Assessment of spatial equity of urban park distribution from the perspective of supply-demand interactions

Urban parks have been widely recognized for the critical functions they provide in enhancing health and wellbeing. However, parks are known to be inadequately provided and non-uniformly distributed in cities, leading to an increasing interest to examine spatial equity of park distribution. Such studies have mostly focused on the distributional attributes of park supply in determining spatial equity, while the role of residents’ demand is usually ignored or not adequately assessed. In addition, people’s preferences for park use were normally ignored and nearest parks were assumed as supplier of park services. Moreover, even though equity assessment is scale-dependent, few studies adopt a multi-scale assessment. We report on a study to address these gaps. A multi-scale Supply-Demand Equity Index (SDEI) was developed to assess spatial equity of park distribution from the perspective of supply and demand interactions, and data were collected at a fine scale of neighborhood level. Residents’ accessibility to their most often used parks and nearest parks were used to assess and compare supply level; while residents’ perceptions obtained from surveys and population density were used to assess and compare demand level. Results showed that supply measured by accessibility to most often used park more accurately reflects supply, and demand assessment on the basis of perception could reflect variations among different social groups and reveal otherwise hidden patterns of spatial inequity. It was also shown that SDEI could identify areas where mismatch between supply and demand occurs. We demonstrated in a single study that different definitions and approaches of quantifying spatial equity can lead to distinct conclusions, therein highlighting that the complex nature of equity requires nuanced approaches and providing a broader view of equity assessment. In addition, the implications of this study for urban park planning and management were highlighted.     

Comparing street tree assemblages and associated stormwater benefits among communities in metropolitan Cincinnati,Ohio, USA

Green infrastructure approaches leverage vegetation and soil to improve environmental quality. Municipal street trees are crucial components of urban green infrastructure because they provide stormwater interception benefits and other ecosystem services. Thus, it is important to understand the patterns and drivers of structural heterogeneity in urban street tree assemblages. In this study, we compared the forest structure of street trees across nine communities along both geographic and demographic gradients in metropolitan Cincinnati, Ohio, USA. Specifically, we used a two-part statistical model to compare both the proportion of sampled street segments containing zero trees, and basal area magnitude for street segments with trees. We made community-scale comparisons based on street tree management, socioeconomics, and geographic setting. Then, using modeled stormwater interception estimates from i-Tree Streets, we investigated the implications of heterogeneity in street tree assemblages for stormwater interception benefits. The forest structure of street trees varied across communities in relation to management practices, namely participation in the Tree City USA program. As a consequence of this structural difference, we observed a stark discrepancy in estimated stormwater interception between Tree City USA participants (128.7 m³/km street length) and non-participants (59.2 m³/km street length). While street tree assemblages did not vary by community poverty status, we did find differences according to community racial composition. In contrast to previous research, basal area was greater in predominantly black (i.e., African American) and racially mixed communities than in predominantly white communities. We did not observe structural differences across geographic strata. This research underscores the importance of proactive management practices for increasing the forest structure of street trees. Our findings regarding socioeconomics and geographic setting contrast previous studies, suggesting the need for continued research into the drivers of structural heterogeneity in street tree assemblages.     

A green infrastructure planning framework–guidance for priority,hubs and types

Green infrastructure (GI) has become an important tool to achieve sustainability and resilience in cities because of its various benefits, including stormwater management, urban heat island mitigation, air quality improvement, and carbon storage. Most existing studies have often focused on a single aspect, while few studies have incorporated the results of GI analysis into the planning process. To address this gap, we propose a planning framework to prepare the GI intervention solutions, aimed at identifying the priority actions, hubs to extract maximum multifunctionality, and preference types at the regional scale. We applied the planning framework to Wuhan city as a case study, and found an overall significant multifunctional potential. Two-thirds of the benefit pair (including spatial autocorrelation and bivariate spatial autocorrelation for benefits) relationships were found to be positive, and block areas approximately 15% of the total area were recommended as hubs to lay out the GI. Warnings should be received for evidence, revealing that industrial areas have higher requirements for GI that can alleviate the thermal environment and improve air quality. Strong positive correlations between various benefits were found in this area, especially based on a relatively large proportion of existing natural land. Further, we classified the types of GI preference by SOM (Self-organizing map neural network), and found that differentiated GI planning and strategy formulation are required by different types of regions. The planning framework provides intuitive guidance for GI intervention solution making, which can provide planners and government officials a deeper understanding of GI discourse based on clearly explained answers of important decision-making questions.     

