The response of vegetation cover to topography and land use in Beijing

Vegetation coverage is closely related to natural factors such as topography and climate, but it is more affected by human factors in the short term. This study aimed to analyze the temporal and spatial variation of vegetation coverage in the central urban area of Beijing and its topographical differentiation, as well as the impact of land use transition on changes in vegetation coverage. We used remote sensing technology to obtain the data of different periods of vegetation coverage in the central urban area of Beijing through the improved pixed dichotomous model and its land-use type supervised classification method. These data, combined with digital earth model data, were comprehensively analyzed by geographic information system. The results showed that, during 1992－2020, the vegetation coverage of the study area generally showed a trend of degradation increase from 1992 to 2011, while the high vegetation coverage increased from 2011 to 2020. Vegetation coverage is significantly affected by topography and is positively correlated with elevation and slope. There is no significant difference in vegetation coverage on the slopes; vegetation coverage is higher on shady slopes and lower on sunny slopes. The urban expansion of the study area continues to occupy forestland, grassland, and cultivated land and is the leading factor of vegetation degradation. However, the development of unused land, urban suburban park construction, and reconversion of farmland to forestland or grassland are the leading factors of the increase in vegetation coverage. This study can provide strong scientific support for the coordination of land use and ecological environment in rapid urbanization areas.