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Measuring biomass and leaf area using non-destructive methods is of great interest to avoid plant degradation. These data are necessary for biomass allocation and estimation of carbon distribution in trees using functional and structural growth models such as GREENLAB. Organ biomass and leaf area are important parameters in plant physiology and production. They are used in structural and functional plant models to simulate tree architecture but are difficult to determine rapidly. Using stem length and internode diameter and leaf length and width to estimate them is a rapid, non-destructive field approach. We used the method on Khaya senegalensis, Pterocarpus erinaceus and Parkia biglobosa in Cote d'Ivoire. Internodes and leaves of the three species were sampled in 2019 and 2020 on three categories of axis in the architecture of individuals of different ages to maximize size variability. All statistical relationships found in the linear, logarithmic, polynomial and power models used to estimate the dry biomass of organs and leaf area were significant in all three species (P = 0.0001). The best models were obtained with the logarithmic transformation of the data. Three equation (linear, power and polynomial) were sufficient to estimate internode dry biomass (IDM), leaf dry biomass (LDM) and leaf area (LA) from the dimensions of the internodes (Volume: VL) and leaves (rachis length: RCL, number of primary leaflets: NLt, length: LLtL and width: LLtW of the largest primary leaflet in Khaya senegalensis and Pterocarpus erinaceus, then number of secondary leaflets: NSeLt, length: LSeLtL and width: LSeLtW of the largest secondary leaflet in Parkia biglobosa). In the field, the scientist will therefore make a choice according to his convenience among these proposed models. The best relationships between the measured organ dimensions and estimated parameters were defined by the following equations: IDM = 0.45*VL + 0.02, LDM = 1.07*NLt*LLtL*LLtW-2.74 and LA = 0.83*NLt*LLtL*LLtW or LA = 0.08*[NLt*LLtL*LLtW]2 + 1.13*[NLt*LLtL*LLtW]-0.27 for Khaya senegalensis; IDM = 1.15*VL0.26, LDM = 0.71*RCL*LLtL*LLtW-1.64 and LA = 0.74*NLt*LtL*LtW + 0.15 or LA = 0.03*[NLt*LLtL*LLtW]2 + 0.65*[NLt*LLtL*LLtW] + 0.23 for Pterocarpus erinaceus then IDM = 1.45*VL0.39, LDM = 0.23*[NSeLt*LSeLtL*LSeLtW*NLt]2–0.4*[NSeLt*LSeLtL*LSeLtW*NLt]-0.11 and LA = 1.81*[NSeLt*LSeLtL*LSeLtW*NLt]0.65 for Parkia biglobosa. This method can be applied to estimate the organ biomass and leaf area of species of the same family as the target species in an agroforestry system.

Pterocarpus erinaceus is a popular tree for medicinal and fodder uses in the Sudano-Sahelian belt of West Africa. It is also used for its wood. P. erinaceus is one of the most exploited tree species in many countries in West Africa. Planks and logs have been exported towards the South-West Asian countries for ten years. This paper analysed the demographic structure, the ecological characteristics of natural stands of P. erinaceus and level of human pressure they suffer in two agro-ecological zones of Burkina Faso and Niger. Transects were installed in four forests of which two were in the Sahelian zone of Niger and two were in the Sudan region of Burkina Faso. Measurements and observations focused on the dendrometric parameters, soil type, vegetation type and the presence of termite mound. The traces of debarking and pruning were noted. Trenching traces have been categorized into 3 classes according to their intensity. The Sudanian zone shows higher densities than the Sahelian zone. The largest individuals of P. erinaceus (the mean diameter and the highest average height) are observed in the W regional park (57.7 ± 18.6 cm and 10.8 ± 2 m) although this park belongs to the Sahelian zone. In all areas, distribution of diameter classes are bells, characteristics of aging stands with predominance of older individuals. Dendrometric characteristics vary according to the agro-ecological zones, soil type and vegetation. Twenty-one percent of P. erinaceus inventoried in the Sahelian zone and 13% in Sudanian area are close to an anthill. P. erinaceus is a species of Sahelo-Sudanese areas, analysis of its demographic structure shows that individuals of small diameter are very poorly represented in all forests. The species is exploited much more in Sahelian zones for feed supplements. The soil type and vegetation type influence the growth of P. erinaceus. Indeed, the strongest individuals were observed on soil clay loam, sandy loam soil and woodland. Key word: Pterocarpus erinaceus, demographic characteristics, Sahelian and Sudanian zones, Niger, Burkina Faso.

En Afrique tropicale, dans les plantations forestières, la majorité des espèces autochtones ont été délaissées au profit d’espèces exotiques à croissance initiale rapide. Cette tendance est encore plus marquée dans les zones soudanienne et soudano-guinéenne à longue saison sèche. Ainsi s’explique le manque de connaissances sur les potentialités et la sylviculture des espèces d’arbres autochtones ou « locales ». Pour contribuer à l’acquisition de ces connaissances indispensables, un arboretum de 2,56 ha a été installé en 1990 à proximité de Korhogo dans le nord de la Côte d’Ivoire. Sa particularité réside dans la mise en place de grandes parcelles de 1 596 m² avec 224 plants par espèce afin d’y mener une sylviculture qui conserverait de 10 à 16 arbres adultes de chaque espèce, exploitables notamment pour le bois d’œuvre, au terme de la révolution. Par manque de maîtrise des techniques de pépinière pour certaines espèces, seules 12 espèces sur 22 ont été plantées avec les 224 plants prévus au départ. Les résultats sont présentés pour l’ensemble des espèces testées, aussi bien en pépinière qu’en plantation. Cet arboretum a été régulièrement suivi jusqu’en 1999 puis ne l’a plus été en raison des évènements politiques qui ont perturbé la bonne administration du pays. Une campagne de mesures a été diligentée en novembre 2019 qui a permis notamment de tirer des conclusions intéressantes sur l’aptitude de 15 espèces à croître en peuplements équiennes monospécifiques, dont deux (Pterocarpus erinaceus Poir. et Anogeissus leiocarpa (DC.) Guill. & Perr.) qui montrent une productivité remarquable. L’ensemble des données recueillies depuis la récolte des graines et tout au long de la vie de l’arboretum sont présentées ici et discutées dans l’espoir que les sylviculteurs de cette zone phytogéographique en tirent le meilleur profit. Les enseignements acquis doivent servir à la restauration des forêts et des paysages grâce aux reboisements auxquels les États se sont engagés pour lutter contre les variations climatiques, la perte de biodiversité et la dégradation des services écosystémiques aux populations.

