Based on the vegetation ecological quality index retrieved by satellite remote sensing in the karst areas of Guangxi in 2000–2019, the status of the ecological restoration of the vegetation and the influencing factors of the ecological restoration potential of the vegetation were analyzed. Then, habitats with a similar ecological restoration potential were categorized and the maximum ecological restoration potential of the vegetation was estimated. Finally, realization and prediction models of the ecological restoration potential of the vegetation were constructed to evaluate the realization degree and provide predictions. The quality of the ecological restoration was good in the study region, and the vegetation ecological quality index showed a fluctuating increasing trend. In the study region, 96.25%, 92.92%, 97.14%, and 99.07% of the total area was shown to have good ecological quality of the vegetation in 2000–2004, 2005–2009, 2010–2014, and 2015–2019, respectively. Terrain, soil, vegetation types, and climatic conditions had significant impacts on the ecological restoration of the vegetation. With the increase in the soil sand content, the changes in the vegetation ecological quality indexes were significant at altitudes of 200 m, 400 m, and 800 m and slopes of 15°, 25°, and 35°. The ecological restoration potential was the highest for forests, peaking at 87.5, followed by shrubs and grasses (87.4), and farmland (85.4). The partial and multiple correlations of the temperature, precipitation, and vegetation ecological quality index were significant, and the climate driving zones were divided into the strong driving zone of temperature and precipitation, temperature-dominated driving zone, precipitation-dominated driving zone, weak driving zone of temperature and precipitation, and non-climate driving zone. There was a high realization of the ecological restoration potential of the vegetation. The vegetation ecological quality in 97.95% of the area was restored, of which regions classified as maintaining growth, having slow growth, and having rapid growth accounted for 79.73%, 18.09%, and 0.13%, respectively, indicating that projects of rocky desertification control and ecological poverty alleviation were well implemented. In the future, the ecological restoration potential of the vegetation is predicted to be mainly low and medium. The areas with low potential are predicted to be mainly distributed in the north and southeast of Hechi, the northwest of Baise, and the west of Chongzuo, where the vegetation ecological quality and ecological restoration of the vegetation are predicted to be good, thus the restoration gap is predicted to be small. The areas with medium potential are predicted to be mainly distributed in the south of Hechi, the south of Baise, and the north of Chongzuo, where the vegetation ecological quality was restored well but further restoration could be beneficial. This research can provide technical support for future evaluations of the ecological restoration of vegetation, as well as construction, in the karst areas in the future.

To clarify the spatial–temporal evolution patterns and climate-driven mechanisms of carbon sinks of forest ecosystems under climate change, we calculated the net ecosystem productivity (NEP) of forests in the Guangxi region using remote sensing and meteorological data from 2000 to 2023. By employing trend analysis, spatial clustering, the Hurst index, and climate contribution evaluation, we analyzed the spatial and temporal changes, sustainability, and the relative contribution of climate impacts on forest carbon sinks. The results are as follows: The carbon sink capacity of forests in Guangxi increased continuously from 2000 to 2023, at a rate of 3.57 g C·m⁻²·a⁻¹, reaching 39.19% higher in 2023 than in 2000. The carbon sink capacity was higher in the southwest and lower in the northeast, with hotspots mainly located in evergreen/deciduous broad-leaved forest areas. The Hurst index indicates that 84.44% of regions are likely to maintain this increasing trend, suggesting stability in forest carbon sink function. The climate contribution rate to forest carbon sinks was moderate, with significant temporal fluctuations. Temperature governed annual variation in forest carbon sinks, influencing up to 36.37% of the area. The annual average contribution rate of climate change to forest carbon sinks was 30.28%, but there were temporal fluctuations and spatial heterogeneity. Over time, climate contributions had a positive driving impact; however, extreme climate events tended to produce a negative effect. The pattern of forest carbon sinks in Guangxi showed a “heat sink-coupling” phenomenon, with 16.23% of the hotspots of forest carbon sinks coinciding with temperature control zones, highlighting the enhancing effect of temperature rise on carbon sinks against a background of water and heat synergy. This study provides a scientific basis for the assessment of forest carbon sink potential and climate suitability management in Guangxi.

Quantifying the spatio-temporal dynamics of forest biomass in both natural and planted forests over large areas has proven challenging. Using a remote sensing data-based method, this study presents a novel approach to separate the biomass gains and losses of planted forests and natural forests and to quantify their independent contributions to total forest biomass changes. Annual forest biomass data were calculated using 1 km spatial resolution maps of planted and natural forests in China for 2005–2020. Planted forest biomass increased substantially from 1.81 Pg C in 2005 to 3.11 Pg C in 2020 at a rate of 0.086 Pg C yr⁻¹. In contrast, natural forests remained relatively stable at 6.44 Pg C over the same period. Driven largely by extensive afforestation efforts, planted forests accounted for 100% of the increase in China’s forest biomass. Notably, 86.2% of the planted forest biomass and 70.3% of the natural forest biomass were located in southern China, which has a warmer climate. The area’s expansion of newly planted forests (i.e., young forests) contributed all of the total increase in biomass carbon storage (1.30 Pg C) in the planted forest category from 2005 to 2020. Forests planted before 2005 with mid-to-old tree age, together with natural forests, played a minor role in the total increase in forest biomass in China during this period. This is likely due to forest harvesting and natural disasters in these forests offsetting the growth of natural forests and mid-to-old-age planted forests over the 2005 to 2020 interval. This study highlights the complex and distinct biomass dynamics of planted and natural forests in China, which are subject to both human management and natural disturbances.