Vegetation Development Dynamics of Fire Experimental Plots at Olokemeji Forest Reserve, Nigeria.

Abstract

An enumeration of trees in the three fire investigation plots of Forestry Research Institute of Nigeria (FRIN) at Olokemeji Forest Reserve, Nigeria was carried out. Since the inception of the investigation Plot A was burned annually at the end of dry season, when the plants were very dry,  Plot B was burned early in the dry season when plants were still wet and Plot C was not subjected to burning, hence the control Plot.  All the trees in each plot were counted and their girths were measured. The data was used to calculate and compare the Shannon-Weiner diversity index for plots and the Importance Values (IV) as a measure of dominance of the species. The late burn plot (Plot A) had changed to savanna woodland formation with a diversity index of 2.76 and the dominant trees were Dalbergia sisso, Gmelina arborea and Crossopteryx febrifuga. Plot B had changed to transitional woodland with a diversity index of 2.83 while the dominant trees were Gmelina arborea, Anogeissus lieocarpus and Malacantha alnifolia. A few fire tender species such as Manilkara obovata and Mimusops andongensis were present. Plot C had developed into a full fledge forest formation with a diversity  index of 3.8 while the dominant trees were Manilkara obovata, Hildegardia barteri and Gmelina arborea. Only plot C had soil litter with a biomass of 153.4g.m₂. Girth size/class curve for plot A showed a characteristic curve for populations under stress while those for Plots B and C showed curves characteristic of stable populations but curve C showed a better ecological status.

Keywords: .fire, Olokemeji Forest Reserve, vegetation development, Nigeria