The study was carried out to estimate annual carbon production by fine root in Quercus variabilis and mongolica natural stands of Chungju region,Korea. Soil samples were taken at 0~30cm, 30~60cm, and 60~90cm soil depth from April to December (monthly increment method) in 2002. Fine root carbon biomass was higher at 0~30cm soil depth than in the other soil depths. Net fine root carbon production (kg ha[-1]) were 2,587kg in Quercus variabilis stands and 3,810kg in Quercus mongolica stands at 0~90 cm soil depth. Fine root turnover rates were ranged from 0.66 to 1.94 in the two forest ecosystems. Nitrogen,P,K, Ca and Mg input per year into the soil (kg ha[-1]) due to fine root turnover at 0~90cm soil depth in this study were 17.0kg,1.0kg, 8.5kg and 21.5kg, and 4.2kg in the Quercus variabilis stand, and 24.0kg, 1.9kg, 9.9kg, 28.1kg, and 5.8kg in the Quercus mongolica stand, respectively.