The Effectiveness of N-Tree Sampling Methods in Estimating Some Quantitative Characteristics of Zagros Forests

Quantitative and qualitative characteristics of forests can provide valuable information on the impact of forests on the environment. Quantitative and qualitative characteristics of forests can provide valuable information on the impact of forests on the environment. Detailed information from forest areas can be obtained by sampling or sampling. Although it is desirable to have complete censuses, sampling methods are preferred in many cases because of the cost and time savings involved. One of the sampling methods is the multi-tree method. In the present study, the performance of 3 to 10 tree sampling method was evaluated in estimating the number of trees per hectare, chest area and canopy cover and its results were compared with full inventory.

In the present study, the performance of 3 to 10 tree sampling method was evaluated in estimating the number of hectares per hectare, chest area and canopy cover .For this purpose, 30 hectares of one hectare of forests of watershed Oladghobad in west of Lorestan province were selected and data on all trees within these plots were recorded. In the next step, using tree simulation in Geographic Information System (GIS) environment, sampling was done using multi-tree method within one hectare plots.

Results of comparing the number of trees per hectareand canopy characteristics showed no significant difference between different polycrystalline methods with full inventory. Also, the results of comparing the mean rank of three characteristics Number of trees per hectare, basal area and canopy cover of each tree in different multi-tree methods with full inventory showed the nearest estimation in nine-tree, four-tree and five-tree methods, respectively. The results showed that the spatial pattern of the trees was due to the clustering of the species and the higher density of the branching species than the clustering species. The most precision for these characteristics was obtained for the three (9.27), four (3.65) and seven (2.67) tree methods, respectively. Finally, three characteristics were tested using E%2×T index. The results showed that three (14139.45), four (2393.16) and six (1678.87) tree methods, respectively, are suitable for sampling in the region's forests. O-ring function was also used to study the spatial pattern of Iranian oak trees.

Also according to the characteristics of the bream cross section, the four tree method, given the smallest distance with the real mean of the community, also has the lowest value (2393.16) according to the E%2×T index, as an appropriate sampling method for watershed forests Oladghobad is recommended.