Quantifying urban tree canopy interception in the southeastern United States

Urban stormwater is a major contributor to surface water degradation in the United States, prompting cities to invest in ways to naturally capture, store, and slowly release runoff through green infrastructure (GI). An often overlooked, yet integral, component of GI is urban tree canopy, which functions as GI through the process of rainfall interception (i.e., rainfall captured and stored within the canopy prior to returning to the atmosphere via evaporation). Nine trees from three native species commonly found in urban areas in the southeastern United States were studied in three parks in Knoxville, TN, USA to quantify interception. Throughfall (rainfall that passes through the canopy) and stemflow (rainfall that travels down the trunk) data were collected with continuous measurements by a network of automatic rain gauges positioned underneath each tree canopy. Data were collected from January 2018 to May 2019 which resulted in 98 storm events collected for each red maple (Acer rubrum) and willow oak (Quercus phellos), and 97 storm events collected for each white pine (Pinus strobus). Annually, red maples, white pines, and willow oaks intercepted 24.4%, 52.4%, and 33.2% of gross throughfall, respectively. Seasonally, white pines performed the most consistently with interception varying only from 49.2% to 57.0% between seasons compared to an interception range of 13.2–39.7% and 17.5–54.2% for red maples and willow oaks, respectively. Results demonstrated the effect of event duration, rainfall intensity, and seasonality on the interception potential of each species. Overall, these observations are a step toward allowing the storage capacity of urban trees to be properly credited as part of efforts to reduce stormwater runoff.     

Greening plans as (re)presentation of the city: Toward an inclusive and gender-sensitive approach to urban greenspaces

Cities around the world are increasingly expanding their sustainability agendas and adopting urban green and blue infrastructure planning as a strategy to become more resilient, healthy and sustainable. However, the development of urban greening governance often lacks a holistic vision that considers social inequities within the planning, implementation and management of green and blue spaces. Further, gender inequities have been a specific dimension particularly overlooked in urban greening planning, despite gender concerns gaining increasing political relevance in recent years. In this research, we assessed the extento to which social and gender equity are being considered in urban greening plans and projects at the local level. We chose Barcelona (Spain) as main case study due to its pioneering role in implementing crosscutting equity and gender policies at the municipal level. Building on document analysis and semi-structured interviews with key stakeholders, we examined how social justice and gender are understood and operationalized in practice, from the design phase to implementation and maintenance of greening projects. Our findings suggest a shift in the role of urban greening which evolved from an ornamental role to a multifunctional vision of greening and is recently incorporating equity and inclusivity concerns. We identified three action areas of inclusive, gender-sensitive urban green planning practices: first, the incorporation of inclusivity and care as guiding visible values to recognize multiple needs of city residents; second, urban design for different uses and perceptions of greenspaces, particularly in relation to accessibility and autonomy; and third, the awareness and expertise from municipal staff vis-à-vis the consideration of social and gender equity in green planning and participatory approaches. Finally, we provide practical examples of the strategies that the City of Barcelona is implementing in each area and discuss some challenges and limitations, including what we identify as ad hoc intersectional greening.     

Equally green? Understanding the distribution of urban green infrastructure across student demographics in four public school districts in North Carolina,USA

