Classification and Ecology of Closed-Canopy Forest in Ghana

Abstract

JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms of scholarship. For more information about JSTOR, please contact support@jstor.org. This content downloaded from 132.211. INTRODUCTIONThe most recent attempts to classify the forest vegetation of Ghana are those of Taylor (1960) and Mooney (1961), who based their classifications on inventories of trees in forest reserves. Their work has two major shortcomings. Firstly, forest which had not been enumerated could not be included. Secondly, the failure of the authors to describe the methods by which their classifications were derived makes it impossible to identify a forest stand other than by its map position, thus greatly reducing their practical value (cf. Greig-Smith 1969a). We have attempted to produce a floristic classification with a defined empirical basis, applicable to all forests in Ghana, and readily permitting identification.The structural complexity and species-richness of tropical forest make difficult or impossible its study by the traditional phytosociological procedures, but numerical methods have proved successful (Greig-Smith 1969b), especially in demonstrating correlations between vegetation and environmental factors in fairly small areas (Austin, Ashton & Greig-Smith 1972; Greig-Smith, Austin & Whitmore 1967). There are relatively few published accounts of the use of numerical methods in a survey of a large area of tropical forest, mainly because of the problem of dealing with a data matrix of the size involved. Webb et al. (1970) analysed tropical and subtropical forests in Australia spanning 20? of latitude, but took only sixty-eight plots and used only eighty-two species in the final analysis. Recent improvements in methodology and computer capacity encouraged us to undertake sampling more intensive than this, using a much larger number of species. Conditions in Ghana are particularly suitable for a survey of tropical forest. Of a total forest zone covering 82 260 km2, the area under forest amounts to 20 530 km2 including 16 790 km2 within forest reserves distributed more or less throughout the forest zone (Anon. 1973). Most reserves can be reached by motor road. The forest flora of West Africa is relatively well known, and is less diverse than that of tropical Asia or America. All Ghanaian forest falls within the categories of Tropical Evergreen Seasonal forest and Tropical Semi-deciduous forest (UNESCO 1973). It has a more or less uneven tree canopy at 10 to 40 m above the ground (emergent trees may reach 60 m); woody climbers are always present. Vascular epiphytes are present except in the driest forests, but not abundant except in the most humid; some of the canopy trees are deciduous in the dry season, but the understorey trees and shrubs are evergreen. Gymnosperms and stem succulents are absent, and palms are generally uncommon; a herb...

Land use dynamics and nutrient characteristics of soils and plants along topo-sequences in inland valley watersheds of Ashanti region, Ghana

“…These soils have been devel- plot (see Fig.1) (see Fig. I (Hall and Swaine 1976). The patchy distribution of secondary forests, which regenerated by a long fallow, was observed in the benchmark watersheds.…”

Reduced density due to logging and its consequences on mating system and pollen flow in the African mahogany Entandrophragma cylindricum

“…Sapelli is a longlived timber tree species of high commercial value found from Sierra Leone east to the Democratic Republic of Congo and to Uganda, in tropical evergreen and semideciduous forests (Hall and Swaine, 1976). In the continuous tropical forest cover of the Congo Basin, trees are widely spaced and density is typically lower than five flowering individuals per hectare.…”

La végétation de la chaîne de l'Atakora au Bénin: diversité floristique, phytosociologie et impact humain

“…Elle est caractérisée à l'instar de la plupart des zones montagneuses par une forte géodiversité. La végétation de cette chaîne a été décrite au Ghana (Hall & Swaine, 1976) et au Togo (Akpagana, 1989). En revanche au Bénin, elle est restée peu explorée (Hahn-Hadjali et al, 2000) en dehors des rares études effectuées sur la végétation et à l'utilisation des ligneux sauvages et son effet sur la végétation dans la région de Natitingou (Sieglstetter & Wittig, 2002).…”