Algerian forest landscapes have experienced rapid degradation in recent decades, driven by climatic and anthropogenic factors. Monitoring land use and land cover changes (LULCC) is essential to understanding this process and thus strengthening in situ conservation policies. This study aimed to analyse LULCC trends in the Chrea Protected Area, part of the Central Tellien Atlas, between 1984 and 2021. LULCC was mapped using Landsat TM for 1984 and 2004, and Landsat 8 OLI_TIRS for 2021. The Maximum Likelihood Classification algorithm was used for the supervised classification of LULC into five distinct classes: forest, dense matorral, open matorral, shrub land, and non-vegetated land. A post-classification approach was employed to detect changes over the study period, categorised into four types: deforestation, degradation, reforestation, and recovery. The changes in LULC showed two main trajectories: recovery, then degradation. Vegetation recovery dominated between 1984 and 2004, over an area of 8,560.3 ha (28.21%). This dynamic succession coincided with the area’s rural depopulation, resulting in a decrease in human disturbance on the landscape. In contrast, most vegetation degradation occurred between 2004 and 2021, affecting 5,344.06 ha (17.61%). This degradation primarily resulted from the conversion of forest to dense matorral and may be associated with increased human pressure on forest resources, using fire to expand or renew fodder areas. This degradation has reduced landscape heterogeneity. This study presents the first data on the trajectories of LULCC in the Chrea protected area over 37 years, which will allow for more effective conservation actions for the precarious forest ecosystems of Algeria.
Deforestation in tropical dry forest ecosystems is one of the primary causes of a reduction biodiversity for flora and fauna worldwide. In response, ecological restoration has become strategy to recover and reverse such degradation. These activities are part of the goals of the United Nations'Sustainable Development Goals and Decade on Ecosystem Restoration (2021-2030). Restoration begins with characterising phenotypic diversity, which provides the basis for selecting tree individuals with desirable traits to serve as seed sources in natural forests. These sources would further feature high adaptability and productivity-factors that enhance seed propagation in nurseries, enabling their subsequent multiplication and implementation in specific areas for restoration processes. The objective of this research was to conduct a systematic review to characterise the current landscape of ecological restoration in tropical dry forests across key South American regions, including the Cerrado and Caatinga in Brazil, the Gran Chaco in Argentina, and the tropical dry forest of the department of Huila in Colombia. The importance of seed sources in restoration programmes was described, and the advances in the implementation of forest species as seed sources were highlighted. To do this, a systematic review was conducted using data from Web of Science, Scopus, and SciELO, with statistical analysis performed in the software R. The results identified 671 articles, and of these, 60 articles were considered to meetthe appropriate criteria for carrying out the study. Finally, the seed sources used in restoration processes in hotspots such as the Cerrado, Caatinga, the Gran Chaco, and the tropical dry forest of the Huila region have had a great impact on the recovery of tropical dry forest through assisted restoration, where the availability of high-quality seed and plant material is ensured.
