The Diversity of Woody Species in the Ecosystems of Sweet Chestnut, Hazel, (Corylus avellana L.) and Italian Cypress Trees in Guilan Forests, Iran

The purpose of this study is to determine the woody species diversity in Sweet chestnut tree, Hazel-tree and Italian cypress ecosystems in the Guilan forests. A lozeng 0.5 ha sample plot was selectively established on each site. In the Sweet chestnut ecosystems , 4 sites were classified, whereas 10 sites of Hazel tree and Italian cypress ecosystems were classified based on species composition. on each plot , physiographic data including elevation ,aspect , slope and floristic data including type of woody species and their populations (abundances) were recorded.Totally, 14 plots were taken from the 14 sites . Simpson?s and Shannon-Wiener?s diversity indices were used to evaluate woody species diversity in the each site. At the same time ,evenness was calculated regarding Simpson?s and Shannon ?Wiener?s indices for each site. species richness was characterized by means of Margalef?s (R1) and Menhinick?s (R2) species richness indices. The results indicated that 22, 19and 20 woody species were found in the Sweet chestnut , Hazel tree and Italian cypress ecosystems, respectively. Diversity indices calculations showed that sites no.1 and 2 (Sheshad and Malaleh respectively, Duran,Shapharoud,Rezvanshahr) had the highest value of diversity of Sweet chestnut ecosystems, while sites no.3 and 4 (Visroud and Averes Koh respectively , Emamzadeh Ebrahim , Shapht) had the lowest, sites no.2 ( Chamlar, Baharestan, Astara ) and 5 (Ghalah- Bin , Agh-Evlar , Talesh) had the greatest value of diversity of Hazel tree ecosystems, while sites no.3 (Ab-Baglee , Baharestan , Astara) and 4 ( Ghalah- Bin , Agh- Evlar, Talesh) had the lowest. finally, in the Italian cypress ecosyetems , sites no.5 (Garmabdasht , Rahim-Abad , Roudsar ) and 3 ( north aspect of Mougshar , Siidan , Rahmat-Abad , Roudbar ) had the greatest value of diversity, while sites no.1 (northwestern aspect of Moughshar , Siidan , Rahmat-Abad , Roudbar ) and 2 ( eastern aspect of Moughshar , Siidan , Rahmat ?Abad , Roudbar ) had the lowest.