References of "Doucet, Jean-Louis"
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See detailDispersal and predation of diaspores of Coula edulis Baill. in an evergreen forest of Gabon
Moupela, Christian ULg; Doucet, Jean-Louis ULg; Daïnou, Kasso ULg et al

in African Journal of Ecology (2013), 52

The African walnut ( Coula edulis) is a tree species of African evergreen forests, the seeds of which are collected and traded by African people. Many animal species consume African walnut diaspores ... [more ▼]

The African walnut ( Coula edulis) is a tree species of African evergreen forests, the seeds of which are collected and traded by African people. Many animal species consume African walnut diaspores; however, their roles as dispersers or predators have yet to be clarified. In this study, we present observations conducted in two different habitats of a Gabonese region over a 3-year period. The originality of this research resides in the combination of three complementary approaches: (i) the use of camera-traps (ii) the exploration of land rodent burrows and (iii) the examination of elephant dung. In total, 408 camera-trap photographs have shown seven animal species involved in the dispersal/predation of C. edulis. Among these seven frugivorous species, the bush pig was found to be the main consumer and predator of seeds. Land rodents (Muridae) are potential predators, as they damaged the seeds and buried them deep in the soil. They may also play a role in the regeneration process as a result of the loss of seeds during transportation. Finally, no seeds appeared to emerge intact from elephant faeces. These results indicate that the natural regeneration rate of this tree species is low, unless other complex mecha-nisms are involved. [less ▲]

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See detailThe Enhancement of Secondary Succession by Western Lowland Gorillas (Gorilla gorilla gorilla) in a Moist Tropical Forest of Southeast Cameroon
Petre, Charles-Albert ULg; Haurez, Barbara ULg; Tagg, Nikki et al

in Folia Primatologica : International Journal of Primatology = Internationale Zeitschrift für Primatologie = Journal international de Primatologie (2013), 84

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See detailRéviser les tarifs de cubage pour mieux gérer les forêts du Cameroun
Fayolle, Adeline ULg; Rondeux, Jacques ULg; Doucet, Jean-Louis ULg et al

in Bois et Forêts des Tropiques (2013), 317(3), 35-49

Volume tables are routinely used by forest planners and managers, but generally with no regard for the conditions in which they are applied (geographical zone, diameter range), which can cause errors in ... [more ▼]

Volume tables are routinely used by forest planners and managers, but generally with no regard for the conditions in which they are applied (geographical zone, diameter range), which can cause errors in estimations of timber volumes. The aim of this study is to test the validity of currently available volume tables, including those used by the government, for three commercial tree species in the forests of south-eastern Cameroon, and if required to propose tables suited to the study zone. The three species concerned are sapelli, Entandrophragma cylindricum, tali, Erythrophleum suaveolens, and assamela Pericopsis elata. Dendrometric data were collected by destructive sampling of 43 trees that were evenly distributed across the diameter range. Stemwood volume was calculated through successive butt-log measurements and linear and non-linear volume tables were adjusted by means of the weighted least-squares method. The results show that the best volume tables for all three species are non-linear. The equations used by the forests authority until now significantly under-estimate standing timber volumes and the estimation errors increase with the size of the trees. The proposed volume tables, once validated, should in future produce more accurate estimations of standing timber in the study zone. Given the international challenges involving Cameroon (FLEGT and REDD+), it is essential that it should have effective tools for estimating standing timber volumes. It is therefore important for Cameroon’s forests authority to conduct a large-scale programme to revise its volume tables. [less ▲]

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See detailRole of the western lowland gorilla (Gorilla gorilla gorilla) in seed dispersal in tropical forests and implications of its decline
Petre, Charles-Albert ULg; Tagg, Nikki; Haurez, Barbara ULg et al

in Biotechnologie, Agronomie, Société et Environnement = Biotechnology, Agronomy, Society and Environment [=BASE] (2013), 17(3), 517-526

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See detailTree allometry in Central Africa: Testing the validity of pantropical multi-species allometric equations for estimating biomass and carbon stocks
Fayolle, Adeline ULg; Doucet, Jean-Louis ULg; Gillet, Jean-François et al

in Forest Ecology & Management (2013), (305), 29-37

There is a lot of uncertainty in the amount and spatial variations of above-ground biomass in Africa, partly because very few allometric equations are available. The aim of this study was to assess the ... [more ▼]