Pterocarpus erinaceus is a native tree species of the Guineo-Sudanian and Sudano-Sahelian zones where natural stands are under constant pressure and heavily exploited for timber, animal feeding and others uses. A part from the overexploitation, climate change could also become a serious threat to the species natural distribution. For that purposes, this study aims to assess the vulnerability of P. erinaceus potential niche to climate change within its natural distribution area in West Africa. Niche predictions are based on 6,981 natural occurrence of the species and 19 global bioclimatic variables available through WorldClim. The future niche of the species is predicted according to three concentration pathways (RCPs 2.6, 4.5 and 8.5) of BC model for 2050 and 2070, thanks to Maxent software. P. erinaceus is currently reported from Senegal to Cameroon. Its potential niche covers the Sudano-Sahelian zone and the Dahomey gap on approximately 17.42% of the total area of these countries. In general, the niche of the species is not sensitive to climate change, regardless of the climate scenario and the year. Compared to its initial niche, the niche of the species will increase from 22.33% to 43.61% in 2050 and from 27.12% to 53.61% in 2070. However, this ecological expansion observed mainly in the Gulf of Guinea, will be associated with a considerable decrease in the Sahel and central Nigeria. This study shows the importance of promoting the development of innovative silvicultural strategies for the extension and restoration of natural stands of P. erinaceus in order to meet sustainably the timber needs of the West African region. It helps also to strengthening the roles of natural forests in providing ecosystem services and mitigating climate change effects., Pterocarpus erinaceus, vulnerability, species distribution modeling, quality wood supply, forest restoration, West Africa, Applied Computing; Climatology; Ecology; Environmental Management; Ecology, Environmental Science.

Efforts to develop allometric models for accurate estimation of biomass and carbon sequestration in Sub-Saharan African savanna ecosystems remain inconclusive. Most available allometric models are not site-specific, and hence do not account for the effects of regional climate variabilities on tree growth and capacity to sequester carbon. In contrast, site-specific biomass allometric models constitute a robust tool for forest and carbon emission management in the context of the reducing emissions from deforestation and degradation program (REDD+). Although site-specific models have been developed for several tropical tree species, such models do not exist for Pterocarpus erinaceus in Burkina Faso. In this study, we investigated biomass fraction patterns and used a system of additive allometric models for predicting aboveground biomass and carbon stocks of P. erinaceus components. Thirty P. erinaceus trees were destructively sampled to estimate the biomass of their stems, branches and leaves. The biomass fraction of each component was assessed and its relationship with tree diameter at breast height (dbh) examined. The best allometric equations of the tree components, selected from three non-linear models with dbh, height (ht) and crown diameter (Cd) as predictors, were combined to develop an additive allometric model, using the Seemingly Unrelated Regressions (SUR) method. The Ash method was then used to estimate the carbon content of the different components. Leaf and stem biomass fractions decreased when the dbh increased, whereas a reverse trend was observed for branch biomass. Dbh was the most correlated independent variable with all biomass components. AGB = e−3.46(dbh)1.62+e−2.45(dbh)2.31+e−2.68(dbh) was the most appropriate additive allometric equation for estimating the biomass of P. erinaceus trees. The carbon content of the leaves, branches and stems was 55.73%, 56.68% and 56.23%, respectively. The developed allometric equations can be used to accurately estimate the aboveground biomass of P. erinaceus in the savannas of Burkina Faso and other similar ecosystems in Sub-Saharan Africa., Environmental science; Biological sciences; Plant biology; Ecology; Mathematical biosciences; Additive allometric models; Biomass fraction; Carbon; Savanna; Sub-Saharan Africa; Tree components.

To study the genetic diversity and structure of the forest species Pterocarpus erinaceus Poir., seventeen polymorphic nuclear microsatellite markers were isolated and characterized, using next-generation sequencing. Three hundred and sixty-five (365) individuals were analyzed within fifteen (15) West African populations. The number of alleles for these loci varied from 4 to 30, and the heterozygosity varied from 0.23 to 0.82. The seventeen (17) primers designed here will allow characterizing the genetic diversity of this threaten species on its natural stands and to better understand the population differentiation mechanisms shaping it.

