  Structure spatiale des arbres des savanes boisées et forêts claires soudaniennes : implication pour les enrichissements forestiers; ; et al in Biotechnologie, Agronomie, Société et Environnement = Biotechnology, Agronomy, Society and Environment [=BASE] (2012), 16(4), 429-440 During the last decade, management of woodlands in the Sudanian region of Benin has been based on enrichment with valuable tree-species. Yet, no previous research has been undertaken to support enrichment ... [more ▼] During the last decade, management of woodlands in the Sudanian region of Benin has been based on enrichment with valuable tree-species. Yet, no previous research has been undertaken to support enrichment design with respect to plant eye view, tree growth magnitude or survival capacity under local forest environments. To fill in this gap, Ripley's K function was used to assess the spatial pattern of trees, diameter classes and dominant valuable species in the Sudanian zone. Data were collected in four sites of variable size (150 X 100 m, 150 X 100 m, 100 X 50 m and 150 X 150 m). Mostly, the spatial patterns of the target species revealed small-clumps. Within these small-clumps, intraspecific repulsions were observed on average at a 3 m scale, while interspecific repulsions were noticed at a 4.5 m scale. Only a weak repulsion between diameter size was also remarked, suggesting that proximity to adult trees would not affect the survival of young plants. With regard to observed repulsion scales, we would suggest using a minimum of a 3 m space between trees of the same species and a 4.5 m space between trees of different species, for enrichment plantings in Sudanian woodlands, if based on the target species. However, this suggested spacing may not be optimal with regard to plant growth. Further investigation is needed to address this aspect. [less ▲] Detailed reference viewed: 11 (1 ULg)Caractérisation des plantations privées de teck (Tectona grandis L.f.) du département de l'Atlantique au Sud-Bénin; ; et al in Biotechnologie, Agronomie, Société et Environnement = Biotechnology, Agronomy, Society and Environment [=BASE] (2012), 16(4), 441-451 Teak plantations are an undeniable asset, representing socio-economic and environmental importance in South Benin. Plantation owners see teak as an asset, enabling them to supplement their income through ... [more ▼] Teak plantations are an undeniable asset, representing socio-economic and environmental importance in South Benin. Plantation owners see teak as an asset, enabling them to supplement their income through timber production and sales. Sustainable management of teak plantations requires a high level of knowledge and understanding of the resource by plantation owners. The snowball sampling method was used in order to reach private teak plantations owners. This is a chain sampling method, which uses information from the first informant (plantation owner) to trace the others in the sample. Data were collected on the socio-economic status of plantation owners, and on both the geographical location and the size of the plantations. Dendrometrical parameters were measured through strip sampling. Factor analysis followed by hierarchical classification and stepwise discriminant analysis were performed in order to build a profile of the owners. We have identified 2,431 owners and 2,624 plantations. Young plantations (up to 5 years old) represent 16.4% of the total plantation area, high forests 12.7% and coppices 70.9%. Overall, these plantations were small in size (average = 0.44 ha). The number of trees per ha was found to be high, regardless of the forest system (respectively 3,371 trees/ha for young plantations, 3006 trees/ha for high forests and 6305 trees/ha for coppice). These high numbers reflect the fact that the trees represent farm-grown timber. Four groups of owners were distinguished: smallholder farmers seeking income (group 1), small city dweller planters and those motivated by securing their properties (group 2), city dweller planters with medium size plantations (group 3); and owners with large-scale plantations (group 4). All groups were willing to secure their land or be involved in the timber trade. The specific characteristics of each group need to be taken into account in considering the sustainable management of private teak plantations in South Benin. [less ▲] Detailed reference viewed: 27 (2 ULg) Functioning of farm-grown timber value chains: Lessons from the smallholder-produced teak (Tectona grandis L.f.) poles value chain in Southern Benin; ; et al in Forest Policy and Economics (2012), 15(February 2012), 98-107 The study examined the functioning of the smallholder-produced teak poles value chain in Southern Benin from an analytical perspective combining the governance structure, the institutional environment ... [more ▼] The study examined the functioning of the smallholder-produced teak poles value chain in Southern Benin from an analytical perspective combining the governance structure, the institutional environment, and the distribution of consumer price among chain actors. The objective was to identify bottlenecks militating against improved functioning of the farm-grown timber value chains. A fieldwork was carried from August 2008 to September 2010, to identify the agents and the organisations involved in the value chain. Data were collected on the functions performed, the costs borne and the income received by each category of agent, the marketing channels within the value chain, the interactions among agents, the consumption of the product, and the role of the organisations connected to the value chain. This was done by combining semi-structured interviews, focus group meetings, and structured interviews. In addition, data were collected on the institutional environment from both primary and secondary sources. The following agents were involved in the value chain: nurserymen, planters, local intermediaries, brokers, traders, and consumers. The forest service was the main governmental organisation involved in the functioning of the value chain. The governance structure in the value chain was driven by a mixture of government and the market. Various weaknesses were found in the forest policy, the forest regulation and their implementation. Planters’ share of consumer price was lower than traders’ return. The relevant policy options to address these issues were discussed. [less ▲] Detailed reference viewed: 17 (4 ULg) Taille des placeaux de caractérisation des teckeraies à sylviculture paysanne au Sud-Bénin; ; et al in Bois et Forêts des Tropiques (2011), 310(4), 69-78 Success of teak, Tectona grandis, plantations in State forests has encouraged involvement of private landowners in this sector, with inadequate planting method and a management system livelihood ... [more ▼] Success of teak, Tectona grandis, plantations in State forests has encouraged involvement of private landowners in this sector, with inadequate planting method and a management system livelihood-improvement oriented. Any assessment and characterisation of this resource therefore demands a study on the representativeness of the sampling units. Three sampling types and twelve sampling units were compared: plots defined by area (100 m2, 200 m2, 400 m2 and 600 m2); plots with a fixed number of trees (7, 9, 11, 13 and 15 trees) and strip sampling (5, 10 and 15 trees). The units were established randomly and a full inventory conducted, with one to four reiterations in each of the eighteen plantations of different ages managed as high stands and coppices. The dendrometric parameters calculated for each observation unit and for the full inventory are as follows: density (Na/ha), basal area (G), arithmetical average diameter of stems (dg), average basal area of stems. The criterion for comparison is the root mean square error relative (RRMSE) to the reference value: from the full inventory. The analysis of results shows that RRMSE can be as high as 36 %, and even more in high stand plantations. Plots with a fixed surface area produce the best estimations for characterising plantations, with approximately equivalent efficiency for 400 and 600 m2 plots, with a RRMSE of 10 % (Na/ha), 13 % for (G) and 7 % for (dg). Strip sampling produced better results than plots with a fixed number of trees, with a better (dg) estimation of 10 % to 12 %. Given the cost of the inventory, 400 m2 sampling plots may be recommended to improve the charaterisation of teak plantations under farm silviculture. [less ▲] Detailed reference viewed: 16 (5 ULg) |
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