Evaluation accuracy of cluster and random systematic sampling methods to estimate of quantitative characteristics in protected forest of Ardal

The main aim of this study was to investigate cluster sampling method and random sampling method with one hundred percent of the estimated inventory features of density and canopy cover in protected forest occupied by Chartagh Ardal forest area for this purpose, 50 hectares of forest of the study area 100% survey with rectangular plots (20×50 m) were measured. In each clustering methods20 clusters were measured with 100 × 250 m demotions. In each cluster, characteristics the number of trees and canopy trees (both large and small diameter of the crown) were measured. In random systematic sampling methods 100 plots were selected in grid inventory with 50×100 m Dimension. The results this study showed a significant difference between the mean estimates of sampling methods with the actual 100% survey. The results of statistical error showed the cluster sampling method with inequality sampling units (5.59% and 9.64%)had more accurate than the cluster sampling method with equality units (6.46% and 10.69% ) and random systematic sampling (8.9 and 11.02% ). The basis of the criterion of authenticity and accuracy of cluster sampling with inequality members had more accurate than the cluster sampling method with equality units. Therefore, the cluster sampling method with inequality sampling units was suitable sampling method in the Chartagh Ardal forest area.