From Park Expansion to Networked Urban Green Infrastructure: Governance Mechanisms in Singapore and Their Transferability to Shanghai

1. Introduction

Urban green space is no longer expected to serve only as amenity planting or recreational land. Parks, greenways, waterways, streetscapes, building greenery, and conservation areas are increasingly planned as a land-based urban landscape system that can mitigate heat, retain and convey stormwater, support biodiversity, improve health, enable active mobility, and strengthen social life [1,2,3,4]. This shift has expanded the policy vocabulary from parks and beautification to urban green infrastructure (UGI), blue-green infrastructure (BGI), nature-based solutions, ecological networks, and urban resilience. The common premise is that connected and multifunctional green and blue spaces can deliver more value than isolated sites [3,4,5,6].

The implementation record, however, is uneven. Connectivity and multifunctionality may be articulated at the regional or citywide planning level but fragmented during land allocation, greenway alignment, project approval, procurement, construction, and maintenance [7,8,9,10]. Agencies may share broad sustainability goals while retaining separate budgets, technical standards, asset registers, and performance indicators. A river restoration project can therefore be designed as a landscape, drainage facility, habitat, and public space, yet later be managed through disconnected operational regimes. The problem is not only how much green space a city possesses, but whether spatial planning, project delivery, stewardship, and learning form a continuous institutional process.

Singapore is widely documented as a case of long-term urban greening. Its trajectory from a “Garden City” to a “City in a Garden” and subsequently a “City in Nature” is associated with statutory land-use planning, an island-wide network of parks and connectors, blue-green projects, vertical greenery, professional horticultural capacity, tree management, and community gardening [11,12,13,14,15,16,17]. Yet visible landscapes can invite superficial lesson-drawing. Tropical vegetation, iconic developments, a city-state government, and comparatively concentrated public authority are not readily reproduced in a large metropolitan region.

Shanghai provides a useful contrast. It is also a global, high-density Asian coastal city, but its administrative territory is approximately 8.6 times that of Singapore and includes a dense central city, new towns, rural areas, coastal wetlands, forests, and ecological conservation land. Shanghai had established 1100 parks by the end of 2025 and continues to develop greenways, waterfronts, the Outer Ring ecological park belt, community gardens, and open shared green spaces [18,19,20,21,22,23]. Its 2026–2030 ecological-space plan places greater emphasis on life-cycle park management, smart supervision, integrated spatial information, ecological monitoring, and collaborative governance [24]. These are policy commitments rather than evidence that implementation is already uniform across the municipality.

This contrast makes the two cities analytically valuable. They share functional pressures but differ in governance scale, climate, urban-rural structure, land arrangements, and implementation complexity. The comparison is therefore not intended to rank their greening performance. It examines how governance mechanisms work under different institutional conditions and how lessons can be adapted rather than copied. Policy-transfer research has long warned that programs detached from their institutional and resource contexts can produce incomplete or inappropriate transfer [25]. Collaborative-governance research similarly shows that formal coordination is insufficient without shared objectives, implementation capacity, and accountable processes [26]. These insights have not been fully integrated into comparative studies of Asian urban landscape, greenway, and UGI governance.

Existing scholarship has documented Singapore's greening history, greenway development, biophilic urbanism, water-sensitive projects, and horticultural participation [11,12,15,16,27,28]. Research on UGI more broadly has advanced concepts of connectivity, multifunctionality, resilience, equity, and collaborative planning [3,4,5,6,7,8,9,10]. Recent Shanghai studies have quantified associations between UGI and thermal mitigation or residents' well-being [29,30], while comparative BGI research has emphasized political continuity, cross-sector coordination, and institutional context [31]. Less attention has been given to the full implementation chain through which a land-based UGI objective becomes a spatial rule, a connected landscape network, a cross-sector project, a maintained asset, an operational dataset, and a continuing public relationship. The resulting gap is not whether UGI can provide benefits, but how policy and practice connect the spatial and institutional stages needed to sustain them.

