Structural Analysis of Shrub – Tree Species in Yobe State, North Eastern Nigeria

Abstract

The study examined the structural characteristics of shrub-tree species in Nangere, Yobe State, Northeastern Nigeria. Ten sampling point of quadrant size 200 by 100 meters were considered and five quadrants were randomly selected for the sampling using table of random number. Plant physical parameters such as the height, crown cover, diameter breast height (DBH), the volume of the tree and girth of the tree were measured on the field. The data obtained from the field were subjected to statistical analysis using correlation coefficient. The volume of tree is considered to be dependent variable height; girth, crown cover and diameter at breast (DBH) were considered to be independent variables. From the result, the height of the trees ranges from 3.25 m to 17.71 m, the girth 0.39 m to 8.00 m, the crown cover 1.20 m to 30.20 m, DBH 0.32 m to 7.20 m and the volume of the trees ranges from 2.06 m3 to 215.03 m3 . The result of the analyses revealed that there is a strong and positive correlation between the height of the trees and volume of the trees, the girth and volume of the trees, the crown cover and volume of the trees as well as the DBH and volume of the trees. The joint contributions of the four parameters (height, girth, crown cover and DBH of the trees) on the volume of the trees in the study area shows that R2 obtained for quadrant one, three, four and five are 0.99, 0.64, 1 and 1.00 respectively implying that the combined contribution of the parameters to the volume of trees in the study area was very high.