Enhancing Urban Sustainability Through Green Infrastructure: Spatiotemporal Analysis of Green Space and Forest Coverage in Sichuan (2002–2022)

Abstract

Integrating green infrastructure in urban planning for urban sustainability to stay environmentally equitable, ecologically resilient, and climate adaptive is gradually becoming significant. Using remote sensing data, GIS analytical methods, and urban forestry indicators, this study analyses the spatiotemporal changes in the urban green space and forest coverage of the Sichuan Province of China during 2002–2022. The results show a 20% to 40% addition to urban green space and a 24% to 38% extension in forest coverage resulting from urban greening programmes and reforestation schemes. Urban sprawl has contributed to biodiversity loss, the fragmentation of habitats, and a reduced carbon sequestration potential, notably in peri-urban areas. To address these issues, we propose sustainable green infrastructure by introducing nature-based solutions, carbon offset strategies, and ecological connectivity corridors. Specific proposed policies encompass enhancing the urban forestry legal framework, establishing ecological red lines, and optimising land use policies by coordinating urban development with ecological conservation. This work provides a scientific foundation for urban planners and policymakers to enhance climate resilience, carbon neutrality, and sustainable urban ecosystems.

1. Introduction

1.1. Research Background and Significance

Urban sustainability underscores the imperative to confront the pivotal challenges confronting contemporary cities in their efforts to regulate urban expansion while preserving natural resources. Benedict and McMahon highlighted the multidimensional benefits that green infrastructure, including parks, urban forests, and green corridors, can bring to support urban sustainability through the provision of ecosystem services, improved air quality, and enhanced biodiversity [1]. In China, the unprecedented rapid urban expansion in recent decades has caused major changes in land use and land cover, especially in such locations as Sichuan Province. A comprehensive understanding of the spatiotemporal distribution of green spaces and forest risk in these regions is imperative for the formulation of effective urban planning and sustainable development policies.

Sichuan Province is located in the southwestern region of China. Since the year 2000, there has been drastic changes to natural land covers. From 2002 to 2022, substantial metropolitan expansion took place, frequently encroaching on green land and wooded regions. This shift strains ecological balance, climate regulation, and the character of urban life. A spatiotemporal analysis of green space and forest coverage in consideration of urbanisation impacts during these times is a valuable tool to assess the resulting implications on environmental sustainability. These key insights help guide policymakers and urban planners in formulating strategies that enhance urban resilience through the implementation of green infrastructure, ultimately addressing ecological constraints affecting the process of urban growth. Urban sustainability is at the forefront in the context of rapid urbanisation. This study discusses the elements of sustainability as an economic, social, and environmental concept. For example, VisitPittsburgh is supporting integrated solutions and exploring the potential recreational and tourism benefits of green infrastructure, which can lead to local business development. Green spaces increase public health and quality of life, concurrently improving social wellbeing. This study has been designed to explore the contributions of green infrastructure to environmental conservation. The conservation of biodiversity and carbon sequestration are two such crucial elements of sustainable urban development.

Recent studies have highlighted the need to incorporate green infrastructure into urban design to promote ecological resilience and offset the negative impacts of urbanisation. For example, green spaces have been linked with protecting indoor environments, reducing urban heat island effects, improving air quality, and preserving biodiversity [2]. In addition, the establishment of urban green infrastructure can help mitigate greenhouse gases and assist in climate change adaptation strategies [3].

1.2. Problem Statement and Research Gap

Green infrastructure has been widely acknowledged as a critical component in fostering urban sustainability. However, there is a major gap in the existing spatiotemporal assessments regarding the changes in green spaces and forest coverage in fast-growing urban areas, such as Sichuan Province. To date, extant studies have focused on urban expansion and its immediate environmental impacts. However, they have rarely discussed the gradual effects of urbanisation on changes to green infrastructure over extended time periods [4]. This oversight impedes the effectiveness of urban planning solutions that incorporate ecological dimensions, thereby hindering a comprehensive understanding of the intricate interactions underlying urban growth and green space transformation.

In addition, though several studies have investigated land use changes in Sichuan, few have examined high-resolution, longitudinal data from 2002 to 2022 to understand the spatiotemporal variations in green space and forest coverage. This time lag hinders the potential to identify long-term trends and the multidimensional consequences of urbanisation on greening infrastructure. Addressing this research gap is essential to formulate appropriate measures that alleviate the threats posed by urban development while simultaneously ensuring urban resilience and strengthening the ecological sustainability of urban land through the effective conservation and use of green infrastructure [5].

The adverse consequences of deforestation, pollution, and other anthropogenic activities have resulted in the impairment of ecosystems, underscoring the necessity of integrating green infrastructure into urban planning to enhance ecological resilience and mitigate the deleterious effects of urbanisation.

