A study was carried out in the Mount Mandara area to assess the populations and renewal status of Parkia biglobosa, a multipurpose species. The study was aimed at contributing to the sustainable management of this resource. Transect methods were used to count individuals of P. biglobosa in fields. Results showed that the density of P. biglobosa was 7 individuals ha-1. The basal area of P. biglobosa individuals varied as follows: Mokolo area (21.41 m 2 ha-1) and Roua-plateaux Zoulgo (20.06 m 2 ha-1). In these zones, big trees of P. biglobosa with large diameters were quite numerous. The average diameters were 79.14 ± 5.04 cm, and the average height was 13.60 ± 0.96 m. The structure of the distribution among the diameters generally was bell shaped, but the distributions varied in each zone. The greatest number of individuals was observed in the [50-70 cm] and [70-90 cm] diameter classes, with a remarkable increased presence of individuals in class [130-150 cm]. The scarcity of the individuals in the diameter range of 10 to 30 cm was noted in the various zones, with their entire absence in the Roua-Plateaux Zoulgo and Méri zones. The rate of regeneration of P. biglobosa was 13 %. This rate was very weak compared to the socioeconomic importance of this species. This regeneration rate will not ensure continued population strength of this multipurpose species. This species is proven of importance, but its capacity of regeneration was too low to ensure its sustainability. It becomes imperative to develop effective strategies for its regeneration and conservation.

The Loranthaceae, commonly referred to "mistletoe from Africa" are used by communities of Cameroon for their numerous therapeutic virtues. The study examined the local various uses of Loranthaceae species in Diamare plain of Cameroon. Participatory rural appraisal method was used with 130 persons, namely traditional healers, breeders, farmers and foresters in order to identify the local uses of Loranthaceae species. We used itinerary botanical survey method in thirty-two (32) villages for the inventory of Loranthaceae species. In each village, two (02) itineraries (1000 m x 20 m) were realized on account of one itinerary in an agrosystem and one itinerary in a natural site. Results revealed five categories of uses of Loranthaceae: human traditional pharmacopoeia, fodder, magical use, ritual use and veterinary medicine. Knowledge of Loranthaceae uses was broadly influenced by age of respondents, traditional healers and people over 41 years old were the major libraries of knowledge on Loranthaceae. Human traditional pharmacopoeia (96.92%) and magical use (82.30%) were the most important categories of uses. Nine Loranthaceae species were inventoried in natural and agrosystem sites, namely Agelanthus dodoneifolius (DC.) Polh. & Wiens, Tapinanthus globiferus (A. Rich.) Tiegh., T. oleifolius (J.C.Wendl.), T. ophiodes (Sprague) Danser and T. voltensis Van Tiegh. ex Balle, Phragmanthera sp., Tapinanthus sp1., Tapinanthus sp2. and Tapinanthus sp3.. The most parasitized species with high rate of parasitism and vulnerability were Ziziphus mauritiana Lam. (58.33%; 6.98%), Acacia albida Del. (45.03%; 13.97%), Azadirachta indica A. Juss. (39.05%; 18.03%), Psidium guajava L. (29.62%; 5.10%) and Citrus limon (L.) Burm. f. (26.31%; 6.36%). Rate of parasitism and rate of vulnerability were positively but weakly correlated (Kendall, r = 0.09).

1 RÉSUMÉ Dans la perspective de contribuer à la gestion saine des agrosystèmes des hautes savanes guinéennes de Ngaoundéré, les litières ont été collectées sous 4 espèces fruitières locales, puis certains bioéléments ont été dosés dans la litière foliaire. Le dispositif expérimental exploité était un bloc complet randomisé à 4 répétitions. Les traitements correspondent aux 4 essences et les répétitions aux quatre localités. L’unité expérimentale était constituée de 4 arbres. La litière totale produite est de ,5541kg/m²/an. La litière foliaire (0,3745kg/m²/an) est la plus importante source de matière organique du sol. Cette production de litière varie significativement suivant les espèces (P˂0,000). Les espèces sont riches en calcium, mais pauvres en phosphore. Ximenia americana est l’espèce la plus riche en bioéléments (2378,12mg/100g de MS). X. americana (665,82mg/100g de MS) et Parkia biglobosa (354,47mg/100g de MS) sont les espèces les plus riches en éléments fertilisants. Ces résultats montrent que ces espèces fruitières produisent une litière foliaire fertilisante. Leur intégration dans les agrosystèmes serait très bénéfique pour la restauration des sols. Néanmoins, il serait nécessaire de suivre la dynamique de ces bioéléments dans les sols. ABSTRACT In In order to contribute to the healthy management of agro systems of the high Guinean savannahs of Ngaoundere, the litter of four local species of fruits tree was collected and certain bio elements were measured. A complete block randomized experimental device of four replications was used. Four treatments were considered and corresponded to the four local species of fruits trees tested. Each locality was considered as a replication. In each locality, four trees of each species were considered. The total litter produced was 0.5541kg/a/year. The foliar litter was the most important source of soil organic matter with 0.3745kg/a/year and varied significantly according to the species (p<0.000). All the species tested were rich in calcium and pover in phosphorus. Ximenia americana was the richest species in bio elements with 2378.12mg/100g of dry matter. X. americana and Parkia biglobosa were the richest species in nutrient with 665.82mg/100g and 354.47mg/100g of dry matter respectively. These results shown that, these species of fruit trees produce a fertilizing foliar litter and their integration in agro systems could contribute to soil restoration. Nevertheless, it would be necessary to monitor the dynamics of these bio elements in soils.

Phenological studies were undertaken on ten indigenous species of socio -economic importance of the Sudano-Sahelian zone of Cameroon. The selected species were Adansonia digitata L., Balanites aegptiaca (L.) Del., Detarium microcarpum Guill. & Perr., Diospyros mespiliformis Hochst. ex A. Rich., Haematostaphis barteri Hook. f., Hexalobus monopetalus (A. Rich.) Engl. & Diels, Parkia biglobosa (Jacq.) R. Br. ex G. Don, Sclerocarya birrea (A. Rich.) Hochst., Tamarindus indica L. and Vitex doniana Sweet. The studies which involve monitoring of the selected species were carried out from 2015 to 2017 along isoyets in the Sudano-Sahelian zone of Cameroon. The main objective of the study was to assess the phenological behaviour of the selected species in their natural habitat, with a view to determining their response to climate change in terms of shading off. If we understand sufficiently about it, and have at least a basic understanding of phenological characteritics, morphological and physiological adaptative behaviour when exposed to environmental change, we will be able to propose appropriate management techniques to optimize the product we required. The results reveal significant differences between species (0.0000 < 0.001), years (0.01 < 0.05) and isoyets (0.01 < 0.05) concerning mean period of defoliation. For the range of defoliation, significant differences exit equally between species (0.0000<0.001), years (0.0002<0.001) and isoyets (0.0002<0.001). Two categories of species are distinguished : deciduous and evergreen. The range of defoliation among species is equally significanly different (0.0000 < 0.001). Clamatic data in relation with phenological manifestations show that even if it is possible to find mean patterns, individual factors remain very important for more refined predictions, before more quantitative explorations, which must be foreseen, are done. These informations are important in the elaboration of efficient domestication strategies Ke ywo rds Cameroon Climate Defoliation Domestication Socio-economic species Sudano-Sahelian How to cite this article:

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