Temporal And Spatial Evolution And Influence Of Vegetation Cover In The Process Of Urbanization In China

As China’s urbanization has shifted from a high-speed growth stage to a high-quality development stage,ecological civilization has become an important part of leading development.As an important part of ecological civilization,the level of vegetation coverage is directly related to the stability and quality of urbanization.However,the ecological and environmental problems caused by the long-term excessive consumption of vegetation resources have become the main reason restricting the high-quality development of China’s economy and society.Although a series of land greening protection and construction measures have effectively curbed the depletion of vegetation resources,the natural nature of vegetation determines that the restoration of vegetation resources is a long and complex process.To thoroughly solve the problem of vegetation ecological environment,urbanization and vegetation coverage must be placed under the same sustainable development framework in order to achieve the coordinated development of the two.In this context,the continuous improvement of China’s vegetation cover level based on the urbanization process will help to achieve the high-quality development of urbanization and the internal consistency of vegetation ecology,and fundamentally solve a series of problems in the development of vegetation cover.Therefore,based on the spatio-temporal evolution of vegetation cover,it is particularly necessary to focus on the internal main logical relationship,dynamic evolution characteristics,causal relationship and transmission path between urbanization and vegetation cover,and make quantitative analysis on empirical evidence,and then put forward the corresponding strategic path.Based on the existing research results,this study first discusses the concept and connotation of urbanization,urbanization process,vegetation and vegetation cover,introduces the sustainable development theory,ecological modernization theory,compact city theory and Environmental Kuznets Curve Hypothesis closely related to this study,and expounds the guiding significance of various theories to this study;Secondly,starting from the development of urbanization and the formation of vegetation cover pattern in China,this paper decomposes and reconstructs the influencing factors of urbanization development and vegetation cover pattern,forms the main logical mechanism framework of urbanization process and vegetation cover,and discusses the effect mechanism of urbanization process on vegetation cover from the perspective of road construction,industrial structure upgrading and protection policy,so as to provide a good logical basis for empirical analysis;Thirdly,the normalized vegetation index data are used to visually analyze the spatio-temporal evolution trend of China’s vegetation cover from 2000 to 2019 from the time and space levels,and the regional differences and spatio-temporal dynamic evolution of vegetation cover are further analyzed by using dagum Gini coefficient and kernel density;On this basis,the urbanization process is divided into two aspects: urbanization speed and urbanization quality.The urbanization quality constructs comprehensive indicators from the five dimensions of economic development,infrastructure,residents’ lives,social development and ecological environment to explore the impact of urbanization on vegetation cover and regional differences;Further,explore the urbanization process to test the transmission path of vegetation cover,and achieve the dual goals of effect evaluation and path identification.At the same time,the threshold effect is used to explore the non-linear relationship between urbanization process and vegetation cover,and further master the internal laws and potential trends of urbanization process on vegetation cover.Finally,based on the above research conclusions,the strategic path to improve the level of vegetation coverage is proposed.The results show that in recent 20 years,the overall vegetation coverage in China has shown a fluctuating upward trend,showing an overall spatial distribution pattern of "high in the East and low in the west",and China’s ecological vulnerability has increased from east to west.From the perspective of overall difference,the overall regional difference of vegetation coverage in China shows a decreasing trend.From the perspective of regional differences,the internal differences in the eastern region show an increasing trend,while the internal differences in the central,Western and northeast regions show a decreasing trend.From the perspective of inter regional differences,except that the inter regional gap between the East and northeast regions is expanding,the overall differences in other regions are basically unchanged or the gap is gradually narrowing,and the development of inter regional vegetation coverage is coordinated.From the source and contribution rate of regional differences,regional differences are the main source of vegetation cover differences,and gradually decline in fluctuations;From the time-space dynamic evolution of the national vegetation cover,the national vegetation cover is increasing and showing a trend of absolute difference decreasing.From the perspective of the spatial-temporal dynamic evolution of the region,except that the polarization trend of vegetation coverage in the western region is becoming more and more obvious,and there is a regional difference and the absolute difference has not been reduced,the vegetation coverage in the eastern,middle and northeast regions is improving as a whole,and the absolute difference is decreasing;The quality of urbanization in the process of urbanization can promote the level of vegetation cover,but the speed of urbanization has no significant impact on vegetation cover.From different regions,the quality of urbanization has a significant role in promoting the level of vegetation cover in the central,Western and northeast regions,but has no impact on the eastern region.From the five dimensions of economic development,infrastructure,residents’ life,social development and ecological environment in the quality of urbanization,the five dimensions play a positive role in promoting the level of vegetation coverage.In addition,the promotion of urbanization on vegetation cover is mainly realized through the transmission path of road construction,industrial structure upgrading and protection policy effects.Further expansion analysis found that there is a significant threshold effect in the process of urbanization,there is a nonlinear relationship between urbanization and vegetation cover,and the improvement of urbanization quality is conducive to the improvement of vegetation cover.