study of plant diversity in the northern zagros forest (case study: marivan region)

silvicultural operation need to notice the species diversity. to this study gomarlang district in marivan region, northern zagros forest was selected. in this study 30 circle sample plots (500 m2) were collected by random method. in every sample plot the kind of species and number of trees and shrub were recorded. in the sample plots the micro plots of 5 m by 5 m (i.e. area of 25 m2) were designed and herbaceous and shrub information was recorded then. species diversity indexes including shannon wiener (h׳), simpson (1-d) and margaleff (r1) were used to evaluate plant diversity in each sample plot. data analyzing was done by past and ecological methodological software's. results showed that 8 tree species, 8 shrub species and 64 herb species observed in the site study. the plant species that identified in the studied region belonged to 16 trees and shrub species in 9 families. overall results showed that the presence of 80 plant species in the study area indicates the high biodiversity in the northern zagros forest and herbaceous layer had the highest richness, evenness and diversity.