The introduction of tree and shrub species in the central district of Zanjan county town

Floristic study is one of the most efficient methods of gaining knowledge about biological capacities, as well as management and conservation of plant genetic resources in ecological systems. Zanjan county town is located in a mountainous region with an area of 6763 km2 and the average altitude of 1663 m.a.s.l. Its favorable vegetation diversity is the result of suitable ecological conditions, diverse habitats and appropriate water resources in the region. The central district of Zanjan county town, with an area of 2600.2 km2, was chosen as a representative to show tree and woody shrub species diversity. In order to identify tree and shrub species, life forms and chorology of plants, samples were collected by the conventional method of floristic studies and were, then, identified using taxonomic references. In total, there were 122 tree and woody shrub species, belonging to 76 genera and 39 families, in the studied area. The richest families included Rosaceae (29 species) and Oleaceae (9 species), which comprised 31.15% of the arboreal and woody shrub species. Mesophanerophytes (37.7%) and microphanerophytes (32.79%) were the dominant life forms in the area studied as determined by the Raunkiaer method. The Irano-Turanian vegetative elements were the most important elements in this area based on Zohary approach. Prunus lycioides was found to be endemic to Iran.