China Land Surveying and Planning Institute

Forests act as critical carbon sink ecosystems, with their carbon sequestration capacity influenced by multiple factors. However, the long-term relationship between forest spatial morphological patterns and carbon storage remains insufficiently explored. This study focuses on Jinhua City, Zhejiang Province, using multi-source data from 2002 to 2020, including morphological spatial pattern analysis (MSPA) metrics, climatic factors, land use types, and socioeconomic data. By employing MSPA and an explainable machine learning (ML) framework, we investigated the relationships between forest carbon storage and key influencing factors. The results indicate that: (1) Incorporating MSPA factors significantly enhances the predictive accuracy of vegetation carbon storage models. (2) NDVI, MSPA factors, and SSD (sunshine duration) are the most critical determinants of carbon storage levels, exhibiting pronounced nonlinear relationships with forest vegetation carbon storage. Specifically, NDVI, D_CORE (density of core), and SSD show the most significant positive contributions, whereas D_ISLET (density of islet), D_BRANCH (density of branch), and D_LOOP (density of loop) exhibit relatively lower and negative correlations. (3) Certain key influencing factors display threshold effects and optimal intervals. In Jinhua City, the significantly higher carbon sequestration benefits are associated with NDVI values ranging from 0.63 to 0.73, D_CORE between 63% and 89%, and SSD of 1482 h, providing actionable guidance for spatial planning. This study provides new insights into forest carbon management in Jinhua, suggesting that optimizing landscape ecological spatial patterns should be prioritized in ecological conservation efforts. Additionally, differentiated strategies should be developed for distinct regions to support sustainable forest management in alignment with China's dual carbon goals. • Relationship between morphological spatial pattern and carbon storage was analyzed. • MSPA factors significantly improve forest carbon storage prediction accuracy. • NDVI, MSPA factors, and SSD are key nonlinear determinants of carbon storage. • Indicators show nonlinear thresholds, guiding tailored spatial planning strategies.

Optimizing Ecological security patterns (ESPs) is critical for advancing territorial spatial restoration and fostering sustainable regional development. While research on ESPs’ construction has grown significantly, key challenges persist, particularly in the accurate identification of priority conservation areas and the integration of socioeconomic development with ecological conservation. To address these challenges, this study selects Jiangsu Province as a representative case. We move beyond single-factor assessments by combining ecosystem service importance evaluation with a multi-factor ecological sensitivity analysis (including water pollution, soil erosion, air pollution, and anthropogenic pressure). A comprehensive ecological resistance surface is then developed, incorporating both natural and anthropogenic disturbance factors, to evaluate spatial patterns of ecological security. Utilizing the Minimum Cumulative Resistance (MCR) model, we delineate ecological corridors and ultimately construct the ESPs by synthesizing ecological sources and corridors. Key results include: Jiangsu’s ESPs comprises 33 ecological patches (total area: 14,622.46 km2, 13.71% of the study region), predominantly composed of water bodies, wetlands, and cultivated land. Thirteen ecological corridors (total length: 1920.38 km) primarily traverse cultivated land, construction land, and water bodies. The optimized ESPs strategy termed “Two Cores, Two Barriers, Three Belts, Multiple Corridors” offers a concrete spatial blueprint. The findings provide effective scientific reference for assessing and managing regional ecological security trends.

This study aims to develop a multi-dimensional framework to systematically identify optimal adjustment zones for converting orchard land into cultivated land, thereby providing a reference for spatial optimization of cultivated land within the context of integrating diverse land occupation activities into the requisition–compensation balance system. The research incorporates land quality evaluation, land-use conversion cost assessment, ecological loss analysis, and scenario-based simulations. The study demonstrates that (1) compared to the common practice of directly converting orchard land to cultivated land by only considering the slope, our multi-scenario optimization model for cultivated land reduces both economic and ecological losses. (2) For cities prioritizing ecological or economic development, selecting strategies under corresponding priority scenarios can maximize the protection of local ecological environments or maintain economic levels, thereby providing reserve resources for cultivated land optimization and adjustment. (3) Under the MMEG (EG: Ecological priority scenario) and MMEM (EM: Economic priority scenario) scenarios (MM: conversion of medium-low-grade orchard land to medium-high-grade cultivated land), the area of cultivated land optimal adjustment zones is the largest. The method of comprehensively identifying cultivated land optimal adjustment zones through multi-dimensional scenario settings is more comprehensive than the conventional approach that only considers slope. This method enhances cultivated land quality more effectively and protects both the ecosystem and the economy.