This study addresses that gap through three research questions:

• Through which governance mechanisms has Singapore linked urban landscape and greenway planning with project delivery, long-term stewardship, monitoring, and public participation?
• Which corresponding governance functions are present or proposed in Shanghai's current policy and practice, and where do implementation questions remain?
• What institutional, spatial, climatic, and operational conditions delimit transfer between the two cities and to other high-density metropolitan regions?

The study makes two contributions. First, it develops an implementation-chain framework that links the spatial connectivity of land-based UGI with strategic commitment, cross-sector delivery, life-cycle stewardship, feedback, and societal embedding. Second, it reframes policy transfer in urban landscape and greenway planning: the transferable unit is not a visually successful project or an organizational chart, but a mechanism that must be matched to local authority, capacity, climate, and accountability.

2. Materials and Methods

2.1. Comparative Design and Case Selection

The study uses a qualitative, mechanism-oriented comparison of urban greening policy and practice. Singapore serves as the reference case for identifying how governance functions are connected, while Shanghai serves as a contrast and adaptation case. This design is intentionally asymmetric: it does not attempt to rank two equivalent systems or attribute ecological outcomes to a single institutional variable. Instead, it asks which functions are visible in each policy and practice record, how they are linked, and what contextual differences constrain lesson-drawing.

The cases combine functional comparability with substantial contextual variation. Both are high-density Asian coastal cities with global economic functions, scarce central-city land, exposure to heat and intense rainfall, extensive public-sector planning, and mature urban greening programs. Singapore is a compact city-state with a 2025 land area of 736.3 km² and a total population of 6.11 million [32,33]. Shanghai covers 6340.5 km² and had 24.8541 million permanent residents at the end of 2025 [34,35]. Singapore's equatorial climate supports year-round plant growth, whereas Shanghai's humid subtropical monsoon climate includes winter cold, plum-rain conditions, summer heat, and typhoon exposure. Singapore's national agencies operate at a scale that overlaps with metropolitan management; Shanghai must coordinate a municipality, 16 districts, subdistrict and town governments, public institutions, state-owned and private actors, and heterogeneous urban-rural spaces.

2.2. Evidence Base and Scope

Evidence was drawn from publicly available policy and planning documents, statutes, official statistics, institutional program materials, and peer-reviewed research. Primary sources were used for current policies, organizational responsibilities, statutory provisions, program design, and reported system scale. Peer-reviewed studies were used to interpret policy development, situate the cases in UGI and governance research, and qualify official accounts. Sources were selected for direct relevance to strategic planning, spatial integration, cross-sector delivery, long-term stewardship, operational information, public participation, or transfer conditions.

In November 2025, one of the authors participated in a 14-day professional study visit to Singapore. The program included site visits to urban parks, green infrastructure projects, planning institutions, and management facilities, as well as lectures and professional exchanges with personnel from the National Parks Board (NParks), project and site managers, and other practitioners involved in urban planning, greenery management, and ecological conservation. Field notes, training materials, and observations from these activities informed the identification of relevant governance issues and helped interpret how formal policies were translated into practice. These materials were used as contextual evidence rather than as a formal interview dataset; factual claims and comparative findings reported in the article were cross-checked against publicly available policy documents, official records, institutional materials, and peer-reviewed research. Promotional statements without verifiable program detail and metrics with incompatible definitions were not used to support comparative claims. The evidence base was used to examine policies, plans, institutional arrangements, and documented practices rather than to treat the references themselves as objects of analysis.

2.3. Analytical Framework and Comparative Procedure

The analytical framework was developed abductively. UGI scholarship emphasizes multifunctionality, connectivity, ecosystem services, and resilience [3,4,5,6], while governance and policy-transfer research emphasizes institutional coordination, implementation capacity, and contextual fit [9,10,25,26,31]. These bodies of literature were combined into six linked dimensions:

• Strategic commitment: continuity of objectives, temporal horizons, and legal or policy authority;
• Spatial integration: treatment of parks, waterways, corridors, streets, buildings, and conservation areas as a connected and multifunctional system;
• Cross-sector delivery: mechanisms through which planning, water, housing, transport, construction, and greenery objectives are jointly translated into projects;
• Life-cycle stewardship: professional capacity, procurement, inspection, maintenance, renewal, and responsibility after project completion;
• Monitoring and feedback: operational data, asset records, evaluation, and the return of evidence to planning and management;
• Societal embedding: public engagement, community stewardship, differentiated access, and negotiation of public value.