Green infrastructure (GI) provides a suite of ecosystem services that are widely recognized as critical to health, well-being, and sustainability on an urbanizing planet. However, the distribution of GI across urban landscapes is frequently uneven, resulting in unequal delivery of these services to low-income residents or those belonging to underserved racial/ethnic identities. While GI distribution has been identified as unequal across municipalities, we investigated whether this was true in public schoolyards within and among urban school districts. We examined schoolyards in four metropolitan areas of diverse socio-economic and demographic compositions in North Carolina, USA to determine if they provided equal exposure to GI, then compared whether this was true of the broader urban landscape. We first classified the land cover of elementary schoolyards and their neighborhoods, then used bivariate and multivariate approaches to analyze the relationships between GI (i.e. tree canopy cover and total GI) and the socioeconomic status and race/ethnicity of the schools and surrounding neighborhoods, respectively. We found that the extent of tree canopy cover and total GI in schoolyards was unrelated to the socioeconomic status and the race/ethnicity of students across the four school districts. In contrast, neighborhoods with lower socioeconomic status and larger populations of underserved race/ethnicity residents had less tree canopy cover and total GI. Although total GI was more evenly distributed in schoolyards, the extent of tree canopy cover and total GI in schoolyards was lower than that in the neighborhoods. This suggests opportunities for school districts to expand GI in schoolyards, leveraging their potential to increase ecosystem services to all children, from increased educational opportunities to improved mental, physical, and environmental well-being.     

Stormwater quality improvement potential of an urbanised catchment using water sensitive retrofits into public parks

Urban stormwater management is undergoing a transition from centralised hydrologically efficient systems to collections of dispersed, multi-functional elements. In response to a better understanding of impervious surface areas, the adoption of water sensitive urban design is promising for new large urban developments. However, spatial and economic constraints prohibit its adoption in established urban areas. We explore the potential for improvement to stormwater quality if 10% of existing parks in an established urban catchment are reserved for stormwater filtration. Spatially explicit hydrologic modelling is used to model the effects of parks in an existing urban catchment in South Australia as networks of bioretention devices. The allocation of 10% of parks that cover less than 16% of the landscape for bioretention devices may result in a 62% reduction (7.8 tonnes per year) of nitrogen from stormwater. The sources and destinations of stormwater pollutants are mapped to explore the strength and weaknesses of park size and distribution within each sub-catchment. Large parks situated lower in the catchment along the main trunk, and distributed smaller parks higher along the secondary stormwater network are shown to be effectively located. The potential for increasing the utilitarian value of many public parks by demonstrating the capacity for significantly improving urban stormwater quality is illustrated in this exploratory model. Opportunities for targeted improvements to stormwater quality are examined in the discussion.     

Can we integrate ecological approaches to improve plant selection for green infrastructure?

Modern cities are dominated by impervious surfaces that absorb, store and release heat in summer, create large volumes of runoff and provide limited biodiversity habitat and poor air quality can also be a health issue. Future climate change, including more frequent and extreme weather events will likely exacerbate these issues. Green infrastructure such as parks, gardens, street trees and engineered technologies such as green roofs and walls, facades and raingardens can help mitigate these problems. This relies on selecting plants that can persist in urban environments and improve stormwater retention, cooling, biodiversity and air pollution. However, plant selection for green infrastructure is challenging where there is limited information on species tolerance to heat and water variability or how these species can deliver multiple benefits. Therefore, we draw on research to illustrate how plant performance for green infrastructure can be inferred from plant attributes (i.e., traits) or from analysis of their natural distribution. We present a new framework for plant selection for green infrastructure and use a case study to demonstrate how this approach has been used to select trees and shrubs for Australian cities. We have shown through the case study and examples, how plant traits and species’ natural distribution can be used to overcome the lack of information on tolerance to both individual and multiple stressors; and how species contribute to the provision of benefits such as stormwater retention, cooling, biodiversity and air pollution mitigation. We also discuss how planting design and species diversity can contribute to achieving multiple benefits to make the most of contested space in dense cities, and to also reduce the risk of failure in urban greening.     

Negotiating the green obstacle course: Ranking priorities and problems for municipal green infrastructure implementation

