Origine et impact du chenal Tchad-Cameroun sur la propagation de Chromolaena odorata (L.) R. M. King and H. Robinson (Asteraceae) de Meiganga à Touboro

L’objectif de ce travail est de déterminer l’origine et les effets du chenal Tchad-Cameroun sur la propagation de Chromolaena odorata, Asteraceae, considérée comme mauvaise herbe dans la zone d’étude. La méthodologie suivie a comporté trois étapes : la prospection générale de la zone d’étude, le choix des itinéraires d’étude et la confection des relevés floristiques de Chromolaena odorata. L’espèce héliophile est présente dans toute la zone d’étude. Dans l’itinéraire 1, de Garoua Boulaï à Meiganga (Centrafrique vers Cameroun), l’abondance-dominance et le recouvrement moyen ont des maxima. Les indices d’abondancedominance et de recouvrement moyen élevés hors chenal dans cet itinéraire justifient l’origine centrafricaine de cette espèce, d’où le nom commun de « bokassa » utilisée par les populations pour la désigner. De Meiganga à Mbaï-mboum (itinéraire 2), Chromolaena odorata recouvre également plus de 3/4 de la surface et les individus occupent 87,5% de cet itinéraire. De Mbaï-mboum à Ngaoundéré (itinéraire 3), les deux indices décroissent simultanément montrant l’influence du chenal sur la résurgence et l’importance de Chromolaena odorata. Les méthodes culturales utilisées pour éradiquer C. odorata sont la coupe des tiges de la plante associée à un dessouchage des organes souterrains.Mots clés : Chromolaena odorata, origine, impact, chenal, propagatio

Contribution des fourmis à la lutte biologique contre les Loranthaceae

Les Loranthaceae sont des plantes parasites qui causent de nombreux dommages sur les plantes hôtes se traduisant par une réduction de la floraison, de la fructification et de la production. Dans le but de trouver une méthode de lutte efficace contre les Loranthaceae, une étude relative à l’activité myrmécophile a été menée au verger de la chefferie de Ndogbong. Un inventaire de la myrmécofaune a été réalisé sur 16 individus de Theobroma cacao dont 9 parasités et 7 non parasités. Trois espèces de Loranthaceae ont été recensées: Phragmanthera batangae (Engler) S. Balle, P. capitata (Sprengel) S. Balle et Tapinanthus preussii (Engler) Van Teghem. Trois sous-familles de fourmis ont été identifiées : les Ponerinae (Odontomachus troglodytes Santschi), les Formicinae (Camponotus sp.) et les Myrmicinae (Crematogaster sp., C. decacrema, C. oxygyne, et Pheidole megacephala Fabricius). Deux espèces de fourmis ont été présentes sur les fleurs et les fruits de P. capitata et T. preussii et contribuent à la lutte biologique contre les Loranthaceae.Mots clés: Myrmécofaune, lutte, Loranthaceae, Ndogbong, Theobroma caca

Les plantes à alcaloïdes utilisées par les populations de la ville de Douala (Cameroun)

Objective: An ethnobotanical survey was conducted from January to February 2013 in Douala town relating to the various uses of alkaloids plants species by the people. Methodology and results: Ten districts were surveyed for the census alkaloid plants. These surveys helped conduct semi-structured surveys based on direct questions concerning the therapeutic uses of these plants by the targeted populations. A total of 73 alkaloid plant species were identified of which 21 were herbaceous and 52 woody. Among these species, 30 are indigenous and 43 exotic. They were distributed in 62 genera belonging to 40 families. The supply is provided from farms, secondary forests, gardens, fallows and markets. Solanaceae, Apocynaceae and Rubiaceae are rich in various alkaloids. Leaves, barks and roots are the plant parts mostly used in recipes for the treatment of various diseases. Drugs are mainly administered through the oral root. Secondary metabolites, including alkaloids are unevenly distributed in plants. They are produced at particular stages of development of the flower, fruit, seed or seedling in a specific organ, tissue or cell. Alkaloid plant species are used as major analgesics, antimalarial and to fight against excess uric acid. They are also used as drugs, laxatives, aphrodisiac and as cholinergic or as anticancer agents. They increased heart rate and stimulate the central nervous system with increased vigilance. Conclusion and application of results: All these properties can justify the inclusion of these non timber forest products in forest management programs for their sustainable exploitation.Keywords : Solanaceae; Apocynaceae; Rubiaceae; alkaloids; exploitatio

) Forest Management for Non-Wood Forest Products and Services in Sub-Saharan Africa

