The efficiency of sampling indices in estimating the spatial pattern of wooden species in central zagros forests (Kalkhani forest in Kouhdasht, Lorestan province, Iran)

It is so important to apply suitable methods to have a reliable estimation of the spatial distribution of trees. This research was aimed to determine and evaluate the spatial pattern of five species by distance- and density-based indices (Quercus brantii, Acer moncepesulanum, Crataegus aronia, Pistacia atlantica & Amygdalus lycioides) in the Kalkhani Forest in Koudasht Lorestan province, Iran. For this purpose, an area of 35 ha was full-callipered. Spatial location, the type of species and big and small diameter crown was measured. The true spatial pattern of five species was determined by nearest neighbor method and Ripley’s K Function. The methods of spatial pattern were used fixed area plots (such as:Variance-to-Mean Ratio, Index cluster, Green, Morisita and Standardized morisita) and distance methods (Johnson and Zimmer, Eberhart, Hopkins, Hinez and C index). Data analysis were accomplished by using of Ecological Methodology and ArcGIS softwares. The results indicated that the main species was Quercus brantii Lindl. with 61.5 % of frequency species .Also, the mean values the highest and lowest crown area belong to Quercus brantii (11.36 m2) and Crataegus aronia (2.89 m2), respectively. The true spatial pattern of the five species trees in the studied stand was clumped. All of the applied density-based indices showed a clumped pattern for five trees species. Among the distance-based indices only“Hines” could estimate the clumped pattern of the studied species. In general, the best indices to determine spatial pattern for studied species were all of density-based indecies and Hines index. Therefore this conclusion in silvicultural operation should be considered on five species.