There is a lot of uncertainty in the amount and spatial variations of above-ground biomass in Africa, partly because very few allometric equations are available. The aim of this study was to assess the validity of using pan-tropical multispecies allometric equations developed by Chave et al. (2005) for estimating the above-ground biomass of trees in Central Africa and/or to develop site-specific equations. The study was conducted in lowland tropical forests of South-eastern Cameroon, at the edge between evergreen and semi-evergreen forests. Data of above-ground woody biomass were obtained from destructive sampling of 138 trees belonging to 47 taxa across a huge range of diameter (5.30–192.50 cm) and wood specific gravity (0.284–1.152 g cm 3). A set of local site-specific multi- and single-species models relating above-ground biomass to tree diameter and wood specific gravity were fitted to the data. The best model was selected using information criterion. Both tree diameter and wood specific gravity were important predictor to consider for the estimation of above-ground biomass at tree scale. Single-species models were not necessarily better than multi-species models including wood specific gravity as a predictor. The best local multi-species model had the same structure and parameters as the pan-tropical equation developed by Chave et al. (2005) for moist forests. The estimates from the pan-tropical multi-species equation were nearly as good as those of the local multi-species equation. Using wood specific gravity from the global data base only slightly increased the estimation errors, because for the study taxa wood specific gravity was highly correlated to wood specific gravity from the global data base. In this study, we showed that the pantropical multi-species allometric equation developped for moist forests can be used to produce accurate estimates of biomass and carbon stocks from diameter measurement in forest inventory and wood specific gravity from global data base at species level. These findings are especially timely given the urgent need to quantify biomass and carbon stocks in the tropics, and given the spatial extent of moist forests in Central Africa. [less ▲]

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See detailLa pratique des inventaires multi-ressources dans les forêts communautaires, ou comment rendre la foresterie communautaire inaccessible aux villageois
Meunier, Quentin; Vermeulen, Cédric ULg; Boldrini, Sylvie et al

E-print/Working paper (2013)

Des inventaires trop complexes imposés aux populations locales risquent de freiner considérablement l'appropriation des futures forêts communautaires gabonaises. La présente fiche technique compare les ... [more ▼]

Des inventaires trop complexes imposés aux populations locales risquent de freiner considérablement l'appropriation des futures forêts communautaires gabonaises. La présente fiche technique compare les avantages et inconvénients des inventaires par poches, des inventaires d'exploitation habituellement réalisés dans les Forêts Communautaires camerounaises et une approche plus simple par normes proposée par l'équipe rédactionnelle. [less ▲]

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See detailThe abundance of charcoal fragments emphasizes the assumption of huge palaeofires in the mixed moist semi-evergreen rainforest of the northern republic of Congo
Gillet, Jean-François ULg; Doucet, Jean-Louis ULg

in Damblon, Freddy (Ed.) Proceedings of the Fourth International Meeting of Anthracology (2013)

In this paper, we study the origins of the northern Congo Republic rainforests. Macroscopic charcoal fragments were systematically recorded through auger investigations and pits observations in four ... [more ▼]

In this paper, we study the origins of the northern Congo Republic rainforests. Macroscopic charcoal fragments were systematically recorded through auger investigations and pits observations in four forest types: the open canopy Marantaceae forest, the dense forest with Marantaceae, the Gilbertiodendron dewevrei forest and the Triplochiton scleroxylon forest. In addition, the charred Elaies guineensis seeds were distinguished from the other charcoals in the pits. Ten selected charcoals, including charred E. guineensis seeds, were dated by AMS. Abundance of charcoal fragments in the soils at various depths indicated several episodes of fires in the region. A dryer climatic phase, between 2320 and 1330 BP, associated with a large scale human occupation related to the important harvesting of oil palm nuts, could explain the widespread Marantaceae forests. Recent slash-and-burn shifting cultivation, c. 200 BP, would allow T. scleroxylon installation. Implications for forest management are discussed. [less ▲]

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See detailPlant-animal mutualistic interaction: the case of the Uapaca trees and the western lowland gorilla (G. g. gorilla)
Petre, Charles-Albert ULg; Tagg, Nikki; Beudels-Jamar, Roseline et al

in Primate Tidings (2012), 27

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See detailRegards croisés sur la foresterie communautaire : l'expérience camerounaise
Doucet, Jean-Louis ULg; Vermeulen, Cédric ULg; De Vleeschouwer, Jean-Yves ULg et al

Book published by Presses Agronomiques de Gembloux (2012)

Le Cameroun est le pays pionnier de la foresterie communautaire en Afrique centrale. En promulguant, en 1994, une loi autorisant les communautés locales à gérer elles-mêmes leurs forêts, l’Etat ... [more ▼]