Les subéraies algériennes, et notamment celle de Zouagha située dans le nord-est du pays, connaissent depuis plusieurs décennies un dépérissement inquiétant sous l’effet combiné des changements climatiques et des pressions anthropiques croissantes. Cette étude a pour objectif d’évaluer l’état de vitalité et les dynamiques structurelles, physiologiques et reproductives des peuplements de Quercus suber L. dans la subéraie de Zouagha, en mobilisant une approche intégrée et multicritère. Vingt placettes (de 30 × 30 m) ont été installées selon un dispositif d’échantillonnage aléatoire stratifié selon différents niveaux d’altitude et d’exposition, afin de permettre une représentation équilibrée des conditions écologiques. Les protocoles ARCHI, DEPEFEU et ICP Forests ont permis de caractériser l’architecture, la défoliation, la fructification et l’état sanitaire des houppiers, complétés par des mesures dendrométriques (hauteur, diamètre, surface terrière, volume) pour estimer la structure et la productivité des peuplements. Les résultats montrent une forte hétérogénéité le long du gradient altitudinal. Les peuplements de basse altitude et exposés au sud, soumis à un stress hydrique et thermique accentué et à une pression anthropique élevée (pâturage, coupes illicites, incendies), présentent les taux de dépérissement les plus élevés (ID = 1,70 %) et une fructification limitée. À l’inverse, les peuplements de haute altitude (> 1 250 m) et à exposition nord se distinguent par une meilleure vigueur, une défoliation réduite et une productivité accrue, traduisant une résilience écologique supérieure. De plus, le test statistique de clustering (K-means) a mis en évidence une segmentation nette du massif forestier en deux groupements écologiques distincts, structurés principalement par l’altitude et l’exposition. En conclusion, le gradient altitudinal et les conditions stationnelles apparaissent comme les principaux déterminants de la vitalité des subéraies de Zouagha. Ces résultats soulignent la nécessité d’une gestion forestière différenciée, adaptée aux contraintes locales, intégrant la réduction des pressions anthropiques et la restauration des sols. À plus long terme, le développement d’un suivi écophysiologique et génétique permettra d’affiner le diagnostic du dépérissement et de renforcer la résilience et la durabilité des subéraies face aux changements climatiques.
Garcinia kola Heckel is a multi-purpose native tree found in Central and West Africa, including Angola, valued for its edible nuts and medicinal uses. Intensive harvesting has led to the extinction of wild populations throughout Benin. This study assessed local people's perceptions regarding (i) the knowledge of the G. kola tree and the perceived threats, and (ii) the proposal for conservation and domestication strategies. Semi-structured interviews were conducted with 755 respondents in 24 municipalities in four phytodistricts of Benin. Data were collected on sociodemographic characteristics, local knowledge on the bitter kola tree, ownership, harvesting practices, cultivation, conservation methods, and perceived threats to G. kola. The relative frequency of citations was calculated. The influence of gender, occupation, and phytodistrict on local knowledge of the bitter kola tree, as well as on cultivation and conservation practices, was assessed using binomial generalised linear models. Multinomial logistic regression was applied to evaluate the influence of gender and phytodistricts on perceived threats. Correspondence analysis was performed to explore the relationship between perceived threats and socio-demographic factors. Results revealed that 19.1% of respondents reported being familiar with the species. The Coastal phytodistrict had the highest proportion of respondents with knowledge of the species (51.1%), followed by the Valley of Oueme (21.1%) and the Plateau (17.1%). Gender, phytodistricts and occupation significantly influenced knowledge, cultivation and conservation practices. The main reported threats were debarking (54.2%), infrastructure development (43.8%), tree mutilation (17.4%), vegetation fires (11.8%), and anarchic cutting (3.47%). Respondents from the Plateau and Valley of Oueme, particularly the men, identified anarchic cutting as the primary threat. This study has provided valuable insights for the domestication and sustainable management of bitter kola in Benin. Domestication efforts should be prioritised in the Coastal and Plateau phytodistricts, where the species is well documented and cultivated. Results of the study highlight the importance of including women in long-term management strategies. Future research should prioritise the cultivation technique for bitter kola, as its dissemination would be crucial to optimise its multiplication in Benin.