This study aims to assess population structure and ecological indicators of woodland vegetation dominated by Pterocarpus erinaceus and Anogeissus leiocarpa as a basis for sustainable management and conservation strategies. We sampled 34 plots each measuring 30 m × 30 m in W National Park in Niger and analyzed structural parameters (tree density, basal area, Lorey's mean height and size class distribution) and ecological indicators (species richness, Shannon diversity index, Pielou evenness index and Importance Value Index) of woodland in general and for the two key species. Mean tree density was 752.6 stems/ha and basal area was 24.5 m2/ha in woodlands including 145.4 stems/ha and 14.1 m2/ha for A. leiocarpa and 3.3 stems/ha and 0.7 m2/ha for P. erinaceus. The woodland was composed of 59 tree species belonging to 34 genera and 17 families. A. leiocarpa had the highest IVI value (0.93), whereas P. erinaceus was among the species with the lowest IVI value (0.03). The mean diameter of both species was higher (24 cm and 47 cm for A. leiocarpa and P. erinaceus respectively) than the mean diameter in woodlands (16 cm). A “reverse J” shape distribution was found for woodland in general and for A. leiocarpa, but P. erinaceus showed a left dissymmetric distribution. Findings of this study showed that urgent actions are needed for sustainable management and conservation of some key species especially P. erinaceus.

Pterocarpus erinaceus Poir (Fabaceae) is an endemic, highly exploited and threatened plant species in arid and semi-arid zones of West Africa. This study was conducted at the sub-regional level across three countries, namely Burkina Faso, Niger and Togo. These countries represent a spatial ecological gradient of P. erinaceus distribution to collect information on population structure and silviculture operating standards that could guide the industry, ensure species regeneration and establish appropriate management strategies for the species. Data were collected in P. erinaceus populations by means of forest inventories. Results showed that the average tree density was 1.17 ± 0.75 trees/ha in the Sahelian zone, 49.20 ± 63.2 trees/ha in the Sudanian zone and 110.9 ± 1.15 trees/ha in the Guinean zone. The average stem diameter values were 26.63 ± 7.89 cm (Guinean zone), 29.02 ± 15.44 cm (Sudanian zone) and 49.63 ± 19.44 cm (Sahelian) with noticeable variability (CV = 53.6%). Significant differences for these parameters were noted between the zones (P

The Niokolo Koba National Park (NKNP) in Senegal is the last refuge of the critically endangered antelope of the subspecies Derby Eland (Taurotragus derbianus derbianus Gray, 1847). Woody plants, that provide shelters and forage for the Eland in NKNP, were assessed for their floristic diversity to characterize its confined habitat. Hence, 156 square plots of 20m x 20m were established randomly in the confined area of the Derby Eland. In each plot, list of plants species, their number of individuals, and the environmental factors (soil hardness and type, altitude, percentages of vegetation cover and fire occurrence) were noted. Fifty (50) trees species belonging to 40 genera and 29 families were recorded. The most represented families were Combretaceae (13.92%), Leguminosae-mimosoideae (12.66 %), Leguminosae-caesalpinioideae (11.39 %), Leguminosae-papilionoideae (7.59 %), Rubiaceae (7.59 %) and Tiliaceae (6.33 %). The most abundant species were Combretum glutinosum Perr. ex DC., (28.79%), Pterocarpus erinaceus Poir. (12.42%), Crossopteryx febrifuga (Afzel. ex G. Don) (7.30%), Strychnos spinosa Lam. (7.18%) and Hexalobus monopetalus (A. Rich.) Engl. & Diels (7.06 %). Altitude, fire occurrence and vegetation cover were the most important environmental factors influencing the distribution of plants species. Results suggest conservation defenders of Eland, for a sustainable management plan, to invest in in-situ fencing in order to increase possibilities of conservation of this critically endangered species in its native area. Key words: Plant inventory, specie composition, confined habitat, wild, sustainable management.

Understanding the role of protected areas in conserving biodiversity is a central goal in conservation biology. Anthropogenic activities around and inside these protected areas and, in particular, roads can alter the spatiotemporal dynamics of biological diversity in protected areas. However, our understanding of how the presence and position of roads affect human attitude, subsequent agricultural practices and biodiversity conservation is limited. In this study, we tested the effects of the proximity of traditional agroforestry parklands to main roads used by park rangers for surveillance on the diversity and abundance of woody species in the Pendjari Biosphere reserve over 16 years (2000–2016). Tree density in agroforestry parklands decreased over time from an average of 20 trees/ha in 2000 to 7 trees/ha in 2016. Species such as Vitellaria paradoxa and Parkia biglobosa, which are economically important, experienced the largest density reduction Trees density was also significantly higher in farms close to the monitoring roads used by park rangers to patrol the park. Farms that are far from the roads were monitored less frequently given that the number of park rangers declined over time. However, there was no significant variation in species richness and diversity over time, perhaps because of the low tree diversity in these systems. This masks evidences of species local extinctions. For example, species such as Pterocarpus erinaceus, Anogeissus leiocarpa, and Burkea africana which were present in the traditional agroforestry parklands in 2000 disappeared by 2016. This is associated with important land-use changes including the conversion of gallery forests into cropland and wooded savannas indicating that human pressure not only affects species occurrence but also their habitats. Our study suggests that where land demand for agriculture is high, it is challenging for local people to maintain sustainable management practices in the absence of collective action. Keywords: Tree abundance, Traditional agroforestry parklands, Biodiversity conservation, Protected areas, Roads, Pendjari biosphere reserve

