The study of the forest coverage rate (FCR) is related to the ecological environment and sustainable development goals (SDGs) of a region. In light of the lack of an organic integration method of “spatiotemporal evolution, correlation analysis, and change prediction” and the lack of a methodology that integrates methods of “remote sensing (RS) and GIS, multi-phase LUCC, and construction of econometric models” in the research methods at present, this study focus on Yunnan, a typical border province located in China with a relatively fragile “innate” ecological environment, as the research area. Based on the interpretation of land use/land cover (LULC) data retrieved from seven periods RS images (1990, 1995, 2000, 2005, 2010, 2015, and 2020), the spatiotemporal evolution of FCR in 129 counties was analyzed. Complementary research methods, such as the spatial econometric model, geographically weighted regression (GWR), and the geographic detector (GD), are used to reveal the influencing factors of FCR. Finally, this study predicts the FCRs of 129 counties in Yunnan from 2025 to 2050. The FCR in Yunnan presents an increasing trend year by year, increasing from 28.96% in 1990 to 49.05% in 2020. In addition, it exhibits spatial agglomeration characteristics with fewer values in the east and more in the west. The analysis of influencing factors show that the increases in the per capita GDP, land utilization rate, and annual average temperature, and the implementation of the Conversion of Cultivated Land into Forest Project (CCFP) will significantly improve the FCR, while the increases in the population density land reclamation rate, the proportion of construction land area, and the proportion of soil erosion land area will significantly reduce the FCR. Furthermore, the FCR is influenced by multiple factors, and the relative factors observed not only show significant spatial differences, but also present complex and diverse patterns, with the additional characteristics of being interwoven and overlapping. This study contributes to expanding and improving the methods and pathways of exploring the spatiotemporal evolution characteristics of FCR in ecologically fragile areas using RS methods, providing a reference for increasing FCR and improving the ecological environment’s quality in Yunnan Province and other ecologically fragile areas.

Both the resource environmental carrying capacity (RECC) and supply-side reform are crucial for achieving sustainable national developments. However, current research on RECC lacks consideration of the supply-side industrial structures and factors, and the relationship between RECC and supply-side reform remains unrevealed. In order to measure the RECC in China at the provincial level from 2005 to 2019, this study constructs an evaluation index based on industrial structure. It utilizes the TOPSIS model coupled with the supply-demand balance method and environmental capacity method while gathering and summarizing the indicators related to natural resource support, socio-economic support, and environmental factor accommodation. The analysis of evolutionary characteristics and spatial heterogeneity is carried out by statistical and spatial econometric methods, and the impact of the supply-side reform policy on RECC is examined using a bidirectional fixed-effect model. The findings indicate the following: (1) China’s RECC demonstrates a clear upward trend, with higher values in the west and lower values in the east. The average annual growth rate from 2016 to 2019 (18.12%) is nearly three times that of the period from 2005 to 2010 (6.28%), indicating a significant acceleration in the increase in RECC post-supply-side reform. (2) The spatial agglomeration of RECC and its sub-system support is observed, as the allocation of nature resources and markets promotes the convergence of regional differences and enhances the spatial convergence of the RECC. (3) The implementation of supply-side reform policies has a positive impact on RECC, with industrial upgrading playing a particularly significant role. This study provides a new idea and method for the selection of evaluation indicators, quantitatively assessing province-level RECC and understanding the potential effects of national supply-side policies on RECC.

The large–scale Project of Returning Farmland to Forest (PRFF) is a major strategic measure taken against the background of the catastrophic floods in 1998, and its policy effect urgently requires an accurate evaluation. Yunnan Province is an ecologically fragile province that integrates border areas, mountainous areas, ethnic groups, and underdeveloped areas. It is of great significance to study the effect of PRFF in Yunnan, which began in 2000, on promoting forest coverage rates (FCRs) in mountainous areas. In response to the shortcomings in the existing research, such as the lack of direct exploration and the limited policy evaluation tools of the effect of PRFF on improving FCRs in mountainous regions, this study takes Yunnan as an example based on land use/land cover (LULC) data interpreted from seven periods of RS images, aiming to study the effect of PRFF on promoting FCRs. After dividing 129 counties into 3 types (flatland county, semi-mountainous and semi-flatland (SMSF) county, and mountainous county), the Difference-In-Differences (DID) model and spatial DID models are used to measure the specific effect of PRFF on promoting FCRs based on county-level administrative units. The results indicate that PRFF has increased FCRs in non-flatland counties by 1.8082%, and the impact of PRFF on increasing FCRs in mountainous counties slightly exceeds that in SMSF counties. Although PRFF has converted some steep slope farmland into forest land, there is no evidence to suggest that the implementation of PRFF has significantly reduced the proportion of farmland and total grain production in non-flatland counties. Therefore, PRFF is an excellent project that promotes the increase in FCRs and benefits in the country and the people. The results can provide a reference for China to achieve the modernization of harmonious coexistence between humans and nature and also offer a reference for other countries to improve FCRs and the local ecology.