Effect of shelterwood logging on diversity of tree species in the Loveh Forest, Gorgan

In order to identify the effect of shelterwood logging on the species diversity in each stages performance, a study was conducted at the Loveh forest, east of Golestan province. Totally, 117 plots with 60×60m were set down with systematic cluster sampling method at the study area. Diameter at breast height (DBH) of trees and species were assessed in each plot. In this study three managed stands including 20 years practiced stands (shelterwood system), 40 years practiced stands (shelterwood system), and improvement stand as well as one unmanaged stand were compared based on Shannon-Wiener, Smith-Wilson and richness indices. The results of analysis of variances showed that difference among four stands were significant (p<0.05) and highest values of Smith-Wilson and lowest value of Shanon-Wiener indices were observed in the natural stands. These differences may be referring to logging and opening crown cover. These results showed that the species diversity was decreased where shelterwood system was applied. The low values of Shannon-Wiener indices and Smith-Wilson indices in 40 years practiced stands compared to 20 years practiced stands confirmed the results.