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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.

 

arboRise presents the film “Kamsé’s Perimeter” to fuel the discussion about reforestation projects.

In the context of climate change, the news is often depressing and there are many preconceived ideas:

• …about reforestation: it would not be sustainable, it would be greenwashing, it would harm local populations, etc.
• …about Africa as well: belief in the impossibility of setting up projects, negative prejudices about the African mentality, idealization of the African peasant, etc.

It is all the more important to talk about projects that work, to correct prejudices. This is why arboRise wanted to share “le périmètre de Kamsé“, a film by Olivier Zuchuat, a Swiss director from the French-speaking part of Switzerland, with the audience of La Ferme des Tilleul. This documentary film shows an image that is quite close to the reality that we also observe in Guinea. We see a form of popular uprising for reforestation, and at arboRISE the uprising speaks to us.

At the end of the evening, with an audience transported into the Sahelian reality, we can retain that there are reforestation projects that work in Africa, each adapted to its context. There is no need for immense means to finance the initial impulse and create a virtuous circle. This is what arboRise has demonstrated since 2021.

Since the implementation of our project in the Linko region is going well, we are considering extending our project to the neighbouring Beyla Prefecture. We are therefore starting a two-day prospection to check that the social and environmental conditions are similar to those in the Linko sub-prefecture and that our method can be applied there in the same way.

Our exploration will take us to the capital of the sub-prefecture of Karala. On this map, we can see the Ivorian border to the north-east, but even without obstacles, we can easily triple the time indicated by Google Maps:

But our route is full of pitfalls, starting with a tree trunk across the road, following the violent storm of the previous night:

 

Then we cross the Dion river, a tributary of the Niger river.

Then, just before nightfall, our vehicle refuses to continue, and this in the middle of the bush! A mechanic and an electrician have to be brought in from Samana (35 km away) to find the cause of the breakdown. These two gentlemen are not only examples of customer orientation but also true repair artists!

…Just after leaving, this is what we find 20 km from our destination:

..fortunately, it was possible to ford the river, and we arrive in Karala at about 11 pm.

Hospitality is not an empty word in Guinea as the Mayor, whom we probably woke up, immediately opens the town’s Maison d’Accueil for us for the night, where rooms, which can be described as luxurious, await us.

The next morning we explained our approach and the arboRise method to the Sub-Prefect, the Mayor and the head of Water and Forests of the Karala sub-prefecture, who undertook to provide us with a list of potentially interested villages.

The return from the borders of Guinea (Karala is 50km from the Ivorian border) went well and confirmed the suitability of this region for our project (same types of trees, same development conditions, etc.). We can now plan a more detailed concept.

Just before Linko, a shock absorber breaks and the women farmers who were ploughing the next field come to shake our hands, long live the Guinean kindness!

It is on this fraternal image that our prospection mission ends.

After the seeds have been coated, when the pellets are dry, you can start direct seeding.

To be more efficient, this activity is done in groups: everyone stands on one side of the field to be planted, in two lines with a space of two metres between each person. The people in the first line each make a small hole in front of them with the hoe, then take two large steps forward and repeat the operation. The people in the back line then place a seedball in each hole and take two large steps forward to the next hole. And so on to the other end of the field.

In this way a density of 5000 diverse seedballs per hectare is achieved, of which about 60% will germinate during the rainy season. Spot seeding eliminates weeds around the sapling and facilitates root penetration into the soil. It also prevents the pellet from rolling off the field when a heavy rainfall falls.

Direct seeding makes it easy for the whole population to participate and creates a collective enthusiasm that motivates everyone.

Today, we visited 7 plots sown last year to measure the germination and survival rate. Suspense! Will the seedlings survive the drought, herbivores, fire and competition from other species?

The observations are very interesting and motivating!

Firstly, at this time of year, the abundant vegetation makes it difficult to identify “our” shoots. So there is no need to use aerial images with our drone, it is green on green. On one of the plots of land, the shoots exceed human size:

The second observation is that natural regeneration also takes care of our fields: many seeds present in the soil or brought by animals have also germinated and it takes the trained eye of our partner Guidre to count the “good” shoots. Fortunately having sown in line helps to spot our plants 🌱🪴

Thirdly there are huge differences between plots, caused mainly by fire and also the nature of the terrain. If the plot has been hit by a bushfire, the seedlings with too short roots die while the others sprout and can survive. This is why we started this year to make “poquets” (small holes in the soil) before placing the seed pellet, which favours the depth of the roots. Of the seven plots visited, two had a survival rate of practically zero, while the other five had a survival rate of between 60% and 80% (not counting natural regeneration!!!).

Fourth observation: it is mainly certain pioneer species that have germinated. The seeds of other species will wait for the right moment, sometimes for several years.

Fifthly: some owners have decided of their own free will to enrich the plantation with other species (alas, often with cashew).

