Phytosociology of Juniperus excelsa M.Bieb. forests in Alborz mountain range in the north of Iran

Juniperus excelsa is one of the specific tree species in the mountainous areas of Iran. It forms the mountainous forests of Irano-Turanian vegetation region. Despite the considerable spread of J. excelsa in Iran, there is no detailed and valid published study on the phytosociology of Iranian juniper stands. The aim of this research is to identify these associations and their characteristics in Alborz mountains in the north of Iran. To this goal, a set of data including floristic data according to Braun-Blanquet method, and important environmental characteristics, were collected. To classify the vegetation, TWINSPAN was used and phytosociology tables were analysed with JUICE software. Diagnostic species were determined by measuring the degree of fidelity and using statistically meaningful measurements. According to the results, the vegetation was classified into six associations and five subassociations. Among them are Cotoneastro nummulariis-Juniperetum excelsae ass. nov., Lonicero ibericae-Juniperetum excelsae ass. nov., Rhamno pallasii-Juniperetum excelsae ass. nov., Rhamno p.-Juniperetum e. ajugetosum chamaecisti subass. nov., Rhamno p.-Juniperetum excelsae gypsophiletosum aretioidis subass. nov., Amygdalo lycioidis-Pistacietum atlanticae hymenocratretosum bituminosoris Kashipazha et al. 2007, Feruletum ovinae ass. nov., Artemisio aucheri-Astragaletum veri Asri 2004, and Artemisio aucheri-Onobrychidetum cornutae ass. nov. The introduced juniper associations were placed in class Junipero-Pistacietea Zohary 1973 and order Juniperetalia excelsae nov.