For each dimension, the analysis compared four elements: the formal instrument or stated policy; the responsible agency or interagency relationship; the spatial or operational application; and the publicly documented output. Recurring relationships across dimensions were then synthesized as mechanisms. In this article, a mechanism denotes a recurring institutional arrangement that connects two or more implementation dimensions; it does not denote an estimated causal effect. The six dimensions are analytical lenses, whereas the five mechanisms reported below combine dimensions where the evidence showed a recurring relationship—for example, professional stewardship with operational data, and public participation with differentiated access. Interpretations were checked against primary institutional evidence and, where available, peer-reviewed analysis. Claims about policy intention were kept distinct from claims about implementation or measured outcomes.

The transfer analysis used four questions: (1) Is the function compatible with Shanghai's distribution of authority and accountability? (2) Can it operate under local spatial and climatic conditions? (3) Are professional, financial, and data capacities available for sustained operation? (4) How are public value, access, and ecological protection balanced? The resulting recommendations are therefore conditional propositions, not evaluated reforms.

2.4. Data Comparability and Study Limitations

Official terms such as “park”, “green space”, “green coverage”, and “park connector” are defined differently across jurisdictions. The analysis therefore uses population, land area, and clearly defined program totals to establish context but does not construct a composite ranking. Singapore's park inventory and Shanghai's park categories are reported to show system scale, not relative superiority. Statements about governance mechanisms are distinguished from causal claims about ecological performance.

The evidence base remains primarily document-based. Field observations and non-recorded professional exchanges provided contextual understanding but were not conducted or analyzed as formal research interviews. The approach may therefore underrepresent implementation failures, informal negotiation, budget constraints, contractor behavior, and uneven frontline practice. Systematic interviews and longitudinal project-performance data would be needed to test whether the identified relationships operate consistently or produce ecological and social outcomes. The results should therefore be read as an interpretive governance framework and a set of testable transfer propositions.

3. Results

3.1. Shared Pressures and Non-Equivalent Urban Conditions

Singapore and Shanghai face a similar strategic question: how can a mature greening program deliver more ecological and social performance when new central-city land is scarce? In both cities, parks alone cannot address all demands for heat mitigation, stormwater management, biodiversity, active mobility, and everyday access. Policy increasingly assigns complementary functions to streets, waterways, infrastructure edges, buildings, residual land, and community spaces. This common problem supports comparison.

The baseline conditions nevertheless differ substantially (Table 1). Singapore's compact urban territory makes island-wide network planning possible and brings water supply, conservation, housing, industry, transport, and recreation into close spatial contact. Shanghai contains both very dense districts and extensive peri-urban and ecological areas. A mechanism that fills a missing corridor in central Shanghai may be inappropriate in a large wetland or rural ecological source area, where limiting disturbance is more important than adding recreational facilities.

The comparison also changes the interpretation of “learning from Singapore”. Shanghai is not beginning from a lack of parks or plans. Its public planning framework already identifies a multi-level, networked, and multifunctional ecological structure [18,19], while rapid park expansion has created a substantial asset base [20,21]. The relevant learning problem is how to make separately funded and managed assets operate as an integrated system over time.

3.2. Five Mechanisms in Singapore's Networked UGI Governance

3.2.1. Temporally Nested Planning and Rule-Based Translation

Singapore's greening strategy has changed in content while retaining a prominent place in national policy. Early planting and environmental improvement were linked to sanitation, urban image, and investment; the City in a Garden agenda expanded connectivity, quality of life, and access; City in Nature emphasizes ecological restoration, biodiversity, resilience, and coexistence with wildlife [11,12,13,14]. The documentary record is consistent with cumulative layering, although it does not by itself demonstrate continuity in every program or budget.

