With due to ever-increasing decrease of forests and expanding need have human to exploiting this valuable source, the expanding forest lands is necessary. One of the most important propounded questions in forest plantation is selecting the suitable species. Proper selection of species for afforestation can increase the efficiency of plantation operation to a special extend, otherwise there will be ecological (e.g. on biodiversity) and economical loss. So complete and general studies on ecological and economical affects of afforestation is necessary for it purpose. This paper was accomplished in order to assessment and comparison of plant biodiversity influencing of plantation with conifer and broad leaved species. In this study three sites (Conifer planted with Thuja orientalis and Cupressus arizonica), broad leaved planted (Robinia pseudoacacia and Fraxinus.rotundifolia) and non planted site as control) were selected in suburb of Sanandaj city (Iran). These sites have similar climatic and physiographical conditions. Systematic Random Sampling was used as a method for data gathering. In each site, 20 circular sample plots with area 16 m2 were selected (60 plots totally) according to the surface –species curve. The samples of herbal species were collected in each plot and the percent of each species covering and the total percent of herbal species covering were evaluated. The data was analyzed applying SPSS and Excel software, using complete randomized design. The treatments were compared by one way ANOVA and Duncan's Multiple Range Test. Frequency and evenness index of herbal species were calculated by using the plant biodiversity indexes. The results show that in viewpoint of plant diversity, frequency and evenness index, there is a significant difference among these three sites. The most diversity and frequency of herbal species is in site planted with broad leaved species. This site has the lowest degree considering evenness index.
