Urban Open Space Systems and Green Cities: History, Heritage, and All That

Abstract

More than half the world’s population live in cities1. According to UN Habitat, we are rapidly approaching the time when five billion people will live in cities, and by 2050 this could be 7.5 billion, with much of the growth concentrated in the global south. The context for this paper is how urban growth is linked to notions of community values which cross-link to concepts of heritage. Urban places are where the majority of the world’s population lives and will increasingly do so. Inextricably linked to this proposition is that urban places are where community memories, identity and sense of place are inherent, and here is the link with heritage. What do these paces mean to us? Are there regional, national and international differences? Parallel with these ideas of urban heritage is the sense of place and attachment people have for green spaces in cities and the incremental loss of green spaces. This prompts the question of how this phenomenon has stimulated scholarly and professional attention on the concept of greening cities. Underpinning the inquiry is an understanding of how urban green growth has become regarded as critical to the well-being of people in urban areas. Central to such concerns is the role of people and their social and cultural values which shape how they see their cities. Notable also is how there has been growing concern for urban conservation since the 1990s and the need to understand cities as people spaces, not just collections of buildings. Discourse on cities as spaces for people has its roots in, and builds on, a paradigm shift in innovative thinking and concepts in the twentieth century which has continued into the twenty-first century. Mindful of this background, the paper opens with a review of the historical background to these concerns on the premise that the past is not always a foreign country2. It then moves into consideration of heritage values and the role of landscape and what we mean by values. This consideration is central to the paper and moves into an overview of the Historic Urban Landscape (HUL) approach as new approaches and tools for urban conservation came into play.

1. Introduction: Retrospective Overview

“What’s past is prologue.”

Shakespeare, The Tempest, The Tempest, Act 2, Scene I.

1.1. Is the Past a Foreign Country: History and/or Heritage?

When we want to know where we are heading, it is useful to understand where we have come from. This premise and the proposition that the past is prologue suggest that history sets the context for the present. My point here at the opening of this paper is that it is important to understand how the past informs the present and conjectures on the future. Contrary to this point of view, the past is a foreign country, as Hartley [1] proposed, where they do things differently there. Whether the past is indeed a foreign country is very much open to question as a dilemma of interpretation with many twists and turns. It is a question that is extensively probed by Lowenthal [2] in ‘a searching exploration of the way societies treat and understand the past’ [3], probing not just the actions of our predecessors but also their feelings/experiences and how these may influence our thoughts and actions.

Whether there is an unequivocal answer on the proposition that yes, the past is a foreign country, or no, it is not3, discourse on the premise suggests an intriguing enigma where there are variations, as in Elgar’s famous orchestral work consisting of 14 variations on an original theme4. In this context, Lowenthal [4] claims that ‘awareness of the past is essential to the maintenance of purpose in life. Without it we would lack all sense of continuity, all apprehension of causality, and all knowledge of our own identity’. Nevertheless, he issues the warning that ‘the past is not a fixed or immutable series of events; our interpretations of it are in constant flux’. History and its interpretations inform how David Lowenthal [5] addresses a penetrating discussion on variations between history and heritage—what they are and what they are not:

“In domesticating the past we enlist it for present causes… (this) aligns us with forebears whose virtues we share and whose vices we shun. We are apt to call such communion history, but it is actually heritage. The distinction is vital. History explores and explains pasts grown ever more opaque over time; heritage clarifies pasts so as to infuse them with present purposes.”

In contending that history and heritage are not synonymous, Lowenthal further proposes that it is heritage that passes ‘on exclusive myths of origin and continuance’ [5]. In this context, therefore, heritage is understood as a process that is intimately connected with the cultural values associated with an understanding of the relationships between people, places and events through time that we deem to be important or significant. In this sense, heritage is to do with intangible aspects of life related to how identities are formed over time and the link between people, events and places. The concept of heritage and its geography also relates to the ways in which society uses the past as a social, political or economic resource. However, heritage is open to interpretation, and its value may be perceived from differing perspectives related to identity formation [6]. Nevertheless, the difference between the cultural and economic uses of heritage may lead to conflicts of interest. Addressing these differences is one of the dilemmas of heritage management in that the construct of heritage is firmly rooted in an understanding of people’s values which are subjectively based and cannot be objectively proved. Notable also is that such an approach to heritage is by no means lionised by focusing on the rich and famous, as with the 1960s and 1970s monuments and sites mindset. This mindset saw emerging criticism of the heritagisation process, where the notion of heritage was seen to reside predominantly and physically in famous monuments and sites—and substantively monuments and sites of the Classical (Old) World—as works of art, as expressed in the now outdated 1964 Venice Charter5. It was also manifested in the concept of universal heritage and associated universal values, as in UNESCO The World Heritage Convention of 1972 [7]. These changes materialised and suffused thinking in the late 1980s/early 1990s, as, for example, in the recognition by UNESCO in 1992 of three categories of cultural landscapes: (i) clearly defined landscape designed and created intentionally by man; (ii) organically evolved landscape (relict and continuing); and (iii) associative cultural landscape (see endnote 9) and in ICOMOS 1994, The Nara Document on Authenticity [8], which specifically challenged conventional thinking in the conservation field by, for example, recognising the international diversity of cultures and heritage as an irreplaceable source of spiritual and intellectual richness. Coincidental has been the broadening of concern with culture and the intangible rather than focusing primarily on things. In the shift away from a concentration on monuments and sites, Logan [9] suggests there has been a widening of the understanding of heritage to include:

”Precincts, historic urban centres, whole towns and villages, cultural landscapes, and historic urban landscapes, associative values and intangible heritage—the talents embodied in people, such as artistic skills in dance, music and painting, or skills in language, or craft and construction skills.”

