows two conclusions:

1. The seedball manufacturing process, which requires a period of seed storage, has a negative impact on the germination rate of the recalcitrant species: of the 6 recalcitrant species among the 26, 3 species (50%) have a significantly lower germination rate than normal, in our experiment.
2. On the other hand, dormancy has little influence on the germination rate when using the seedball method: of the 12 species that require an intense treatment to lift dormancy, 7 species germinated normally. Of the 14 species that require only a moderate treatment to break dormancy, 3 species germinated poorly.

 

Contrary to the hypothesis that anemochorous, barochorous and autochorous species should be better adapted to direct-seeding and seedball protection, the results show no significant relationship between seed propagation type and germination in direct seeding:

• 6 out of 8 anemochorous species germinated (75%)
• 10 out of 15 zoochorous species germinated (66%)
• 1 out of 3 barochore species germinated (33%)

 

Regarding the treatments applied, the no treatment (group C) and the T1 treatment (soaking) produced the best results on average, for both counts.

For eight of the 17 species that germinated, no treatment produced the best results in both counts. For six other species no treatment was superior in one of the two counts. Only 3 species preferred treatments, but in 2 cases it was soaking (which is anyway provided at the rainy season). Only one species, Lophira lanceolata, benefited from coating, in one of the two counts.

Hence it seems possible to conclude that, under the climatic and ecosystemic conditions of Linko, for the above species except for Lophira lanceolata, Vitellaria paradoxa and Afzelia africana, the absence of treatment leads to a better germination rate. Contrary to our main hypothesis, seed coating (seedball method) has a lesser or even counterproductive impact on germination rate. Burying the seeds untreated in small holes seems to be sufficient to protect them from birds, rodents and pests.

This is a major learning for the arboRise project: giving up seed coating will significantly simplify the planting process. In addition, the resources allocated to pelleting can be used to double the quantity of seeds harvested and thus reach a density of 10,000 seeds per hectare, or 1 seed per m2.

The survival rate on the experimental plot will be measured one year after sowing, in May 2023. Afterwards, the plants that have survived on the experimental plot will be used to collect cuttings, which will be useful for enriching the fields reforested by arboRise.

 

[1] Niang Diop F., Sambou B., Lykke A. M. : Contraintes de régénération naturelle de Prosopis africana : facteurs affectant la germination des graines, International Journal of Biological and Chemical Sciences, 2010, p. 1693-1705. file:///C:/Users/phili/Downloads/65578-Article%20Text-130554-1-10-20110415%20(1).pdf

Is planting trees in direct sowing possible in Switzerland? This is what we wanted to find out in the context of the “anything is possible” operation that we initiated in December 2021. Remember: as in Guinea, we were looking for several “field families” interested in making a plot of land available for reforestation, and several “seed families” ready to collect forest seeds to spread them on these plots.

After the formation of the groups and numerous exchanges throughout the year, to study the plots of land made available, to take into account the expectations of their owners, and to establish a procedure for the harvesting of seeds, the harvests could start in September. Each “seed family” was responsible for collecting the seeds of the tree species chosen for a specific plot.

And we all got together on Saturday 29 October to scatter all the seeds on the Herbolaria field in La Rippe!

Marking the reforested area was our first step, to prevent the young plants from being inadvertently cut down during agricultural work. We visualised the outer boundary of the reforested area with a light barrier for 80 metres. The aim was to create a protective forest hedge about one metre wide on the northern part of the land.

Then the actual sowing could begin: everyone took one or more species of seeds and a small scraper. To avoid predation by birds, each seed was sown in a small hole and then covered with soil. Fortunately, the soil had been freshly ploughed, which greatly facilitated the swarming! We had about 600 Byzantine hazelnut trees, 300 holly seeds, 200 elder seeds, 150 chestnuts, 50 walnuts, 400 acorns, 200 maple samaras, and a mixture of 400 peach and apricot pits. So about 2300 seeds to be distributed in 4 parallel lines along the 80 metre long northern edge of the field. Quite a job! Fortunately, the weather was very pleasant and the atmosphere friendly.