Le Cameroun est le pays pionnier de la foresterie communautaire en Afrique centrale. En promulguant, en 1994, une loi autorisant les communautés locales à gérer elles-mêmes leurs forêts, l’Etat s’engageait dans un long processus de décentralisation. L’asbl Nature +, l’ONG SNV et Gembloux Agro-Bio Tech (Université de Liège) furent parmi les premiers acteurs à accompagner les communautés rurales dans leurs démarches d’auto-gestion. En 2010, ces trois organisations, grâce à un financement du Fonds des Forêts du Bassin du Congo, ont mis en commun leurs expériences au sein du projet « Partenariats pour le Développement des Forêts Communautaires ». Ce projet a appuyé le développement technique, institutionnel et organisationnel de regroupements de forêts communautaires dans trois zones (Ngambé Tikar, Lomié et Ebolowa). Visant le renforcement des capacités selon le principe de « l’apprentissage par l’action encadrée », le projet a permis de rendre les associations locales davantage autonomes. Ce livre nous fait découvrir le quotidien des forêts communautaires dont il expose sans ambages les forces et les faiblesses. Richement illustré, il prend le pari que la beauté des images suscitera intérêt et questionnement. [less ▲]

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See detailEcology of Pericopsis elata (Fabaceae), a Timber Species Considered as Endangered, in Southeastern Cameroon
Bourland, Nils ULg; Kouadio, Yao Lambert; Lejeune, Philippe ULg et al

in Biotropica (2012), 44(6), 840-847

Pericopsis elata (Fabaceae) is a tall tree of high commercial value of the moist semi-deciduous African forests. As a result of logging which started decades ago, it is considered as threatened and ... [more ▼]

Pericopsis elata (Fabaceae) is a tall tree of high commercial value of the moist semi-deciduous African forests. As a result of logging which started decades ago, it is considered as threatened and included on both IUCN Red List and CITES Appendix II even though essential biological parameters controlling its population dynamics remain unknown. This study aims at improving the knowledge of the species ecological parameters and at assessing the impact of selective logging on its populations in an 118,052 ha forest in Cameroon. After inventorying the species in 1,432 ha, mortality and growth were assessed over continuous 5- and 2-year periods in unlogged and logged areas, respectively. Phenology was monitored in the unlogged forest during 5 years. The population structure followed a bell-shaped curve. Mean annual diameter increments in both environments did not differ significantly between unlogged and logged areas. P. elata is a deciduous species that flowers at the end of the main dry season. The minimum reproduction and effective flowering diameters were, respectively, 32 and 37 cm. Fruit maturation took place during 7 months. With a minimum logging diameter of 90 cm, the recovery rate computed over a 30-year period was greater than 100%. Selective logging harvested only 12.1% of the total number of seed trees and had little influence on the species biological parameters. Securing sufficient regeneration as a post-logging action is probably the most important consideration for achieving long-term sustainability. Implications for the conservation status of the species are discussed at the regional level. [less ▲]

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See detailLes équations allométriques pantropicales sont-elles valides en Afrique centrale
Fayolle, Adeline ULg; Ernst, Gaëtan; Bouissou, Christina et al

Scientific conference (2012, October 24)

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See detailDynamique forestière et enrichissements forestiers. Site de Mbang. Rapport n° 9.
Doucet, Jean-Louis ULg; Amandé, Jean; Bracke, Charles et al

Report (2012)

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See detailInteractions between western lowland gorillas (Gorilla gorilla gorilla Savage & Wyman 1847) and timber exploitation: Preliminary insights in a Gabonese logging concession
Haurez, Barbara ULg; Petre, Charles-Albert ULg; Doucet, Jean-Louis ULg

Poster (2012, August 15)

Interactions between western lowland gorillas (WLG) and a timber exploitation were studied in Central Gabon. WLG densities were estimated in two sites with different logging histories (not logged vs ... [more ▼]

Interactions between western lowland gorillas (WLG) and a timber exploitation were studied in Central Gabon. WLG densities were estimated in two sites with different logging histories (not logged vs. logged one month before), and nesting behavior was described. Seeds dispersed by WLG were identified through fecal analysis and germination trials assessed seed viability after gut passage. Four treatments were realized for the most abundant species: passed seeds, passed seeds in fecal matrix, seeds surrounded by fresh pulp and seeds extracted from fresh fruits. Relatively high WLG densities were observed in the concession (3.7 weaned gorillas/km² in unlogged forest and 1.7 weaned gorillas/km² in logged forest). WLG nested preferentially in open areas (particularly open terra firme and swamp forest) and frequently used old logging road network for nesting and feeding. WLG dispersed sixteen species during the course of the study (February-May 2011). The most dispersed species was Santiria trimera (Burseraceae). The germination successes of S. trimera were significantly higher after gut passage (N=378; P<0.001) because of pulp removal and seed coat scarification. This pilot study suggests that timber exploitation and WLG conservation are not mutually exclusive. WLG are important agents of forest regeneration by dispersing seeds in logged areas. Nest sites in logging gaps could be particularly favorable for seedlings development. This consideration must encourage forest managers to strengthen WLG-conservative practices in their concessions. [less ▲]

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