Transformative Power of Urban Green Spaces: Global Insights and Chinese Perspectives

(USA) William C.Sullivan,JIANG Bin

1 Background

Over the past three decades,a compelling body of research has unfolded around the profound impact that green landscapes have on human health and well-being[1-3].This transformative work has been led by landscape architects,researchers,and community members alike.Landscape architects design these green spaces not merely as aesthetic elements[4]but as vital components of public health and urban planning.The multifaceted importance of green landscapes has been rigorously investigated across numerous disciplines,resulting in an enriched,nuanced understanding of their impacts on human health.But with so many studies and so much information demanding our attention,it is nearly impossible to keep up.

2 Key Questions

What is the state of our understanding of the impact of urban green spaces on human health and wellbeing? What are the pressing questions that must be addressed next to create healthier individuals,families,communities,and nations?What do the specific conditions in China suggest about the most important research questions regarding green landscapes and human health and wellbeing need to be addressed next?

Below,we address each of these questions and end with a call to action for landscape architects who are primarily researchers and for those who are primarily designers.

3 The Multidimensional Impact of Green Urban Landscapes

Thousands of studies have demonstrated the physical,psychological,social,and mental health benefits of interacting with green landscapes.Considering the compelling evidence,it's clear that urban green spaces are much more than aesthetic choices;they are a cornerstone of public health,social cohesion,and sustainable living.Landscape architects wield a powerful tool set that extends far beyond beautification,encompassing therapeutic design,economic support,and climate resilience.Therefore,our role is critical in interpreting and shaping human-nature relationships;an endeavour that has direct implications for mental health,social fabric,physical well-being,child development,and the economic vitality of communities.

Let's begin with mental health.Hundreds of studies have demonstrated the psychological benefits of interacting with green landscapes.The positive impact on stress reduction[5-7],mood enhancement[8],and improved capacity to recover from cognitive fatigue[9-10]is well-documented.There is growing evidence that exposure to green spaces can reduce some of the symptoms of depression and anxiety[11-13].Green spaces can also promote residents' mental health by eliciting positive emotions and enhancing community safety[14-16].

One of the most universally applicable benefits of green spaces is their role in aiding recovery from cognitive fatigue,a phenomenon experienced by individuals across nearly the entire lifespan.Cognitive fatigue,sometimes referred to as mental fatigue,is a common byproduct of our increasingly busy and technologically driven lives[17-18].It manifests as reduced attention span,diminished effectiveness in problem-solving,and a general sense of mental exhaustion.Research has shown that even brief interactions with nature can result in significant improvements in attentional functioning and mental clarity[19-20].This is not merely a ＂feelgood＂ factor;it has tangible implications for productivity,emotional well-being,and even longterm mental health[21].

Regarding social cohesion,landscape architects have been pivotal in designing spaces that foster community-building and social equality.Urban green spaces encourage social interaction,foster a sense of belonging,and promote social equity,aligning perfectly with broader public health objectives[22-24].The understanding that landscape architects bring to the ways in which spatial elements influence behaviour provides a cornerstone for public health strategies that transcend traditional medical interventions,thereby promoting social equity.

Research has shown that the distribution of green spaces affects mental health differently across socioeconomic groups.Enhancing green spaces in economically and socially less developed areas can reduce psychological stress,a benefit that may be more muted in densely populated and compact urban centers[15-16,25].Interestingly,the therapeutic impact of green spaces on mental health can be greater in central urban areas than in suburbs[26].Furthermore,disparities in green space access correlate with varying levels of health inequality.Areas with more green space tend to show reduced health disparities related to low income and all-cause mortality[27].

The role of green spaces in promoting physical health is also evident.Green spaces contribute to increased physical activity,reduced obesity rates,and lower risks of chronic conditions[28-30].They also enhance immune function[31-32]and the diversity of human microbiota[33-34].Regarding child development,the influence of green spaces is unmistakable.Regular exposure to green environments fosters cognitive,physical,and emotional growth,enriching the lives of our youngest citizens[35-37].There is also growing body of research demonstrating that urban green spaces support the health and functional fitness of aging individuals[38].When landscape architects create well designed places that improve accessibility and mobility,older adults can enjoy the health and social benefits of green landscapes as they age[39].