Pterocarpus erinaceus Poir. (Fabaceae) est un arbre des forêts claires et des savanes arborées d’Afrique, très prisé pour son bois, son fourrage et ses vertus thérapeutiques, cause de sa surexploitation en Côte d’Ivoire. La présente étude analyse la structure démographique des peuplements naturels et les potentialités de régénération de cette essence en fonction de l’intensité d’exploitation dans les trois types de savanes (guinéenne, subsoudanienne et soudanienne) de la Côte d’Ivoire en vue de leur conservation. Des mesures dendrométriques (diamètre à 1,30 m du sol, hauteur totale et hauteur du fût de l’arbre) ont été effectuées dans 30 transects de 200 m de large, sur des individus de P. erinaceus de diamètre égal ou supérieur à 5 cm dans six sites. La régénération a été évaluée dans 186 placettes de 30 m x 30 m équidistantes de 50 m à l’intérieur des transects. Les résultats révèlent que les plus grandes valeurs moyennes de densité d’arbres et de densité de régénération ont été obtenues en savane guinéenne (9,9 arbres/ha et 33,8 tiges/ha) et subsoudanienne (12,6 arbres/ha et 25,2 tiges/ha) alors que le diamètre moyen (33,9 cm), la hauteur totale moyenne (10,6 m) et la hauteur moyenne du fût (3,83 m) présentent des valeurs significativement plus élevées (p

The West African Chimpanzee Pan troglodytes verus is Endangered (A4cd ver 3.1) in Senegal (Humle et al. 2008), mainly due to habitat fragmentation and destruction. We gathered qualitative and quantitative data on the tree species preferences of the West African Chimpanzee for nest building in order to gain insight into habitat dependence. Between March 1998 and Febrary 2000 we identified tree species in which a sample of 1790 chimpanzee nests had been built, and ranked species in preference order. We compared this sample to the relative abundance of tree species in the chimpanzee habitat to determine whether particular species were chosen for nesting. We observed that about a quarter (25.42%) of nests were built in Pterocarpus erinaceus, which is considerably greater than would be expected from the abundance of this species in the habitat (6.35%), indicating a strong preference by chimpanzees. We examined the physical traits of the most-used tree species and concluded that height and wood hardness may be key choice features. P. erinaceus is threatened in Senegal due to extensive cutting, which may endanger chimpanzees living outside the boundaries of protected areas. In the current anthropogenic setting our results provide conservation managers with information on how to protect a key aspect of the chimpanzee natural environment.

We determined the contribution of ligneous species to the diet of cattle, sheep and goats across three agro-ecological zones of Burkina Faso, and assessed their ethno-veterinary uses by livestock keepers. Regular observation and GPS-tracking of one cattle, one sheep and one goat herd each in three villages served the investigation of browsing activities on pasture. Livestock keepers (25 per village) were interviewed on the use of ligneous plants by livestock and for disease treatment, and on changes in use over the past two decades. Across the three zones 75 species were of importance. Cattle preferred Afzelia africana, Pterocarpus erinaceus and Piliostigma sp., while small ruminants primarily fed on Balanites aegyptiaca, Ziziphus mauritiana and Acacia sp. Contribution of browsing to daily eating time was highest for goats across seasons and zones; for sheep and cattle browsing was important during the hot dry season with no differences between zones. Livestock keepers reported increasing browse use by their animals, while browse species use for traditional animal health care has decreased. The combination of anthropogenic pressures and climate change affect survival and regeneration of the most preferred trees and shrubs, and threaten livestock keepers' current management practices; this needs to be counteracted adequately.

The Pendjari Biosphere Reserve located in the Sudanian zone of Benin, is a protected area well managed, but mainly aimed at wild animal conservation. This study assessed its effectiveness to conserve habitat species composition and population structure of three endangered African tree species: Afzelia africana Sm., Pterocarpus erinaceus Poir. and Khaya senegalensis (Desv.) A. Juss. We randomly sampled 120 plots in the protected and surrounding unprotected habitats by inventorying plant species. For the three target species, we estimated adult and juvenile densities and recorded size classes. According to floristic composition four habitats groups were recognized in relation to human disturbance, vegetation type, and moisture. These were protected savannas, unprotected savannas, old fallows and gallery forests. The estimated adult densities of A. africana were similar between protected (14 ± 1.2 tree/ha) and unprotected savannas (17 ± 0.9 tree/ha) while for P. erinaceus the adult density was significantly higher in protected (12 ± 3.7 tree/ha) than in unprotected savannas (5 ± 1.9 tree/ha). Estimated adult density of K. senegalensis was also significantly higher in protected gallery forest (40 ± 5.8 tree/ha) than in unprotected one (29 ± 4.8 tree/ha). Juvenile densities of A. africana, K. senegalensis and P. erinaceus were higher in protected habitats than in unprotected ones but the difference was not significant. Skewness coefficient indicated that populations of investigated trees were declining in their protected habitats. However, in the case of A. africana and K. senegalensis populations seemed to be mostly threatened in the protected area. We concluded that although the studied protected area is effective to conserve some habitats species compositions, protection is not sufficient to guarantee future conservation of some threatened tree species.

We examined the potential of dendrochronology to assess biomass productivity of individual savanna species from a semi-arid ecosystem in southern Senegal. The 9 tree species examined in this dendrochronologial study included: Acacia macrostachya, Acacia seyal, Balanites aegyptiaca, Combretum glutinosum, Cordyla pinnata, Pterocarpus erinaceus, Terminalia macroptera, Daniellia oliveri, and Combretum nigricans. Dendrochronologial analyses were applied on cross-sectional disks obtained from the tree stem to reconstruct past tree growth (diameter and biomass) histories. Despite challenges with discerning annual tree rings in these savanna species (associated with ring suppression, wedging, indistinct ring boundaries, and fires), tree species (A. macrostachya, A. seyal, and T. macroptera) with the highest dendrochronology potential produced a clear thin band of marginal parenchyma. A. macrostachya had rapid annual diameter and biomass growth increments in the juvenile years (ages 1–10), compared to T. macroptera which showed greater growth past this early juvenile period. Given the same species, generally wetter forests had lower annual and cumulative growth rates that were likely due to increased inter-tree and tree-grass competition for soil moisture in the wetter forests. We concluded that dendrochronology is well suited for retrospective annual biomass assessment in savanna trees of Senegal, West Africa.

