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In Central Africa, the degradation of tree resources exacerbates the effects of climate change (high variations of temperatures, dry air, etc.). However, attempts to limit this degradation by developing community forestry, individual forest plantations and agroforestry have often produced disappointing results. Contributing factors include a lack of land tenure security, which is required for planters and/or their descendants to benefit from the labour they invest in planting trees. Another is the vulnerability of isolated plantations, which can be destroyed by bushfires, wandering livestock, and illegal trees cutting. In semi-arid zones of northern Cameroon, as in the wetlands of D.R. Congo, research-and-development projects have combined two approaches to address these issues. The first seeks to establish Simple Management Plans (SMP) of village territories; the second to disseminate simple techniques for the collective management of natural forests and for setting up individual agroforestry plots using plantation or Assisted Natural Regeneration (ANR). The evaluation of these projects, based on surveys of villagers and forest inventories, shows that the combination of these two approaches may indeed enable villagers to slow the degradation of their natural resources and engage in a dynamic reconstruction of the tree component of their territories. However, the success of these combined approaches is contingent on several conditions. First, villagers must collectively see resource degradation as a danger and their restoration as an opportunity for a better future. The support of traditional authorities and administration also is required. Finally, to ensure that rebuilt agro-systems are well adapted to the current and future needs of populations under evolving environmental conditions, the support of research and development is often necessary from the earliest stages. This was the case for the enrichment of Faidherbia albida parklands in northern Cameroon and for improving systems of shifting cultivation by planting trees and implementing ANR in DR Congo (Texte intégral)

Slash-and-burn agriculture (S&B) is the leading factor behind the degradation of tropical forests and represents an ecological and economic dead end. Many authors have noted that this system is very difficult to improve without the support of public policy. In dryland Africa, especially in Niger and northern Cameroon, grants funded by projects and through levies on profits from bundled cotton sales have made it possible to support the conservation of young trees on fields when fallows are cleared and during weeding. This Assisted Natural Regeneration (ANR) support policy was promoted by the state corporation responsible for the development of cotton crops and was accompanied by a delimitation and demarcation of fields. From 1990 to the present, this policy has resulted in the conservation of over one million Faidherbia albida, and, in so doing, the expansion and densification of agroforestry parklands. In the equatorial wetland, of D R Congo, the experience is much more recent. Simple Management Plans of village territories were put in place since 2010 to secure rural land tenure. ANR methods have also been promoted to conserve young trees growing spontaneously in cultivated fields, after S&B, when fallows are cleared and during weeding. In areas where environment was too degraded, leguminous trees have been planted using taungya method. Trees conserved or planted improve fallow productivity in terms of firewood and other forest products, accelerate the restoration of soil fertility and block the invasion of savanna pyrophytic vegetation, before a new 'slash-and- charcoal' cycle. Over 150 farmers have used ANR and 1700 ha of Acacia auriculiformis have been planted. The use of simple techniques requiring little labour or inputs, associated with land tenure security policies, allows a gradual transition from S&B to more productive and sustainable agroforestry systems (parklands in the Sahel and improved fallow in forest areas).

Traits and functions of Apple?ring acacia (Faidherbia albida (Del.) Chev.), iconic species of sahelian agroforesters, are well known of agro?pastoralists farmers and scientists. Traits include its deep taproot system reaching the water table on alluvial soils, its inverted phenology, and the leaves being present in the dry season and absent during the rainy season, and its ability to vegetative propagation (root suckers, coppices of stumps and branches). For functions, its general positive impact on associated crop, production of forage (leaves and fruit) and firewood are also widely recognized. However, the area extension of Faidherbia agroforestry systems (parklands) is still far below what it could be, despite the isolated actions of many extension services and NGOs. The example of northern Cameroon shows that research on crop productivity under Faidherbia helped changing the perception of this tree by services and operators of agricultural development, in the 1990s. Then it was possible to "boost" the restoration of these parklands on a large scale, mobilizing public funding, associations and farmer organizations and subsidizing (even at a low level) Assisted Natural Regeneration. The results of socio?economic surveys and pruning trials, conducted in 2012, confirm, at least, the interest of farmers for pruning the trees and fire?wood sustainable productivity of this method. Demand of farmers, on the right of pruning trees and freely use the wood harvested has been taken into account in the draft amendment to the Law on the forest regime, introduced in 2012, to the Cameroon parliament. These studies on Faidherbia albida have helped Cameroonian farmers to keep more than one million young trees, but also have helped to change the law in the sense of increasing the rights of peasants on the tree. This concern planted trees, often exotic, but also natural species kept and maintained by farmers, such as shea?butter tree (Vitellaria paradoxa) and many other multipurpose species. (Texte intégral)

