Intensive practices in forest soils result in dramatic nitrogen (N) losses, particularly ammonia (NH3) volatilization, to adjacent environmental areas. A soil column experiment was conducted to evaluate the effect of bamboo biochar on NH3 volatilization from tea garden and bamboo forest soils. The results showed that biochar amendment effectively reduced NH3 volatilization from tea garden and bamboo forest soil by 79.2% and 75.5%, respectively. The soil pH values increased by 0.53-0.61 units after biochar application. The NH4 +-N and total N of both soils were 13.8-29.7% and 34.0-41.9% higher under the biochar treatments than under the control treatment, respectively. In addition, the soil water contents of the two biochar-amended soils were significantly higher (P < 0.05), by 10.7-12.5%, than that of the soils without biochar amendment. Therefore, biochar mitigates NH3 volatilization from the tested forest soils, which was due to the increases in soil NH4 +-N, total N and water contents after biochar amendment. Our main findings suggest that biochar addition is an effective management option for sustainable forest management.