Abstract The contribution of Non-Wood Forest Products (NWFPs) and services in livelihood support has been reviewed. Quite a number of NWFPs are also important articles of commerce and contribute significantly to the economies of various African countries. The non-consumptive role of forests has been examined in terms of eco-tourism while the social and economic viability of the production of NWFPs and services have been reviewed from subsistence and commercial perspectives. Conditions that enable long-term viability in the management of forests for NWFPs and services have been reviewed. Need for sound ecological data in relation to resource stock and yield were noted as important in determining ecological sustainability. A number of institutional issues important to SFM were noted, including setting up of strong producer organizations, enabling policies and legislative frameworks, and relevant institutions within the government that provide supportive roles. Multiple use management was noted as an important concept towards sustainable forestry and clearly demonstrates how forests can be managed for both wood and NWFPs. From an analysis of lessons learnt from the above, various recommendations were made

Poverty and poor education are key determinants of high household food insecurity among populations adjoining forest concessions in the Congo Basin

Background: The trees and non-timber forest products (NTFPs) of the Congo Basin play a key role in alleviating food insecurity among millions of people around the world. Although many studies have been conducted both nationally and regionally on issues of food insecurity in the Congo Basin, little is known on the effects of timber exploitation on household food insecurity statues of forest dependent communities in this region. This study focused on the determination of the principal indicators of household food security status of populations living around six selected forest concessions in the Congo Basin. Method: We randomly surveyed 724 households in thirty-four communities living in six popular forest concessions around the Congo Basin. Food consumption pattern data was collected using a validated food-frequency questionnaire in 2012. Household Food Insecurity Access Prevalence (HFIAP) was assessed using the HFIAP indicator and households were categorized into four levels of household food insecurity status as follows: Food secure (HFIAS = 0); mildly food insecure (HFIAS 1–8); moderately food insecure (HFIAS 9–13); and severely food insecure (HFIAS 14–27). Results: The majority of the households interviewed were headed by women (73.1 %, 76.6 %, and 58.6 % for Cameroon, DRC and Gabon respectively), most of them married (84.6 %, 100 %, 57.6 % for Cameroon, DRC and Gabon respectively) with an average age range of 30–49 years. Most of the household members were engaged in farming and/or illegal logging as the main revenue generating activities. Results of global household food insecurity categorized 63.8 % of households in Cameroon as fully food secure and 36 % as food insecure. In the DRC (92.9 %) and Gabon (92.7 %), almost all the survey households were categorized as either moderately or severely food insecure; clearly elucidating the existence of severe insufficiency in the quantity and quality of food meant for human nutrition in these areas. The means of household food insecurity scores for the DRC (17.40 ± 4.15) and Gabon (14.9 ± 5.87) were significantly higher when compared to the average score for Cameroon ((7.55 ± 6.62) at p < 0.0001. This literally means that many of the households especially in DRC and Gabon face enormous difficulties in obtaining an adequate dietary energy supply. Gender (female), educational level (illiterate), and age (young) were positively correlated to food insecurity levels. Conclusion: Our results revealed that, despite the potential contribution of the Congo Basin forests, through enhancing access to different forms of quality foods such as bush meat, wild foods, and medicine, not forgetting the provision of agricultural land, local construction material, and income generation resources, the prevalence of food insecurity among the population adjoining forest concessions in the region is severe. This prevalence is alarming around forest concessions of the DRC and Gabon and in one concession of Cameroon. Given that poverty and poor education were positively correlated to household food insecurity, they were considered the paramount determinants of household food insecurity in this region

Perceived nutrition benefits and socio-demographic factors affecting consumption of forest foods in eastern and southern Cameroon