Landscape architects frequently collaborate with healthcare professionals in the creation of therapeutic landscapes,tailoring green spaces to meet specific health needs.This includes designing healing gardens in hospitals and sensory gardens in dementia care facilities,where green landscapes significantly complement medical treatment[40].In the educational sector,landscape architects have become instrumental in integrating green spaces into school environments.These outdoor learning areas facilitate experiential learning,contributing to students' academic success and fostering a commitment to environmental care[35,41-42].Additionally,urban green spaces are recognized for their economic contributions to communities.The work of landscape architects not only enhances property values but also supports local businesses,thus serving as a socioeconomic force that links ecological and economic wellbeing[43-44].One final example concerns the role that urban green spaces play in creating more climate resilient cities.Landscape architects employ innovative designs that serve as natural defences against climate-related threats such as heat islands effect and flooding[45-47].For example,by strategically allocating urban green spaces to provide shade,adjust water evaporation,and reduce surface radiation,it is possible to increase air humidity,thereby aiding in the regulation of extreme temperatures during both daytime and nighttime[45-47].Many studies demonstrate that green landscapes are not merely aesthetic choices but critical infrastructure for sustainable living[48].

By recognizing the seminal role of landscape architects in both designing these spaces and understanding their impacts,we can appreciate the complexity and essential nature of green landscapes.This multidimensional view sets the stage for the critical questions we must address next.

4 Important Questions to Pursue

Let's examine research questions that lay the groundwork for future inquiries into the impact of green landscapes and human well-being.

First on our agenda is the question of equity in access to green spaces.As urbanization continues at a staggering pace,a pressing concern is whether the distribution of green landscapes is equitable across various social and economic demographics.This question is particularly significant because unequal access can exacerbate existing health disparities.To address this issue,it is necessary not only to comprehensively understand the structures and characteristics of green spaces through mapping their availability,their quality and features,but also to understand how different communities engage with these green spaces.We should also explore the extent to which different populations interact with green spaces during various times and seasons,as well as the types and purposes of activities that these population groups carry out.By doing so,we can consider the issues of green justice in a more comprehensive and thoughtful manner[49-50].

Shifting our attention,let us consider how much green space contact is necessary for health and welln-being[5,51-52].That is,what type of exposure to green space is necessary[53]? We need greater understanding of the impact that varying dose of urban nature might have.While it's clear that green spaces are beneficial,the specificslike size of the space,diversity of the plants and animals,and the kind of exposure-the frequency of exposure,duration of exposure,density of vegetation-are less understood[2,54].By carefully examining these variables,researchers can offer more targeted recommendations for design and planning,enriching the dialogue on what makes a green space truly ＂effective＂ for public health.

Next,we focus on the importance of longitudinal studies to understand the longterm impacts of sustained interaction with green spaces[55-56].Much of the current research provides snapshots,offering valuable but limited insights into immediate benefits of exposure to urban nature.This is particularly true for studies focusing on mental health.Although these crosssectional studies can identify correlations between green spaces and public health outcomes,longterm studies will likely unearth more subtle effects[57],such as how constant exposure to green landscapes might contribute to chronic health outcomes or even generational shifts in public health metrics.

Our next question centers on cultural specificity and its role in shaping the health impacts of green landscapes.Cultural practices and traditions can significantly modify how people interact with and benefit from green spaces[58-59].For instance,the concept of ＂forest bathing＂ in Japan provides a unique lens through which to view and experience the mental health benefits of green landscapes[60].Understanding these cultural nuances can make research more globally relevant while also uncovering new dimensions of how humans relate to their environments.

Finally,as we explore future research,an unavoidable question is how findings from this research can be translated into effective policies and public awareness,especially in varied governance structures and cultural contexts.Here,artificial intelligence (AI) offers intriguing possibilities[61].Advanced data analytics and generative AI can sift through massive sets of environmental and health data,enabling precise and timely interventions in specific landscapes.Machine learning models are on the verge of being able to predict the effectiveness of specific green landscape features,thus aiding urban planners and policy-makers in decision-making processes that are both scalable and personalized[62-64].The integration of virtual reality or augmented reality technology and AI will provide new methods for exploring the impacts of green landscapes on human health[62-64].

By addressing these pivotal questions,we will deepen our understanding of the complex relationship between green landscapes and human well-being.The aim is not merely to add to the existing body of knowledge but to fuel a transformation in how we conceive of and engage with the green spaces that enrich our lives.If this piques your curiosity,you'll find the specific conditions in China to offer a case study that's both rich and uniquely challenging.

5 Specific Conditions in China: Research Directions

In examining the impact of green landscapes on human well-being,China stands as a uniquely instructive case study.With a diverse geographic landscape,rapid urbanization,and intricate social dynamics,China offers a myriad of challenges and opportunities for scholars focused on the interplay between green spaces and human health.This section identifies key avenues for research tailored to the Chinese context.

