Effect of extreme cold on trees and shrubs of tehran city in 2008

the purpose of this study is to evaluate the effect of extreme cold winter 1386on shrubs and trees cover. The transect method and ratio estimation were used to determine the percentage of damagein some urban park of tehranprovince. In every park (according to it''s area) 5 transect were selected with length about 100 meters in the direction of slop and condition of winter climate in 2008 were analyzes. For this purpose daily and monthly temperature data of Mehrabad and Aghdasieh station of Tehran were analyzed during a statistical duration of 1951 – 2008. The results of climate showed that total least that is recorded-10/8 in 2008 after about 35 years. Mobile average that is used for sustainability of plants duration several days was -8 for 19 days at 2008 winter. So this temperature could damage plants. The results showed that maximum damage of trees and shrubs of tehran parks belong to Catalpa speciosa، Cupressusarizonica and Ailanthus altissima with 70، 62 and 40 percent respectively that could used as a recipe for planting.