Floristic composition of agroforestry parklands in the semi-arid zone of Ghana: A special focus on Faidherbia albida (Delile) A. Chev

Abstract

In order to understand the dynamics of regeneration, growth, population and possible upscale for the benefit of agroforestry parkland trees in the semi-arid areas of Ghana, a study was conducted to determine the population density, diversity, relative dominance, importance value indices (IVI) and use categories of parkland tree species in the Sudan and Guinea Savannah vegetation zones of Ghana, with special reference to F. albida. Tree inventories were conducted on 80 sampled farms covering a total area of 74.2 hectares across 8 communities distributed in 4 districts in the Sudan and Guinea savannah zones. Mean farm size was 0.93 hectares. Fifty-four tree species belonging to 24 families were encountered during the study. A Simpson's diversity index of 2.72 was determined as the overall diversity index of tree species on farmlands. Tree population densities in the sampled communities ranged between 4 (Katiu) and 11 (Kugri) trees per hectare. The predominant uses of parkland trees include food, medicine, shade, fuelwood and wood for construction. Others include fencing, soil improvement, direct income from sale of tree products, erosion control, fodder, tools, deity, packaging and craft. Ranking parkland tree species according to their Importance Value Indices (IVIs) in the various study ecological zones, it was evident that Faidherbia albida is highly ranked in both ecological zones due to its multipurpose functions such as fodder (pods and leaves) provision, shade provision in the dry season, and its contribution to improved growth and yield of crops grown under its canopy. Faidherbia albida populations should be increased on farmlands through programs like the Farmer Managed Natural Regeneration (FMNR) and possible domestication.