While West African chimpanzees (Pan troglodytes verus) were elevated to Critically Endangered status by the IUCN in 2016 as a result of significant population declines in recent decades, little is known about the population in Senegal. We surveyed the West African chimpanzees outside protected areas in the Kedougou region of southeastern Senegal between November 2014 and July 2015 using recce walks (n = 57, totalling 300 km of pedestrian survey distance) in potential chimpanzee habitats. We recorded direct observations of chimpanzees or indices of chimpanzee activity, such as sleeping nests, footprints and faeces. We accumulated 21 direct contacts with chimpanzees and recorded 3489 chimpanzee nests. We mapped the distribution of chimpanzee sleeping sites and indicators of anthropogenic activity by regional administrative units to facilitate species management and conservation planning in the immediate future. In addition, we identified the habitats and tree species used by chimpanzees to construct their nests in order to explore nesting tree preferences. Chimpanzees used almost 40 tree species in the Kedougou region but 84% of nests were associated with eight tree species, namely Pterocarpus erinaceus, Diospyros mespiliformis, Anogeissus leiocarpus, Hexalobus monopetalus, Cola cordifolia, Lannea sp., Parkia biglobosa and Piliostigma thonningii. Among these eight nesting tree species, 60% of the corresponding nests were located in three species: P. erinaceus, D. mespiliformis and A. leiocarpus. Chimpanzees nested more often in woodland habitat than in gallery forests, although the latter accounts for only a small percentage of available habitat. This study is the most geographically extensive survey of chimpanzees in Senegal to date, broadening our knowledge of the species' northwestern-most distribution in West Africa.

The behaviour of sheep, goats and cattle on a shrub and tree savannah in the sub-humid zone of West Africa was studied during the dry (February to May), rainy (June to September) and cool season (October to January). Two mature females per animal species were followed by two observers during 3 days per month and behaviour activities were recorded every 15 min of the daily grazing time. When browsing, the plant name, plant part and plant height reached during prehension were recorded. The distance travelled and the grazing circuits were recorded with a step counter and a Geographic Position System device. The knowledge of farmers concerning appreciated browse species relative to the browse species consumed by animals in the area was also investigated. During the dry season sheep, goats and cattle spent around 25% of their time browsing and 20%, 16% and 31%, respectively, of their time grazing. During the cool season, goats (17%) browsed more than sheep (7%) and cattle (5%) (Pb0.05). During the rainy season, sheep browsed 20% of the time while cattle spent only 7% of their time browsing, while goats were tied, with no opportunity for browsing. Browsing leaves was the most important part of the browsing activity. During the cool season, browsing height was the same (1.0 m) for cattle and goats, but lower for sheep (0.6 m) (Pb0.05). In the dry and cool season, sheep and goats walked shorter distances than cattle. The plant species with the highest frequency of consumption were Acacia dudgeoni Craib, Ficus gnaphalocarpa (Miq.) A. Rich, Dioscorea togoensis Knuth, Cordia myxa L., and Manguifera indica L. for sheep and goats and Afzelia africana Sm., Kaya senegalensis (Desv.) A. Juss, Pterocarpus erinaceus Poir. and Dicrostachys cinerea (L.) Wight and Arn. for cattle. Species with a high frequency of citation by farmers were A. africana (92%), K. senegalensis (88%), P. erinaceus (86%), Faidherbia albida A. Chevalier (80%), A. dudgeoni (70%) and F. gnaphalocarpa (69%). In conclusion, browse species make an important contribution to the diet of ruminant animals in the sub-humid zone and farmers are familiar with the species consumed by ruminant animals.

Objective: The objective of this study is to identify the plant species and to characterize the vegetation of the Ouoghi forest reserve in the commune of Savè (Center-Benin). Method and results: Floristic and forest inventories were carried out through 144 relevés in according to the Braun-Blanquet method. A total of 246 plant species were identified. They belong to 178 genera and 63 families. Multivariate analyzes with the Community Analysis Package (CAP) software made it possible to individualize 3 vegetation formations comprising 8 plant groups. This is the shrub savannah with Prosopis africana and Pennisetum polystachion, the tree savannah with Hymenocardia acida and Pennisetum polystachion, the tree savannah to Vitellaria paradoxa and Pennisetum polystachion, the tree savannah to Pterocarpus erinaceus and Hyptis suaveolens, the woodland savannah with Daniellia Oliveri and Chromolaena odorata, the woodland savannah at Isoberlinia doka and Pennisetum polystachion, the woodland savannah at Daniellia oliveri and Andropogon tectorum and the tree flood savannah to Daniellia oliveri and Leersia hexandra. The floristic and structural parameters change from one group to another. Thus, the specific richness varies from 49 to 153 species and the diversity of families is between 22 and 49 with a predominance of Leguminosae. The density varies from 95 to 275 stems / ha, basal area from 2.35 to 8.44 m² / ha. Conclusion and application of results: The study evaluated the floristic diversity of the Ouoghi reserve. In addition, it indicated the need for its integral protection for its dynamics towards dry dense forest vegetation. Sustainable management of this site needs implication of local population.

