Studies were carried out in the Kalfou Forest Reserve to make an assessment of the flora diversity and to develop preservation guidelines facing the increase in its degradation. The composition of woody species, structure, diversity, density, dominance, frequency of species and family importance value were described and evaluated in all the forest reserve area. A total of 86 species representing 58 genera and 28 families of woody species were identified. The families of Combretaceae, Fabaceaecaesalpinioideae and Fabaceae-mimosoideae were the most abundant families in the Kalfou Forest Reserve. The density of stems ≥ 10 cm circumference and the basal area were higher in the Doulouk and Gonoray parts of the reserve. The distribution of stems of the main species in classes of circumference had shown a reverse "J" shaped curve. The number of stems of shrubs species was important and strongly influenced globally the diameter and the height of the stems which were lower. Species diversity was a slight difference among the various parts of the forest reserve area. The species abundance showed that, 20% of the species were infrequent. The dynamic of renewal of species were ensured by the weakly regeneration: seedling (2.03%), rejection issues (41.97%) and the death rate of individual species was 8.02%. Disturbances and the vulnerability of the seedlings did not ensure species sustainability. Preservation systems and adequate management were therefore recommended in order to ensure sustainable management of the Kalfou Forest Reserve resources.

The study focused on fuel wood economic value and the influences of woody cutting on woody species in the flooded plains woodland area. Sahelian woodland suffers from cutting down trees for fuel wood, to insure household energy demands. Investigations were carried out near a sample of users of resources and an inventory of stems of exploited species in woodland. Households in 15 villages and four markets were explored and 496 actors included in the exploitation and the use of firewood and charcoal, as regard 204 men and 292 women, were interviewed individually. Fuel wood quantity and economic value was made through a register. Through 48 transects of 2 000 m length and 20 m each, the availability, the intensity of cutting down trees, measurements and observations were made and noted on stems. Stems which the circumference > 10 cm were counted and their diameter was measured. The sources of domestic energy mostly used were firewood and charcoal which remained easily accessible and available. Completely stem cut down and partial stems cut were noted as the exploitation mode. The charcoal was produced traditionally, using furnace. Significant quantity of firewood (2186.59 t) and charcoal (28340 t) were estimated. It varied periodically a year with a substantial drop. The quantity sale represent 95 % and brought annual income of 122035.8 $ (Firewood) and 31 630 $ (charcoal). The incomes contributed significantly in the rural households' economy and brought an additive to their much reduced agricultural yields. A number of 33 woody species were noted as the mostly exploited for fuel wood. Among them Anogeissus leiocarpus, Balanites aegyptiaca, Prosopis Africana, Detarium microcarpum and Pseudocedrela kotschyi were firstly mention. The total number of stumps and the partial cut of stems were significant representing respectively 20.91 % and 9.64 % of stems counted. The exploitation was intensive and selective on stems. Cutting down of stems was constituted a major factor for requested species degradation. Results indicated evidence of the impacts of fuel wood exploitation on the woody species. The study concludes that fuel wood yield in the sahelian woodland has not yet reached alarming proportions and can be contained. It could be an imperative to set up an alternative system to ensure sustainable management of resources. Solutions through introduction and popularization of natural gas, biogas, solar energy and the improved hearths could effectively contribute to reduce the intensity of this activity and to guarantee the maintenance of the ecological balance on the already fragile sahelian ecosystems.

In order to assess the diversity, regeneration and structure of wild edible fruit trees, a study was carried out in the Laf-Madjam forest reserve and its surroundings. A semi-structured interview with local residents and a floristic inventory of woody plants (8 transects of 1000 m × 20 m each) were carried out. 24 species were cited as being used by the local residents. A total of 2134 individuals subdivided into 69 species, 43 genera and 27 families were counted, including 448 edible fruit individuals divided into 25 species, 19 genera and 14 families. The latter with important IVIs are: Balanites aegyptiaca, Sclerocarya birrea, Ziziphus mauritiana and Hexalobus monopetalus. Diversity is medium in edible fruit trees (HSI=3.10 bits, E= 0.67). Fruit trees with individuals of diameter ≥ 21 cm are in the majority. Inverted "L" and bell-shaped gaits are observed. The regeneration rate of fruit trees is higher in Annona senegalensis, H. monopetalus, and B. aegyptiaca. The involvement of local people in the management of the reserve's fruit trees is important for sustainable management.

Background This study aimed to contribute to the valuation of medicinal plants used in the treatment of diseases affecting the populations of the district of Yagoua. Methods Ethnobotanical data was collected in 10 villages from June to August 2020 in Yagoua. A total of 300 informants (193 men and 107 women) were interviewed through semi-structured interviews, key informant interviews and guided field visits. All informants were local residents between the ages of 15 and 60, and key information holders were selected based on recommendations. The frequency of citation (FC) made it possible to appreciate the local phytotherapeutic importance of each species, the Degree of Fidelity (DF), identified the species most used in the treatment of a particular disease and the informant consensus factor (ICF) was used to determine the homogeneity of knowledge in the use of medicinal species. Results 98 plant species were identified belonging to 85 genera and 47 families. The Caesalpiniaceae families dominate (9 species). 10 species have a high frequency of citation. A total of 31 diseases were recorded, 8 of which had a high frequency of occurrence. It was found that men have more knowledge about plants (64.33%); the age group 26–36 is interested in the use of plants. 150 recipes were identified, of which 78.67% were monospecific. 49.44% of the species used by the population are collected in the bush, 5 morphological types represented 68.36% of woody plants and 31.64% of herbaceous plants, sarcochores are the most represented diaspore types with 51.02%. Leaves and barks are the organs most frequently used for the preparation of recipes; decoction is the most commonly used method of preparation and the oral route is the most commonly used way of administering medicines. More than half of the species recorded have a level of fidelity equal to 100% and the informant consensus factor shows high values. Conclusion The study area is rich in important plant resources for which the populations must be aware and must also take into account their vulnerability by advocating reforestation, domestication and sustainable use.

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