Pentaclethra macrophylla Benth. dans la forêt communautaire de Payo (Est- Cameroun): inventaire, productivité et commercialisation

Cette etude a ete conduite a l'Est du Cameroun, dans la foret   communautaire de Payo. Elle a pour objet d'evaluer l'importance   ecologique, productive et socioeconomique de P. macrophylla. Le dispositif d'inventaire est constitue de quatre transects de 40 m x 2000 m2 (8 ha chacun) avec un taux de sondage de 2%. Toutes les tiges de diametre a hauteur de poitrine .10 cm ont ete marquees, georeferencees, comptees et leur diametre mesures a la hauteur 1,30 cm. Les observations et entretiens, ainsi que le suivi de la filiere de commercialisation ont ete realises a Payo puis dans la ville de Lomie. L'espece est abondante dans les forets secondaires jeunes avec une densite de 6 tiges/ha. Le diametre moyen et la surface terriere des tiges recencees sont respectivement  estimes a 56,91 ± 14 cm et 19,46 m2/ha. Lfindice de regeneration   naturelle est evalue a 4,8 et influence par lfintensite lumineuse qui   parvient dans le sous bois. La production de 35 arbres pour une saison de fructification est estimee a 5 157 graines soit en moyenne 147,34  graines/arbre. La production annuelle est estimee a 1 261 255 graines  equivalant a 11 571 combo (unite de mesure locale). La valeur marchande de ces graines est estimee a 5 785 572 Frs CFA (11836 $US).   Lfexploitation des graines de P. macrophylla represente ainsi de bonnes perspectives de revenus pour cette localite.Mots cles : Production, commercialisation, Pentaclethra macrophylla, foret communautaire

Predominant melliferous plants of the western Sudano Guinean zone of Cameroon

Between September 2003 and March 2005, melissopalynological methods were used to access the predominant melliferous plants (PMP) in 104 honey samples collected from the Soudano Guinean highlands zone of west Cameroon. A total of 19 PMP from 11 families were identified, Asteraceae is the most represented. Trees and herbs were frequently exploited. Spontaneous PMP were more represented. Perennial PMP were highly visited by Apis mellifera adansonii. PMP with white colour flower are the most utilized by bees compared to other colours. When seasonal exploitation was considered, the proportion of PMP exploited in the rainy season was higher. Eucalyptus saligna, Terminalia mantaly and Pterocarpus soyauxii were frequently exploited.Key words: Apis mellifera adansonii, melliferous plant, predominant, harvested

Diversité floristique sous canopée en plantation forestière de Mangombe-Edea (Cameroun)

Floristic diversity under canopy in forest plantation of Mangombe-Edea (Cameroon). Trees plantation of Mangombe is situated in rain forest of low altitude. Six plots among which one of Mansonia altissima (A.Chev.) A.Chev., 2 of Lovoa trichilioides Harms, 3 of Terminalia ivorensis A.Chev. and one perturbed natural forest are concerned by this study. The work consisted to the evaluation of the floristic diversity under canopy in order to appreciate the influence of forest plantation on natural regeneration. A total of 26 families, 42 genders and 46 species were censured. Meliaceae and Apocynaceae are present in all the plots. In plot one of T. ivorensis, M. altissima and natural forest, the low value of equitability of Pielou traduces the dominance of flora by few species and the transitory situation of the ecosystem. On contrary the rest of plots present a good repartition of individuals among the species. One can notice a weak organization of the ecologic system in M. altissima plot, this corresponds to favourable conditions of environment for installation of many species represented by a few number of individuals. Shannon indices, relatively low in plot one of T. ivorensis characterize an ecosystem where one species is dominant. Globally, the regeneration under canopy is reconstituted progressively and remains less diversified than the nearest natural forest. Creation of genetic pool through selective entertainment under canopy will permit polycyclic management of plots for sustainable production of wood