Temporal continuity is reinforced by nested planning. The Long-Term Plan addresses needs over approximately 50 years or more, while the statutory Master Plan guides development over 10–15 years and is reviewed regularly [38,39,40]. Development-control mechanisms translate broad objectives into site decisions. The Landscaping for Urban Spaces and High-Rises program, for example, uses landscape-replacement requirements to integrate greenery into dense development rather than relying only on voluntary decoration after design [41]. The Parks and Trees Act provides an additional legal basis for park, tree, and planting-area protection [42].

The mechanism is therefore not “having a long-term vision” alone. It is the combination of a stable strategic direction, periodic plan revision, statutory land-use control, and project-level requirements. Each time horizon has an implementation function. This reduces the risk that biodiversity, connectivity, or landscape replacement remain aspirations disconnected from land and approval decisions.

3.2.2. Networked Multifunctionality Across Green, Blue, and Grey Space

Singapore's UGI is not confined to conventional parks. Nature reserves and nature parks form ecological cores; regional and neighborhood parks, therapeutic landscapes, community gardens, and building greenery provide distributed nodes; park connectors, Nature Ways, streets, waterways, and the Rail Corridor form linear links [13,14,16,36,37,41,43]. This arrangement combines ecological movement, shade, walking and cycling, recreation, stormwater functions, heritage, and access.

The Rail Corridor illustrates adaptive reuse of linear infrastructure. The former railway has been retained as a continuous green and heritage corridor while access points, community nodes, paths, and ecological planting have been incrementally improved [43]. Its significance lies less in a single design language than in protecting continuity and allowing multiple public values to accumulate along an existing line.

Multifunctionality is not identical to maximizing use everywhere. Nature reserves and sensitive areas apply designated routes, opening rules, permits, and behavioral restrictions [44]. The network therefore contains differentiated nodes: highly accessible community and recreational spaces coexist with protection-first areas. Connectivity and public access are calibrated to ecological sensitivity rather than treated as universal design requirements.

This finding supports UGI research that treats connectivity and multifunctionality as system properties [3,4,6]. It also adds an implementation condition: diverse spaces can function as a network only when planning and management rules recognize that nodes have different primary purposes and acceptable intensities.

3.2.3. Project-Level Interagency Co-Production

Singapore's National Parks Board is a central greenery and biodiversity agency, but major UGI functions depend on other statutory boards. The Urban Redevelopment Authority controls land-use planning and development requirements; the Public Utilities Board manages water supply, drainage, and flood risk; the Housing and Development Board shapes public housing environments; and the Building and Construction Authority influences the built environment [13,41,42,45,46,47].

Bishan–Ang Mo Kio Park demonstrates how coordination becomes spatially productive. The Public Utilities Board and National Parks Board converted a concrete drainage canal into a naturalized river integrated with park topography [27,46]. In ordinary conditions the river and banks support recreation, habitat, and landscape experience. During high flows, lower areas contribute to conveyance and temporary inundation, with risk managed through spatial design and warnings. The case did not emerge by adding planting after a drainage project; water safety, public space, and ecological restoration were jointly framed.

The case is consistent with project-level co-production: participating agencies framed water safety, public space, and ecological objectives early enough to affect land form and technical design [27,46]. Public sources provide less detail on negotiation, budgets, and long-term allocation of operating responsibility, so the case supports the presence of a coordination mechanism rather than a general claim about interagency effectiveness.

3.2.4. Professionalized Life-Cycle Stewardship and Operational Data

The durability of UGI depends on work that is less visible than planning and design. Singapore supports professional capacity through the Centre for Urban Greenery and Ecology, which provides horticulture, arboriculture, landscape, and related training, and through the Landscape Company Register, which establishes organizational and personnel requirements [48,49]. Public authorities can therefore influence industry capability through training, registration, procurement, and contract management rather than relying solely on in-house labor.