Cultivated land concentration and contiguity, as a core element of agricultural modernization development, holds strategic significance for enhancing agricultural production efficiency and ensuring national food security. This study employs vector patches as research units and classifies spatial connections between patches into direct and indirect connections. We quantify six types of spatial relationships between patches using binary encoding, enabling precise delineation of concentrated contiguous cultivated land. A Patch Connectivity Index is proposed. Combined with the Patch Area Index and Patch Shape Index, an evaluation system for cultivated land concentration and contiguity is established. Using Suixi County as a case study, we investigate the spatiotemporal evolution of its cultivated land concentration and contiguity from 2019 to 2023. Overall, patch connectivity exhibits a “single-element dominant, multi-element complementary” structural pattern, while the evaluation grading of cultivated land concentration and contiguity follows a normal distribution. Between 2019 and 2023, the average patch area decreased while the average number of connections between patches increased, indicating significant improvement in cultivated land concentration and contiguity levels. By adjusting spatial relationships between patches, the effective integration and utilization of cultivated land resources can provide theoretical foundations and practical references for agricultural modernization development.

Abstract. The penetration depth of Synthetic Aperture Radar (SAR) signals is a critical parameter for assessing subsurface characteristics and detecting concealed structures. Although numerous empirical and scattering models have been proposed to estimate signal penetration depth (SPD), there remains a lack of understanding of SPD in various settings. In this study, we deployed a ground-based SAR system equipped with L-band (1.5 GHz) and S-band (3.0 GHz) SAR sensors and a microwave anechoic chamber to carry out experimental studies of SPD in soil with different volumetric water content (VWCs) and in hard surfaces of varying thicknesses of gravel and asphalt. At an incidence angle of 40°, the laboratory measurements indicate that the L-band SPDs in homogeneous clay with VWC levels of 4% and 18% are approximately 45–50 cm and 30–35 cm. The L-band signal can penetrate asphalt up to 9 cm, gravel up to 5 cm, and a composited layer of 2 cm gravel and 7 cm asphalt. The S-band can penetrate loose and compacted clay of 20‒25 cm and 15‒20 cm, respectively. The SPD in silt loam was about 15‒20 cm.

The inequity in the distribution of green spaces in megacities has a detrimental effect on the physical and mental well-being of their inhabitants, highlighting the necessity for careful and strategic urban planning, along with appropriate regulatory interventions. Nevertheless, scholarly articles addressing the equity of access to urban green spaces primarily concentrate on urban parks, with limited studies examining the influence of alternative types of green spaces. This research initially recognized and categorized informal green spaces (IGS) located within the Third Ring Road of Chengdu, utilizing the UGS-1m dataset and area of interest (AOI) data, in accordance with a well-defined classification framework. Then, the G2SFCA method and Gini coefficient were employed to assess the impact of IGS on the green space accessibility, especially scenario analysis of open and shared use of green space. The findings indicate that (1) IGS in the narrow sense constitute 21.2% of the overall green spaces within the study area, resulting in a reduction of the Gini coefficient by 0.103; (2) IGS in the broad sense, including public affiliated green spaces, shows an even more positive effect on improving the equity of green space supply, with a reduction of the Gini coefficient by 0.28; (3) there exists great spatial disparity in accessibility improvement effect by different types of IGS, so public policies must be customized to reflect local circumstances, taking into account the practicality and associated costs of management and maintenance of various IGS as well as accessibility enhancement; (4) certain older residential areas may not be amenable to effective enhancement through the use of IGS alone, and these should then adopt a multidimensional greening strategy such as green-roof. The findings of this research offer valuable insights for the planning and management of green spaces in densely populated urban environments, thereby aiding in the development of more refined models for the development of “Garden Cities”.

• Weak Enforcement: One of the significant factors identified was the weak enforcement of zoning laws, which hampers effective land-use planning. • Financial Constraints: Limited financial resources were highlighted as a barrier to implementing necessary changes in rezoning regulations. • Stakeholder Engagement: The importance of involving local communities and stakeholders in the rezoning process was emphasized to ensure that the plans meet the needs of the population. Woldia town has a land-use plan aimed at guiding urban development and addressing challenges. However, the plan's implementation has not effectively tackled the town's real issues, resulting in frequent rezoning, which often reflects a failure to properly execute the plan. The factors behind these rezoning are not well studied, with existing research providing inconsistent findings and failing to identify the primary cause for frequent rezoning requests. Therefore, this study aims to investigate the factors influencing rezoning in Woldia and identify the key drivers behind the frequent requests. A mixed-methods approach, including structured questionnaires and semi-structured interviews with residents, urban planners, and government officials, was employed. Data were analyzed using the Relative Importance Index (RII) and Henry Garrett's ranking technique. The findings reveal that the most significant factor driving rezoning is weak enforcement of existing laws, followed by the misuse of government power, the local government's weak financial capacity, the lack of proper land-use regulations, and financial constraints faced by private developers. These issues hinder the efficient implementation of land-use plans and lead to inconsistent rezoning. The study emphasizes the need for stronger legal frameworks, improved governance, and increased financial resources for urban development. This research contributes to urban planning literature by providing insights into rezoning dynamics in emerging economies. The findings offer valuable policy recommendations, including stronger enforcement mechanisms, financial incentives for sustainable development, and inclusive community engagement in zoning decisions. Addressing these issues is critical to ensuring equitable and sustainable urban growth in Woldia and similar towns.