نوع مقاله : مقاله کامل علمی پژوهشی
1 دانش آموخته کارشناسی ارشد دانشکده منابع طبیعی دانشگاه تربیت مدرس
2 گروه جنگلداری، دانشکده منابع طبیعی، دانشگاه تربیت مدرس،
3 استاد دانشکده منابع طبیعی و علوم دریایی نور
4 استادیار دانشکده منابع طبیعی و علوم دریایی نور
عنوان مقاله [English]
This investigation has been conducted to determining plant species diversity in relationship to the physiographical factors in western Bodjnourd forests (North of Iran). To cope with the aim of study, 220 ha of these forests (called Joezak-Darkesh forest) at 1400-2000 m a.s.l. with different geographical aspects and slope steeps of 0-80 percent were identified. Number of 55 sample plots of 20 × 20 m as random-systematic distribution was selected to determination of the trees and shrubs. In addition, within each plot 9 micro-plots 2 × 2 m were confined to recognition of ground non-woody flora. The highest value of species similarity was obtained between two low height classes (< 1800 m). Indices of diversity, richness and evenness did not differ with changing slope. Maximum and minimum value of Simpson’s diversity index and Margalef’s species richness were found in the 1400-1600 and 1800-2000, respectively. The highest Simpson’s diversity was observed for the warmer aspects (eastern) and the lowest for the cooler aspects (northern). It may be deduced that the present temperature of the landform could be affecting factor on plant diversity and richness of forest stands of this region. In the site study, presence of some vegetation elements associated with Hyrcanian vegetation appears a vegetation figure that it can be investigated more completely by botanists and phytogeography researchers.