Biodiversity and soil properties in Pine (Pinus nigra Arnold.) and Ash (Fraxinus excelsior L.) plantations (Case study: Alandan Forest,Sari)

The significance of biodiversity maintenance in sustainable forest management has been indicated at many scientific studies. The present study was conducted to investigate the impact of Pine (Pinus nigra Arnold.) and Ash (Fraxinus excelsior L.) plantations on diversity of herbaceous vegetation cover and soil properties in Alandan site of Sari Forest area of the Iranian Caspian Forests. herbaceous vegetation cover percentage and natural regeneration number of woody species were measured, using six plots (20×20 m.) at each stand, which have been selected by random systemic statistical method. Soil sampling was made at center of each plot up to 30 cm depth at 10 cm intervals, using coring method (8 cm diameter). Soil tested propertirs consisted of: C, N, pH, EC, particle density and bulk density. Biodiversity indices (Shannon, Simpson), richness indices (Menhinick, Margalef) and uniformity indices (Equitability, Evenness) were estimated, using PAST software. The results showed that the biodiversity richness and evenness indices for herbaceous species cover and woody species regeneration at pine stand were greater than at the ash stand (p<0.05). There were significant differences in some of the soil properties between the both investigated stands (p<0.05). Despite the common believe about unfavorable biological conditions in coniferous stands, findings of this investigation suggested that the conditions under the pine canopy might be suitable for presence of some herbaceous and woody species with similar ecological needs, 25 years after plantation