Composition and biodiversity of understory plants in natural forest and plantations of Kelarabad, Chalus

The purpose of this study was to investigate the composition and biodiversity of herbaceous cover and regeneration in natural forest (dominated by hornbeam-iron tree), plantations (pure and mixed alder and maple) and degraded forest areas (without tree cover) in the Kelarabad of Chalus. A total of 16 large sample plots (20 × 20 m2) to record the vegetative characteristics of the trees and 144 small sample plots (1 × 1 m2) to record the number of regenerated woody species, type and percentage of herbaceous species. The variety of indices were used to compare biodiversity. The highest percentage of herbaceous species belonged to the Brachypodim pinnatum L., while in the degraded area the percentage of Rubus caesius L. was dominant. Among the understory herbaceous plants, hemicryptophytes and cryptophytes were the most abundant biological form. Also, according to the results, the highest percentage of regeneration species was related to the dominant tree species in each forest stands, and among regeneration species, Phanerophytes were the most abundant biological form. Investigation of biodiversity indices in both herbaceous and regeneration layers indicates the negative effects of forest degradation as well as the positive role of natural forest in the study area. As a general conclusion, the present study demonstrates the protective role of temperate broadleaf mixed forest stands for the richness and diversity of herbaceous plant species and the sustainable regeneration and conservation of understory communities.