Quantifying the Competition Concerning Trees Quantitative Characteristics of Natural Stands in Arasbaran Forest

Competition is an interaction between a species’ members or different species under the ecological needs to use the same resources. The present research aimed to quantify the competition in a mixed stand in the Arasbaran forest. Sampling was a distance method. The diameter at breast height, total tree height, two diameters of the tree's crown, and the distance of the trees were measured (one tree as the target and four neighboring as the competing trees). Data was analyzed using the distance-dependent and distance-independent competition indices. The results showed that the distance indices value were 0.29 to 31.71 and distance-independent indices were 0.94 to 4.43. There was a significant negative correlation between the stand quantitative characteristics and the distance between trees with the value of distance indices in most cases. The correlation between canopy diameter and area with distance indices was positive and significant, but with distance-independent indices was slight and not significant. Competition quantification in mixed stands will provide to know the relationship between the amount of competition and the quantitative characteristics. Consequently, and can provide knowledge for silvicultural treatments, and forest management strategies to balance the competition level in natural stands to reach the desired mixed structure.