Globally, accelerating high-density, high-quality urban development has positioned urban regeneration, reconciling livability, equity, and sustainability, as a critical governance priority. The UN Sustainable Development Report 2021 advocates enhanced sustainable infrastructure and integrated approaches to drive green transitions¹. China’s 14th Five-Year Plan (2021–2025) has elevated urban regeneration to a national strategy, shifting focus from spatial expansion to stock revitalization through spatial quality enhancement and functional restructuring. In this context, urban park green spaces, as core components of urban ecosystems and public space systems, serve as vital media for advancing social cohesion, urban resilience, and equitable renewal². Most current studies on Chengdu’s green spaces calculate accessibility based on static population distributions. But they largely neglect quality elements like service facilities and recreational capacity in equity assessments. While some attempts link accessibility to socio-economic status, a systematic ’social equity-green space service’ framework remains absent. Consequently, current research reflects limitations in scale, demographic coverage, responsiveness to diverse group needs, and policy optimization strategies.

This study adopts a green space equity lens. It interrogates Chengdu’s park city optimization. This optimization is achieved through inclusive urban regeneration. The study is informed by Portland’s systematic ecological network governance. It addresses a core research question: How to precisely respond to differentiated green space needs of vulnerable groups while enhancing multidimensional equity in small-park layout quality within high-density urban fabrics? The research seeks to contextualize spatial justice theory, achieve equitable resource distribution, and generate actionable pathways for just urban renewal.

This study breaks through the traditional structure of spatial justice theory, which mainly focuses on the distribution of spatial resources. It constructs a three-dimensional green space fairness evaluation model(distribution-quality-rights). For the first time, the model incorporates the right to participation of residents into the evaluation system. It verifies the feasibility of this approach through a case study in Jinniu District. Specifically, this research reveals the structural contradictions in the construction of Chengdu’s park city. In addition, it deciphers the nature of the institutional innovation of the Portland model. This study goes beyond the transplantation of experience at the material space level. It proposes a path of inclusive renewal implementation. This aims to achieve a paradigm shift in the supply of green space from equalisation to precise compensation.

Urban regeneration, as a multidisciplinary practice, centers on countering urban decline through enhanced spatial quality, economic revitalization, and sustainable development. China’s cities now prioritize stock regeneration, necessitating inclusive governance mechanisms in spatial planning. Globally, inclusive regeneration and green space equity consensus demands: (1) Mitigation of environmental gentrification; (2) Protection of residents’ right to housing and development; (3) Fairness, participa- tory engagement, and anti-exclusion safeguards for vulnerable populations, such as low-income households, ethnic minorities, and elders, to secure regeneration benefits and prevent displacement.

This paradigm integrates five dimensions: distributive justice, participatory governance, collaborative pluralism, cultural sensitivity, and economic inclusion. Market-driven displacement pressures and capital’s profit demands obstruct multi- stakeholder reconciliation. Consequently, institutional safeguards become essential to combat gentrification. Green and low-carbon regeneration fundamentally embeds carbon neutrality, climate adaptation, and biodiversity conservation to enhance ecological functionality, resident well-being, and urban resilience. Yet high land costs and scarcity constrain green space scaling, spatial optimization, and long-term maintenance viability. Consequently, inclusive regeneration prioritizes procedural equity through rights protection and participatory processes, whereas green space regeneration focuses on ecological quality enhancement. Synergistically integrating high-quality green infrastructure provides dual foundations for sustainable urban transformation: advancing social justice while upgrading ecological performance.

China’s inclusive regeneration is predominantly state-dominated. Citing Poznan, Poland’s experience, Xiang Pengcheng demonstrates that community gardens, seasonal beaches, and optimized cycling infrastructure mitigated green gentrification while enhancing public health¹⁶. Drawing on UK experience, Wang Zhenpo finds that resident participation in China remains largely tokenistic, requiring strengthened rights to information and oversight¹⁷. Citing the case of Malaysia, Liu Jian et al. (2025)emphasise that empowering the community to participate directly in planning can meet diverse needs¹⁸.