Ethnobotanical information relevant to the management of savanna vegetation was obtained through interviews with 57 elderly villagers living near Delta du Saloum National Park, Senegal. Local people had observed a change in the local environment from forest to savanna during their lifetime and considered it primarily a result of frequent intensive fires and declining rainfall. Most people preferred the woody vegetation to be dense. In particular, nine woody species were useful for construction, 10 for protection in agricultural fields, 19 for medicine and 10 for livestock fodder. Some of the locally highly preferred species were also considered to be declining in the local environment, they included Cordyla pinnata, Pterocarpus erinaceus, Daniellia oliveri, Parkia biglobosa, Khaya senegalensis and Pericopsis laxiflora. Highly preferred and declining species were characteristically large trees, non-thorny, with edible fruits and of Sudano-Guinean to Guinean affinity. The study furthermore identified a close coincidence between the interest in conserving tree species diversity in protected areas and the priorities of local people which included preservation of plenty of large trees (including many fruit trees), maintenance of a variety of species, improvement of woody regeneration, and reduction of fire intensity and frequency. Focusing management strategies on increasing populations of such declining and highly preferred species, by active fire protection for instance, would enhance the natural resource value considerably and thereby the quality of life for the local people.

Termites are one of the most abundant invertebrates in tropical ecosystems, where they play a major ecological role in litter decomposition. Despite their important role, termites can cause considerable damage to wood structures in most tropical countries. The aims of this study was to evaluate termite attack in four economically important species in Togo including Antiaris africana Engl (Moraceae), Pterocarpus erinaceus Poir (Fabaceae), Triplochiton scleroxylon Schum (Malvaceae) (all local species) and teak or Tectona grandis Linné (Lamiaceae). For the latter species, termites were infested on 83.49% of 630 feet examined. However, the rate and type attacks differ from one plantation to another. On the studied forest species, termites were collected on about 97% of Triplochiton scleroxylon feet. For this species, at least 31% of examined feet have had their wood attacked. For the other two species, Pterocarpus erinaceus and Antiaris africana respectively about 80% and 67% of examined feet were attacked by termites. Amitermes evuncifer, Ancistrotermes guineensis and Microtermes lepidus were species of termite often harvested from trees examined. However the last two species namely A. guineensis and M. lepidus are encountered on the bark of trees inside veneers unlike A. evuncifer harvested in the heart of the wood. Therefore, the latter species deserves special attention as likely to cause serious damage not only to these species but also other species not taken into account in this study. It is therefore necessary to consider adequate control methods against these species.

Protected areas constitute strategy for biodiversity conservation. Unfortunately, these sanctuaries of biodiversity are submitted to a high human pressure in Togo. This study carried out in the Aledjo protected area, aimed to make an analysis of various forms of human footprints and their impact on its plant resources. Methodological approach was based on forest inventory completed by inquiries. Ninety-four wooded species belonging to 35 families were counted. Floristic data analysis showed that seven species: Isoberlinia doka Craib & Stapf, Daniellia oliveri (Rolfe) Hutch. & Dalz., Berlinia grandiflora (Vahl) Hutch. & Dalz., Pterocarpus erinaceus Poir., Zanha golungensis Hiern, Khaya senegalensis (Desv.) A. Juss., Pentadesma butyracea Sabine was prominent. Five vegetation types were identified: riparian forests, dry forests, open forests, savanna woodlands, tree/shrub savannas with variable structural characteristics. The diversity indices in these plant communities are well significant and indicate a good distribution of species in the area. Several human activities such as fuel wood, fruits and medicinal plants gathering, carbonization, pasture were found within the protected area. Local authorities and associations are involved in the management of the protected area, but the participation of local populations needs to be improved. Resume Les aires protegees constituent une strategie de conservation de la biodiversite. Malheureusement, au Togo, ces sanctuaires de biodiversite sont soumis a de fortes pressions humaines. Cette etude, realisee dans l'aire protegee d'Aledjo, visait a faire une analyse des diverses formes d'empreintes humaines et de leurs impacts sur ses ressources vegetales. L'approche methodologique s'est basee sur un inventaire forestier, complete par des enquetes. Nous avons denombre 94 especes ligneuses, appartenant a 35 familles. L'analyse des donnees floristiques a mis en evidence sept especes dominantes, a savoir Isoberlinia doka Craib & Stapf, Daniellia oliveri (Rolfe) Hutch. & Dalz., Berlinia grandiflora (Vahl) Hutch. & Dalz., Pterocarpus erinaceus Poir., Zanha golungensis Hiern, Khaya senegalensis (Desv.) A. Juss. et Pentadesma butyracea Sabine. Nous avons identifie cinq types de vegetation: les forets galeries, les foret seches, les forets claires, les savanes boisees et des savanes arborees/arbustives avec des caracteristiques structurales variables. Les indices de diversite dans les communautes vegetales sont eleves et indiquent une bonne distribution des especes dans l'aire. On a releve dans l'aire protegee plusieurs activites humaines, comme la collecte de bois de feu, de fruits et de plantes medicinales, la carbonisation et le pâturage. Des autorites et des associations locales sont impliquees dans la gestion de l'aire protegee, la participation des populations locales etre amelioree.