Digital systems reinforce, but do not replace, professional stewardship. NParks has described a greenery-management model using digital tools for parks and streetscapes, while TreesSG provides public access to part of a large tree inventory [50,51]. Taken together, these sources indicate an effort to connect digital records with professional management. They do not, however, permit an independent assessment of data completeness, workflow consistency, or maintenance outcomes. TreesSG should therefore be interpreted as one visible component of a wider management arrangement, not as evidence that a public map constitutes a complete life-cycle system.

This link addresses a recurrent UGI implementation problem: capital budgets create assets, but fragmented maintenance budgets and short contracts determine whether ecological and public functions persist [8,10]. Singapore's example suggests that life-cycle governance requires three mutually reinforcing capacities: competent public clients, capable providers, and records that survive individual projects and contracts.

3.2.5. Differentiated Access and Sustained Civic Participation

Singapore's public participation occurs through several channels. Community in Bloom supports gardening groups in residential, educational, and other community settings; Friends of the Parks organizes place-based partnerships; and Master Plan 2025 used exhibitions, workshops, and community engagement [52,53,54]. Their program design provides institutional hosts and opportunities for repeated interaction. Public descriptions alone do not establish the continuity, representativeness, or site-level outcomes of participation across all groups.

At the same time, the system does not equate participation with unrestricted access. Nature reserves and sensitive sites use rules and permits to protect ecological functions [44]. This combination is important: societal embedding includes both opportunities to co-create and obligations to respect ecological limits. Participation can strengthen stewardship and legitimacy, but it must be designed around the carrying capacity and purpose of each space.

Taken together, the five mechanisms can be read as an implementation chain rather than a checklist (Figure 1). The evidence shows recurring linkages among strategic direction, spatial rules, interagency projects, stewardship, operational information, and civic relationships. The framework proposes that weak linkage at any stage may constrain long-term performance; testing that proposition requires project-level and longitudinal evidence.

3.3. Shanghai's Emerging Policy Alignment and Remaining Implementation Questions

Shanghai's published plans contain several counterparts to the functions identified in Singapore. The Shanghai Master Plan (2017–2035) and the 2021–2025 ecological-space plan establish a multi-level ecological pattern, park system, greenways, forest and wetland objectives, and links to urban renewal [18,19]. Waterfront programs, the Outer Ring ecological park belt, neighborhood greening, vertical greenery, and park opening and sharing provide spatial platforms [18,19,20,21,22,23]. The 2026–2030 plan goes further by calling for differentiated park management, life-cycle management mechanisms, a smart park supervision platform, multi-actor collaborative governance, a unified and dynamically updated industry spatial map, ecological monitoring networks, data sharing, and ecosystem-service valuation [24].

These provisions show policy alignment with several implementation-chain functions, but they should not be interpreted as completed institutional integration. The public record reviewed here does not establish how consistently project briefs align water, biodiversity, shade, mobility, and public-space objectives; how construction information is transferred into maintenance; whether sectoral data systems use compatible identifiers and update rules; or whether participation arrangements persist beyond individual programs. These are implementation questions rather than demonstrated deficiencies.

Table 2 therefore separates documented policy or practice from the unresolved question that would need operational evidence. The comparison does not support importing Singapore's organizational form. It identifies functions for which Shanghai has existing or planned counterparts and clarifies what would need to be tested.

4. Discussion

4.1. Governance Capacity as a Link Between Spatial Form and Long-Term Performance

The comparison supports a more cautious proposition: UGI performance should not be inferred from visible form or total green-space supply alone. Connected park and greenway corridors, naturalized waterways, community gardens, and digital tree maps are shaped by governance arrangements, while their long-term value is likely to depend on how those arrangements continue after construction. The documentary evidence indicates a relatively continuous linkage in Singapore among strategy, planning rules, cross-sector projects, professional stewardship, operational information, and civic relationships. It does not demonstrate that this linkage is complete or that it directly causes specified ecological or social outcomes.

