In order to determine the rate of litter decomposition of Fagus oreintalis at two beech stands, litters from Vaz and Asalem with different parent material were collected in autumn. Parent material of Vaz was calcareous and Parent material of Asalem was acidic. Litters of each region, put in four vases for 400 days in laboratory conditions. Sampling was taken within 21 days. Then C/N and energy was measured in each interval. On the first day, the amount of energy was 4439.06 cal/gr and 4440.23 cal/gr in litter of Vaz and Asalem respectively. The decomposition rates (k) were 0.40 and 0.19 in litter of Vaz and Asalem respectively. During the process of decomposition, energy of the leaf litter decreased in both regions. Energy of litter reduced from 4439.06 to 3953.68 cal/gr and from 4440.23 to 4038.94 cal/gr, in Vaz and Asalem respectively. C/N of litter reduced from 59.95 to 30.26 and from 47.7 to 26.99, in Vaz and Asalem respectively. A Linear relationship existed between amount of energy and C/N (r2=0.52 & r2=0.28, in Vaz and Asalem respectively). The slope of the regression line in litter of Asalem region was more than Vaz region. (Regression equation in litter of Vaz region: y = 0.033x – 91.66 and for Asalem region: y = 0.019x – 45.53).