The open Isoberlinia spp. woodlands found on slopes and valley floors in Togo's Sudanian region are subject to various pressures including clearance for crop-fields, cutting for timber or fuelwood and gathering of non-timber forest products. The resulting degradation is worsening poverty among the local people who depend on these forests. To support their sustainable management for the benefit of these local populations, the impacts of human pressures on the forest structure first need to be analysed. The forest inventories conducted covered 4 783 trees in 225 study plots. More than one hundred woody species were listed, belonging to 79 genera and 32 families. The most frequent were Isoberlinia doka, Pterocarpus erinaceus, Lannea acida, Isoberlinia tomentosa, Vitellaria paradoxa, Daniellia oliveri and Parkia biglobosa. The surveys identified four main parameters determining ecological gradients: moisture, topography, soil substrate and human influence. Nine woodland fades were identified: four open woodland types, three tree savannah types and two in fallow areas. Three structural components were determined by analysing tree diameter structure for the nine facies. Finally, relatively undisturbed natural forest areas with stable and continuously regenerating flora and regular forest structure were easily distinguished from degraded forest areas characterised by a lack of large trees and low regeneration potential. The human pressures exerted on these fragile woodland areas clearly suggest replanting in the degraded areas, using low-cost multiplication techniques, although raising awareness among the neighbouring populations about the need for conservation remains essential to ensure participatory management., Les forêts claires à Isoberlinia spp. du domaine soudanien du Togo, rencontrées aussi bien sur les versants que dans les plaines, subissent diverses pressions telles que les défrichements agricoles, l’exploitation du bois de service et de feu ou encore la collecte des produits forestiers non ligneux. Ces forêts ainsi dégradées accentuent la paupérisation des populations riveraines qui en dépendent. Afin de contribuer à leur gestion durable au profit de ces populations locales, il s’avère nécessaire d’analyser l’impact des pressions anthropiques sur la structure de ces forêts. Des inventaires forestiers y ont été conduits. Les travaux ont porté sur 4 783 arbres au sein de 225 placeaux de mesures. Plus de cent espèces ligneuses ont été inventoriées comprenant 79 genres et 32 familles, les plus fréquentes étant Isoberlinia doka, Pterocarpus erinaceus, Lannea acida, Isoberlinia tomentosa, Vitellaria paradoxa, Daniellia oliveri et Parkia biglobosa. Les relevés ont permis de déterminer quatre gradients écologiques majeurs : l’humidité, la topographie, le substrat édaphique et l’anthropisation. La classification a identifié neuf faciès forestiers dont quatre en forêts claires, trois en savanes boisées et deux au sein de jachères. En outre, trois composantes structurales ont été définies en analysant la structure diamétrique des neuf faciès. Enfin, il a été aisé de distinguer, d’une part, les forêts naturelles peu perturbées, présentant une stabilité floristique bénéficiant d’un flux de régénération continu, ainsi qu’une régularité de structure, et, d’autre part, les forêts dégradées qui se caractérisent par l’absence de tiges de grande taille et le faible potentiel de régénération. La pression humaine qui s’exerce sur ces forêts fragiles ne peut qu’inciter à reboiser les espaces dégradés, en mettant à profit les techniques de multiplication végétative à faible coût. Reste surtout à atteindre une prise de conscience de la part des populations riveraines pour ce qui a trait à la conservation de ces milieux, et aboutir à une gestion participative., Los bosques abiertos de Isoberlinia spp . del dominio climático sudanés de Togo, ubica- dos tanto en pendientes como en llanuras, sufren diversas presiones como desmontes para uso agrícola, extracción de madera o leña y también la recolección de productos forestales no maderables. Estos bosques así degradados acentúan la pauperización de las poblaciones colindantes que depen- den de ellos. Para contribuir a un manejo sostenible que beneficie a la población local, es necesario analizar el impacto de las presiones antrópicas en la estructura de dichos bosques. Se realizaron inventarios forestales y los estudios se centraron en 4 783 árboles en 225 parcelas de medición. Se han inventariado más de 100 especies leñosas que incluyen 79 géneros y 32 fami- lias, las más frecuentes son Isoberlinia doka, Pterocarpus erinaceus, Lannea acida, Isoberlinia tomentosa, Vitellaria paradoxa, Daniellia oliveri y Parkia biglobosa . Las observaciones permitieron determinar cua- tro gradientes ecológicos principales: humedad, topografía, sustrato edáfico y antropización. La clasificación ha identifi- cado nueve facies forestales: cuatro en bos- ques abiertos, tres en sabanas arboladas y dos en barbechos. Además, al analizar la estructura diamétrica de las nueve facies, se definieron tres componentes estructurales. Por último, fue fácil distinguir, por un lado, los bosques naturales poco alterados y que presentan una estabilidad florística que se beneficia de un flujo de regeneración conti- nuo y de regularidad estructural y, por otro lado, los bosques degradados que se carac- terizan por ausencia de tallos de gran tamaño y su bajo potencial de regeneración. La presión humana a la que se ven someti- dos estos bosques frágiles sólo puede servir de estímulo para la reforestación de los espacios degradados aprovechando las técnicas de multiplicación vegetativa de bajo costo. Sobre todo hace falta lograr la concienciación por parte de las poblaciones colindantes en todo lo referido a la conser- vación de estos entornos y conseguir un manejo participativo.