This paper sets out the results of a study exploring, and ranking in order of perceived significance, the priorities and obstacles faced by smaller cities when implementing green infrastructure (GI) projects. The study captured the views of 49 municipal officers and elected representatives in cities of less than 500,000 population across four countries in northwest Europe, using a closed card sorting methodology as part of a semi-structured interview format. The results show a clear hierarchy in priorities, with particular attention paid to anthropocentric benefits to residents, especially the importance of aesthetics and liveability as a key objective in GI delivery, and the desirability of securing visible benefit to residents within the electoral cycle; longer-term objectives linked to environmental and economic challenges, although acknowledged in corporate policies, attract a lower priority when it comes to delivery, and may encounter trade-offs against other desired benefits. The greatest obstacle to GI delivery is not funding, as found in other studies, although this remains significant; rather, it is difficulty of collaborations and fragmentation within the city organisation which participants attributed to a lack of leadership and prioritisation of green initiatives. Capacity is also a clear issue, and the results highlight a lack of resources (including funding) but also skills in assembling evidence in support of projects, and staff time to bid for and deliver new GI proposals. When comparing these findings to others from larger cities, particularly those with a population over 1 million, the results suggest differences in prioritisation, critical mass, resources and capabilities and capacities influencing GI implementation, these are important to consider as they may prevent transferability of GI best practices from larger cities, who tend to be more active and innovative, to smaller scale cities. Co-production of knowledge, could offer considerable potential to improve GI implementation, but the design of any such schemes should recognise the issue of capacity by providing resources to allow participation of practitioners in smaller municipalities. Finally, respondents highlighted increasing environmental awareness of local communities and whilst the effect of this is yet to be seen, this was considered as having considerable potential in improving GI implementation in smaller municipalities.     

A systematic review on the ecosystem services provided by green infrastructure

Urbanization and climate change are endangering the sustainability of public spaces through increased land artificialization, ecological fragmentation, reduced resource availability, and limited accessibility to natural and seminatural areas. Properly managing Green Infrastructure (GI) can contribute to mitigating these challenges by delivering multiple provisioning, regulating, supporting and cultural Ecosystem Services (ES). This would facilitate the implementation of strategically planned GI networks in cities for urban regeneration purposes. In this context, this study developed a systematic review on the ES provided by GI using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. The analysis of 199 eligible articles indicated that more efforts should be made to address more ES at once, which connects to the need for conceiving GI as a strategically planned network of areas aimed at delivering diverse benefits. Based on the methods used in the items reviewed, geoprocessing tools and multi-criteria decision analysis are proposed to develop systems of indicators capable of accounting for multiple ES. These systems should also rely on multidisciplinary and participative procedures to encompass various facets of GI and represent the priorities of all relevant stakeholders.     

How the COVID-19 pandemic changed patterns of green infrastructure use: A scoping review

The use of green infrastructure (GI) has been established as a way to alleviate stress and the COVID-19 pandemic has placed a new emphasis on the importance of GI as both a coping mechanism and a source of recreation. This scoping review seeks to address whether the COVID-19 pandemic affected the use of GI, specifically the ways in which the pandemic altered visitation patterns and the frequency of the use of GI. This review identifies studies that explore the relationship between the COVID-19 pandemic and GI use and assesses whether the pandemic has altered the use of GI, including whether GI use increased, decreased, or remained the same and examines potential changes in visitation structure as well as other effects studied. This review also discusses how future planning for GI can consider the lessons learned from the pandemic. Key findings suggest that GI use increased, as did visitors’ appreciation for GI and its benefits. The use of local GI to one’s home also increased in importance. Decreases in visitation were typically a result of COVID-19 lockdown restrictions and fear of viral transmission within GI.     

Estimating the willingness to pay for green space services in Shanghai: Implications for social equity in urban China

The willingness to pay can be considered as the fiscal dimension of equity in a planning context. The common solution in most western countries for such fiscal inequity is to apply taxation to rebalance; however, there is no equivalent tax category in China, where residential segregation has already occurred and intensified. This paper re-examines the traditional economic aspects of urban green space in relation to size, type and proximity level, and questions whether green fiscal equity appeared in China by exploring how homebuyers in different price ranges value green space services. Specifically, this paper uses the empirical case of Shanghai, China, to test the hypothesis via the quantile hedonic approach. The results show that people at the lowest percentile level paid a higher value for accessing urban public goods than people at the higher income percentiles, and that wealthy people prefer to purchase green space services privately. These results indicate that the traditional social equity problem may not appear in the Chines context, instead urban China’s problem with social quity may be more related to the privatisation of green space provision, which is only accessible to homeowners and the resulting decline of public green space developments, which primarily affects low-income renters.     

