Comparison of Plants Diversity in Natural Forest and Afforestations (Case Study: Darabkola, Mazandaran)

This paper aims to study the plant biodiversity in a natural forest and the adjacent 20-years-old plantations of Alder (Alnus subcordata C.A. Mey.), Velvet Maple (Acer velutinum Boiss.), Chestnut-leaved Oak (Quercus castaneifiolia (C.A. Mey.) and Cypress (Cupressus sempervirens var. horizontalis) in Darabkola, Mazandaran province, north of Iran. For this purpose, one sample plot, each 1 ha; was selected in every plantation as well as in the natural stand. In each sample plot 10 microsample plots, each 100 m2; were selected random-systematically. All of the plants were determined in the sample plots and their coverage percent were estimated in four seasons. Moreover, various parameters of the stands and soil properties were measured in each sample plot. For determination of plant species diversity in these plots, Shanonn’s and Simpson’s indices were used, while for determination of species richness and equitability, Margalef’s and Heip’s indices were applied. The results showed that Alder plantation and natural forest had the highest values, whereas Cypress plantation had the lowest value for species diversity. The highest Species diversity in other plantations was for Velvet Maple, Chestnut-leaved Oak and Cypress, respectively. The analysis of PCA showed that seasonal differences of species diversity on our studied plots were affected by the crown canopy of plants in the upper-story, and the under-story crown canopy of plants with the number and density of plant species in the under-story as well as by environmental parameters including rainfall, temperature and relative light intensity.