Application of Random-pairs, Joint-point and Line-intercepet methods for estimating quantative characteristics of Zagros forests (Case study: Research and educational forest of Razi University of Kermanshah)

In this study three sampling methods named Random-pairs method، Joint-point method and Line-intercept were used for estimating quantative characteristics of Zagros Oak (Quercus brantii) forests with regard to accuracy in research and educational forest of Razi University (Kermanshah province). Random-pairs method and Joint-point method were used for estimating trees per hectare، and for estimating percentage of canopy cover Line-intercept method with Random-pairs method and Joint-point method were examined. For each method 50 samples were selected using systematic-random design and number of trees and higher and lower diameter of crown were measured to obtain trees per hectare and percentage of canopy cover in each sample. The results showed that none of methods can provide an acceptable estimate of density and percentage of canopy cover based on accepted accuracy; the Random-pairs method has more accuracy level for crown coverage for this kind of forests.