Urbanisation is one of the main factors transforming ecosystems, with marked effects on floristic composition and society-nature relations. In the Dakar region, despite rapid urbanisation, interactions between urbanisation gradients, woody vegetation, and social perceptions remain poorly documented. This study analyses the effects of urbanisation on the structure, diversity, and origin of woody species, as well as on community motivations towards trees. The methodological approach is based on an urbanisation gradient comprising an urban area (Hann Bel Air), a peri-urban area (Mbao), and a rural area (Bambilor), combining floristic inventories and socio-economic surveys. A total of 3,363 individuals representing 128 species and 74 families were inventoried. The rural area has the highest species richness (53 species), abundance (2,053 individuals), and diversity (H' = 4.53 bits), while the urban area has lower species richness (38 species) but relatively high evenness (E = 0.80). Woody plant density increases very significantly (P-value < 0.001) from urban to rural areas (69.56 +/- 44.97; 52.62 +/- 29.21 and 114.06 +/- 48.13 individuals.ha-1, respectively), reflecting land availability and different land uses. The floristic composition varies significantly along the gradient, with a dominance of exotic species, notably Leucaena leucocephala in urban areas (2.74%), Anacardium occidentale in peri-urban areas (6.05%), and Mangifera indica in rural areas (10.62%). Surveys reveal that the motivation to plant trees decreases from urban to rural areas, where planting initiatives are mainly carried out by forestry services rather than local populations. These results highlight the need for differentiated tree cover management that integrates ecological dynamics and socioeconomic dimensions to promote sustainable development strategies, tailored to each zone of the gradient.
Un arbre a besoin de lumière pour sa croissance et son développement. Il existe cependant chez certaines espèces la capacité, ou préférence, à tolérer l’ombrage sans que cela soit préjudiciable à leur développement. Cette préférence écologique induit différentes stratégies chez ces espèces qui se traduisent par un compromis, entre performance et sécurité, dans la réalisation des fonctions de soutien mécanique, de conduction et de protection contre les bioagresseurs. Le regroupement des essences forestières partageant des stratégies de croissance communes est essentiel pour une utilisation judicieuse, responsable et rentable du bois. L’étude des stratégies écologiques et des traits fonctionnels associés permet en effet de mieux comprendre la biodiversité mais également l’élaboration de la qualité du bois au sens des propriétés technologiques utiles pour l’Homme. Trois stratégies écologiques liées au tempérament vis-à-vis de la lumière ont été étudiées. Elles comprennent des espèces pionnières exigeantes en lumière, des espèces hémi-héliophiles et des espèces tolérantes à l’ombre. Les espèces étudiées sont des feuillus tropicaux du Gabon ayant été caractérisés sur les plans anatomique, physique, mécanique et chimique. Les méthodes utilisées englobent des méthodes académiques et des nouvelles méthodes rapides et non destructives de détermination des propriétés du bois. Les résultats obtenus montrent que les espèces d’ombre ont de meilleures performances physique et mécanique, et donc un meilleur soutien mécanique, comparées aux espèces pionnières et hémi-héliophiles. Ces performances élevées sont liées à leurs parois très épaisses, leurs nombreux vaisseaux de petits diamètres, une densité de bois élevée et des taux de lignine et d’hémicelluloses importants. Elles peuvent être utilisées en ingénierie des matériaux dans les constructions lourdes ou les structures porteuses par exemple. Il a été trouvé une quantité significative d’extractibles chez les espèces pionnières par rapport aux espèces hémi-héliophiles, mais statistiquement similaire à celle des espèces tolérantes à l’ombre ; ce qui leur confère une bonne protection contre les bio-agresseurs. Elles pourraient de ce fait être utilisées pour des constructions en extérieur. Cependant, celles-ci étaient plus sensibles aux variations dimensionnelles dues aux variations d’humidité. Dans l’ensemble, les espèces hémi-héliophiles n’étaient pas statistiquement différentes des espèces pionnières et tolérantes à l’ombre
Fiche descrivant les propriété physiques, mécaniques, et techniques de l'essence de bois Didelotia africana, Didelotia letouzeyi, Didelotia p.p.