1.3. Research Objectives and Contributions

This study aims to analyse the spatiotemporal patterns of green space and forest coverage in Sichuan Province in 2002–2022 in the context of urban expansion and environmental sustainability. For quantifying the changes in major environmental indicators, such as forest coverage, urban green space rate, population density, and urban area (

Table 1. Description of variables.

Variable	Description	Source
Forest Coverage (%)	Percentage of land covered by forests in Sichuan Province	National Forestry Database
Urban Green Space Rate (%)	Proportion of urban areas covered by green space	China Urban Construction Database
Population Density (people/km2)	Number of people per square kilometre in Sichuan Province
Urban Area (km2)	Total built-up area in Sichuan Province

), this study employed a combination of high-resolution satellite images and a Geographic Information System (GIS)-based spatial analysis. These variables are critical to studying urban sustainability because forest coverage and green space provide ecological balance, while the population density and urban area measure the degree of urbanisation. However, few studies have performed longitudinal assessments on the relationship between green infrastructure coverage and accelerated urbanisation in Sichuan Province, although urbanisation and land use change have been extensively studied across China [4]. This study addresses this gap by presenting a long-term perspective on the evolution of green infrastructure which could inform urban planners and policymakers. These findings will assist in the development of sustainable urban development strategies to promote ecological resilience and reduce the environmentally harmful effects of urbanisation [5].

By employing advanced spatial analysis methods, this study provides a comprehensive understanding of the dynamic relationship between urban growth and green infrastructure. These insights are crucial for the development of targeted policies that balance urban growth and ecological conservation to ensure a sustainable urban environment for future generations [6].

1.4. The Structure of the Paper

This paper is organised so that it offers an overview of the interaction between green infrastructure and urban sustainability in Sichuan Province. In Section 2, Materials and Methods, the study area, data sources, and analytical techniques are described, including the GIS-based spatial analysis and statistical modelling [4]. This section presents important variables, namely the forest coverage, urban green space rate, population density, and urban area. Section 3, Results, describes the results of the spatiotemporal dynamics of green spaces and forests, the impact of urbanisation on urban green infrastructure, as well as land use change and environmental implications. The results presented in Section 3 are discussed in the broader context of sustainable urban planning in Section 4, Discussion, along with detailed comparisons of the findings with previous research and policy implications [5]. This section also discusses the limitations of this research as well as future research avenues. Section 5, Conclusion, concludes with key takeaways, suggesting policy interventions and emphasising the need to balance urbanisation with ecology. The balanced combination of qualitative and quantitative methods allows a systematic investigation of the influencing factors and the hierarchy of spatial influence of the green infrastructure in Sichuan Province and its potential contribution towards urban sustainability.

2. Materials and Methods

2.1. Study Area Description

The different geographical types in Sichuan Province in southwestern China significantly affect the distribution of urban green space and forest coverage. The province is dominated by the Sichuan Basin in the east and the mountains in the west. The Sichuan Basin is among the most fertile and populous regions in the world, where agricultural and urban processes and green infrastructure interactions with urbanisation happen intensively. The west Hengduan Mountain regions are high-altitude habitats dominated by forests that play an essential role in ecological stability and carbon storage. The green space and forest coverage in Sichuan is unevenly distributed (Figure 1). Dense forest areas are mainly concentrated in the western and northern mountainous regions, while the urban areas in the middle of the Sichuan Basin have a higher degree of fragmentation of green space. The province’s climate ranges from subtropical humid conditions in the basin to cold, alpine conditions in the mountains, further determining the distribution of vegetation and ecological sustainability [7]. This would provide valuable insights into a variety of patterns, which are vital for sustainable urban planning and green infrastructures, serving to advance ecological resilience in the context of growing urbanisation and climate change.

This study investigates Sichuan Province in southwestern China, which has undergone rapid urbanisation over the decade. This province is rich in diverse geographical types, affecting the cross-spatial distribution of urban green spaces and forest coverage. The research field is considered to be aligned with the United Nations Sustainable Development Goals (SDGs), specifically SDG 11 (Sustainable Cities and Communities) and SDG 15 (Life on Land). The data collection and analysis methods examine the changes in urban green spaces and forest coverage from 2002 to 2022 to assess their possible implications towards these SDGs. It is hoped that this will explain the necessity of green infrastructure for urban sustainability.