Les Forêts Sacrées Dans Les Hautes Terres De l’OuestCameroun : Intérêt Dans La Conservation De La Biodiversité

La végétation des Hauts plateaux de l’Ouest-Cameroun est pratiquement domestiquée, les espèces originales sont réfugiées dans des reliques de forêts, dans des zones à accès difficile dans des forêts ripicoles le long des cours d’eau ou dans des forêts dites forêt sacrées. Le présent travail vise à évaluer la diversité floristique et à faire une analyse qualitative et quantitative de la flore de quelques forêts sacrées dans l’Ouest du Cameroun. Le statut de conservation des espèces a été également déterminé. Le recensement des individus s’est fait dans 41 placettes de 25 m x 25 m établies dans les forêts sacrées de Bafou, Baleveng, Bamendou, Mbing Mekoup, Bamendjinda et de Bamendjo. Le nombre de placettes par forêt dépendait de la taille de la forêt. À l’intérieur de chaque placette, tous les individus de diamètre supérieur ou égal à 10 cm à hauteur de poitrine (1,30 m) ont été considérés. Les indices de diversité de Shannon et de Simpson ont été utilisés pour évaluer la phytodiversité ; les valeurs d’importance des espèces et des familles ont été calculées. Le test d’ANOVA a été utilisé pour comparer statistiquement les données. Globalement, 2 829 individus de diamètre ≥ 10 cm appartenant à 91 espèces, 85 genres et 47 familles ont été inventoriés. Les valeurs des indices de diversité sont faibles (de 0,73 et 2,49 bits par placette pour l’indice de Shannon ; de 0,02 à 0,89 par placette pour l’indice de Simpson). Elles traduisent la faible diversité floristique de la zone. La surface terrière varie de 14,44 m2.ha-1 à 65,6 m2. ha-1 par forêt. L’analyse factorielle des correspondances individualise la flore en trois grands groupes suivant un gradient topographique, hydrologique et anthropique. La classification ascendante hiérarchique confirme les résultats de l’analyse factorielle des correspondances en individualisant trois grandes classes de flore. Le facteur altitude semble être le facteur principal qui influence l’individualisation de ces groupes déterminés par les analyses multivariées. D’après la liste rouge des espèces menacées de l'Union Internationale pour la Conservation de la Nature ; six espèces du total enregistré sont en situation de vulnérabilité (Prunus africana, Podocarpus mannii, Entandrophragma utile, Entandrophragma candollei, Cordia platythyrsa, Antidesma venosium). Cette étude souligne l’importance de la flore des forêts sacrées, les données obtenues pourront servir de bases pour une gestion durable de ces forêts. The vegetation of the Western Highlands is almost domesticated, and the original species are found in forest relics called sacred forest. These sacred forests also have an important number of floristic species. This work aims to assess the floristic diversity and to make a qualitative and quantitative analysis of the flora of some sacred forests in West Cameroon. The conservation status of the species was also determined using IUCN redlist. The census of individuals was carried out on 41 plots of 25 m x 25 m established in the selected forests. The number of plots per forest depended on the size of the forest. Within each plot, all individuals with a diameter greater or equal to 10 cm at breast height (1.30 m) were considered. The Shannon and Simpson diversity index were used to assess phytodiversity; importance values for species and families were calculated. The ANOVA test was used to compare the data. Overall, 2829 individuals with a diameter of ≥ 10 cm belonging to 91 species, 85 genera and 47 families were inventoried. Diversity index values are low (0.73 and 2.49 bits per plot for the Shannon index; 0.02 to 0.89 bits per plot for the Simpson index). These reflect the low floristic diversity of the area. The basal area varies from 14,44 m2. ha-1 to 65.6 m2. ha-1 per zone. Correspondence factor analysis individualizes the flora into three major groups following a topographic, hydrological, and anthropogenic gradient. Clustering hierarchical analysis confirms the results of the AFC by grouping the flora into three main classes according to the altitude. Amongst the species recorded, six others are in a vulnerable situation (Prunus africana, Podocarpus mannii, Entandrophragma utile, Entandrophragma candollei, Cordia platythyrsa, Antidesma venosium). This study highlights the importance of sacred forest vegetation as a basis for sustainable management of these forests

