Main Article Content
The study was carried out in the oak forests that is located in the Southwest part of Iran. The objective of this research was to determine the plant ecological groups and site classification in this region. Data were collected from 96 sample plot using the systematic-random method. The size of sampling plot was 20 m× 50 m for the tree and shrub layers, and 8 m × 8 m for the herbaceous layer. In each plot, topographical factors (elevation, slope, aspect) and percent cover of herbaceous and the crown cover of tree species were recorded. Multivariate analysis methods were used to classify and determine the relationship between species composition and environmental factors. The results of TWINSPAN and MRPP analysis showed that eight groups were recognized. The most important environmental factors associated with plant composition in oak communities were the slope, elevation, aspect, respectively. The ordination results (HRDA) indicated that the topography factors influenced on the establishment of indicator species. Furthermore, they were one of the limiting factors of the growth, presence, and absence of woody and herbaceous species.