Let's begin with the urban-rural divide intensified by China's fast-paced economic growth.There is a pressing need to study equitable access to quality green spaces within the context of this growth at the rural-urban fringe.Cities,grappling with intense competition for land,often compromise on green spaces,while rural areas,although naturally abundant,may lack the design and infrastructure to optimize these spaces for public health.Scrutinizing these disparities could result in a more inclusive approach to public health policies across different geographical settings.

As for the design elements of green spaces,a harmonious balance between ecological,aesthetic,and functional factors is essential.A focused set of studies in this area could unveil the characteristics that make green spaces not only beautiful but also practical and ecologically sound.The urban ecosystem services provided by green spaces,such as climate regulation,biodiversity,aesthetic experiences,and recreation,have significant implications for China in addressing various challenges.These challenges include issues such as land use conflict,climate change adaptation,population migration,and cultural diversification in cities[47].Insights from research in this area will aid in averting negative outcomes like aggressive planning and social inequities,as noted in recent studies[65-66].

Privatization presents another avenue for exploration.The commercial attractiveness of green spaces,ranging from waterfronts to historical sites,has led to a rise in their privatization.This trend begs the question: How does the privatization of green spaces impact public health within communities? Analyzing the health and well-being contributions of public versus private green spaces can shed light on this critical issue.The disparities in socio-economic conditions among different social groups are worth emphasizing in terms of the differential exposure to green spaces,including both structural and qualitative differences.

The conventional focus on the visual elements of green landscapes should be broadened to include sensory factors such as sound.Research could examine the extent to which urban green spaces act as buffers,contributing to overall wellbeing by absorbing noise pollution[8,67].Moreover,the concept of a soundscape extends beyond mere noise reduction.It involves preserving and cultivating natural sounds that enrich the environment and human experience.Creating multisensory landscapes,which include both sight and sound,can offer more immersive experiences.These enriched environments have the potential to reduce stress and anxiety,thereby enhancing human health and well-being across multiple dimensions[13,68].

Air quality is another critical area of interest in urban environments.Given the high levels of pollution in major cities,research into how effectively green landscapes act as ＂green lungs＂absorbing pollutants,is critical.Such studies could identify key factors,such as the variety of plant species and specific soil conditions,that optimize the air-purifying capacity of green spaces.Additionally,the scarcity of green space in densely populated cities such as Beijing and Shanghai calls for innovative solutions to efficiently purify air.Options such as rooftop gardens,vertical greening,and pocket parks present promising alternative for dense cities.Alongside these options,smart design and urban planning play an essential role in enhancing air purification efforts.

Cultural influences on green landscapes also warrant attention.The impact of traditional philosophies like Feng Shui and Qi on the design and utilization of green spaces could offer rich insights into the cultural dimensions of public health and environmental interaction[69].Although Feng Shui is not a traditional discipline or science,it was developed from long-term experiences and preferences of people in selecting and designing residential settings.The wisdom from our ancestors may possess significant academic and practical value.Still,it is important to carefully distinguish the valuable aspects from those that are not valuable and establish an effective bridge between Feng Shui evaluation and empirical research.

Finally,regarding government policies and urban planning,multiple assessments of recent urban green spaces initiatives is necessary.Here,artificial intelligence might have a role to play,offering real-time data analysis that can measure the success of greening projects and predict future challenges and potential solutions.

By exploring these diverse research directions,we can develop a comprehensive understanding of how green landscapes intersect with China's unique conditions.The objective is not merely academic,but aims to create tangible improvements in the quality of life for hundreds of millions,thereby contributing to the creation of healthier,more vibrant communities across this vast nation.So,where does that leave us.

6 A Call to Action

For landscape architects,both in academia and in professional practice,the mission is twofold.First,an urgent need exists to convert empirical research into sustainable design strategies that are not just functional but measurably beneficial.Second,there's a call for a greater role in policy development to ensure that the benefits of green landscapes are both recognized and integrated into our cities and communities on a grand scale.

The role of the landscape architect has never been more crucial.It's not just about shaping the land but about improving lives,deepening our understanding of how the built environment influences well-being,and turning that knowledge into actionable,public-good outcomes.

Acknowledgement: Thanks for the edition made by Ms.Annebella Tsz Ho Choi,Ms.Wanying Liang and Ms.Wenyan Xu.