This interpretation extends urban landscape and greenway research on multifunctionality. Existing frameworks explain why UGI can deliver multiple ecosystem services and why size and connectivity matter [3,4,6]. Shanghai research has provided empirical evidence on thermal mitigation and pathways linking green infrastructure with well-being [29,30]. The present study does not retest those outcomes; it argues that multifunctionality also has an institutional dimension. Each additional function introduces an actor, standard, risk, or maintenance obligation. Without coordination, multifunctionality may remain a list of aspirations attached to a project whose agencies are separately accountable. The implementation-chain framework therefore treats institutional connectivity as a counterpart to spatial connectivity.

The findings also qualify celebratory accounts of biophilic urbanism. Singapore's tropical vegetation and flagship landscapes are important, but they are not the most portable elements [15]. The comparison directs attention instead to less visible governance functions: nested time horizons, enforceable development requirements, joint problem definition, professional public-client capacity, persistent asset records, and differentiated use rules. Similar comparative work on BGI governance has also identified political continuity, institutional coordination, and stable arrangements as important implementation conditions [31].

4.2. Policy Transfer Should Be Modular and Conditional

Policy-transfer scholarship distinguishes learning from direct copying and emphasizes the risks of incomplete transfer [25]. The Shanghai–Singapore comparison shows why the mechanism, rather than the project, should be the transfer unit. A naturalized waterway cannot be separated from flood responsibility, public-safety rules, land availability, maintenance knowledge, and monitoring. A tree database is ineffective without inspection protocols and data-update responsibilities. A community garden program requires organizers, professional support, land permission, and a durable agreement.

Modular transfer does not mean selecting isolated attractive practices. A module includes its enabling relationships. For example, Shanghai can adopt the function of Singapore's centralized coordination without reproducing a city-state institution: joint project briefs, shared spatial data, aligned acceptance criteria, and responsibility matrices can provide horizontal coordination across existing agencies. Likewise, digital asset management can be distributed across municipal and district systems if identifiers, minimum fields, interfaces, and update duties are common.

Four conditions determine whether a mechanism is portable. Institutional fit asks whether authority and accountability exist at the required scale. Spatial and climatic fit asks whether the design logic respects local hazards, ecology, and urban form. Operating fit asks whether finance, skills, providers, and data maintenance are sustainable. Public-value fit asks whether access, equity, ecological protection, and participation are balanced. These conditions are more useful than a binary judgement that a “Singapore model” is or is not applicable.

4.3. Implications for Shanghai and Other High-Density Asian Cities

For Shanghai, the analysis yields five propositions for testing rather than a ranked reform agenda. The first is that a traceable planning–project–monitoring loop could reduce loss of intent between plans and delivered assets. Pilot projects could state how each site or corridor contributes to the wider urban landscape and greenway network, heat and flood resilience, biodiversity, accessibility, and life-cycle cost, and then test whether post-completion findings influence later design guidance and procurement.

The second proposition is that the planned industry spatial map [24] would be more useful as a shared blue-green working layer for decisions than as a display product alone. A pilot layer could combine ecological source areas, corridors, broken links, canopy and shade deficits, flood and heat exposure, service gaps, and potential retrofit spaces. It should also distinguish where access might be increased from where disturbance should be reduced. This distinction matters because central-city infill, new-town development, rural landscapes, forests, and coastal wetlands require different UGI strategies.

The third proposition concerns life-cycle stewardship, a direction now explicit in Shanghai's 2026–2030 plan [24]. Pilot handover requirements could connect design intent, species and material information, inspection needs, ecological targets, maintenance methods, and renewal responsibility. Multi-year outcome-oriented contracts could be tested where ecological maturation cannot be evaluated in a single annual cycle. Evaluation should also examine provider access, transaction costs, and the risk of reducing ecological performance to easily counted work quantities.

The fourth proposition is that operational digitalization should be evaluated through defined workflows. Sensors, remote sensing, and artificial intelligence may add value when they help identify canopy loss, screen tree risk, detect irrigation failure, or prioritize inspection, but they should not substitute for professional assessment. A pilot could evaluate data completeness, update timeliness, response time, verified risk reduction, and reduced duplicate collection rather than device or dashboard counts.