Can green roofs help with stormwater floods? A geospatial planning approach

Increasing urbanization, impervious space, and the impact of climate change are threatening the future of cities. Nature-based solutions, specifically urban green infrastructures, are seen as a sustainable strategy to increase resilience against extreme weather events, including the escalating occurrence of stormwater runoff flooding. Consequently, urban planners and decision-makers have pushed their efforts toward implementing green infrastructure solutions to reduce the impact of stormwater floods. Among others, green roofs help store water and decrease stormwater runoff impacts on a local scale. This research aims to investigate the effect of surface permeability and green roof implementation on reducing stormwater flooding and subsequently provide urban planners with evidence-based geospatial planning recommendations to improve urban resilience in Helsinki. First, we modeled the current impact of stormwater flooding using the Arc-Malstrom model in Helsinki. The model was used to identify districts under high stormwater flood risk. Then, we zoomed in to a focus area and tested a combination of scenarios representing four levels of green roof implementation, two levels of green roof infiltration rates under 40-, 60-, 80-, 100 mm precipitation events on the available rooftops. We utilized open geographic data and geospatial data science principles implemented in the GIS environment to conduct this study. Our results showed that low-level implementation of green roofs with low retention rates reduces the average flood depth by only 1 %. In contrast, the maximum green roof scenario decreased most of the average flood depth (13 %) and reduced the number of vulnerable sites. The proposed methodology can be used for other cities to develop evidence-based plans for green roof implementations.     

Challenges of urban green space management in the face of using inadequate data

Effective urban planning, and urban green space management in particular, require proper data on urban green spaces. The potential of urban green spaces to provide benefits to urban inhabitants (ecosystem services) depends on whether they are managed as a comprehensive system of urban green infrastructure, or as isolated islands falling under the responsibility of different stakeholders. Meanwhile, different urban green space datasets are based on different definitions, data sources, sampling techniques, time periods and scales, which poses important challenges to urban green infrastructure planning, management and research. Using the case study of Lodz, the third largest city in Poland, and an additional analysis of 17 other Polish cities, we compare data from five publicly available sources: 1) public statistics, 2) the national land surveying agency, 3) satellite imagery (Landsat data), 4) the Urban Atlas, 5) the Open Street Map. The results reveal large differences in the total amount of urban green spaces in the cities as depicted in different datasets. In Lodz, the narrowly interpreted public statistics data, which are aspatial, suggest that green spaces account for only 12.8% of city area, while the most comprehensive dataset from the national land surveying agency reveals the figure of 61.2%. The former dataset, which excludes many types of green spaces (such as arable land, private and informal green spaces), is still the most commonly used. The analysis of the 17 other cities confirms the same pattern. This results in broader institutional failures related to urban green infrastructure planning, management, and research, including a lack of awareness of green space quality (e.g. connectivity) and benefits (ecosystem services), and the related political disregard for urban green spaces. Our comparison suggests that a better understanding of green space data sources is necessary in urban planning, and especially when planning urban green infrastructure.     

消费者视角下的北京农产品品牌资产研究——以“小汤山”蔬菜为例

为了能够完善北京农产品品牌资产的建设、提升和维护,故选择“小汤山”蔬菜作为测试品牌进行实证研究。通过构建品牌资产模型来研究消费者视角下的北京农产品品牌资产的构成因素和影响,利用Pearson相关系数进行相关性分析,从而得到消费者视角下的北京农产品品牌资产由品牌认知度、区域联想、品牌感知和品牌忠诚4个维度构成,且存在一定相关关系,共同作用、影响着品牌资产。最终研究表明,北京农产品品牌资产的提升,需要其进一步提高品牌知名度,增加品牌的区域联想,加强消费者对农产品的品牌感知,从而让消费者形成品牌忠诚,最终使得农产品品牌资产得到提升,促使企业获得营收。     

Landscapes Toolkit: an integrated modelling framework to assist stakeholders in exploring options for sustainable landscape development