The objective of this study is to convert agricultural residues, particularly cocoa pod shells from the Ivory Coast, into low-cost bioadsorbents. In this context, biochar can be produced from agricultural residues for use in removing water pollutants. The main question was whether the adsorption efficiency of biochar produced from this biomass can be improved by physical activation with carbon dioxide (CO₂). To this end, an assessment was made of the effectiveness of raw and activated biochar in adsorbing cadmium (Cd2⁺) from an aqueous solution under conditions close to those of drinking water (pH = 6 and temperature = 22 ± 1 °C). The results of the adsorption indicated that raw biochar, obtained by pyrolysis of cocoa pod shell biomass at 400°C, was more effective at removing Cd2⁺ (removal rate = 72.0 ± 1.1% and adsorption capacity = 14.4 ± 0.3 mg/g) than activated biochar, which was produced by pyrolysis of the same biomass at 900°C followed by activation with CO₂ at 800°C (removal rate = 65.3 ± 1.8% and adsorption capacity = 13.0 ± 0.4 mg/g). The experiment indicates that the chemical surface properties of adsorbents significantly influence the adsorption of Cd2⁺, while physical properties have a minor impact. This study revealed that raw biochar pyrolysed at 400 °C was more efficient than activated biochar in adsorbing Cd2⁺, thus offering an easily available, environmentally friendly, and inexpensive adsorbent for improving drinking water quality. Therefore, it is not systematically necessary to activate biochar to be effective in removing pollutants from water.
Tool wear is a major issue in the forest industry, and extensive research has been carried out to understand its causes and to limit tool degradation. Among these causes, the properties of the machined wood-highly variable between species-play a crucial role. Sixty years ago, Andre Chardin (d. 1987) conducted a 15-year experimental study on tool wear during the sawing of tropical woods. Out of 4,000 cutting tests, 835 standard tests with uniform chip thickness were performed on 554 trees representing 285 species, 200 genera and 59 families, at both green and air-dry moisture contents. The tested woods were highly diverse, reflecting the wide variability typical of tropical species. Tool wear varied greatly, partly due to plastic bending of the cutting edge under high mechanical stress. The relationship between tool tip recession and cutting length followed a power law with a median exponent of about 0.7, which was lower for tests showing tip bending and for dry wood compared with green wood. Silica content emerged as the dominant factor influencing wear, given its large variation among species, while extractive content was not significant. Wood density and moisture content also affected wear, though to a much lesser extent. Grouping the tests by moisture (dry versus green) and silica content (siliceous versus non-siliceous) highlighted the combined effects of density and moisture on edge recession. Tooltip bending occurred frequently (42%) for dry non-siliceous woods, less often (10%) for dry siliceous or green non-siliceous woods, and rarely (3%) for green siliceous woods. Tool face burning was also common (42%) in dry non-siliceous woods. For the 78% of tests without tool tip bending, progressive linear regression on logarithmic wear and wood parameters yielded a 58% predictive value: silica (42%), moisture (8%), specific gravity (7%), and extractives (0.4%). The minimal impact of extractives contrasts with their known influence on steel corrosion and friction, likely due to opposing effects of different extractive compounds across species.
The Brazilian planted forest sector plays a vital role in economic and environmental sustainability, favouring mechanisation to meet market demands. However, studies addressing operational performance in the northeastern region remain scarce, particularly under varying site and stand conditions. Moreover, there is a lack of predictive models that link forestry forwarder productivity to operational costs and extraction strategies adapted to local site variability. It is noteworthy that forest extraction in Brazil faces challenges due to the variability of edaphoclimatic conditions, impacting forestry forwarder productivity and operational costs. This study aimed to evaluate how specific operational factors (such as extraction distance, forestry forwarder load capacity, forest productivity, and time allocation within the machine's operational cycle) influence the efficiency and costs of timber extraction. Field data were collected in southern Bahia, a strategic area for the pulp and paper industry, across stands with distinct productivity levels and forest rotations. Time and motion studies, linear regression, and cost analysis revealed that predictive models explained up to 92% of forestry forwarder productivity. A strong inverse correlation was found between productivity and extraction distance. This result highlights the importance of minimising long hauls to reduce costs. Productivity was directly proportional to forest yield, with the forestry forwarder loading process representing up to 42% of the operational cycle. The use of higher-capacity forestry forwarders has optimised extraction, with an average of 21 m(3) per trip. Cost analysis showed a 26% increase in cost per cubic metre with decreased forest yield and a 61% increase with longer extraction distances. These findings define optimal operational parameters for Southern Bahia, Northeastern Brazil, emphasising cost efficiency and performance improvements.