Afforestation/Reforestation Based on Gmelina Arborea (Verbenaceae) in Tropical Africa: Floristic and Structural Analysis, Carbon Storage and Economic Value (Cameroon)

The study was carried out in three selected plantations. Sampling was made infive 100x20 m2 plots per site. Overall, 32 species, 36 genera and 17 families were surveyed. Hymenocardia acida, Combretum adenogonium, Daniellia oliveri, Entada africana, Terminalia macroptera, T. laxiflora, Lannea schimperi, Lophira lanceolata, Maytenus senegalensis, Ochna schweinfurthiana, Protea madiensis, Psorospermum senegalense, Piliostigma thonningii, Sarcocephalus latifolius and Securidaca longepedunculata were the most important species. The richness index ranged from 2.53±0.05-7.74±0.03. Shannon index was 3 in all sites. Density ranged from 98±2.01-253±10.23 stems/ha. Basal area was statistically significant among the sites (p70 %). The vertical structure showed three types of figures; L shape, symmetrical bell shape and unsymmetrical bell shape. These structures confirmed a good regeneration of timbers in the sites. There was a positive correlation of the species dispersal in the sites (p<0.001). The amount of AGB was 23.50±0.38 t C/ha. The amount of C sequestration was 86.28±16.57 t CO2eq/ha. The ecosystem service payments ranged between 258.87±24.88-8629.25±248.16 €/ha with the lowest values for CDM price and the highest for REDD+price. A financing of such projects is required in the frame of creating adaptation and attenuation measures to global warming effects

Expériences sylvicoles au Cameroun : Croissance, mortalité et adaptabilité des espèces de bois d’oeuvre dans la station forestière de Mangombé (1964 - 2010)