2.2. Data Collection and Sources

Using remote sensing data, an extensive spatiotemporal analysis was performed on the green space and forest coverage in Sichuan Province between 2002 and 2022. Our data collection balanced accuracy with a wide range of sources. The primary data used were captured by high-resolution satellites, such as Landsat and MODIS, covering two decades of land use and land cover changes. Satellite images were processed to derive vegetation indices and classify land cover types to accurately map green and forested spaces. We also used data from the Global Forest Watch platform, a comprehensive source of information on forest extent, loss, and gain. Natural forests constituted 30% of Sichuan’s land cover as of 2020, with a further 6.9% made up of non-natural tree cover [8]. We augmented this remote sensing data with a dataset of official statistics from the Sichuan Provincial Forestry Department to further elucidate afforestation strategies, forest management practices, and the role of regional policies in shaping green infrastructure—for example, Liu et al. have shown that planting shrubs and trees has significantly affected the tree cover in Sichuan, increasing it to 38.03% in 2018 [9]. Additionally, spatiotemporal changes in ecosystem service values in the province were calculated based on land use data from the years 2000, 2005, 2010, 2015, and 2020. Some high and low vegetation density areas of green space in Sichuan (Forest) are shown in Figure 2. Such diverse data sources enabled a thorough analysis of the ecological changes in Sichuan, as well as a better understanding of how urban change has impacted green space (Figure 2).

2.3. Analytical Methods

This research explored the spatiotemporal dynamics of green space and forest coverage in Sichuan Province from 2002 to 2022 using a GIS and remote sensing. Land use and land cover assessments were conducted using Landsat and MODIS high-resolution satellite images. These images were processed to derive vegetation indices, such as the Normalised Difference Vegetation Index (NDVI), allowing for the classification and quantification of green spaces and forested areas. A GIS platform allowed for the integration and analysis of spatial data to visualise the evolution of green infrastructure over time. By overlaying datasets for the transformation of urban sprawl and vegetation cover, we examined patterns of urban growth and changes in vegetation cover over time, obtaining valuable information on the influence of urbanisation on vegetation cover and landscapes.

The NDVI based on remote sensing combined with a GIS has been widely used to monitor long-term changes in the landscape due to its high spatiotemporal consistency and well-validated vegetation indicators [10]. But it has biases towards detecting the species diversity or vertical structure. Factors that contribute to the absolute difference in green space and forest coverage were evaluated by means of statistical and regression models. Ordinary least squares (OLS) regression was then used to see how the relationships between green space metrics and socioeconomic determinants (population density and urban growth rates) changed. Despite its generality, OLS does not account for spatial heterogeneity [11] and so it is still popular for its simplicity and interpretability (

Table 2. Comparison of analytical methods for urban green infrastructure studies.

Method	Strengths	Limitations	Suitability for This Study
NDVI + GIS	High spatiotemporal consistency; well-validated vegetation indicator	Limited in detecting species diversity or vertical structure	Long-term landscape change tracking
OLS Regression	Simple and interpretable; baseline for linear relationships	Ignores spatial heterogeneity	Preliminary association analysis
GWR	Captures spatial variation in relationships; local modelling	Computationally intensive; sensitive to bandwidth choice	Uncover localised urban green dynamics
Random Forest (RF)	High predictive accuracy; handles nonlinearities	Black-box nature; lacks spatial interpretability	Less suitable for spatially explicit policy implications
Support Vector Machine (SVM)	Good with high-dimensional data; robust classification	Requires kernel tuning; weak in spatiotemporal explanation	Not ideal for urban pattern explanation
Deep Learning (e.g., CNNs)	Extracts complex features from large imagery datasets	Requires large labelled datasets; low interpretability	Overkill for limited variable analysis

).

The spatial non-stationarity was addressed via geographically weighted regression (GWR) to model the local variations in these relationships. GWR fits a regression equation at every location of the dataset, providing a better understanding of how green infrastructure is distributed and influenced by local factors for the province overall. Although GWR is computationally intensive and sensitive to the choices made in terms of bandwidth [12], it is able to reveal localised urban green dynamics.

The integration of these analytical methods allowed for a full assessment of the spatiotemporal patterns and driving forces of changes in green infrastructure in Sichuan, which could be used for sustainable urban planning and environmental protection practices.

3. Results

3.1. Spatiotemporal Trends of Green Space and Forest Coverage

Sichuan Province has undergone significant changes in its forest coverage and urban green space during the last two decades, indicating the effects of policy intervention and urbanisation dynamics. The forest coverage area in Sichuan increased significantly from about 24% in 2002 to approximately 38% in 2022 (Figure 3). More robust periods of growth were observed between 2002 and 2004 and again between 2010 and 2015, likely indicating the impacts of large-scale afforestation programmes—the Grain for Green Programme and the Natural Forest Protection Programme [13]. These initiatives encouraged reforestation by returning marginal agricultural lands to forests and limiting deforestation in ecologically sensitive areas [14]. However, beginning in 2017, the forest coverage plateaued, suggesting that there are limits of the potential to expand forest coverage owing to land use constraints and policy recalibration. Additionally, the forest recovery was uneven, with notable increases in mountainous western areas and a relatively little upsurge in the eastern Sichuan Basin, where urbanisation pressures are high [15].

