The aim of this study was to determine the influence of the extent of root pruning on nutrient content, biomass, vitality and nursery growth of oak seedlings (Quercus castaneifolia C. A. Mey.). At the end of the first year of nursery growth the main root of oak seedlings was pruned by scissors at distances of 15, 30 and 45 centimeters from collar. Then, oak seedlings were planted in the field and vegetative characteristics were recorded after four growing seasons. Results showed that collar diameter growth, height growth and length of terminal inter node were significantly affected by root pruning treatments (p0.05). The lowest total biomass of oak seedlings was observed at 45 cm treatment. The pruned roots at distance of 15 cm from collar had lowest nitrogen content. Highest level of the Phosphorous content of leaves was observed at treatment of 30 and 45 cm. This study suggested that for access to better growth of oak seedlings, the 30 and 45 cm pruning treatments should be selected. The pruning treatment of 15 cm is only suitable for total biomass increasing.