The Effects Of Sample Plot Size And Shape On Accuracy Of Inentory Using Systematic Sampling In Acaica Nilotica (Sunt) Plantation:Case Study Sawlell Forest In Blue Nile Sudan

Abstract

The present study compares between different sizes and shapes of sample plot in forest inventory depending on systematic sample method in Sawlell forest in the Blue Nile State. Different sample plot sizes of Acacia nilotica, by namely 0.05, 0, 1 , 0.15 hectare with different shapes: circular, square, rectangular were compare to find their effect on forest inventories concerning diameter at breast height, basal area, height, number of trees, and volume estimates the complete enumeration was taken as control. The selected study area was Sawlell forest in Blue Nile State. The forest age is approximately 21 years the research was done in Maya site. The karab site is not re preventative area and for graf site is covers by the plantation of khaya senegalensis , Eucaly ptus and Tectona grandis. The study showed significant difference between the different sizes and shapes of the sample plots .The study clearly indicates that the most accurate results of diameter, height, basal area, number of trees and volume estimates were achieved by circular sample plots compared to square and rectangular sample plots. The present study indicated that the total number of trees obtained by 0.1 hectare systematic sampling is close to the total number of trees for the compartment given by the total enumeration. Also the results indicated that the diameter distribution using 4.0 cm class range is similar to the distribution provided by the complete enumeration