We demonstrates a significant trend for the urban green space rate in Sichuan, with a gradual increase from around 20% in 2002 to nearly 38% in 2022. This increasing trend can be credited to urban greening programmes driven by the government, such as increased parks, green corridors, and ecological restoration in major cities, such as Chengdu [14]. Despite this progress, fluctuations between 2007 and 2012 indicate a range of intermittent challenges, likely linked with competing demands for land resources and infrastructure development (Figure 4). These issues need to be addressed, as disparities exist among highly urbanised regions struggling to keep their green space per capita as the population continues to grow rapidly and densification occurs. Developing policies to preserve and grow urban greenspace, especially in high-density cities, is critical to avoid worsening environmental impacts and improving the quality of life among residents. In short, the spatiotemporal dynamics study of green infrastructure in Sichuan Province highlights that human-related approaches based on policies play a fundamental role in local sustainability paths.

3.2. The Relationship Between Urbanisation and Green Infrastructure

The challenge of rapid urbanisation in Sichuan Province in the past two decades has brought opportunities and threats for the restoration of urban green infrastructures in the region. There is a definite inverse correlation between urban fabric development and green space. Densely populated areas have grown rapidly, especially in the Chengdu Plain Economic Zone, causing a loss of peri-urban green belts and natural environments. Urban sprawl contributes to habitat fragmentation, biodiversity loss, and rising environmental strain. Initiatives like the Chengdu–Chongqing Economic Circle promote urbanisation through integrated infrastructure while taking into account sustainability and ecological considerations.

To address the environmental challenges posed by urbanisation, Sichuan has undertaken several green infrastructure projects to promote urban sustainability. This influence can be seen in Chengdu’s “Park City” concept, which integrates the countryside’s ecological quality and people’s wellbeing into the development of urban green spaces. Such initiatives also range from creating green corridors and rooftop gardens to conserving natural waterways, thereby enhancing the green coverage in urban areas. Another project, the Sichuan Province “14th Five-Year Plan” policy, which depicts eco-environment conservation and high-quality economic development as the two wings of achieving economic growth, aims for the establishment of an eco-friendly civilisation and low-carbon pledges in life [16]. These techniques help counterbalance the detrimental impact of urbanisation on green infrastructure, promoting a harmonious coexistence of urban development and environmental sustainability.

3.3. Ecological and Carbon Sequestration Impacts

In the last 20 years, rapid urbanisation in Sichuan Province has brought opportunity and threat for the restoration of urban green infrastructures. The comparison of green space and urban fabric development in terms of numbers indicates an inverse correlation (Figure 5). These rapidly growing, densely built-up regions have resulted in various natural environments and peri-urban green belts disappearing, particularly in the Chengdu Plain Economic Zone. Sprawling urban development contributes to habitat fragmentation, the loss of biodiversity, and increased environmental strain. Urban–rural integration through interlinked infrastructure integrates elements of sustainability and ecology initiatives, such as the Chengdu–Chongqing Economic Circle. In an effort to tackle the environmental challenges caused by urbanisation, Sichuan has enhanced urban sustainability through several green infrastructure projects. For example, through Chengdu’s “Park City” constellation fusion, the ecological quality of the countryside and the wellness of human society become the product of urban green spaces. Such initiatives also span from green corridors and terrace gardens to natural spring conservation, thus increasing the green cover in urban areas. And Sichuan Province’s “14th Five-Year Plan” policy portrays eco-environment conservation and high-quality economic development as the means to achieve economic growth through the construction of an eco-civilisation and low-carbon commitment for life [16]. These strategies are utilised to ameliorate the negative effects—such as the loss of green infrastructure—associated with urbanisation.

The carbon sequestration impact of Sichuan’s green infrastructure is also supported by the evidence that forest coverage is increasing significantly, allowing the province to absorb more atmospheric CO₂. Figure 5 shows the evolution of the natural forest area from 1.3 to 1.8 million hectares in the province in 20 years, which has greatly increased the carbon sink potential of the province. In comparison, artificial forests, albeit on a much smaller scale, have crept up steadily, suggesting that they contribute positively to carbon sequestration. This transition is shown in Figure 6, where the total forest coverage has increased from less than 28% in 2002 to about 38% in 2022. Implemented with significant public support, the Grain for Green Programme has had a powerful effect on returning farmlands to forests, preventing carbon emissions and bolstering carbon sinks. The implications of this programme are consistent with general studies on carbon sequestration, reinforcing the role of afforestation and sustainable forest use in a long-term strategy to achieve ecological harmony. Moving forward, Sichuan should continue to prioritise green infrastructure, while ensuring continuous monitoring and adaptive management are conducted to provide sustainable ecological and carbon sequestration benefits.