After planting trees it was great to regain our strengths over a succulent pumpkin soup!

Many thanks to Odile, Anne, Garance, Chantal and Philippe for your energy and stamina during this memorable day. See you in spring 2023 to admire the first shoots and measure the impact of the semi-direct!

ArboRise wins 3rd place at the “Prix Diaspora” of the Fedevaco !  

The Diaspora and Development Prize is an initiative of the Federation of Cooperation of the Canton de Vaud, which aims to promote the involvement of the canton’s diasporas in the development of their countries of origin. Through this award, which takes place every two years, Fedevaco aims to increase the impact of diasporas in their home and host countries and to strengthen their position as actors of cooperation and sustainable development.

Since our vice-president, Mariame Camara, is originally from Guinea, it seemed relevant to us that arboRise submitted her application, which was accepted by Fedevaco (see the publication of 20 October 2021). We were thus able to follow the seven high-quality training modules and develop our development project in parallel, of which the following is a summary (the document is available on request):

In sub-Saharan Africa most urban families use charcoal for cooking. The nuisance for them is high and the recurring costs are high as well. On a global level, turning trees into charcoal is a major deforestation factor and increases global warming.

As an alternative, we recommend biogas, which works like a cow’s stomach: vegetable waste is introduced into a sealed tank – the biodigester – which converts it into methane, which is used for cooking instead of coal. The liquid that remains – the digestate – is an excellent fertiliser, also useful for fish farming. A few kilos of waste per day make a family self-sufficient. This saves them the cost of buying bags of charcoal, which represent about 10% of their annual expenses.

Our project aims to develop a small domestic biodigester production unit in Conakry with a technician trained in Burkina Faso, to sell this equipment to families on the outskirts of the city, who cook in an open yard and have access to vegetable waste. The production of a biodigester costs CHF 125/piece and will be totally made in Guinea.

A demonstrator will present the advantages of our solution at meetings of women’s associations in each neighbourhood. After two weeks of testing, each interested housewife will be able to purchase the biodigester with a system of staggered payments. In 18 months she will be the owner and will then save the cost of buying coal.

In addition to recycling vegetable waste (offcuts from market gardening), our technique will also provide organic fertiliser to farmers on the outskirts of Conakry, while reducing deforestation.

We are starting this year with a pilot phase to check the feasibility and feel the reaction of the market. We need CHF 6’000 to pre-finance the first 50 biodigesters. 

 

Competing in the category of social economy projects, our domestic biodigester project was chosen by the Diaspora Prize Jury for its simplicity and ecological contribution.

 

This distinction honours us and we warmly thank Fedevaco for the organisation of this Prize. In addition to the lessons learnt from the training course, it also allowed us to meet some really great people. The passion and commitment of all 14 project leaders must be acknowledged here. Congratulations also to the other 3 winners!

 

Preliminary results of our scientific experiment (see publication of 15 August 2022)

Organising the harvest of forest seeds requires knowledge of the fruiting periods of each species. We recommend establishing a harvesting schedule according to the model in the table below, which is the result of our field surveys, combined with online resources  [1]. The ideal harvest periods are shown in green (orange: possible start and end of harvest). They correspond to the ecosystem and climatic conditions in the Linko sub-prefecture. This overview of maturity periods allowed us to form three groups of species, to increase harvesting efficiency.

To optimise the germination rate with the method of direct seeding of seedballs, we then analysed four characteristics of our 40 species: seed dormancy and dormancy-breaking pre-treatments [2], seed propagation mode, seed weight and desiccation tolerance.

As dormancy can have an impact on the germination rate, we identified the type of dormancy  [3] of each species according to the scientific literature  [4]. Then, to determine the type of pre-treatment to be administered to each species to lift the dormancy, we consulted the practical recommendations of the Centre National de Semences Forestières de Ouagadougou, which is an authority on the topic in West Africa. One may note the little congruence between the scientific source and the experience of practitioners.

