This research was carried out to evaluate the effect of rangeland conversion to afforestation with Cupressuss arizonica and Celtic caucasica on soil carbon emission. In order to determine the rate of carbon and carbon dioxide emission by tele-alkaline method with a stacking chamber, monthly was performed with 5 replicates per treatment and for one year. The analysis of carbon dioxide emission was done by one way ANOVA and Duncan's test. The results showed that the rate of carbon emission in Cupressus arizonica, Celtise caucasica and rangeland treatments was 110.49, 104.92 and 91.22 kg/ha/month, respectively and rate of carbon dioxide emission was 406.78, 384.71 and 48.433 kg/ha/month, respectively. The rate of carbon and carbon dioxide emission in 12 months in the area under consideration was also significant at 5% error level, have been with the highest carbon and carbon dioxide emissions in October and the lowest in August. In terms of seasonal distribution, the rate of carbon and carbon dioxide emission in rangeland and Cupressus arizonica treatments was not significant, but in the Celtise caucasica treatment was significant at 5% error level, with the highest carbon and carbon dioxide emission was in autumn, spring, winter and summer, respectively. In total, C.arizonica and C.caucasica reduced about 5/5% and 18% carbon and carbon dioxide emissions, respectively, than the adjacent rangeland did. Therefore, we can reduce the rate of carbon emission by appropriate management plans such as proper land use change.