3.4. Comparative Analysis of Urban vs. Rural Areas

We illustrates the relationship between green infrastructure and other aspects of sustainability, including the effects that urban green spaces and forest coverage have on sustainability. The figure presents how green infrastructure can affect carbon neutrality, climate resilience, biodiversity conservation, and social equity, which corresponds with the comparative analysis findings of urban versus rural areas. It provides an idea of how green infrastructure contributes towards the overall scope of urban sustainability.

Over the last 20 years, there has been significant urban growth in Sichuan Province, resulting in a considerable discrepancy in the access to green parks in urban and rural areas. Cities like Chengdu have developed a significant amount of green space in recent years, with its per capita green space reaching 9.5 m² in 2002 and 15.2 m² in 2022 (Figure 7). Much of this growth can be credited to concerted plans and policies that are making cities better places to live. It is the opposite for rural areas, where the green infrastructure increased only from 8.3 to 9.1 m² per capita over the same period. Despite population increases in urban areas and the evident changes in new developments—with significant investments in public parks and recreational opportunities—rural populations still rely on natural landscapes that may not always be accessible or well maintained (Figure 8).

Figure 9 depicts the spatial analysis detailing the discrepancy in the green space distribution, showing that cities have a greater density and accessibility than rural areas. This disparity has public health and social equity implications, as access to green spaces has been shown to reduce stress and improve mental and physical health. Even though urban areas are making headway in terms of green infrastructure, rural regions need specific strategies to improve access to green spaces (Figure 10). There is a need for focused policies to mitigate these disparities. Promoting initiatives for community-based mechanisms and formulating budgets for the transformation, development, and maintenance of green spaces in rural regions can be efficient steps in reaching urban–rural sustainable equality.

4. Discussion

This study makes several unique contributions to the evolving field of urban sustainability and green infrastructure assessment. Unlike previous studies that used temporal snapshots at 5- to 10-year intervals or focused only on urban/regional geospatial analyses, this study utilises 20 years (2002–2022) of moderate temporal resolution satellite data to depict the long-term spatial and temporal dynamics of provincial green space and forest coverage in Sichuan Province. This includes the introduction of localised spatial modelling through geographically weighted regression (GWR), which provides a more nuanced understanding of the heterogeneity of urban green interactions in the province. Especially in Sichuan, spatial adaptation analysis tools are urgently needed due to the complex topography and unbalanced urban–rural development.

In addition, the use of a qualitative ecological policy review combined with spatial analysis distinguishes the methodology from the usual statistical mapping exercises. By analysing policy drivers in specific regions, including the Grain for Green Programme and Chengdu’s “Park City” model, this work interweaves geospatial science and urban governance. To the best of our knowledge, this is the first systematic integrated study of green infrastructure and policy assessments for a region in Sichuan Province over a 20-year timeframe.

In contrast, while global examples such as Singapore’s “Garden City” or Copenhagen’s “five-minute city” do reflect best practices in integrating green infrastructure, these examples typically emphasise compact, single cities with a high governance capacity and system-based solutions. By extending the discussion to large-scale, disparate provincial systems in developing regions, this study also provides practical implications for urban governance in rapidly and unevenly urbanising countries.

Through our spatiotemporal analysis of green space and forest space in Sichuan from 2002 to 2022 we can analyse urban planning considering the pressures of urbanisation, the state’s utilisation of green spaces and forest resources, and the effect of urban sprawl. Urbanisation has resulted in reduced green spaces and fragmented forest habitats, thus influencing ecological conservation. Nevertheless, the observed increase in the rates of forest coverage and urban green space during the study period suggests that existing efforts in reforestation and urban greening may be having beneficial effects. It emphasises the need to include green infrastructure in urban planning towards sustainability objectives. The results imply that policies focusing on the conservation and enhancement of green areas, eco-corridors, and urban forestation can increase biodiversity and climate resilience. For instance, the Grain for Green Programme significantly increased the forest extent and helped to conserve biodiversity. These findings also highlight the importance of integrated urban greening policies that consider metrics about biodiversity, the carbon capture potential, and habitat connectivity [17].