In the graph below, which represents the 40 species sorted by seed maturity period and the level of pre-treatment intensity recommended by practitioners, it can be seen (red dotted line) that species maturing in the dry season (November-April, on the left of the graph) need pre-treatment to lift their dormancy more often than those maturing before the rains arrive. The 17 dry season species have a pre-treatment intensity of 4.8, while the 23 wet season species have an intensity of 2.9. This seems logical since dry season germination would result in a high mortality rate for the seeds of these early species, which is why they more frequently have dormancy mechanisms.

In our experiment, we applied the required pre-treatments to test groups 1 and 3 to measure the impact of dormancy and of its lifting on germination rates. Our hypothesis was that coating could inhibit dormancy breakage (for physically dormant species) or delay it (for physiologically dormant species).

The seed propagation mode, in the table below, confirms our observation that species adopt different reproductive strategies, depending on whether they mature in the dry season or in the rainy season: in the group of 17 dry season species 7 species are anemochorous and 6 species are zoochorous, while the proportion of zoochorous is significantly higher among species that mature in the wet season:

	Anemochorous	Zoochorous	Barochorous	Autochorous
Maturity in dry season	41%	35%	18%	6%
Maturity in the rainy season	22%	61%	9%	8%

It seems that dry season species rely more on natural elements (wind, gravity) for their dissemination. By contrast, rainy season species tend to use animals, perhaps because the latter, protected by the vegetation cover of the wet season, travel greater distances at this time of year. This zoochorous propagation of half of the 40 species selected by arboRise could, in the long term, naturally strengthen arboRise’s reforestation action (especially as the arboRise project aims, in the long term, to establish a forest corridor favouring the movement of fauna between the Haut-Niger national park in Guinea and the Comoé national park in Côte d’Ivoire).

The number of seeds per kilo, and therefore the average weight per seed, is not surprising: seeds spread by wind (anemochores) and self-propelled by explosion (autochores) are the lightest, whereas seeds spread by fauna (zoochores) or gravity (barochores) are the heaviest on average:

	Anemochorous	Zoochorous	Barochorous	Autochorous
Number of seeds by kilo	7600	2470 [5]	3410	10833
Average weight of one seed	0,13 gr	0,40 gr	0,29 gr	0,09 gr

The weight per seed also matters in terms of the process of making seedballs, since heavy seeds are easier to handle.

 

More fundamentally, these observations raise several subsidiary questions:

• Which types of seeds are most suitable for direct sowing? It could be hypothesised (2) that anemochorous, barochorous and autochorous species, which are naturally propagated by wind, gravity or explosion, are better suited to the semi-direct, than zoochorous species which sometimes require passage through the intestinal transit of the animal carrying them.
• Which type of seed benefits most from being coated in clay and charcoal pellets? Here we can hypothesise (3) that coating is detrimental to physically dormant zoochorous species, which are intended to be swallowed and excreted, whereas other species are most often consumed and would benefit more from the protection of a pellet.

Our publication of 30 October will answer these questions and present all the final results of the experiment !

 

[1] https://www.prota4u.org/database/ ; https://worldagroforestry.org/ ; https://tropical.theferns.info/

[2] According to the guidelines of the Centre National de Semences Forestières in Ouagadougou

[3] Legend : ND = non dormant ; PD = physiological dormancy ; MPD = morphological dormancy ; PY = physical dormancy 

[4] Baskin C., Baskin J: Seeds – Ecology, Biogeography, and, Evolution of Dormancy and Germination 2nd Edition, Academic Press, 2014.

[5] 2470 seeds on average, if we exclude two exceptions: Milicia excelsea (475’000 seeds per kilo) and Ficus vallis-choudae (100’000 seeds per kilo)

Reforestation is one of the main ways to fight global warming. To be sustainable, reforestation projects must meet the needs of local communities and work with – not against – nature. And to be cost-effective, they must use local resources – especially seeds – and minimise the complexity of the reforestation process. Direct seeding with seed pellets is a solution that meets both these requirements. How big is the germination rate with seedballs? We were curious to understand this question.

