To explore the temporal and spatial evolution of carbon sinks in state-owned forest regions (SOFRs) and the efficiency of increased carbon sinks, this study used panel data from 19 periods in 40 key SOFRs in Heilongjiang Province from 2001 to 2019. Additionally, combined with geographic information system (GIS) and remote sensing (RS) technology, the individual fixed-effect model was used to estimate the number of forest management investment (FMI) lagging periods, and the panel threshold model was used to investigate the differences in the FMI efficiency in various forest regions. From 2001 to 2019, the carbon sink of key SOFRs in Heilongjiang Province showed an upward trend over time, with a growth rate of 20.17%. Spatially, the phenomenon of “increasing as a whole and decreasing in a small area” was found, and the carbon sink of each forest region varied greatly. The standard deviation ellipse of the carbon sink presented a “southeast–northwest” pattern and had “from southeast to northwest” migration characteristics. The FMI amount from 2001 to 2019 showed an upward trend, with a total of CNY 46.745 billion, and varied greatly among forest regions. Additionally, the carbon sink amount in each SOFR affected the FMI efficiency. The threshold of the model was 5,327,211.8707 tons, and the elastic coefficients of the impact of FMI below and above the threshold on the carbon sink were 0.00953 and 0.02175, respectively. The latter’s FMI efficiency was 128.23% higher than that of the former. Finally, the increase in FMI to a carbon sink followed the law of diminishing marginal benefits. Therefore, the government should rationally plan the level of FMI in each SOFR to improve the FMI cost-effectiveness and help achieve the goal of “carbon neutrality”.

Off-farm diversification offers an important pathway out of poverty while health-impaired rural farmers can hardly seize the opportunity in developing countries. This paper investigates how chronic illness shapes livelihood structure and income generation in rural China. Our sample consists of 3850 rural households in Southern China and we rely on instrumental variable regressions to identify causal effects. We find that farmers with chronic illness tend to diversify towards local off-farm employments, rather than migrants, since local off-farm employments are more likely to act in a strategically complementary way to farming. Further analysis shows that income returns of diversification tend to be substantially higher for the health-impaired. While the relationship between diversification and income presents a conventional inverted U shape for the healthy, it is best categorized as upward sloping with diminishing marginal effects for farmers with chronic illness.

Although forest tenure devolution has been widely implemented, limited research has examined the carbon sequestration effects of property rights, particularly the interactions among rights within the tenure bundle. This research quantifies the structure of forest tenure at the village level over a 20-year period (2000–2019) and links it with village-year satellite observations of forest carbon sequestration. Using two-way fixed effects regression, interaction effect models, and mediation analysis, the research examines the carbon responses to devolved forest tenure, with particular attention to the interactions among tenure rights and the heterogeneity across forest types. Empirical results indicate that the logging right constitutes the core component of the tenure bundle that promotes carbon sequestration in mature forests and shrublands. When the logging right was completely absent, the impact of ownership on carbon sequestration became insignificant. Tenure rights bundles interact significantly in shaping carbon sequestration outcomes in mature forests. Specifically, longer tenure duration reinforces the effects of ownership and logging rights, whereas transferability tends to substitute for their returns. In terms of young plantations, only official certification of ownership would promote their carbon sequestration and there are no interaction impacts between rights. Further analyses combining farmer behavior find that the reduction in logging intensity, rather than frequency, is a significant channel for logging rights to promote carbon sequestration of mature stands. Ownership increases the frequency but the intensity of afforestation/reforestation, which in turn increases carbon sequestration of young plantations.

Conservation set-asides face a trade-off between soil erosion control and grain security. Using the Grain for Green Program (GGP) in China’s Loess Plateau as a case study, this study aims to reveal the main source of productivity improvements that help offset the possible negative effect of conservation set-asides on grain supply. For empirical estimation purposes, we combine county-level remote sensing data with detailed grain production information from 209 counties in the Loess Plateau, spanning from 2000 to 2015. The satellite image interpretation and statistical records show that the area of arable land has decreased while the grain supply has been increasing in the Loess Plateau since 2000. A multiple-mediation analysis reveals that the GGP has a negligible total effect on the grain supply, which contributes to the positive mediating effect of multiple cropping, rather than technological progress. Further analysis shows that the increasing land-use intensity exerts higher water stress on areas with less rainfall. The results indicate that studies investigating conservation set-asides and food security relationships should not overlook the changes in land-use intensity, especially in water-scarce areas.