4.1. Implications for Sustainable Urban Planning

The results from this study hold significance for sustainable urban planning in Sichuan. Ecological conservation is connected to the adaptation to climate change and biodiversity. City officials can expand green spaces and develop proper urban planning to avoid the negative effects of urbanisation. Forest ecosystem protection can be realised by setting ecological red lines and no-forest development zones [18]. Green building standards also help to promote sustainable development and minimise emissions through sustainable urban design. The implementation of green space management strategies also requires public mobilisation and information dissemination. For example, community participation in green space management can increase environmental awareness and promote sustainable urban planning [19]. It emphasises the importance of a harmonious relationship between agroforestry systems and urban settlements under the assumption of long-term sustainability.

The “Park City” in Chengdu, Sichuan Province has demonstrated a successful implementation of urban nature-based solution initiatives. The project involves incorporating greenery into the city while improving the ecological quality of the city and the quality of life of the city residents. These strategies involve the creation of parks, green corridors, and rooftop gardens. As a result, the greening of urban spaces has contributed to increasing the area of green spaces, improving air quality, and reducing the urban heat island effect. The city has witnessed a considerable increase in public parks, offering more recreational areas for citizens. The initiative has also increased the city’s biodiversity with habitat creation for a range of species. Chengdu’s “Park City” has unique strengths compared to other regions in carrying out sustainable urban development projects. This serves as an extensible model for how green infrastructure makes cities more sustainable, while also delivering practical lessons to other municipalities facing similar issues.

4.2. Policy Interventions and Green Infrastructure Strategies

If sustainable urban development is the goal for Sichuan, then there is a need for effective policy interventions and green infrastructure strategies. Green building standards and sustainable urban design have been undertaken to reduce emissions and promote sustainability (

Table 3. Comparative analysis of current green space policies in Sichuan.

Policy Area	Key Measures	Goals	Challenges
Urban Green Space Planning	Green space system, park expansion	Increase green space, improve urban ecology	Land conflicts, rapid urbanisation
Forest Protection and Restoration	Forest protection, reforestation, Grain for Green Programme	Restore forests, protect biodiversity	Funding, illegal logging
Ecological Protection Zones	Ecological red lines, no-development zones	Protect ecosystems, biodiversity hotspots	Balancing development, enforcement
Green Building and Low-Carbon Cities	Green building standards, sustainable urban design	Reduce emissions, promote sustainability	High costs, limited awareness
Public Participation and Awareness	Ecological education, community engagement in green space management	Raise awareness, increase participation	Limited outreach, public reluctance

). Nonetheless, there are several existing barriers to upscaling these strategies, such as the high cost and limited awareness among the public [20]. Increasing awareness and public participation could be carried out through ecological education and community involvement in the management of public green space. However, limited outreach and public reluctance have inhibited the effectiveness of these initiatives [17]. The different current green space policies were compared to determine the more effective practices that could be followed in Sichuan. Policymakers are still using the current policies to assess whether more comprehensive considerations are needed.

4.3. Comparison with International Case Studies

An analysis of Sichuan’s green infrastructure policies in comparison to international case studies provides insight into collective strategies while revealing unique challenges in advancing urban sustainability. Sustainability is also central, as seen in Copenhagen’s Nordhavn district, which embodies the “five-minute city” ideal with varied architectural styles, generous green projects, and mixed-use areas spread over a compact plan with easy access to metro stations. This makes the neighbourhood a more inviting place for the public and encourages less use of cars, which is both environmentally and socially sustainable [20]. Another excellent example of unparalleled green areas is Singapore, where its transformation into a “Garden City” demonstrates the careful integration of nature into urban settings. Implementing natural surroundings has improved such characteristics as biodiversity, as seen in projects such as the Bishan-Ang Mo Kio Park, a project which replaced concrete canals with natural river landscapes, enhancing stormwater management [21]. This is a prime case for biophilic practices and green infrastructure to address environmental concerns.

Nevertheless, there are challenges associated with implementing green infrastructure. For instance, the Caofeidian Eco-City project in China struggled greatly despite its lofty sustainability ambitions. During the years-long project, significant issues arose that resulted in a myriad of criticisms about the project being a “ghost city” as well as falling into delays as it struggled with high costs and funding difficulties [22]. This highlights the significance of thorough planning, community involvement, and economic feasibility in the successful implementation of sustainable urban initiatives. As such, Sichuan’s endeavours must take into account these aspects in order for green infrastructure outputs to be effective, sustainable, and successful over the long run.

4.4. Limitations and Future Research Directions

Although this study has provided some insight into the spatiotemporal dynamics of green space and forest coverage in Sichuan from 2002 to 2022, a few limitations need to be addressed. The use of remote sensing data may cause uncertainty due to differences in the sensor resolution and atmospheric conditions during data capture. Also, the study considers the numbers primarily, limiting its realisation of qualitative aspects of green spaces, including biodiversity, ecosystem health, and social benefits, which are important for thorough urban sustainability evaluations [23]. Furthermore, the analysis did not capture socioeconomic driving forces leading to land use changes, resulting in insufficient information for revealing determinants driving the dynamics of green infrastructure.