For tropical species, the average germination rate under direct seeding is 38% and the establishment rate is 17% [1]. Establishment performance can be improved by protecting the seeds from natural predators. This is done with the seedball technique [2]. Coating seeds with a natural mixture of clay and charcoal can prevent up to 30% of losses to rodents, birds and pests. Seedballs are currently used in reforestation in Kenya and Ivory Coast [3], but the performance of the seed ball technique has never been scientifically measured for African tree species. Most scientific experiments [4] involving seedballs target crops such as wheat, etc., and not trees. With the support of the Research Challenge of ETH for Development, we wanted to fill this scientific gap by comparing the germination rate with and without the seedball technique. Indeed, according to our statutes, arboRise’s mission is “to experiment with natural reforestation methods that enhance biodiversity and to share the results of these experiments“.

Experimentation method

The objective is to verify the validity of hypothesis (1), according to which the seedball method [5] has a positive impact on the germination rate of 40 tropical forest species in the Linko region of Guinea. The impact of a pre-treatment to lift dormancy will also be evaluated.

The field experiment was conducted by our local partner, the NGO GUIDRE (Guinée Développement Rural et Environnement) in Faranah. Mr Pépé Philippe Kpogomou, an agricultural engineer and Prefectural Director of the Environment, Water and Forests in Kérouané and then in Faranah, supervised all the work and implementation.

The experiment was structured as follows:

• An experimental area of about 1 hectare was identified in Linko, cleared, and then surrounded by a 220m fence to prevent livestock from grazing on the shoots

• At the end of the harvest in each group of villages, 800 seeds of each species were collected. The seeds from the first and second groups were stored in sealed plastic bags until the seeds from the third group were harvested. Then all seeds were brought to Linko for pre-treatment.
• To compare the germination rate, from 11 to 13 May 2022, the 800 seeds per species were treated as follows:
  • Control group: 200 seeds of each of the 40 species, without any pre-treatment or coating (“naked” seeds)
  • Test Group 1: 200 seeds of each of the 40 species, with pre-treatment to break dormancy [6]
  • Test Group 2: 200 seeds of each of the 40 species, without any pre-treatment but with a clay/charcoal coating
  • Test Group 3: 200 seeds of each of the 40 species, with pre-treatment to break dormancy and with a clay/charcoal coating

• Then, on 14 May 2022, the groups of 200 seeds were sown with a line and a row spacing of 25cm between each seed and 50cm between each row. Each block of one species is separated from the block of the next species by 50cm. Each block is identified by a separate sign.

• The germination rate of each line was measured (shoots were counted) once on 18-19 July 2022 and again on 15-16 August 2022.

The results of the experiment are currently being analysed and will be published shortly. Thanks to ETH4D for its financial support and to the entire GUIDRE team for its ability to meet the challenges of the field!

 

[1] NurseryToForest Solutions; Grossnickle, S.; Ivetić, V.; University of Belgrade – Faculty of Forestry Direct Seeding in Reforestation – A Field Performance Review. REFOR 2017, 94–142, doi:10.21750/REFOR.4.07.46.

[2] Madsen, M.D.; Davies, K.W.; Boyd, C.S.; Kerby, J.D.; Svejcar, T.J. Emerging Seed Enhancement Technologies for Overcoming Barriers to Restoration: Emerging Seed Enhancement Technologies. Restor Ecol 2016, 24, S77–S84, doi:10.1111/rec.12332.

[3] www.seedballskenya.com , http://www.seedballsci.com/

[4] Gornish, E.; Arnold, H.; Fehmi, J. Review of Seed Pelletizing Strategies for Arid Land Restoration. Restor Ecol 2019, 27, 1206–1211, doi:10.1111/rec.13045.

[5] https://en.wikipedia.org/wiki/Seed_ball

[6] According to the guidelines in the catalogue de semences of the Centre National de Semences Forestières in Ouagadougou.