Effect of Different Forest Types on Soil Properties and Biodiversity of Grassland Cover and Regeneration in Central Hyrcanian

        In this study we evaluate the effects of different types on soil Physical and chemical Properties and plant species biodiversity in the hyrcanian forests of Iran. For this porpuse 33 sample plots were established in 5 vegetation types consist of pure beech (Fagus orientalis), Ash plantation (fraxinus excelsior), spruce plantation (Picea abies), mixed forest and degraded forest. In each vegetation type, a square-shaped surface area of 4 hectares (200 × 200 m2) was separated and the sample plots with an area of 400 m2 (20×20 m) to evaluate the herbaceous community and regeneration of woody vegetation were implemented by systematic random sampling method. A soil sample was taken from a depth of 10-0 cm to assess physical and chemical characteristics of the soil in each plot. The results showed that there was a significant difference between the understory diversity indices in 5 vegetation types based on Simpson and Shannon Wiener diversity indices, and the mixed  and degraded forest have the highest values. Also, the results of the comparison of vegetation biodiversity indices in the regeneration part showed that Margalef, Menhinick, Simpson and Shannon Weiner indices had significant difference among the vegetation types and the mixed forest had the highest values. The results of analysis of variance of soil characteristics showed that only soil moisture content, acidity and carbon percentage had significantly different among the vegetation types. Totally, the results of this study clearly showed that the mixed forest had the best performance in terms of plant biodiversity indices and physical and chemical of soil characteristics than other vegetation types.