References of "Doucet, Jean-Louis"
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See detailEcological wood anatomy of 155 African tropical hardwoods
Beeckman, Hans; Fayolle, Adeline ULg; Doucet, Jean-Louis ULg et al

Conference (2013, April 19)

In this study we aimed at identifying the anatomical characters expressing life history traits of woody species from the northern Congo Basin. We crosschecked three databases: the botanical inventories ... [more ▼]

In this study we aimed at identifying the anatomical characters expressing life history traits of woody species from the northern Congo Basin. We crosschecked three databases: the botanical inventories produced during the CoForChange project (857 spp.), the database of life history traits established by the CIRAD (France) and GxABT (Belgium) (464 spp.), and the anatomical database Inside Wood (761 spp. and genera for tropical Africa). A total of 155 shared species was obtained. We performed correspondence analyses between the anatomical characters and two main groups of traits: leaf phenology and light-requirement. Results showed: (i) that wood anatomy is involved in leaf phenology and light-requirement in a significant way (7.56% of the variance on axe1), (ii) that evergreenness was correlated to IAWA characters 14 to 18 (scalariform perforation plates, e.g. Olacaceae) and deciduousness to characters 118 to 122 (storied structures, e.g. Malvaceae and Meliaceae), (iii) that pioneer (P) and non-pioneer light-demanding (NPLD) species showed similar traits but were different from shade-tolerant (ST) species, (iv) that deciduous and evergreen species showed separate distributions, and (v) that wood anatomy validated the well documented strong correlation between evergreen species and ST species, with an inversion of the tendency for deciduous species correlated to P and NPLD species. We conclude that anatomical characters can be used as indicators of life history traits in species-rich biomes. Further investigations are needed to increase the input of wood anatomy in explaining the life history traits in African tropical species. [less ▲]

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See detailWestern lowland gorilla populations and logging concessions: is the coexistence possible?
Haurez, Barbara ULg; Petre, Charles-Albert ULg; Doucet, Jean-Louis ULg

Conference (2013, April)

Timber exploitation is rapidly expanding throughout the Congo Basin. Around 26 % of the moist forests are devoted to logging activities. Logging concessions largely overlap with the range of western ... [more ▼]

Timber exploitation is rapidly expanding throughout the Congo Basin. Around 26 % of the moist forests are devoted to logging activities. Logging concessions largely overlap with the range of western lowland gorilla (WLG) considered as critically endangered by IUCN. However, this species could play an essential role in maintaining vegetal diversity notably through seed dispersal services. Particularly some tree species harvested for their timber may be dispersed by WLG. In this communication interactions between WLG and a timber exploitation are studied in Central Gabon. WLG density is estimated in an Annual Allowable Cut (AAC), and nesting behavior is described. Seeds dispersed by WLG are identified through fecal analysis and germination trials are conducted to assess seed viability after gut passage. Four treatments are realized for the most abundant species: passed seeds, passed seeds in fecal matrix, seeds surrounded by fresh pulp and seeds extracted from fresh fruits. A relatively high WLG density is observed in the AAC (2.0 weaned gorillas/km²). WLG nest preferentially in open terra firme forest and frequently use old logging road covered with herbaceous vegetation for nesting and feeding. They avoid nesting in closed terra firme forest. Seed dispersal and impacts of the passage in gorilla’s gut on seed germination are currently described. Germination success after gut passage depends on the seed species and varies from 0.0 to 100% in the course of monitoring time. The first results of this study suggest 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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See detailLes forêts communautaires, c'est aussi une histoire de femmes
Meunier, Quentin; Boldrini, Sylvie ULg; Morin, Amélie et al

Learning material (2013)

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See detailLes équations allométriques pan-tropicales plurispécifiques sont-elles valables en Afrique centrale ?
Fayolle, Adeline ULg; Doucet, Jean-Louis ULg; Gillet, Jean-François ULg et al

in Picard, Nicolas; Henry, Mathieu (Eds.) Compte-rendu de l'Atelier scientifique régional sur les équations allométriques en Afrique Centrale : PREREDD, Yaoundé 2-5 avril 2013 (2013, April)

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See detailRelation entre composition floristique et accumulation de biomasse dans deux types de forêts de la Réserve de Biosphère du Dja (Cameroun)
Djuikouo, Marie Noel K.; Doucet, Jean-Louis ULg; Nguembou, Charlemagne K. et al

Poster (2013, April)

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See detailLes forêts vierges du Bassin du Congo - mythe ou réalité ?
Morin-Rivat, Julie ULg; Bourland, Nils ULg; Gillet, Jean-François ULg et al

Scientific conference (2013, March 21)

Les forêts du bassin du Congo ont longtemps été considérées comme des massifs historiquement épargnés par l'action de l'homme. Des résultats plus ou moins récents de recherches scientifiques remettent en ... [more ▼]

Les forêts du bassin du Congo ont longtemps été considérées comme des massifs historiquement épargnés par l'action de l'homme. Des résultats plus ou moins récents de recherches scientifiques remettent en question cette vision des forêt denses humides africaines. [less ▲]

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See detailLettre d’information trimestrielle du projet Développement d’Alternatives Communautaires à l’Exploitation Forestière Illégale
Boldrini, Sylvie; Moumbogou; Meunier, Quentin et al