Ce mémoire intervient suite à des politiques de conservation par subventions et des premiers essais d'émondage de Faidherbia albida. Sur deux terroirs villageois du pays Toupouri (Gane et Sirlawe), les questions posées sont de comprendre les évolutions des terroirs et leurs liens avec la conservation de l'espèce, d'évaluer la production de biomasse annuelle et de rendre compte des intérêts et modalités de mise en oeuvre de gestion communautaire pour le faidherbia. La saturation foncière a entraîné des mutations agricoles qui permettent de poursuivre la conservation des arbres. La densité observée s'échelonne de 10 à 30 faidherbias par hectare. La production annuelle de biomasse assure les besoins en bois de feu des terroirs villageois pendant près de trois mois. La politique de taxe appliquée par les services forestiers n'est pas efficace pour la gestion de l'espèce. Une gestion communautaire est complexe compte tenu des droits de propriété individuelle forts sur l'arbre et des difficultés à structurer la société en collectifs à cette fin. Les pouvoirs politiques doivent initier un processus de négociation entre les acteurs pour une gestion du Faidherbia albida plus efficace que les taxes ou la foresterie communautaire en l'état actuel.

A major part of anthropic impacts on natural tropical forests in central Africa is related to unmanaged shifting agriculture and fuelwood extraction by local communities, mainly along access tracks (roads, rivers,...)and at the edge of forests. Assisted Natural Regeneration has been largely designed and used in dry countries. In a EU projet in DRC and Congo (Makala), we have adapted these techniques to shifting agriculture. We used the capacity of sprouts and seeds of remaining local forest species and induced specific management techniques amongst farmers. The results show a very good reactivity and regrowth of natural forest species with a low cost and low technicity involvement of farmers. Social acceptance is the most critical factor for successfull large scale development of such techniques. Such techniques can also be adaptated to industrial concessions in their efforts to rehabilitate deforested and/or unproductive areas and in their efforts towards sustainable management and certification.

L'objectif principal du projet MAKALA est de sécuriser la ressource en bois pour l'approvisionnement en énergie de deux villes de RDC et une ville du Congo, par une amélioration de la gestion des forêts (naturelles et plantées) et de l'efficacité de la transformation énergétique, en vue d'augmenter durablement le niveau de vie des populations locales. Le Cirad intervient dans ce projet en tant qu'organisme de recherche spécialisé dans l'agriculture tropicale et tout particulièrement dans la foresterie, l'agroforesterie et la fourniture de bio-énergie. Le CIRAD dirige le projet et intervient, entre autre, dans le WP3 qu'il co-coordonne avec l'ULG-Gembloux. Le WP3 porte sur la gestion des forêts naturelles, ce qui inclue les parcelles utilisées par les agriculteurs avec le système d'agriculture itinérante sur brûlis (slash-and-burn) et par conséquent les jachères et les pratiques agroforestières. Ce WP3 s'intéresse à l'usage et aux fonctions de ces forêts plus ou moins dégradées du point de vue des populations rurales (savoirs locaux) ce qui nécessite une méthode spécifique intégrant des approches anthropologiques et sociales. L'intervention des auteurs du présent rapport est plus spécifiquement centrée sur le WP3. Nous contribuons à définir des objectifs et des modalités d'interaction entre sciences humaines et sociales et sciences écologiques et biotechniques pour construire des démarches de recherche congruentes. L'intervention est principalement axée sur la multifonctionnalité des systèmes agroforestiers. La mission a consisté à mettre au point une méthode opérationnelle d'évaluation socio-économique, agronomique et forestière des premiers essais de Régénération Naturelle Assistée (RNA) réalisés par le projet Makala sur le Plateau Batéké, ce qui inclue les méthodes d'enquête. Pour cela, un stagiaire de SupAgro Montpellier, Baptiste MARQUANT (BM) a été installé. Suite à la formation E-learning qu'il avait suivi, BM a proposé un premier protocole d'étude. Le questionnaire d'enquête a été testé et des améliorations proposées. On trouvera en annexe 5.2 le protocole définitif d'enquête qui a été retenu par BM, celui est en cours de traduction en Lingala. Outre les variables sur la structure et le fonctionnement de l'exploitation agricole, les stratégies et savoirs des agriculteurs, les fonctions et traits des arbres ont été déclinées en sous-variables : produits, services et fonctions socio-culturelles. Le travail a été mené de façon participative avec une démarche réflexive à laquelle chacun était convié. Le protocole d'inventaire des parcelles de RNA a été discuté et précisé sur trois parcelles contrastées.