Background In the past forty years, the Chinese government has steadfastly implemented a series of major forestry ecological projects aimed at protecting the ecological environment, preventing soil erosion, resisting floods and other disasters, and increasing biodiversity.The Natural Forest Protection Program(NFPP) is one of them.The government has spent huge amount of investment for the project construction in the past 20 years, which has aroused widespread concern in the society.This paper is to reflect the ecological benefits of NFPP in China, incarnate the great role of ecological engineering, and realize the sustainable development of forestry.

Methods  Using the distributed measurement method and based on type Ⅱ survey data in Da Hinggan Mountains Forestry Group, the eco-production values of the NFPP in main vegetation types of the Da Hinggan Mountains Forestry Group were assessed according to the State Forest Ecosystem Services Assessment Specification (LY/T 1721-2008).

Results 1) During the implementation of NFPP, the total value of eco-production increased by 1 851.62×10⁸ RMB Yuan/a (an increment of 69.96%), and the descending order of values was biodiversity conservation (increased by 499.33×10⁸ RMB Yuan/a), carbon fixation and oxygen released (increased by 390.22×10⁸ RMB Yuan/a), soil conservation (increased by 358.62×10⁸ RMB Yuan/a), water conservation (increased by 280.90×10⁸ RMB Yuan/a), atmosphere environmental purifying (increased by 243.36×10⁸ RMB Yuan/a), and nutrients accumulation (increased by 79.19×10⁸ RMB Yuan/a).2) The eco-production values of different forest stand types showed an increasing trend, the highest increased value of Larix gmelini eco-production was 53.29%, the order of added value in forest stand from high to low was Larix spp.(an increment of 53.29%), Betula spp.(an increment of 13.01%), Populus spp.(an increment of 2.19%), Querus spp.(an increment of 0.66%), Pinus sylvestris var.mongolica (an increment of 0.41%), Picea spp.(an increment of 0.25%) and Salix babylonica L.(an increment of 0.15%).3) The increment of the eco-production value of half-mature forest was up to 66.05%, followed by the young forest increased by 17.22%.In addition, the eco-production value of near-mature forest, mature forest and over-mature forest showed a decreasing trend.4) Reasonable and effective implementation of forest protection will make the forest volume and ecological productivity have great growth space, and the ecological productivity of forest areas has great potential for development.

Conclusions  Therefore, the implementation of NFPP plays a positive role in promoting the ecological productivity value of different forest types in the study area.The composition and proportion of different age forest groups in the study area were affected, which led to the growth and decline of the ecological productivity value of different age groups.Furthermore, the implementation of the NFPP will play a significant positive role in improving the ecological environment in the study area.Accordingly, this study will provide scientific reference for evaluating the changes of forest ecological service function and analyzing the ecological benefits of NFPP area in China.