Determining proper area and shape of sample plot for crown cover estimation using forest simulation in Zagros Region

Zagros forests have a great effect on water and soil conservation in the west part of Iran. Therefore, it is important to prepare a complete management program for this area. The necessary qualitative and quantitative data can be gathered via inventory. Crown cover is a suitable factor to study in this area because the forests can not produce industrial wood. Consequently, volume is not a suitable factor to study. In this research, it is aimed to determine the suitable area and shape of sample plot for crown cover estimation. In Kohgiloye-Boyerahmad Province, a 2 hectare plot in Servak Forests near Yasuj was surveyed by full callipering method and the position of each tree was determined. Using GIS, a 30 hectare forest map was simulated according to the real field data. 30 sample plots in three shapes of circular, rectangular and square were chosen in a systematic random network (100×100 m). The surface area varied between 500 to 2500 m2. Standard deviation of the crown cover percent for each area and each shape was calculated. The "F" test of the figure's results showed that the least sample surface area for crown cover inventory is 800 m2 for all shapes. Comparing the ratio of perimeter to surface area of three chosen shapes, 800m2 circular sample plot was chosen as the suitable sample plot for the study area.