Au Cameroun, l’exploitation du bois a entraîné la réduction du couvert forestier et son appauvrissement en espèces de bois d’oeuvre. Pour remédier à cette situation, de nombreuses plantations forestières ont été crées, puis abandonnées quelques décennies plus tard pour des raisons diverses, ce qui n’a pas permis de capitaliser l’ensemble des connaissances sylvicoles escomptées qui devaient permettre de réhabiliter les forêts et limiter les risques d’épuisement des stocks d’essences commerciales. Le dispositif sylvicole de Mangombé fait partie de ces initiatives, il ne compte plus que 27 parcelles d’arbres constituées de 15 espèces sur une quarantaine plantées. Ce travail, présente l’état de cette station forestière à travers l’étude de la croissance, de la mortalité des arbres et de l’adaptabilité des espèces. Dans chaque parcelle, toutes les tiges ont été inventoriées et leur diamètre à 1,30 m mesurés. Ce paramètre a permis d’établir la structure de population et d’apprécier la possible rentabilité économique des espèces. Les meilleures performances de croissance des arbres sont obtenues chez Gmelina arborea Roxb. (Gme-1 : 56 m²/ha) ; Araucaria cunninghamii Aiton ex D. Don (Ara-1 : 63 m²/ha) et Aucoumea klaineana Pierre (Auc-3 : 80 m²/ha). Les valeurs élevées des écarts types indiquent une croissance disproportionnée des individus à l’intérieur des parcelles. Les espèces présentant une faible mortalité et une proportion importante de tiges exploitées ainsi que de bonnes caractéristiques de croissance comme G. arborea, Dipterocarpus alatus Roxb. ex G. Don. (51 m²/ha) et A. klaineana se sont mieux adaptées au site de plantation et peuvent être recommandées pour les initiatives de reboisement dans la zone. La faible production observée chez un nombre élevé d’espèces est économiquement non rentable au regard des investissements onéreux consentis à la mise en place de la plantation.© 2015 International Formulae Group. All rights reserved.Mots clés: Mangombé, Cameroun, plantation forestière, sylviculture, croissance des arbres, mortalité, adaptabilitéEnglish Title: Sylvicultural experience in Cameroon: Growth, mortality and adaptability of wood species in Mangombe forest plantation (1964 - 2010)English AbstractIn Cameroon, logging has led to a reduction in forest cover and an impoverishment of several wood species. To solve this problem, many forest plantations had been created, then abandoned a few decades later for various reasons. This did not make it possible for foresters and policy makers to acquire expected knowledge from these experiences, which would have led to forest rehabilitation and reduced the risk of commercial wood extinction. Mangombe tree plantation is part of these experiences, which is a remnant of 15 out of 40 originally planted tree species distributed in 27 plots. This work presents the state of Mangombe forest plantation through the study of the growth, mortality of the trees and adaptability of species. All the trees were censored and their diameters measured in each plot. These measurements facilitate the establishment of the population structure and appreciate the economic profitability of the species. The best growth performances of trees were obtained with Gmelina arborea Roxb. (Gme-1 : 56 m²/ha) ; Araucaria cunninghamii Aiton ex D. Don (Ara-1 : 63 m²/ha) and Aucoumea klaineana Pierre (Auc-3 : 80 m²/ha). High values of standard deviations indicate a disproportionate growth of the individuals inside the plot. Species presenting a low mortality and a significant proportion of exploited stems as well as good growth characteristics such as G. arborea, Dipterocarpus alatus Roxb. ex G. Gift. (51 m²/ha) and A. klaineana were better adapted to the site and can be recommended for future initiatives of afforestation in the zone. The low production of certain species is economically non profitable considering the high investment during the establishment of the plantation.© 2015 International Formulae Group. All rights reserved.Keywords: Mangombé, Cameroon, forest plantation, sylviculture, trees growth, mortality, adaptabilit

Variabilité Structurale Des Peuplements D’arbres En Forêt De Montagne Du Parc National De Kahuzi-Biega Et Ses Environs, RD. Congo

This work aims to determine the change in the diametric structure, density, basal area, height and dominance of trees dbh ≥ 10 cm depending on altitude range or forest types. The study was conducted in 30 ha in Kahuzi Biega National Park and surrounding areas in DR Congo. In total, 16,797 individual trees were surveyed. The number of family, genus and species regress following the altitudinal gradient as the density increases. Mountain ecosystems in Kahuzi-Biega and its surroundings are dominated by Meliaceae, Euphorbiaceae, Moraceae, Fabaceae and Rubiaceae families. The Chi square analysis showed that the diametric structure of vegetation succession following a progressive dynamic and varies according to altitude gradient. The average basal area was 35 m²/ha. The analysis of variance (ANOVA) and post hoc Tukey test does not prove the impact of altitude on the basal area. But it becomes low in elevation due to the reduced diameter of the trees. The vertical structure was analyzed according to the classification IUFRO (International Union of Forest Research Organizations). The maximum height was 48 m and becomes lower in altitude. The tree height diameter relationship varies according altitude range so that the models H/D in this area should be developed for each forest type. We determine that the dominance of woody species following the altitude effect; only Strombosia scheffleri and Xymalos monospora dominated by its basal area, abundance and frequency of the various altitude horizons

Moabi (Baillonella toxisperma Pierre): Arbre à usage multiple de forêt dense humide du Cameroun

