Comparative Study of the Growth and Yield of Some Multipurpose Trees in a Tropical Rain Forest of South-western Nigeria

The survival of 22 species of exotic and indigenous multipurpose trees and shrubs grown in a 14-year old arboretum, located in Ibadan, South-western Nigeria was evaluated. The assessment was followed by wood yield analysis on 9 selected species which include Cordia alliodora, Pterocarpus soyauxii, Treculia africana, Cassia siamea, Blighia sapida, Pentaclethra macrophylla, Dialium guin and Vitellaria paradoxa. There was no significant provenance variation in the survival of all the species in the arboretum, but the selected species differed significantly in most of the growth and yield parameters. Gmelina arborea, an exotic species, recorded the highest wood yield (44.78 m³/ha/year) while Pterocarpus soyauxii, an indigenous species, recorded the lowest wood yield 0.5 m³/ha/year). Variations within species in wood yield were also observed. Linear regression equation for predicting yield from easily controllable variable like crown diameter was established for each of the species. Significant positive correlation coefficients between yield and crown diameter were obtained (0.40 < r < 0.76). The possibility of the use of the MPTS to develop a sustainable multiple landuse system is discussed.