A survey on the accuracy of the inventory method of sample plots with 1000m2 area under random-systematic network for estimation of amount and distribution of stand volume, basal area and tree number in diameter classes

Abstract

After performing the first and Second 20-years periods of forest projects, even with proper execution of the programs, most of them have many problems yet. One of the most important factors that caused these problems is the method of data preparing and processing. The hypothesis of this research project is “there is a significant difference between the result of random-systematic inventory and full caliper method”. After sampling in plots with 1000 m2 area under a random-systematic grid, correlations between variables were surveyed. Volume, basal area and tree number amount and distributions in diameter classes were compared with the Willcoxon test between the two inventory methods. Conclusions are: data obtained in current random-systematic method in plots with 1000 m2 area have acceptable accuracy just for fuelwood species and hornbeam (Carpinus betulus). For beech (Fagus orientalis) and other species, accuracy decreases with increasing in diameter and heterogen distribution in forest stand