African forests act as sources of both plant and animal foods that provide significant amounts of nutrients and healthy boosting bioactive compounds. This study investigated the relationship between knowledge, perceptions and socio-demographic attributes towards consumption of forest foods. A total of 279 females in charge of decision making with respect to food preparation, were randomly selected from 12 villages in southern and eastern Cameroon, and interviewed using researcher administered questionnaires. Multivariate logistic regression analysis was used to identify the socio demographic factors and perceptions affecting consumption of forest foods. Baillonella toxisperma (African pearwood) (98%), Irvingia gabonesis (bush mango) (81%) and Trichoscypha abut (Mvout) (70%) were identified as the most nutritious foods. Among the animal forest foods, bush meat (11%) and Imbrasia spp. (edible caterpillars) (10%) were identified as the most nutritious. Consumption of forest foods was higher among polygamous families and also positively related to length of stay in the forest area, as well as age of female respondents. Education had an inverse relationship with use of forest foods. Perception towards the nutritional value of forest foods were also found to positively influence consumption of forest foods. Since negative perceptions were found to influence consumption, there is need to invest in awareness campaigns to strengthen the current knowledge levels among the study population.Les for\ueats africaines sont des r\ue9servoirs d\u2019aliments v\ue9g\ue9taux et animaux fournissant des quantit\ue9s importantes de nutriments et compos\ue9s bioactifs stimulants naturels. La pr\ue9sente \ue9tude analyse la relation entre les connaissances, les perceptions et les caract\ue9ristiques sociod\ue9mographiques de la consommation des aliments issus des for\ueats. Un total de 279 femmes responsables du choix et de la pr\ue9paration des aliments familiaux ont \ue9t\ue9 choisis au hasard dans 12 villages du Sud et de l\u2019Est du Cameroun, et interview\ue9 \ue0 l\u2019aide de questionnaires administr\ue9s par des chercheurs. L\u2019analyse de r\ue9gression multi-vari\ue9e a \ue9t\ue9 utilis\ue9e pour identifier les facteurs sociod\ue9mographiques et les perceptions qui affectent la consommation desdits aliments. Baillonella toxisperma (Moabi) (98%), Irvingia gabonesis (mangue sauvage) (81%) et Trichoscypha abut (Mvout) (70%) ont \ue9t\ue9 identifi\ue9s comme les aliments v\ue9g\ue9taux les plus nutritifs. Pour ce qui est des aliments forestiers d\u2019origine animale, la viande de brousse (11%) et Imbrasia spp. (chenilles comestibles) (10%) ont \ue9t\ue9 identifi\ue9s comme \ue9tant les plus nutritifs. La consommation des aliments issus des for\ueats \ue9tait plus \ue9lev\ue9e parmi les familles polygames et positivement corr\ue9l\ue9e \ue0 la dur\ue9e de s\ue9jour dans la zone foresti\ue8re, ainsi qu\u2019\ue0 l\u2019\ue2ge des femmes interrog\ue9es. Le niveau d\u2019\ue9ducation avait une relation inverse avec l\u2019utilisation des aliments forestiers. La perception de leurs valeur nutritives avait \ue9galement une influence positive sur leur consommation. \uc9tant donn\ue9 que les pr\ue9jug\ue9s qui ont longtemps marqu\ue9s ces aliments influencent n\ue9gativement leur consommation, il est n\ue9cessaire de sensibiliser et de renforcer le niveau de connaissance des populations \ue9tudi\ue9e sur la valeur nutritive de ces produits

Physico-chemical characteristics and fatty acid profile of Baillonella toxisperma Pierre traditionally extracted edible oil from Cameroon forests

Baillonella toxisperma Pierre oil is an edible oil obtained from the seeds of wildly growing timber producing B. toxisperma tree species in Cameroon and the rest of the Congo Basin forests of West and Central Africa. This oil can be an important source of fat that can be used as a source of food to humans and/or a source of raw materials in the cosmetics, pharmaceutical and nutraceutical industries, to produce important commercial products. In the present study, samples of the seeds of B. toxisperma were harvested from three representative villages, each from the site in South and East of Cameroon. Seed oil was extracted using the traditional extraction method of B. toxisperma oils in rural Cameroon. Physico-chemical characteristics including colour, refractive index, viscosity, oil yield, acid value, peroxide value, saponification value, iodine value and α-tocopherols and fatty acid composition of crude oil of B. toxisperma nuts were all investigated. The oil yields from these seeds ranged from 38.2% to 45.6%. The peroxide, saponification and iodine values ranged from 2.13 to 2.69mEq/kg, 182.13 to 188.30 mg KOH/g and 54.41 to 57.98 I2g/100g, respectively. The highest acid value and α- tocopherols were 14.87 mg KOH/g and 24.3 mg/100g, respectively. The main fatty acids of Baillonella toxisperma Pierre oils were oleic, stearic and palmitic acids. Linoleic acid contents varied between 58.6% and 56.97%. The ratio of unsaturated to saturated fatty acids content in these oils was 2:1. The fact that the physico-chemical characteristics and fatty acid profile are comparable to common vegetable oils shows that the B. toxisperma oil of the researched species from Cameroon is a potential source of valuable oil which might be used for edible, cosmetic, pharmaceutical and other industrial applications. This characterization is a bench mark for monitoring the quality of Baillonella toxisperma Pierre oil, from Cameroon and can be used to enhance its local and international trade

Perceived nutrition benefits and socio-demographic factors affecting consumption of forest foods in eastern and southern Cameroon

