Spatial-temporal Evolution Characteristics And Affecting Factors Of Urban Greening Level In China

As an important part of urban environment,urban greening construction is an important way to improve the quality of urban environment,realize urban ecological civilization,ecological livability and high-quality development.With the rapid development of urbanization in China,more and more attention has been paid to the improvement of urban environmental quality.The study on the level of urban greening construction is of practical urgency to the scientific understanding of urban environmental construction,to the promotion of high-quality development of urban environment,and to the solution of urban ecological environmental problems.In this paper,292 prefecture level and above cities are taken as the basic research unit to build a comprehensive evaluation index system of urban greening level,comprehensively measure the level of urban greening in China from 2000 to2017,identify the stage of greening development,analyze the overall difference and regional difference characteristics of greening level,depict the spatial-temporal pattern of urban greening from time sequence evolution and spatial differentiation,and explore the influence of spatial-temporal distribution of greening Response factors.The results show that:(1)From 2000 to 2017,the overall level of urban greening in China was not high,with an average of 0.244,among which Lijiang City was the highest(0.501),Anshun City was the lowest(0.118).There are significant differences in the number of cities with different greening levels.The greening level gradually changes from low level to lower level,and the overall greening level is significantly improved.The overall and internal differences in the three regions of the East,the middle and the West are gradually decreasing,but the regional differences are slowly increasing.(2)The spatial pattern of urban greening level in China is gradually decreasing from east to west,but from 2012,it gradually evolved into a green spatial pattern of "leading in the East,leaping in the west,lagging in the middle".Overall,the cities with high greening level are mainly distributed in the eastern coastal cities,while the areas with low greening level are basically consistent with the pattern of plateaumountainous areas in China.Under natural conditions,the change of greening level shows certain regularity characteristics.The north subtropical climate area(IV)has the highest greening level,and the plateau climate area has the lowest urban greening level.(3)The spatial distribution of urban green level in China has a positive correlation with the aggregation characteristics,and the hot spot is relatively stable,the cold spot is expanding.Among the three regions,the eastern region is the stable region of the hot spot,the western region is the growth region of the hot spot,and the central region is the agglomeration of the cold spot.(4)Climate condition is the decisive factor of urban green space pattern in China,government management is the main influencing factor,and urban development degree and regional economic development level are the important influencing factors.