Objective  The rapid urbanization construction leads to a series of ecological and social problems such as global warming and lack of recreational space, which seriously affects the urban ecological environment and human health, as well as restricts the sustainable development of social economy. For the second green belt in Beijing, which is located in the urban fringe, it is of great significance to study the spatial optimization of country park ring layout based on the coordinated improvement of carbon sequestration and recreational services.

  Method  Based on RS and GIS technology, firstly, the net primary productivity provided by the region was calculated by CASA model to characterize the temporal and spatial distribution trend of carbon sequestration service provided by ecological space. Secondly, the kernel density analysis model and neighborhood analysis were used to explore the temporal and spatial distribution of regional comprehensive recreational function. Minimum cumulative resistance model was used to help identify the potential recreational corridors. Finally, the CA-Marcov composite model was applied to predict the changing trend of the ecological spatial pattern in 2023, so as to comprehensively support the optimal location of country park ring in the second green belt of Beijing municipality area.

  Result  Based on the differences of carbon sequestration services and recreation potential provided by different regions, combined with the current ecological spatial distribution of the second green belt in Beijing and the simulation results of the evolution of ecological spatial pattern in 2023, 59 proposed land areas of country parks guided by the coordinated development of carbon sequestration and recreational services were selected.

  Conclusion  The country park ring site selection method that cooperatively improves the two functions of carbon sequestration and recreation has certain advantages in spatial quantitative research. The relevant evaluation results provide a scientific basis for the layout optimization of country park ring and other ecological space construction in the second green belt of Beijing.