Jean Cossi Ganglo

Environmental and wood biophysical variabilities in teak plantations in Togo (West Africa).

Abstract This survey addresses the influences of ecological factors on wood biophysical properties of teak wood in plantation in Togo. On national scale, these plantations are discriminated in six ecological groups using a correspondence factor analysis. The same analysis applied to the wood biophysical properties permits to discriminate Togolese teak in six groups also. Within these six biophysical groups, wood density ranged from 600 to 800 kg/m3. Mesurements of colour permit to classify these plantations in three categories. Natural durability of these plantations varies from highly durable to durable. At Tchorogo forest site scale, a survey using synusial approach to phytosociology permitted to describe three phytocoenoses with different productivity index which are Icacina senegalensis phytocoenose, Ressantia indica phytocoenose and Daniellia oliveri phytocoenose.

Caractéristiques structurelles et écologiques des phytocénoses de sous-bois des plantations privées de teck du département de l’Atlantique (Sud-Bénin, Afrique de l’Ouest)

Abstract Structural and ecological characteristics of private Teak plantations in the Atlantic Department, South Benin, were studied according to the synusial approach of phytosociology in order to contribute to the sustainable management of the plantations. The study of dendrometric characteristics of Teak plantations was done by establishing two temporal plots, each of 1 are. In each plot, the stem girth of the trees and the total height of three mean trees were measured. A total of 99 vegetal synusias has been described, then combined into 18 phytocoenoses. Ecological characteristics are also studied.

The Psychotria vogeliana-community in the spontaneous undergrowth of teak (Tectona grandis L. f.) plantations in south-Benin: ecological and sllvicultural indicatory values

Abstract The spontaneous undergrowth of teak (Tectona grandis L. f.) plantation in Djigbé forest (south Benin) has been studied. The Psychotria vogeliana-community is identified from ten representative phytosociological relevés. This community is an indicator of sandy plateau soils generally associated with the least productive plantations. Its composed of 91 species with a mean of 32 species per relevé. The study of distribution spectra reveals the abundance of phanerophytes, secondary forest species and phytogeographically widespread species; they represent respectively 86%, 48% and 50% of the total number of species. The analysis of species diversity indicates that the Psychotria vogeliana-community is somewhat diversified, but the species abundance is weakly balanced (2.1 for Shannon-Wiever index and 0.48 for evenness index).

Phytocénose à Mallotus oppositifolius et Macrosphyra longistyla dans le sous—bois des plantations privées de teck (Tectona grandis) de la commune d'Abomey-Calavi, Sud-Bénin

Abstract A study has been undertaken in the natural undergrowth of private teak plantations in Abomey—Calavi using the synusial approach to phytosociology. Pedological and topographical factors and private teak plantation production within plant communities have been studied. Mallotus oppositifolius and Macrosphyra longistyla community is identified on acid clayey—sandy soils. It is composed of eight vegetal synusia and represents the fourth stage growth of the vegetation succession in the study area. Mean diameter of teak in this plant community varied between 5.7 cm and 15.8 cm while the mean height is between 6.5 m and 13 m and, the basal area between 10.7 m2/ha and 18.9 m2/ha. This community is indicative of the most productive forest sites of the municipality.

Le groupement végétal à Icacina trichantha Oliv. dans le sous-bois naturel des plantations de Teck (Tectona grandis L. f.) du sud et du centre-Bénin : composition et diversité floristique, valeurs indicatrices écologique et sylvicole

Abstract The natural undergrowth of Teak (Tectona grandis L. f.) plantations in south and center Benin has been assessed. The Icacina trichantha-plant community is identified in Djigbé forest. On the basis of ten representative phytosociological relevés, this plant community is composed of 93 species with a mean of 37 species per relevé. The analysis of species diversity indicates that the Icacina trichantha-community is somewhat diversified with 2.32 for the Shannon- Weaver index and 0.50 for the Pielou evenness index. The Icacina trichantha-plant community is frequently found on rocky acid soils at middle positions of steep slopes (10 to 40%). Teak plantations associated with of this plant community are among the most productive of Djigbé forest.