Two generalised height-diameter models, based on the non-linear mixed-effects modelling technique, were developed for thuya (Tetraclinis articulata Vahl.) and maritime pine (Pinus pinaster Ait.) in Tunisia. These models incorporate both fixed parameters, reflecting the average growth patterns across all sampled trees, and random parameters which capture variability specific to each growth environment. The random effects were estimated in advance and are related to the dendrometric characteristics of each plot. The dataset comprised measurements from 594 thuya trees across 50 temporary plots and 797 maritime pine trees across 69 temporary plots, selected using systematic sampling for each species. Compared with the same non-linear fixed-effect models, the developed generalised height-diameter models significantly reduced the residual variance ( sigma ) by 53% (from 1.09 to 0.51) for thuya and 67% (from 8.55 to 2.80) for maritime pine. The models also improved the adjusted coefficient of determination (2 Raj ) from 38% to 71% for thuya and from 49% to 83% for maritime pine. The application of these generalised height-diameter models requires only the measurement of tree diameter and the estimation of stand characteristics (dominant plot height, Ho, basal area per hectare, G, and number of stems per hectare, N). With minimal sampling requirements, the models offer a cost-effective and time-efficient alternative to direct height measurement while ensuring a high level of accuracy.
Reconciling agricultural activities with biodiversity conservation is a core concern for sustainable development. Establishing cocoa agroforests in the Guinean savannah lands of Central Cameroon would modify the floristic composition of their woody vegetation. The aim of this study is to analyse the consequences for the woody biodiversity of these areas of converting savannah lands to cocoa agroforests. To do so, the study conducted sociological surveys among a sample of 105 savannah cocoa farmers to understand the techniques they use and their choice of associated species. Vegetation surveys were then carried out in 1 ha of savannah and cocoa agroforests, to determine their floristic richness and diversity. The study showed that converting savannah to cocoa agroforests caused a change in tree and shrub density and in their richness and diversity. In intact savannah lands, 547 individuals of 25 species were counted, compared with 1,093 individuals of 32 species in cocoa agroforests. While the conversion ofthis savannah land into cocoa agroforests led to a densification of its woody species and enriched agrodiversity, it also favoured a loss of indigenous woody species to the benefit of exotic species. This is why it is so important, for reasons of sustainability, to favour an integrated system that combines both exotic and indigenous species within each stand.
Clearing and restoring land invaded by alien trees in South Africa is strategic to adapt to climate change. As funding falls short of needs and alien clearing operations exhibit limited effectiveness while usually leaving or burning trees on site, there is a case for biomass-based value chains. However, financial feasibility for the main products of interest (bioenergy and biochar) is disputed due to sub-optimal supply chains. These must be improved to cope with a scattered, heterogeneous, and poorly mapped resource. To this aim, we surveyed key stakeholder categories based on an analytical framework derived from the literature and validated our results with a stakeholder workshop. This represents a first attempt to study and improve invasive tree-based supply chains with relevant results for other contexts. We find a complex governance of supply chains, without coordination with alien clearing programmes, a diversity of models, and mixed reports about the fluidity of interactions with landowners. We conclude with six recommendations: (i) establishment of a biomass users association (information dissemination and connections with public actors); (ii) support to large-scale biomass users (innovation potential, sustainability certification); (iii) centralised funding (consistent planning of alien clearing); (iv) generalisation of collaborative landscape platforms (improved access to sites, targeted support to value chains); (v) enhanced law enforcement (lower transaction costs and greater bargaining power for biomass suppliers); (vi) improved coordination between stakeholders (articulation with alien clearing, higher integration).