Future studies should seek to overcome these limitations, ideally by combining high-resolution satellite observations with in situ measurements to improve the classification accuracy and capture more subtle changes in the green infrastructure over time. Through the integration of qualitative metrics, such as biodiversity mapping and ecosystem service assessments, a broader and more qualitative picture of the costs and benefits associated with urban green space could be painted [12]. Moreover, interdisciplinary studies of the socioeconomic forces affecting land use shifts can yield a better understanding of policy actions and planning methods that encourage sustainable urban growth. A participatory approach of engaging local communities may also help identify culturally relevant green infrastructure solutions and increase public support for conservation initiatives [24].

5. Conclusions

5.1. Summary of Key Findings

This research investigates the spatiotemporal evolution of the urban green space and forest coverage in Sichuan Province from 2002 to 2022. Some cities experienced a higher urban green space coverage (

Table 4. Summary of research findings.

Key Area	Findings
Urban Green Space Changes	Urban green space coverage increased in some cities but declined in high-density urban centres due to rapid urban expansion.
Forest Coverage Trends	Overall forest coverage fluctuated, with noticeable afforestation efforts but losses in peri-urban areas due to development.
Urbanisation Impact	Urban expansion led to a decline in green space and fragmented forest areas, particularly in rapidly growing cities.
Policy and Management Gaps	Existing policies support green space expansion, but enforcement challenges remain, particularly in balancing economic development and conservation.
Sustainability Considerations	Climate change and urban heat island effects highlight the need for stronger green infrastructure and adaptive planning measures.

), while high-density urban centres underwent a negative change in urban green space coverage owing to rapid urban expansion. This suggests that the path towards greener cities is increasingly paved by relatively old endeavours but that the dual purpose of development and conservation has not yet been resolved. Forest coverage trends varied, with complete afforestation areas but also urban sprawl, resulting in losses. You will learn about the loss of green areas and forests, especially in urban parts with rapidly growing cities, as urbanisation results in the loss of green space and the fragmentation of forests.

This study also identifies gaps in policy and management. Policies already exist to help expand green space and conservation, although enforcing these policies can be a challenge, particularly when it comes to balancing economic development and conservation. As climate change and the urban heat island effect become increasingly pronounced, sustainability considerations and awareness are critical, and better green infrastructure and planning measures are needed. Overall, the results demonstrate that urban planning needs to adopt an integrated view that safeguards ecological conservation and helps urban centres reach sustainability targets. Research opportunities include investigating techniques for improving the resilience of urban areas and understanding the implications of environmental greening on urban planning.

Between the years 2002 and 2022, the forest coverage and green space per capita in parks in major cities in Sichuan Province have increased significantly (

Table 5. Changes in forest coverage and per capita park green space in selected Sichuan cities (2002–2022) [25].

City	Forest Coverage (%) 2002	Forest Coverage (%) 2022	Change (%)	Green Space per Capita (m2) 2002	Green Space per Capita (m2) 2022	Change (m2)
Chengdu	36.5	40.2	3.7	9	14.5	+5.5
Mianyang	38	41	3	8.5	13	+4.5
Zigong	35	38.5	3.5	7.8	12	+4.2
Panzhihua	34	37.5	3.5	8	12.5	+4.5
Deyang	36	39.5	3.5	8.2	13	+4.8

). For example, the forest coverage in Chengdu City increased from 36.5% to 40.2%, and the green space area per capita increased from 9.0 to 14.5 m², which is an increase of 3.7% and 5.5 m².

In addition, the spatial regression analysis showed a significant negative correlation (r = −0.61) between the urban population density and green space accessibility, especially in areas with rapid urban expansion. This finding emphasises the importance of rationally planning the distribution of green space during rapid urbanisation to ensure residents’ quality of life and sustainable urban development.

In summary, this study reveals the trends of urban green space and forest coverage in Sichuan Province through long-term data analysis and spatial modelling, which provide a scientific basis for formulating and optimising urban greening policies.

5.2. Policy Recommendations

Based on the study findings, several policy recommendations can be made to enhance urban sustainability in Sichuan. First, it is important to strengthen the protection and expansion of urban green spaces. Rapid urban expansion has increased the urban green space coverage in some cities but decreased it in dense urban centres (Table 5). Policies should focus on increasing green spaces, such as parks and green areas, in urban areas to improve urban ecosystems and provide habitats for biodiversity. For example, Chen et al. [17] highlighted the importance of urban green spaces in enhancing ecological resilience. In addition, Zhang et al. [14] stated that farmland-to-forest programmes are effective in forest restoration and biodiversity protection. Therefore, similar programmes should be continued and expanded to increase forest coverage and improve the ecological environment.

