Investigation of woody species diversity in relation to physiographic factors (Case study; Yew habitat of Kalaleh-Arasbaran)

Physiographic factors, due to their special role in determining some climatic and edaphic parameters, always influence the diversity and richness of plant species. Due to the importance of Arasbaran vegetation area, the present study was conducted to investigate the biodiversity of woody species of Kalaleh yew habitat in relation to physiographic factors. For this purpose, 62 plots of 4 square areas in systematic random method with 200×300 m grid in three class of height (less than 1200, 1400-1200 and more than 1400 meters above sea level), three class of slope (less than 40, 40-60 and more than 60%) and in four main geographical directions was performed in the region and in each plot name of woody species and two large and small diameters of their crowns were recorded in the inventory forms. canopy area characteristic was used to calculate the diversity, uniformity and richness indicators of woody species. According to the results, the mean of Shannon-Wiener diversity indices, Smith- Wilson uniformity and Margalef richness index of woody species were calculated 1.61, 0.55 and 0.92, respectively. The highest species richness and diversity of woody species was observed in altitude of 1200 to 1400 meters and more than 1400 m and the highest index of uniformity and diversity was observed in western and northern geographical directions. The effect of slope was not significant on any of the studied indices. Therefore, planning for the preservation and restoration of forests in the study area should be prioritized in low height areas (less than 1200 m) and with particular attention to the eastern and southern directions of the study area.