Le Moabi est un grand arbre de la for&#234;t dense humide du Cameroun. Cet arbre &#224; usages multiples, est recherch&#233; par l&#8217;industrie foresti&#232;re pour la qualit&#233; de son bois et par les populations rurales pour ses produits autres que le bois tels l&#8217;&#233;corce et les racines pour leurs importances m&#233;dicinales, les fruits pour la fabrication d&#8217;huile. Ces formes d&#8217;exploitations concurrentielles, tr&#232;s souvent sans soucis de durabilit&#233; ont consid&#233;rablement r&#233;duit les populations d&#8217;arbres, avec pour cons&#233;quence la raret&#233; des produits d&#233;riv&#233;s. Face &#224; cette forte pression anthropique qui s&#8217;exerce sur le Moabi dans le sud Cameroun, il a paru n&#233;cessaire d&#8217;effectuer une &#233;tude socio&#233;conomique et &#233;cologique dans les villages &#224; fortes activit&#233;s d&#8217;exploitation. En effet, la compr&#233;hension des atouts socioculturels et des divers liens et usages que les ruraux tissent autour de cet arbre, l&#8217;estimation des stocks disponibles dans les terroirs villageois est un pr&#233;alable imp&#233;ratif &#224; l&#8217;&#233;laboration des r&#232;gles de gestion durable. Les enqu&#234;tes aupr&#232;s des utilisateurs et les inventaires forestiers ont &#233;t&#233; r&#233;alis&#233;s dans sept villages. La distribution de cette esp&#232;ce est estim&#233;e &#224; 0,8 arbre/ha pour les individus d&#8217;un diam&#232;tre &#224; 1,3 m sup&#233;rieur &#224; 10 cm. Cet arbre rev&#234;t une importance socioculturelle et incarne des pouvoirs divins ind&#233;niables pour 65% des ruraux. Les femmes repr&#233;sentent 56,5% des exploitants des produits forestiers non ligneux issus de cet arbre. Elles sont plus que les hommes, tributaires de l&#8217;exploitation des fruits et des &#233;corces du Moabi. De ce fait, elles sont les principales victimes des conflits d&#8217;int&#233;r&#234;ts. Les &#233;corces et le latex sont utilis&#233;s en pharmacop&#233;e. La production d&#8217;huile &#224; partir des fruits peut g&#233;n&#233;rer jusque 1 050 000 Fcfa de rentr&#233;es financi&#232;res dans le village Melondo. L&#8217;importance de ce gain incite &#224; promouvoir l&#8217;extraction d&#8217;huile de Moabi dans le cadre de la diversification des sources de revenus et de la lutte contre la pauvret&#233;.Mots cl&#233;s: Moabi, usages multiples, gestion soutenue, communaut&#233; rurale, Camerou

Can the Mangombe forest plantation contribute to restore and conserve biodiversity?

This research, conducted in the tropical rainforest, is focused on restoration of tree diversity through natural regeneration mechanism in the 49 year-old Mangombe forest plantation. 12 plots were surveyed, 6 with large transects and the 6 others under regrowth. In each plot, two subplots with 400 m² each were demarcated for the inventory of all stems with diameter greater than 2.5 cm. A total of 2239 stems comprising 107 species distributed in 93 genera and 42 families were identified over 9600 m². There was a slight difference between species richness of plots with large transect (79 species, 72 genera and 35 families) and regrowth plots (85 species, 76 genera and 38 families) while the basal area in the plots with large transects (10.76 m²/ha) was significantly greater than that of regrowth (8.65 m²/ha). Species with high important value index have an affinity with forest undergrowth such as: Tabernaemontana pachysiphon, T. crassa, Mallotus oppositifolius and Heinsia crinita. The undergrowth is diversified with different life feature and a high number of small size trees indicating a vigorous regeneration. This can be favoured by: microclimate undergrowth, canopy gaps, abundance of litter fall that brings humus to the soil, type and age of plots, planted species and the complexity of spatial and vertical structure of the stand.© 2016 International Formulae Group. All rights reserved.Keywords: Mangombé – Cameroon, Natural regeneration, dense humid forest, tree plantation, biodiversit

Assessment of Fuel Wood Values and the Influence of Wood Cutting on the Easily Flooded Plain Woodland of the Sahelian Area, Cameroon

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 &gt; 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