Urban regeneration abroad commonly employs collaborative governance to address challenges such as migration, ageing, and economic disparities. For instance, Curran et al.(2012)observed Brooklyn’s "Moderately Green" project utilizing community- led micro-regeneration to mitigate the social injustices associated with retrofitting¹⁹. Africa is facing the dilemma of peri-urban sprawl. Through analyzing Maputo’s inhabitants’ lifeworlds, Axel Prestes Dürrnagel uncovered the necessity for new planning agendas. These agendas must connect everyday realities with instrumental rationality. Ultimately, this integration seeks to dismantle colonial planning’s destructive legacies, particularly the alienation and displacement it generated²⁰. Sustainable regeneration thus necessitates integrating inclusiveness with low-carbon greening³¹. Equitable greenspace provision underpins spatial inclusion. Simultaneously, inclusive governance blocks green gentrification and secures fair co-benefit distribution. Collectively, these mechanisms form an integrated framework for achieving urban sustainability.

In Chinese scholarship, Yu Kongjian et al⁸. pioneered the integration of green space equity into evaluation frameworks. However, three persistent limitations remain:(1) an overemphasis on quantitative metrics at the expense of quality and accessibility equity; (2) inadequate consideration of the differentiated needs of vulnerable groups; (3) deficient participatory mechanisms that undermine procedural justice. China’s urbanization context intensifies equity challenges through spatial mismatch and institutional barriers. International studies consistently show that successful inclusive regeneration demands dual integration: spatial optimization must be coupled with governance innovation. Consequently, future research must establish multidimensional frameworks to coordinate distributional, interactive, and procedural equity through interdisciplinary convergence and leveraging digital tools.

Traditional spatial justice theories are often constrained by unidimensional resource-allocation perspectives. This study adopts a multidimensional approach, establishing a ’space-quality-rights’ framework to evaluate park equity. Moving beyond singular distributional paradigms, it integrates key dimensions of spatial justice: the spatial dimension addresses distributive justice in green space access for disadvantaged groups; the quality dimension assesses equity in facility functionality, ecological services, and fulfillment of diverse needs; and the rights dimension reconfigures power dynamics to shift from elite dominance toward polycentric governance, securing citizens’ participatory rights.

Chengdu’s central urban area comprises five municipal districts (Jinjiang, Qingyang, Jinniu, Wuhou, Chenghua) within the G4202 Ring Expressway. This study utilizes: 2025 Chengdu administrative boundaries, urban park green space data, remote sensing imagery, residential area data, land use data, and supporting datasets. (road networks, hydrography).

The research commenced on 10 June 2025. Chengdu administrative boundaries, territorial spatial planning, and green space planning data were retrieved from public platforms, including the Chengdu Municipal Public Data Open Platform and the Geospatial Data Cloud. Subsequently, the TianMap-Chengdu platform was accessed to extract urban green park vector layers, with shapefile format datasets downloaded via built-in functions.

The research results are categorized and presented in Table 2.

ArcGIS served as the primary platform for spatial data processing, enabling spatial statistics and quantitative assessment of surveyed data.

To capture authentic resident travel behavior, this study quantifies park accessibility via network analysis by deriving bulk shortest-walk durations from residential areas to park entrances. Travel cost was operationalized as walking time from neighborhoods to park gates. Time thresholds were stratified by park type using a 20-minute acceptable walking limit.

Given park green space quality indicators’ influence on service capacity, this study includes: area, shape index, environmental carrying capacity, woodland coverage, and water body percentage. Indicator sourcing and computation methods are detailed in Table 3.

Twelve parks in Chengdu’s central metropolitan district were systematically identified. Using the above formula, the original quality indicators of several parks were quantified in Table 4.

This study employs the entropy method to calculate comprehensive quality scores for each park. Derived from information theory, entropy quantifies information disorder: higher values indicate greater uncertainty, while lower values denote higher certainty. The calculation procedure follows these steps:

(1) Determine evaluation indicators: Select a set of metrics corresponding to decision-making criteria. This study employs five indicators: park green space area , shape index , environmental carrying capacity , woodland coverage , and the percentage of water bodies .

(2) Indicator normalization: Raw data were normalized to resolve scale-related differences. We applied the min-max method using the following formula:

Where denotes the normalised indicator, represents the value of the jth raw indicator for the ith park, and indicates the total value of the jth raw indicator.

Weight Calculation: For each evaluation metric, compute its entropy value. The weights of evaluation metrics are then determined based on their entropy values, calculated as follows:

Where denotes the weight of the indicator, denotes the entropy value of the jth indicator, denotes the coefficient of variation of the jth indicator, and represents the weight of the jth indicator.

Park green space quality indicator weights were calculated as presented in Table 5.