Second, policies should address the challenges posed by urbanisation and its impacts on green and forested areas. Urban expansion leads to the loss of green spaces and the fragmentation of forested areas, especially in rapidly growing cities. To mitigate these impacts, urban planning should incorporate green infrastructure into the overall development strategy. This includes establishing ecological reserves and implementing regulations to prevent the further loss of green spaces. Liu and Chen [19] highlighted the need to develop a unified urban greening policy that takes into account biodiversity indicators and the carbon capture potential. In addition, public participation and awareness efforts are essential to encourage community participation in green space management and promote sustainable urban development.

The findings have important implications for policymaking and practical actions to enhance urban sustainability. It is recommended that policymakers prioritise protecting and expanding urban green spaces. This can be achieved by creating more parks, green corridors, and rooftop gardens. For example, Chengdu’s “Park City” initiative has been successful in increasing green space and improving the air quality. Urban planners should incorporate green infrastructure into their overall development strategies. This includes establishing ecological reserves and implementing regulations to prevent the further loss of green spaces. In addition, public participation and awareness efforts are essential to successful green space management. Involving local communities in planning and maintaining green spaces can help ensure the long-term sustainability of the urban environment.

5.3. Implications for Climate Resilience and Carbon Neutrality

This study has important implications for climate resilience and carbon neutrality. Increasing forest coverage and urban green space contributes to an improved carbon sequestration and ecological resilience. Urban green spaces and forests play an important role in mitigating the impacts of climate change by reducing the urban heat island effect and improving air quality. For example, Zhang et al. [14] highlighted the importance of urban green space in improving carbon sequestration and sustainability. The findings suggest that expanding green space and forests can help cities achieve carbon neutrality goals by increasing carbon stocks and reducing greenhouse gas emissions. Furthermore, this study highlights the need for a cohesive urban greening policy that considers biodiversity indicators and the carbon capture potential. Liu and Chen [20] highlighted the importance of integrating green infrastructure into urban planning to increase climate resilience. By creating more green spaces and protecting existing forests, cities can increase their ability to adapt to climate change and mitigate the effects of urbanisation. The findings also highlight the importance of citizen participation and awareness, which promotes sustainable urban development and enhances efforts to achieve climate resilience. Future research should focus on exploring innovative strategies to increase carbon sequestration and climate resilience through green infrastructure.

5.4. Future Research Prospects

This study also provides a basis for future research. Several key areas are proposed for future research (

Table 6. Suggested future research areas.

Research Focus	Description
Remote Sensing and GIS Analysis	Utilise advanced spatial analysis tools to track real-time changes in green space and forest coverage.
Carbon Sequestration and Climate Impact	Assess the role of urban green spaces and forests in mitigating carbon emissions and climate change.
Comparative Policy Analysis	Study green space policies across different cities and regions for best practices and effectiveness.
Biodiversity and Ecosystem Services	Examine how urban forests and green spaces contribute to biodiversity conservation and ecosystem benefits.
Public Participation and Urban Planning	Investigate community engagement strategies in urban green space management and decision-making.

). First, remote sensing and a GIS analysis should be utilised to track real-time changes in green spaces and forest coverage. This will provide more accurate and timely information on the impacts of urbanisation and climate change on ecological landscapes. Li et al. [4] highlighted the importance of advanced spatial analysis tools to evaluate urban forest carbon sequestration. Future research should focus on developing more sophisticated models to predict and monitor green space and forest changes.

Secondly, there is a need to further explore the role of urban green spaces and forests in carbon emissions and climate change mitigation. Fan et al. underscored the significance of green infrastructure in climate adaptation. Future research should evaluate the carbon sequestration capacity of different types of green spaces and forests and consider measures to enhance their carbon storage capacity [11]. Moreover, a comparative analysis of policies across different cities and regions can facilitate the identification of optimal practices and enhance the efficacy of policies. This underscored the necessity for a cohesive urban greening policy that incorporates biodiversity indicators and the carbon capture capacity.

Future research should focus on several key areas to further understand the impact of green infrastructure on urban sustainability. One potential area is the long-term impact of green infrastructure on urban sustainability. This includes studying the long-term impact of green spaces on air quality, biodiversity, and climate resilience. Another area is the effectiveness of different policy measures. Researchers could evaluate the success of different policies that promote green infrastructure development and identify best practices. Finally, the role of public participation in green space management deserves more attention. Future research could explore ways to involve local communities in planning and maintaining green spaces and evaluate the impact of public participation on the success of green infrastructure projects.