If we count the number of stems from all origins (arboRise direct seeding and natural regeneration), we get roughly 10,000 stems per hectare, or 1 plant per square metre (which is much higher than the 5,000 seed pellets we sow on each hectare). This density will decrease over the next few years, due to natural competition between the trees, until it reaches about 1000 trees per hectare in twenty years.

Beyond the germination rate, it is also the biodiversity to which arboRise contributes, since we facilitate the dispersion of our mix of 40 species on the land we sow.

The training of the Community Management Committees has started!

As a reminder, in each of the 26 villages where arboRise carries out its reforestation activities, we have formed a Community Management Committee of 15 to 17 members (including several women) whose mission is to develop activities and infrastructures for the population (in all areas: environment, agriculture, health, mobility, etc.).

For 2 days we welcome 52 delegates (2 per CMC) from the 26 villages to Linko. They are provided with food and accommodation and receive a comprehensive training on good governance, good leadership behaviour, structuring their committee and building hedgerows.

At the official introduction to the seminar the Sub-Prefect made a strong plea for the project and formulated very clear expectations in particular to eliminate the practice of slash and burn (as required by Guinean law). All the official speeches are recorded by a journalist and broadcast in full several times on the local radio, which allows us to explain our approach in all the villages that are not yet participating and to prepare the ground for the future.

Each delegation will then pass on this knowledge to the other members of the Committee in each village. A first step towards the sustainability of our action! Indeed, developing local skills and empowering communities is essential to ensure a sustainable impact of our action. Capacity Building belongs to the Sustainable Development Goals !

The Community Management Committees also form a platform for the exchange of good practices: they are encouraged to identify good examples in their village and to share these models with the CMCs in other villages. The CMCs will also assist farmers who are short of manpower to build firebreaks and hedgerows. In this way, a positive emulation and mutual help is created within the whole region, a wish frequently expressed by the population in interviews conducted by Léa Ackerer in April 2022.

Back in Guinea to conclude our 2021-2022 reforestation campaign and draw conclusions just before the winter season. The rains have already started and the country is a real paradise. The countryside is green, the mango trees are bursting with fruit, the clothes look even more colourful than usual, and the trees are not to be outdone, like this magnificent flamboyant in bloom:

With our partner Guidre we start with a series of workshops to draw the lessons from the six months of campaigning in the field: what worked well? what surprised us? what were the obstacles? how do people feel about our approach? etc. By cross-checking everyone’s perceptions with the observations from Léa Ackerer’s interviews, we get a fairly coherent overall picture of our impact and the potential for improvement.

Then we list all the risks of our project together. Collective intelligence ensures that nothing is forgotten and that each threat is assessed at its true value (level of impact, degree of probability). And of course, for each risk we identify the prevention or mitigation measures.

The next topic is the quality of our partnership, which is very important to us! As our cultural filters are different, we tackle the question from the perspective of experience and share significant anecdotes that, on both sides, have marked our perception of each other, both good and bad. After looking back and we look forward and formulate our respective wishes for the future strengthening of our partnership.

We end with a game of arboRise, which shows that our field supervisors are well aware of all the levers of prosperity and know how to manage their cultivation choices admirably. Our project offers an alternative to cashew monoculture that allows the population to benefit from the income from carbon credits.

In conclusions: our strong partnership allows us to anticipate risks and simulate several scenarios to optimise our environmental and social impact.

Members of the association play a “serious game” developed for arboRise by the ForDev of the ETHZ. The aim? to better understand the stakes of our action in Guinea. By playing it is easier to put yourself in the shoes of the families participating in our project. By observing the other players, we also discover how others react differently to the same reality.

Because a game is also a way of resolving tensions that may arise during a change. Whether it is the construction of windmills in Switzerland or the creation of a protected nature reserve in a tropical country, the ecological transition brings about changes that disrupt the lives of the inhabitants. Any conflicts that arise can be resolved in court or behind bars. But these are win-lose outcomes that are not sustainable. It is preferable to seek an amicable settlement, through mediation for example. The serious games developed by the ComMod association are precisely mediation tools: they allow participants to

• take a step back from the context of the conflict
• become aware of the issues at stake for the other parties involved
• observe their ways of managing the situation
• test new ways of dealing with the situation and observe the effects on others
• invent solutions that work for everyone

What do we learn from the game?

1. We have an impact on the land on the spot and it is important to choose land families that have enough land
2. The conditions we offer through carbon credits must be more attractive than the income from cashew monocultures
3. We must encourage co-management to encourage each village community to manage itself
4. We will need to help spend the future income we generate wisely and fairly

Can’t wait to try it? contact us!

Our collaboration with the Water and Forests Department of the Ministry of the Environment and Sustainable Development (MEDD) is essential for the smooth running of the project.

After a year of operations in the field, we take stock of the situation with Mr Kemo Camara, the head of the Water and Forests section in Kérouané.