The fifth proposition is that durable civic stewardship requires explicit roles and evaluation. Multi-year agreements could clarify what residents, organizations, professional staff, and park managers contribute to community gardens and small green spaces. Pilots should examine continuity, representation, site outcomes, and administrative burden rather than attendance alone. In ecologically sensitive areas, participation may appropriately focus on monitoring, education, or regulated visitation rather than physical intervention.

These propositions can be tested through a limited portfolio of contrasting sites, such as a central-city waterfront or road corridor, a comprehensive urban park, a community garden network, and an ecologically sensitive peri-urban site. Each pilot could use a common minimum architecture: a cross-sector project brief, an identified spatial role in the wider network, a life-cycle responsibility matrix, persistent asset and habitat records, and a post-completion review. Mechanisms should be incorporated into routine planning or procurement only after their operating costs, capacities, ecological outcomes, public value, and distributional effects have been evaluated (Figure 2).

The framework may also be useful beyond the two cases, particularly in metropolitan regions seeking to connect fragmented urban landscapes while capital delivery and long-term stewardship are governed through different organizations. This wider relevance remains a proposition: comparative research in additional cities is needed before the framework can be treated as generalizable.

4.4. Limitations and Research Agenda

Four limitations should guide interpretation. First, the study is primarily document-based and is supplemented by field observations and non-recorded professional exchanges conducted during a study visit to Singapore. These activities provided contextual understanding but were not conducted or analyzed as formal research interviews. They may reflect the perspectives of the institutions and practitioners encountered and cannot substitute for systematic interviews with a broader range of stakeholders. Public documents likewise reveal formal intentions and program architecture but may not capture negotiation, underfunding, contractor behavior, or uneven district implementation. Interviews with planners, water managers, park operators, arborists, contractors, and community organizations would be needed to test the operational account.

Second, outcome data are not standardized across the cases. The study does not estimate whether one governance mechanism caused a specific biodiversity, temperature, flood, health, or cost outcome. Future research should connect governance variables with longitudinal site performance.

Third, the two-case comparison cannot establish that the mechanisms are unique to Singapore. Comparative work involving Hong Kong, Seoul, Tokyo, Shenzhen, or other dense metropolitan regions could test whether different institutional arrangements produce similar implementation-chain functions.

Fourth, transfer recommendations are propositions, not evaluated reforms. Pilot studies should document transaction costs, professional capacity, data quality, public acceptance, ecological outcomes, and distributional effects. Equity deserves particular attention: UGI investments can improve environmental quality while also producing uneven access or development pressure [7].

5. Conclusions

Singapore and Shanghai illustrate a common transition in mature greening programs: policy attention is moving from park expansion alone toward the performance of connected, multifunctional urban landscapes and greenway networks. The comparison identifies a relatively continuous linkage in Singapore among long-term strategy, statutory and project rules, spatial networks, interagency delivery, professional stewardship, operational data, and civic participation. This is an interpretation of documented policy and practice, not evidence that the chain is complete or that it causes specified outcomes.

Shanghai already possesses a substantial park and ecological-space system, and its 2026–2030 plan now explicitly addresses life-cycle management, smart supervision, integrated spatial data, ecological monitoring, and collaborative governance. These commitments indicate policy convergence with several functions identified in Singapore, but their implementation across projects, agencies, districts, and asset owners remains to be evaluated. Singapore's centralized city-state structure cannot be reproduced, and its planting models and technical parameters require climatic adaptation. The relevant lessons are therefore functional and conditional.

The broader conclusion is that urban greening policy travels best as a mechanism with known enabling conditions, not as a branded model or physical template. For high-density cities, spatial connectivity must be matched by institutional connectivity. When planning, delivery, stewardship, monitoring, and public value are connected, UGI is more plausibly governed as enduring urban infrastructure rather than as a sequence of isolated projects. Whether the proposed mechanisms improve ecological, social, or economic performance should be tested through longitudinal and comparative research.: