The Yangtze River delta urban agglomeration of China has experienced a significant development bloom in the last 30 years. To explore the spatial structure, a series of methods have been applied in this study: a mathematical analysis to ascertain the framework of cities in this urban agglomeration, a research on the expansion of completed areas, and population density on the basis of the grid analysis. It has been identified that a single-nucleus and several-centers model could be the best model to suit the spatial structure. This model, similar in many classical cases of spatial-structure model of conurbations and urban agglomerations, can be utilized to speed up urbanization, provide reasonable modes to industry spreading, establish special functional cores, and protect the environment in both urban and rural regions.

Under the backdrop of achieving carbon neutrality and accelerating urbanization, China’s forests face unprecedented pressures. This study explored the spatiotemporal characteristics of forest loss in the urban agglomeration in the middle reaches of the Yangtze River (UAMRYR). The dynamic mechanism of forest loss caused by fire, logging, construction, and pollution was also analyzed using spatial database development, polygon superposition analysis, grid system construction, and coordinate system calculation. The results show that the forest loss in the UAMRYR experienced three stages: continuous acceleration (1990–2010), peak (2010–2015), and slight decline (2015–2020). Rapid urban expansion is the primary cause of forest loss, and the three metropolitan areas had the fastest urban expansion and the most severe forest loss. Due to the success of afforestation efforts, the forest loss caused by fire, logging, and pollution was restored by 80%, while most of the forest losses caused by construction are permanent. Given the current forest loss trends, large expanses of forests in the UAMRYR are at risk of being destroyed and causing serious damage to the region’s ecological environment. Forest losses can be significantly reduced by guiding the rational expansion of cities, supporting afforestation for urban construction projects, strengthening forest fire risk investigation, and implementing ecological reconstruction of polluted areas.

Central China is a highly concentrated area of urban expansion and a major grain-producing region that accounts for 28.75% of the country’s total grain yield. This study investigates the spatiotemporal relationships between urban expansion and grain production in Central China from 2000 to 2025 using spatial database construction, grid-based analysis, GeoDetector, geographically weighted regression (GWR), and structural equation modeling (SEM). The main findings are as follows: (1) From 2000 to 2025, urban expansion accelerated substantially, with the urban population increasing by 205.86% and construction land expanding by 169.15%. This expansion was accompanied by the loss of 8659.63 km² of cultivated land. Nevertheless, total grain production increased by 43.44% during the same period. (2) Three major pathways linking urban expansion and grain production were identified. Urbanization was negatively associated with grain production through cultivated land loss, while economic development, technological progress, and agricultural investment were positively associated with grain production. Meanwhile, growing grain demand was associated with adjustments in grain cropping structure and multiple cropping intensity. (3) Agricultural investment played an important connecting role between economic development and grain production by supporting technological innovation, mechanization, and cropping structure adjustments, thereby helping sustain grain production despite declining cultivated land area. (4) The six major metropolitan areas experienced the greatest cultivated land losses but also substantial grain production growth. Despite intensified land-use pressures, spatial gains in grain production exceeded spatial losses. Improvements in grain production per unit of sown area accounted for 58.91% of the total production increase in these areas, highlighting the importance of enhanced agricultural production capacity in sustaining grain production growth.