Abstract:Abstract:The main planting tree species and area of returning farmland to forest were analyzed in Zigui County, and the carbon fixation and oxygen release benefit was counted. The results showed the area of non-timber product forest was maximum, and that of broadleaf forest was secondly, and that of coniferous forest was minimum. The tree species which area was more than 1 000 hm2 were in the following order: Juglans regia, Robinia pseudoacacia, Citrus reticulate, Castanea mollissima, Amorpha fruticosa, Camellia sinensis. The carbon fixation amount and the oxygen release amount of returning farmland to forest in Zigui County were 64 780.7t·a-1 and 110 468.7 t·a-1, respectively. The project of returning farmland to forest plays an important role for ecological environment and fixing carbon and reducing discharge of the whole county.