Pterocarpus erinaceus Poir. est une espèce endémique des zones sahélo-soudanienne et soudano-guinéenne, recherchée pour son bois, son fourrage et son intérêt médi- cinal. Ces usages se traduisent par une mu- tilation répétée des individus, entraînant une dégradation sensible des peuplements naturels. Les structures démographiques de P. erinaceus selon les zones pédoclima- tiques et l’effet des principales variables environnementales et de l’intensité d’ex- ploitation sur ses effectifs ont été évalués au Niger et au Burkina Faso. Des mesures dendrométriques (diamètre, hauteur to- tale, hauteur du fût, diamètres perpen- diculaires du houppier) sur les individus d’un diamètre supérieur ou égal à 5 cm à 1,30 m du sol ont été effectuées dans huit forêts. Dans chacune, les mesures ont été conduites selon deux transects perpendi-culaires. La densité de P. erina- ceus augmente de manière significative (P < 0,003) de la zone sahélo-soudanienne à la zone soudano-guinéenne : 1,2 ± 0,7 pied/ha dans la zone sahélo-soudanienne ; 2,6 ± 2,2 pieds/ha dans la zone nord-sou- danienne ; 6,1 ± 4,6 pieds/ha dans la zone sud-soudanienne ; 15,0 ± 1,1 pieds/ha dans la zone soudano-guinéenne. L’analyse des structures en diamètre et en hauteur révèle une augmentation de la fréquence des indi- vidus jeunes suivant le gradient pluviomé- trique. Par contre, l’intensité de l’exploita- tion est plus élevée dans les zones les moins arrosées, où l’espèce s’avère menacée.

Au Togo, l'exploitation de nombreuses essences de bois d'oeuvre de valeur telles que Pterocarpus erinaceus Poir. est menée sans respecter les principes d'aménagement forestier durable. Cette étude établit la situation sur l'exploitation et l'exportation du bois de P. erinaceus dans le pays et évalue les impacts de la surexploitation sur la dynamique des peuplements riches en cette espèce. L'étude est menée travers l'analyse des données d'inventaires forestiers réalisés dans la plaine centrale du Togo. Les inventaires ont été matérialisés suivant deux transects au sein de deux milieux contrastés, une zone où l'espèce est excessivement exploitée et une zone où elle est protégée. L'analyse de variance des paramètres structuraux indique une différence significative entre les diamètres moyen et dominant, les hauteurs totale et fût des arbres recensés dans la zone exploitée et de ceux de la zone protégée. Pour la zone exploitée, la répartition des arbres en classes de diamètre fait état d'une distribution typique en «L» décroissante traduisant une dynamique régulière de la popu-lation, alors qu'il s'agit d'une distribution en cloche symétrique pour les arbres de la zone protégée, caractéristique de peuplements ayant atteint un état d'équilibre. L'espèce présente une bonne capacité de régénération ouvrant de bonnes perspec-tives pour la production de plants en pépinière et pour des essais de plantation partir d'espèces locales telles que P. erinaceus, en vue de restaurer des formations naturelles dégradées. Étant donné la pression exercée sur ces formations, l'adoption effective de mesures de protection et de conservation de l'espèce est indispensable pour limiter la dégradation irréversible de ses écosystèmes et d'autres qui subissent le même sort, notamment par la mise en place de normes d'exploitabilité, le respect de la réglementation en vigueur en matière d'exploitation des ressources forestières au Togo. (Résumé d'auteur)

Colloque avec actes et comité de lecture. Internationale.; International audience; Xylophone belongs to the idiophone group of instruments which is very present in the African traditional and popular music. Its sound percussion quality is related to the resonance and the intrinsic properties of used wood. In spite of numerous studies of the acoustic properties of wood, very few works are available on Pterocarpus species in general and notably on Pterocarpus erinaceus. In this study, the variability of acoustic properties of vène (Pterocarpus erinaceus Poir), used for xylophone instrument manufacture in Mali and the relationships between these properties and the basic density and extractive content were investigated in order to provide information about its overall suitability for xylophone making. A free-free flexural method, known as “Bing”, was used to determine the main mechanical properties for the xylophone instrument manufacture i.e. the damping coefficient and the specific dynamic modulus while the basic density and the extractives (EC) content were determined according to international standards ISO 3129 and ASTM D1105 (1996), respectively. The results showed that the dynamic specific modulus, the basic density and the extractive content are significantly higher for wood from Guinean area than for wood from Soudanian area. For all provenances the values determined for these properties have been significantly higher for wood from external (EHW) and median heartwood (MHW) than for wood from internal heartwood (IHW). The damping coefficient, the loss factor is significantly greater for wood from Soudanian area than for wood from Guinean area, and regardless of provenance, the loss factor was significantly greater for wood from IWH than in MHW and EHW.

Pterocarpus erinaceus (Poir.) est l’une des espèces des domaines climatiques soudanien et guinéen du Togo. Son importance socio-économique tient à ses nombreuses utilisations. Toutefois, la sylviculture et les propriétés technolo- giques du bois sont mal connues. C’est dans ce contexte qu’un travail a été mené pour déterminer les propriétés physiques et mécaniques (densité, retraits, PSF, MOE, MOR, compression, dureté) de son bois en relation avec les conditions du milieu. Les résultats observés sur les bois de 19 arbres, âgés de 18 à 60 ans environ, prélevés dans deux zones écolo- giques (Parc de la Kéran, zone souda- nienne ; Abdoulaye, zone guinéenne), montrent des différences de densité, d’infra-densité, de contrainte de rupture en compression et d’anisotropie des retraits. Ces propriétés sont plus élevées à Kéran qu’à Abdoulaye. Pour les retraits, le PSF, le MOE, la contrainte de rupture en flexion et la dureté, il n’y a pas de dif- férence significative entre les deux sites. Cette étude met en évidence des corréla- tions attendues entre la densité et la dureté. Elle montre aussi que les proprié- tés physiques et mécaniques du bois de vène sont très peu influencées par l’âge cambial.