Comparative analysis of density, diversity and similarity of forest tree species in three selected states of northern Nigeria

Abstract

This study compared forest tree density, species diversity, and similarity in some selected States of northern Nigeria. Fifteen percent intensity of the survey was carried out on 150 ha, 50ha in each of the States for the studies. A total number of two hundred and forty-nine Quadrants of 30m x 30m, (83 Quadrates in each of the States under study) were randomly distributed within the plot of 10,000m^²/ha. Number of species, corresponding number of individuals, and diameter of individuals found in the Quadrates were taken. Basal Area, Frequency, Relative Frequency, Relative Density, Relative Dominance, and Importance Value Index (IVI) were analyzed. Shannon-Wiener diversity Index, Species Evenness, Species Richness, Index of Dominance, Index of Similarity, and Index of Dissimilarity analysis were carried out. ANOVA was used to evaluate the differences in the stand densities. The results revealed that 47 species, 17 Families, 13 Orders, and 1 Kingdom were encountered in the Study area. Adansonia digitata had the highest value of BA; Relative Dominance; and IVI. Relative Density ranged from 1.09 to 7.14. The result of Shannon-Wiener Diversity Index ranged from -68.31 to -42.33; Species Richness ranged from 8.30 to 13.49; Evenness Index ranged from -48.86 to -26.08; Index of Dominance ranged from 294.11 to575.47. Index of Similarity ranged from 0.60 to 0.86. There were no significant differences (p>0.05) between the tree densities in the Study Area. Evaluating tree density patterns and tree species diversity is important for the forest managers to understand the complexity and resources of forests.