ABSTRACT

Stands of Nauclea diderrichii and Terminalia ivorensis within the arboretum of Forestry Research Institute of Nigeria were assessed for stand density and diameter growth rates of the tree species. Total enumeration of all the trees for both species was carried out and their diameters at breast height (dbh) measured. Nauclea diderrichii stand had the highest density of 430 trees ha^-1 and a total basal area of 4.32m²ha^-1 while Terminalia ivorensis stand had a density of 400 trees ha^-1 and a total basal area of 26.83m²ha^-1. The diameter growth rates for the two species were determined by calculating their mean annual increments (MAIs) in DBH. Nauclea diderrichii had an average DBH of 10.98cm and a mean annual increment (MAI) of 1.10cmyr^-1 while Terminalia ivorensis had an average DBH of 24.31cm and MAI of 2.43cmyr^-1. This study showed that Mean annual increment generally increased with reduction in stand density. Permanent sample plots (PSP) should be established in the arboretum for continuous inventory to provide data for academic and research activities; and also for sustainable management of the tree resources.