E-print/Working paper (2013)

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See detailLes formations végétales du Sénégal : description et menaces
Doucet, Jean-Louis ULg

Conference given outside the academic context (2013)

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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 ULg 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 detailNature+ asbl - Rapport d'activités 2012
Federspiel, Michèle; Doucet, Jean-Louis ULg; Daïnou, Kasso ULg et al

Report (2013)

En 2012, Nature+ a rencontré ses missions, notamment : en mettant en oeuvre trois projets de foresterie communautaire financés par des bailleurs internationaux ; en participant à la gestion durable de ... [more ▼]

En 2012, Nature+ a rencontré ses missions, notamment : en mettant en oeuvre trois projets de foresterie communautaire financés par des bailleurs internationaux ; en participant à la gestion durable de près de 2,7 millions d’hectares de forêts denses humides tropicales grâce à nos collaborations avec des sociétés forestières engagées dans les processus de certification FSC ; en accueillant dans nos divers projets 10 étudiants en fin de cursus universitaire ainsi que 11 doctorants. Huit universités différentes ont ainsi reçu un appui administratif, technique et scientifique de Nature+ ; en attribuant sa 2eme bourse de formation à un chercheur congolais. [less ▲]

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See detailEssais de propagation par semis et marcottage aérien de Coula edulis Baill. et perspectives pour sa domestication
Moupela, Christian; Doucet, Jean-Louis ULg; Daïnou, Kasso ULg et al

in Bois et Forêts des Tropiques (2013), 318(4), 3-13

Le noisetier d’Afrique, Coula edulis Baill. Olacaceae, est un arbre des forêts denses humides africaines. Il produit des graines d’une grande valeur nutritive qui sont régulièrement récoltées et ... [more ▼]

Le noisetier d’Afrique, Coula edulis Baill. Olacaceae, est un arbre des forêts denses humides africaines. Il produit des graines d’une grande valeur nutritive qui sont régulièrement récoltées et commercialisées par les populations d’Afrique centrale et de l’Ouest. Cependant, le manque d’informations relatives aux techniques de multiplication de l’espèce est la principale contrainte à sa domestication et à son intégration dans les systèmes agroforestiers locaux. L’étude, conduite parallèlement en pépinière et en milieu naturel, vise à mieux caractériser la germination de C. edulis et à déterminer ses aptitudes au marcottage aérien. Les résultats obtenus indiquent que la germination de C. edulis est très lente et échelonnée avec des taux de levée très faibles, voire nuls. De plus, les prétraitements appliqués aux graines se sont révélés inefficaces pour améliorer la vitesse et le taux de levée des semences. En revanche, le marcottage aérien permet de produire des plants de C. edulis d’une vigueur bien supérieure et dans un délai plus court que les semis en pépinière. Les résultats préliminaires du marcottage aérien sont prometteurs et ouvrent des perspectives intéressantes pour la multiplication et la domestication de l’espèce. L’intégration de Coula edulis dans les systèmes agroforestiers des plants issus du marcottage aérien est donc envisageable. [less ▲]

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See detailLarge trees drive forest aboveground biomass variation in moist lowland forests accross the tropics
Slik, J. W. Ferry; Paoli, Gary; McGuire, Krista et al

in Global Ecology & Biogeography (2013), 22

Aim Large trees (d.b.h. 70 cm) store large amounts of biomass. Several studies suggest that large trees may be vulnerable to changing climate, potentially leading to declining forest biomass storage. Here ... [more ▼]

Aim Large trees (d.b.h. 70 cm) store large amounts of biomass. Several studies suggest that large trees may be vulnerable to changing climate, potentially leading to declining forest biomass storage. Here we determine the importance of large trees for tropical forest biomass storage and explore which intrinsic (species trait) and extrinsic (environment) variables are associated with the density of large trees and forest biomass at continental and pan-tropical scales. Location Pan-tropical. Methods Aboveground biomass (AGB) was calculated for 120 intact lowland moist forest locations. Linear regression was used to calculate variation in AGB explained by the density of large trees. Akaike information criterion weights (AICcwi) were used to calculate averaged correlation coefficients for all possible multiple regression models between AGB/density of large trees and environmental and species trait variables correcting for spatial autocorrelation. Results Density of large trees explained c. 70% of the variation in pan-tropical AGB and was also responsible for significantly lower AGB in Neotropical [287.8 (mean) 105.0 (SD) Mg ha-1] versus Palaeotropical forests (Africa 418.3 91.8 Mg ha-1; Asia 393.3 109.3 Mg ha-1). Pan-tropical variation in density of large trees and AGB was associated with soil coarseness (negative), soil fertility (positive), community wood density (positive) and dominance of wind dispersed species (positive), temperature in the coldest month (negative), temperature in the warmest month (negative) and rainfall in the wettest month (positive), but results were not always consistent among continents. Main conclusions Density of large trees and AGB were significantly associated with climatic variables, indicating that climate change will affect tropical forest biomass storage. Species trait composition will interact with these future biomass changes as they are also affected by a warmer climate. Given the importance of large trees for variation in AGB across the tropics, and their sensitivity to climate change, we emphasize the need for in-depth analyses of the community dynamics of large trees. [less ▲]

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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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