African forests act as sources of both plant and animal foods that provide significant amounts of nutrients and healthy boosting bioactive compounds. This study investigated the relationship between knowledge, perceptions and socio-demographic attributes towards consumption of forest foods. A total of 279 females in charge of decision making with respect to food preparation, were randomly selected from 12 villages in southern and eastern Cameroon, and interviewed using researcher administered questionnaires. Multivariate logistic regression analysis was used to identify the socio demographic factors and perceptions affecting consumption of forest foods. Baillonella toxisperma (African pearwood) (98%), Irvingia gabonesis (bush mango) (81%) and Trichoscypha abut (Mvout) (70%) were identified as the most nutritious foods. Among the animal forest foods, bush meat (11%) and Imbrasia spp. (edible caterpillars) (10%) were identified as the most nutritious. Consumption of forest foods was higher among polygamous families and also positively related to length of stay in the forest area, as well as age of female respondents. Education had an inverse relationship with use of forest foods. Perception towards the nutritional value of forest foods were also found to positively influence consumption of forest foods. Since negative perceptions were found to influence consumption, there is need to invest in awareness campaigns to strengthen the current knowledge levels among the study population.Les for\ueats africaines sont des r\ue9servoirs d\u2019aliments v\ue9g\ue9taux et animaux fournissant des quantit\ue9s importantes de nutriments et compos\ue9s bioactifs stimulants naturels. La pr\ue9sente \ue9tude analyse la relation entre les connaissances, les perceptions et les caract\ue9ristiques sociod\ue9mographiques de la consommation des aliments issus des for\ueats. Un total de 279 femmes responsables du choix et de la pr\ue9paration des aliments familiaux ont \ue9t\ue9 choisis au hasard dans 12 villages du Sud et de l\u2019Est du Cameroun, et interview\ue9 \ue0 l\u2019aide de questionnaires administr\ue9s par des chercheurs. L\u2019analyse de r\ue9gression multi-vari\ue9e a \ue9t\ue9 utilis\ue9e pour identifier les facteurs sociod\ue9mographiques et les perceptions qui affectent la consommation desdits aliments. Baillonella toxisperma (Moabi) (98%), Irvingia gabonesis (mangue sauvage) (81%) et Trichoscypha abut (Mvout) (70%) ont \ue9t\ue9 identifi\ue9s comme les aliments v\ue9g\ue9taux les plus nutritifs. Pour ce qui est des aliments forestiers d\u2019origine animale, la viande de brousse (11%) et Imbrasia spp. (chenilles comestibles) (10%) ont \ue9t\ue9 identifi\ue9s comme \ue9tant les plus nutritifs. La consommation des aliments issus des for\ueats \ue9tait plus \ue9lev\ue9e parmi les familles polygames et positivement corr\ue9l\ue9e \ue0 la dur\ue9e de s\ue9jour dans la zone foresti\ue8re, ainsi qu\u2019\ue0 l\u2019\ue2ge des femmes interrog\ue9es. Le niveau d\u2019\ue9ducation avait une relation inverse avec l\u2019utilisation des aliments forestiers. La perception de leurs valeur nutritives avait \ue9galement une influence positive sur leur consommation. \uc9tant donn\ue9 que les pr\ue9jug\ue9s qui ont longtemps marqu\ue9s ces aliments influencent n\ue9gativement leur consommation, il est n\ue9cessaire de sensibiliser et de renforcer le niveau de connaissance des populations \ue9tudi\ue9e sur la valeur nutritive de ces produits

Trees for Food and Timber: are community interests in conflict with those of timber concessions in the Congo Basin?

Much of the Congo Basin is managed for timber from dozens of species. More than 60% also produce non-timber products, including foods. For five multiple use tree species in Cameroon, Democratic Republic of Congo (DRC) and Gabon (Entandrophragma cylindricum, Baillonella toxisperma, Erythrophleum suaveloens, Dacryodes buettneri and Gambeya lacourtiana), we studied gathering and consumption by communities, edible caterpillars hosted, the densities of trees around villages and in concessions and the impacts of timber harvesting . We also studied the consumption of forest foods and the nutritional values of fruits and seeds of various tree species. Villagers walked up to six km during day trips to collect fruits or caterpillars, gathering from concessions if the village was within or near it. When foods were gathered from trees smaller than the cutting diameter (which varied by country and species), there was no conflict with timber harvesting. However, the volume of edible caterpillars hosted increased with diameter and harvestable trees were the most productive. Caterpillars, tree fruits and seeds provide fats, vitamins and minerals that complement agricultural foods. Densities of B. toxisperma, valued for its edible oil, were higher around villages than in concessions. The proportion of commercial trees harvested for timber varied from less than 3% to more than 50%, depending on the species. Different species had different geneflow distances, meaning viable regeneration could be expected with residual adults at different maximum distances. E. cylindricum had more effective dispersal than E. suaveolens. The production of timber and nontimber products can be sustained from the same concessions, for different stakeholders, with appropriate practices and arrangements