Sachant qu'il est toujours difficile de rassembler des statistiques à l'échelon européen ou mondial, nous avons demandé à Eric B0ILLEYde nous faire part de certaines données sur le commerce des bois tropicaux, fournies en grande partie par l'U.C.B.D. (Union pour le Commerce des Bois Durs en Europe), qu'il a analysées pour les lecteurs de Bois et Forêts des Tropiques.
Le Laboratoire d'Ecologie Terrestre de Toulouse a mis sur pied, les 10 et 11 juillet1997, un symposium sur la mangrove et les différents aspects de la recherche concernant son écosystème, dont les organisateurs étaient : R.Dooo, f. FROMARD, Z. RAFII.
To use wood species appropriately and optimally, it is imperative to know their chemical composition. The application of near-infrared spectroscopy (NIRS) provided a valuable approach to correlate wood properties with tree ecological traits and their adaptive responses. The study aim was to verify that different chemical compositions exist for a wide range of species grouped into distinct ecological temperaments. Thus, 25 tropical Gabonese hardwoods, mainly secondary species, were studied and divided into three ecological temperaments: pioneer, hemi-heliophilous, and shade-tolerant. The spectra studied were obtained using a Spectrum Two N spectrometer (PerkinElmer) on the transverse faces of 368 unground samples of heartwood by reflectance in the range 1000 to 2500 nm. These were then subjected to pre-processing (standard normal variable and second derivative), followed by principal component analysis and partial least squares discriminant analysis. The discrimination model used showed high performance in cross-validation and prediction at 93.2% and 88.3%, respectively. The results indicated differences in NIRS signatures between the three ecological temperaments. The hemi-heliophilous and shade-tolerant species had similar NIRS signatures but different concentrations of chemical compounds (derived from NIRS spectra analysis). The pioneers had a different profile from the other two ecological temperaments. No significant difference in cellulose content was found between the three ecological temperaments. Hemicelluloses and lignin concentrations were higher in the shade species. The pioneer species had significant levels of extractives.
Clearing and restoring land invaded by alien trees in South Africa is strategic to adapt to climate change. As funding falls short of needs and alien clearing operations exhibit limited effectiveness while usually leaving or burning trees on site, there is a case for biomass-based value chains. However, financial feasibility for the main products of interest (bioenergy and biochar) is disputed due to sub-optimal supply chains. These must be improved to cope with a scattered, heterogeneous, and poorly mapped resource. To this aim, we surveyed key stakeholder categories based on an analytical framework derived from the literature and validated our results with a stakeholder workshop. This represents a first attempt to study and improve invasive trees-based supply chains with relevant results for other contexts. We find a complex governance of supply chains, without coordination with alien clearing programs, a diversity of models, and mixed reports about the fluidity of interactions with landowners. We conclude with six recommendations: (i) establishment of a biomass users association (information dissemination and connections with public actors), (ii) support to large-scale biomass users (innovation potential, sustainability certification), (iii) centralised funding (consistent planning of alien clearing), (iv) generalisation of collaborative landscape platforms (improved access to sites, targeted support to value chains), (v) enhanced law enforcement (lower transaction costs and greater bargaining power for biomass suppliers), (vi) improved coordination between stakeholders (articulation with alien clearing, higher integration).
