Study of Shrub and Grassy Herbal Diversity in Natural Stand and of forestated Stands in Caspian Forest

Biodiversity is necessary for mankind life duration, economical issues and for ecosystems stability and function . The most important aspect of this study is determining evenness and diversity important indexes for the herbal and shrub layers in natural and afforestated stands. In this study the diversity of grassy and shrub species in natural and afforestated stands of forests in north of Iran were studied and compared from the view point of diversity and evenness indexes. In order to do this study natural stand which are approximately at the same height above the sea level were selected. The area of each stand was 30 hectares and the inventory was done by a random- systematic method with 10 percent intensity. In each stand 30 circle shape sample pieces with a 5R measurement (500 m 2 ) were selected. In order to study the herbal layer in the center of each sample piece micro plots by the measurement of 125 m 2 were made. The results showed excessiveness of diversity and evenness of herbal layer and shrub species in the