Domestication paysanne des arbres fruitiers forestiers : cas de Coula edulis Bail, Olacaceae, et de Tieghemella heckelii Pierre ex A. Chev., Sapotaceae, autour du Parc National de Taï, Côte d'Ivoire

In Côte d'Ivoire agriculture has confined the forest to national parks and state forests. Forest species are disappearing from the rural landscape and the products of these species get ever rarer. Thus, the rural population goes out collecting these products in national parks and state forests, the access to which is legally is forbidden. This situation leads to numerous conflicts that threaten the long term conservation of these last forest relics. How to ensure this long term conservation and sustainable management of national parks and state forests, or simply of biodiversity in Côte d'Ivoire?

Maintaining local forest species in the rural landscape may contribute to biodiversity conservation. The path to follow is, that farmers themselves domesticate the forest species they are interested in.

Domestication is a process in several steps one being to bring into cultivation the wild plants. For this study, the following questions were raised :

• Which are the forest species that farmers around Taï National Park want to domesticate and for what reasons?
• Are these species apt to be domesticated and is their propagation easy on the farm?
• How do the farmers conceive the domestication and which socio-cultural and economic factors determine their decisions?
• How do the forest species perform as to growth and development during on-farm domestication?

To answer these questions, a number of enquiries, direct and participative observations and experiments on farms in the Taï region were undertaken.

After a participative analysis of local useful forest species in the rural environment, two fruit tree species have been selected, with the agreement of the farmers, to become the subject of this study. They are Makoré ( Tieghemella heckelii, Pierre ex A.Chev., Sapotaceae) and Attia ( Coula edulis Baill., Olacaceae). Farmers found problems in obtaining seeds or seedlings of those for biological, ecological or phenological reasons, and this justified our choice. Biology, ecology and socioeconomic aspects of both species have been described.

On-farm propagation of the species in both vegetative and generative way, using simple techniques available to farmers was experimentally done

Both types of propagation were successful with Makoré:

• Germination was rapid and abundant; germination levels up to 90% were reached four weeks after sowing in the tree nursery. These seedlings started branching after two months and measured between 25 and 68 cm high after 4 to 5 months in the nursery;
• layered branches developed roots after eight weeks;
• 73% of cuttings developed roots in a sandy substrate and 41% on a sawdust substrate. No effect could be found of rooting hormone treatment;
• Plants reproduce AUBREVILLE's model, which is the basic architectural model of the species by vegetative propagation.

With Attia:

• germination was very slow; the germination strategy of the species is of the Durian type and seems to be suicidal, without success and negatively selective in tropical rain forest; germination levels attain 44 to 75% depending on the length of observation in the nursery. Seedlings branch in a sequential sylleptic way.
• the vegetative propagation of the species is not autonomous.

Domestication is a very complex process that involves biological, ecological and economic aspects of the species under study as well as the socio-economic situation of the participating farmer. After having treated biological and economical aspects of the species the socio-economic situation of farmers that showed interest in domestication during the study was analysed. Domestication over time from protoculture to the actual cultivation of Makoré in the Taï region was discussed. Protoculture consists of caring for trees issued from natural regeneration and was practised until 1969. At that time forest resources were still abundant and planting trees was a taboo for the farmers. Between 1969 and 1989 the first timid steps were set towards really cultivating forest fruit trees. Farmers secretly planted local forest fruit trees. From 1990 on there has been a certain dynamism to start cultivating these trees, especially Makoré. Makoré seed oil was the primary motivation for domesticating Makoré for 79% of the farmers (N=49), 21% planting them for their seeds and their timber. Three quarters of Makoré farmers were men. Makoré is mainly planted intimately mixed with tree cash crops to optimize the labour factor. Land tenure and land and tree property rights did not seem to hamper domestication. Due to the very long germination period of Attia, it has not been possible to obtain enough seedlings to study the farmers' response to domestication. But the farmers' attitude towards propagation of this species has changed: they have seen germinated C. edulis seeds and they know now that generative propagation is possible.

Growth and development of Makoré seedlings on the farm were analysed in relation to the cultural system in which Makoré was introduced, and to light and mycorrhizae levels. Growth of Makoré seedlings was found to be positively correlated with the quantity of available light. The species is thus clearly a non-pioneer, but tolerant to full sunlight. In the cultural system 'fallow with Chromolaena odorata after rice culture', Makoré seedlings and saplings found the best ecological conditions during the first stages of development. All soils on which Makoré grew in the Taï region, contained mycorrhizal spores, the closed forest soils most of them. However, no correlation was found between spore density and seedling growth rate.

All the results were taken together in order to formulate the perspective of domestication by farmers of local forest fruit tree species. In general the cultural blockage against planting indigenous tree species has been dissolved amongst the farmers of the Taï region. The process of domestication thus has started to the west of Taï National Park. Thanks to this process agroforestry systems allowing the conservation or restoration of forest biodiversity in the rural landscape are now being developed in the region. The extension of the agroforestry techniques used by the farmers in this study is advised.