Deux modèles hauteur-diamètre généralisés, basés sur la technique de modélisation non-linéaire à effets mixtes, ont été développés pour le Thuya (Tetraclinis articulata Vahl.) et le pin maritime (Pinus pinaster Ait.) en Tunisie. Ces modèles renferment en plus des paramètres fixes qui expriment un comportement moyen identique à tous les arbres, des paramètres aléatoires propres à chaque environnement de croissance, estimés préalablement à l’aide des modèles non-linéaires à effets mixtes et mis en relation avec les caractéristiques dendrométriques des placettes. Les données utilisées proviennent des mesures de 590 arbres sélectionnés dans 50 placettes temporaires pour le thuya, et de 797 arbres également choisis dans 69 placettes temporaires pour le pin maritime, par échantillonnage systématique pour chaque espèce. Comparés aux mêmes modèles non-linéaires à effets fixes, les modèles hauteur-diamètre généralisés développés ont permis une réduction significative de la variance résiduelle () de 53 % (passant de 1,0910 à 0,5111) et 67 % (passant de 8,5500 à 2,8049), tout en faisant passer le coefficient de détermination ajusté () de 38 % à 71 % et de 49 % à 83 % pour le thuya et le pin maritime, respectivement. L’utilisation des modèles hauteur-diamètre généralisés développés dans cette étude ne nécessite que la mesure du diamètre des arbres et l’estimation des caractéristiques du peuplement (hauteur dominante de la placette, H₀, surface terrière par hectare, G, et nombre de tiges par hectare, N). Grâce à un faible effort d’échantillonnage, ces modèles permettent de réduire les coûts et le temps généralement consacrés à la mesure de la hauteur des arbres forestiers, tout en maintenant un niveau de précision élevé.
The Andes region of Colombia, known for its extensive coffee cultivation, also holds the country’s largest areas of successional forest. This analysis evaluated the use of forest, bamboo, and agroforestry systems in coffee farms as part of an agroecological transition strategy. The research was carried out in three municipalities on the Popayán plateau, located in the Department of Cauca in southwestern Colombia. Using a combination of qualitative and quantitative methods – including the Shade Tree Advice tool to assess ecosystem service provision – the study examined how these systems are integrated into the livelihoods of coffee-growing families. The results confirmed that these farms, managed by peasant families, use a diversified approach to land use that balances ecological sustainability with economic needs. Most farms incorporate successional forests, bamboo groves, and agroforestry systems as part of their adaptation strategies to the growing risks posed by climate change. Local knowledge played a key role in identifying the tree species that support ecosystem services essential to coffee farming. Leguminous and fruit trees are most commonly used to provide ecosystem support, including regulation and supply functions. Other native species are additionally used for shade and live fences. These results are valuable for selecting tree species for propagation in nurseries, planting on farms, and providing shade for coffee crops. Likewise, they strengthen the agroecological transition processes, support the certification of farms and contribute to improving the income of coffee-growing families and organisations.
La conciliation des activités agricoles et la conservation de la biodiversité restent au cœur des préoccupations actuelles du développement durable. L’établissement des agroforêts à cacaoyers dans les savanes guinéennes du Centre-Cameroun contribuerait à la modification de la composition floristique des ligneux. L’objectif de cette étude est d’analyser les conséquences de la conversion des savanes en agroforêts à cacaoyers sur la biodiversité ligneuse dans ces savanes. Pour y parvenir, l’étude s’est appuyée sur des enquêtes sociologiques auprès d’un échantillon de 105 cultivateurs de cacao en savane afin de comprendre les techniques utilisées et leurs choix pour les espèces associées. Des relevés floristiques ont par la suite été réalisés dans 1 ha de savane et d’agroforêts à cacaoyers, en vue de déterminer leur richesse et leur diversité floristique. L’étude montre que la conversion des savanes en agroforêts à cacaoyers a induit une modification de la densité des ligneux, de la richesse et de la diversité floristiques. Ainsi, dans les savanes intactes, 547 individus répartis en 25 espèces ont été dénombrés, contre 1 093 individus répartis en 32 espèces dans les agroforêts à cacaoyers. Bien que la conversion des savanes en agroforêts à cacaoyers entraîne une densification des ligneux et un enrichissement de l’agrodiversité, elle favorise néanmoins la disparition des espèces ligneuses indigènes dans les savanes, au profit des espèces exotiques. C’est là toute l’importance de privilégier un système intégré qui combine à la fois les deux types d’espèces au sein du peuplement associé dans la perspective du développement durable.
