**Abstract**

As a fundamental part of the urban function, urban green space faced a longterm maintenance requirement. The maintenance of urban green space (i.e., trimming, irrigation, fertilization, pesticide, and plant waste removal) can have environmental impacts, such as energy consumption and greenhouse gas (GHG) emission. This chapter focuses on the adjustment of the plant communities' combinations in urban green space to reduce the environmental impacts in long-term maintenance. The plant communities in urban green spaces are a combination of four plant layers: woodland, shrubs, herbicides, and grassland. In this chapter, we will start to investigate the environmental impacts in the maintenance of urban green space. Then we introduced the quantitative method life cycle assessment (LCA), to quantify the environmental impacts of the maintenance tasks. We analyzed the maintenance environmental impact (MEI) index of 95 plant community samples (20 m 20 m) in Zhengzhou (China) through LCA and sorted out the changing curves of the MEI index during the change of the combined amount in each plant layers. Finally, we sorted out the MEI strength of the plant layers and summarized the low MEI plant community model. The low MEI model can save energy consumption and GHG emissions of the maintenance tasks, to contribute to the sustainable development of the urban green space.

**Keywords:** urban green space, plant community maintenance, environmental impact, energy consumption, GHG emissions