At present, stakeholders wishing to develop land use and management change scenarios at the landscape scale and to assess their corresponding impacts on water quality, biodiversity and economic performance, must examine the output of a suite of separate models. The process is not simple and presents a considerable deterrent to making such comparisons and impedes the development of more sustainable, multifunctional landscapes. To remedy this problem, we developed the Landscapes Toolkit, an integrated modelling framework that assists natural resource managers, policy-makers, planners and local communities explore options for sustainable landscape development. The Landscapes Toolkit links spatially-explicit disciplinary models, to enable integrated assessment of the water quality, biodiversity and economic outcomes of stakeholder-defined land use and management change scenarios. We use the Tully–Murray catchment in the Great Barrier Reef region of Australia as a case study to illustrate the development and application of the Landscapes Toolkit. Results show that the Landscapes Toolkit strikes a satisfactory balance between the inclusion of component models that sufficiently capture the richness of some key aspects of social-ecological system processes and the need for stakeholders to understand and compare the results of the different models. The latter is a prerequisite to making more informed decisions about sustainable landscape development. The flexibility of being able to add additional models and to update existing models is a particular strength of the Landscapes Toolkit design. Hence, the Landscapes Toolkit offers a promising modelling framework for supporting social learning and adaptive management through participatory scenario development and evaluation as well as being a tool to guide planning and policy discussions at the landscape scale.     

Optimizing urban green space patterns to improve spatial equity using location-allocation model: A case study in Wuhan

Green space allocation aims to support the UNs sustainable development goals (SDGs) and to mitigate the conflicts between supply and demand. Previous studies have shown that the uneven distribution of populations and natural locations of green space results in environmental inequity. However, there is still a lack of knowledge on strategies for reducing mismatches of supply and demand by optimizing spatial patterns in highly dense cities. Developed urbanized areas are featured in fewer spaces for greening. In this study, we set three scenarios for coordinating the provision and demand of urban green spaces at a block scale. Taking the main city of Wuhan as an example, we apply the location-allocation model in order to identify potential sites for new green spaces. Then, the simulations of the three scenarios are used to depict various development strategies by evaluating the improvement of green equity. Our results show that the levels of green space accessibility are lower on the west side of the city center, while relatively higher on the east side, due to abundant natural resources. The Gini coefficient is 0.715, indicating unequal access for citizens to green space. Increasing green areas could enhance green equity, and the most effective way to allocate new increments is based on the accessibility. For developed cities, blocks with lower accessibility should be given priority when increasing green areas; doing so could offset the shortage of large green areas and reduce green inequity within daily walking distances. Optimal green space planning of small and functional parks near communities has the potential to meet higher recreational demands in densely populated areas.     

Understanding how built urban form influences biodiversity

This study seeks to contribute to a more complete understanding of how urban form influences biodiversity by investigating the effects of green area distribution and that of built form. We investigated breeding bird diversity in three types of housing development with approximately the same amount of tree cover. No significant differences in terms of bird communities were found between housing types in any of the survey periods. However, detached housing, especially with interspersed trees, had more neotropical insectivores and higher overall diversity of insectivores. Based on our results and theory we suggest a complementary approach to managing biodiversity in urban landscapes – instead of maximising the value and quality of individual patches efforts could go into enhancing over-all landscape quality at the neighbourhood scale by splitting up part of the green infrastructure. The relatively small differences in bird communities also suggest that different stakeholder groups may be engaged in management.     

Aligning fragmented planning structures through a green infrastructure approach to urban development in the UK and USA

Globally green infrastructure (GI) planning has developed with alternative conceptual and implementation viewpoints. In the UK and USA this has led to the establishment of a dual narrative; one identifies a set of conceptual principles within the wider global GI debate, whilst the second focusses on localised interpretations of these principles within divergent delivery approaches. Such plurality adds a level of complexity to the development of GI policy and subsequent investments, which can be understood if both narratives are debated simultaneously. A number of factors have influenced this process; the most prominent being the dislocation between GI policies, practice and funding. This paper addresses this fragmentation proposing that a ‘policy-implementation’ gap exists within national and sub-national planning practice which limits the transferability of global principles into delivery. Therefore although the conceptual understanding of GI is grounded in the global literature, greater variability is evident in the application of these principles within localised (i.e. national, regional and sub-regional) planning. The paper extends this debate through a discussion of whether a consensus for the conceptual advancement and implementation of GI is a necessary aim of its development. It concludes that such plurality of understanding is both a positive and negative attributes of GI planning, highlighting the complexity of attempts to align global and local development narratives for GI.