Grounded in spatial justice theory, this study assesses urban green space equity by conceptualizing these spaces as manifestations of democratized spatial entitlements and socio-spatial interactions. We construct a tripartite evaluation framework (Space-Quality-Rights) to comparatively analyze Portland and Chengdu’s green space practices. Focusing on spatial injustices in Jinniu District’s small parks, we propose planning optimization pathways.

The research identifies spatial resource allocation as a core indicator of spatial justice amid rapid urbanization. Portland’s 1979 UGB policy effectively curbed urban sprawl. This is exemplified by the Pearl District’s transformation from derelict indus- trial land into a high-density, mixed-use neighborhood²¹. This compact development model maximizes existing infrastructure utilization while reducing auto-dependency. Furthermore, Portland implements infill development strategies, as seen in the South Waterfront brownfield regeneration, where light rail integration enabled high-density residential development^24,25.

Conversely, Chengdu exhibits boundary-free spatial expansion patterns, exacerbating spatial imbalances, particularly green space supply-demand disparities in historic areas like Jinniu District. In response, Chengdu innovated a multi-tiered park system (regional-urban-community) with tiered deployment strategies to enhance citywide coverage²⁹. Signature initiatives include the 7,000-kilometer Tianfu Greenway Network, which guarantees universal park access through linear connectivity, effectively integrating fragmented green assets.

Equitable distribution of green space resources constitutes a fundamental tenet of spatial justice in urban renewal. Our findings empirically validate the thesis advanced by Xie Yinghui (2021) and He Simin (2025): park supply-demand imbalances in Jinniu District primarily stem from fragmented spatial distribution and heterogeneous land-use patterns. Geospatial analysis reveals pronounced disparities in green space allocation and pocket park service levels across the district, exhibiting a center- periphery improvement gradient. Portland replicates this spatial injustice^28,29. Evan Elderbrock et al. (2024) demonstrate that inequitable distribution persists, with bivariate analyses identifying right-of-way canopy coverage as the most significant determinant²⁴. Donovan et al. (2021) tested whether planting urban trees in Portland, Oregon, promotes gentrification, finding that greater tree canopy cover within a neighborhood was significantly associated with higher median home sale prices²⁶. This study extends traditional spatial justice theory by incorporating Yang Lijuan et al.’s (2020) imperative to integrate socio-natural space dynamics, human agency, and embodied spatial experience within renewal frameworks³⁰. Empirical evidence includes Portland’s 2024 Tree Equity Project, where participatory GIS mapping of tree deficits and safety risks directly informed priority zoning policies²⁷. Similarly, Chengdu’s Shuangliu District established a co-creation mechanism engaging 300 + resident co-creators in siting and designing 26 pocket parks, with 180 + community proposals adopted to counter elite-dominated planning. These cases advance spatial justice discourse by linking facility quality and rights-based empowerment, offering transferable models for global eco-urbanization. Moreover, this paper breaks away from the traditional spatial justice theory that emphasizes the equity of resource distribution³³. Instead, the paper incorporates the sharing of rights into the fairness evaluation dimension. This incorporation is verified in the case study of Jinniu District.

However, this study has limitations. First, the distribution of rights is primarily shaped by policy and institutional factors, resulting in a passive state of community resident participation. Such participation is only actively exercised when significant inequities emerge in urban green space resource allocation. Moreover, owing to regional policy disparities, the transferability of rights-sharing equity evaluation indicators requires further validation. Second, Data accuracy was compromised by technological and methodological constraints. Third, the preliminary research in Chengdu’s central urban area yielded an inadequate park sample size. Future research should therefore employ improved data collection techniques and expand the sample to enhance the study’s generalizability.

Grounded in spatial justice theory, this study conducts a systematic comparative analysis of Portland and Chengdu, examining divergences in spatial configurations, facility standards, and rights protection mechanisms. We subsequently develop a triaxial ‘Space-Quality-Rights’ evaluative framework. Portland exhibits racially stratified green space distribution, a legacy of historical segregation. The city prioritizes eco-technical specifications yet perpetuates implicit participatory barriers. Conversely, Chengdu’s urban expansion has induced green space deficits in historic cores, where technology-driven planning and cultural integration enhance implementability but compromise efficacy.

This research establishes an empirical foundation for spatially optimized urban regeneration in China. It also contributes to global eco-city discourse through quality enhancement and rights-sharing paradigms.