Methodology

Two methods have been used in this study: the interpretation of aerial photographs and ground traversing. It became necessary to use aerial photographs for a number of reasons. The time frame and the project budget would not permit the use of satellite images. The use of satellite image analysis was also not adopted because of the spatial scale of study and the known complexity of the land use and cover, which required a better spatial resolution than that of the easily available current satellite programmes. The photographs used were black and white prints flown in 1974 at a scale of 1: 40,000, and borrowed from the Survey Department of Ghana. A print lay-down was prepared to obtain a general view of 25 km² centred on each of the three study villages, Yensiso, Sekesua and Amanase. Land use and cover was visually delineated on the basis of geometrical shapes, lineations, height of vegetation, presence or absence and the density of tree tone and texture of the land surface. These together with the accounts of the land use and cover history of the areas, as indicated by the people, as well as common knowledge, formed the basis of the final interpretation of the photographs.

The elements and distribution of the current (1993) land use and cover were examined using walking line transect observations over a total distance of 5.295 km at the three sites. Surface cover and use categories were measured along the traverses using chain and line tape. The categories identified are described below.