Notably, in the attitudinal changes, the ordinary became a cause for heritage celebration, what Sexson [10] nicely calls ‘the ordinarily sacred’. Berliner [11] suggests that a modern focus on heritage is because:

“Heritage is a crucial value in the world today. This is reflected in the fact that all over the globe, humans share the catchy idea that something from the past, often from their past, must be institutionally preserved for future generations. There is very little opposition to it (although there are conflicted views on what should be preserved), and almost everybody nods of (sic) approval to the necessity of heritage… Most researchers in this field—myself included—attempt to show that, around the world, groups of people interact diversely with patrimonial productions, from their own perspective, and engage in culturally contingent heritage experiences.”

Accordingly, the question we need to ask, and one that is inherent in the concept of the past as prologue, is how has the past set the stage for our thinking and actions? Such a question should prompt also a consideration of people’s values and spirit of place associated, for example, with urban settings6. Further, it is important to remember that the past is not just back in the distant annals of history. The recent past can be equally significant where its recency is no impediment to its study [12]. Notable here is that values and spirit of place reside as much in the meaning and symbolism of places as in tangible physical fabric [13,14]. Inevitably, and rightly so, such concerns as people’s values and sense of place cross-engage with approaches and research directions in heritage management, understanding cultural significance of places, and, notably, the role of landscape [15]. The link between heritage and landscape is concisely interpreted by Harvey [16]:

“The recent histories of heritage and landscape studies appear to be closely linked, with their epistemological, ideological and methodological twists and turns progressing amid a common broad intellectual and interdisciplinary space… Heritage and landscape are two concepts that appear to have sat comfortably together within academic, policy and popular imaginations for some time.”

1.2. Role of Landscape

The role of landscape is introduced at this point because people see and make landscapes as a result of their shared system of beliefs and ideologies [17]. In this way, ‘landscape is a cultural construct, a mirror of our memories and myths encoded with meanings which can be read and interpreted’ [18]. The inimitable J. B. Jackson declared landscape ‘a rich and beautiful book [that] is always open before us. We have but to learn how to read it’ [19]. In addressing the cultural landscape construct, he particularly focused attention on the significance of the vernacular–everyday–landscape, as ‘identified with local custom, pragmatic adaptation to circumstances related to vernacular culture’ [which] would imply a way of life ruled by tradition and custom [20]. Wang et al. [21] suggest that Jackson’s ‘key message here is that cultural landscapes should not be seen as a static entity’ and that he thereby ‘emphasised the contemporary as well as the historical importance of engaging with people in a place’. Fundamental to understanding the significance of the cultural landscape paradigm in urban conservation is the fact that landscapes are not static entities. They change through time, resulting in us being able to recognise layers in the urban landscape.

Quintessentially, cultural landscapes need to be seen as living history/living heritage, as critically examined by Poulios [14,22], not dead history, including the history of ordinary everyday people. Here is the (cultural) landscape physically reflecting the process of place-making through time, replete with human associations anchored in ideologies, values, and meanings, leading in turn to a sense of place and identity. It represents, as discussed at length by Harrison, a cultural view of the human setting which keeps ‘the past alive in the present for the future’ [23]. Extending the discourse into urban settings, J. B. Jackson [24] elegantly summarised the concept of an urban sense of place and identity with the observation that:

“Most of us, I suspect, without giving much thought to the matter, would say that a sense of place, a sense of being at home in a town or city, grows as we become accustomed to it and learn to know its peculiarities. It is my belief that a sense of place is something that we ourselves create in the course of time. It is the result of habit or custom.”

Lowenthal subsequently revisited the topic of the past in The Past is a Foreign Country—Revisited [25], incorporating extensive additions of new material and updates. He unequivocally sets out in the opening sentences of the introduction the fundamentals of the book:

“The past is everywhere. All around us lie features with more or less familiar antecedents. Relics, histories, memories suffuse human experience. Most past traces ultimately perish, and all that remain are altered. But they are collectively enduring (my emphasis). Noticed or ignored, cherished or spurned, the past is omnipresent. “What is once done can never be undone… Everything remains forever somewhere here” wrote Václav Havel7. The past is not simply what has been saved; it “lives and breathes… in every corner of the world” adds a historian8”

The intellectual range and aim of the book are set out in a review [3] with contributions by A. B. Murphy, M. Price, D. C. Harvey, D. DeLyser and a response from David Lowenthal. Murphy et al. in the opening comments reflect that the book is ‘a work of extraordinary breadth and depth… Lowenthal’s goal is to explore various ways in which the past has been conceptually appropriated and deployed over space and time. The value of such an effort lies in the insights it provides into the importance of the relationship human societies develop with the past’. In his inevitable but thought-provoking modus operandi, Lowenthal has the last word on the reviews of his book. Here, he suggests he is ‘loath to align my capacious past (DeLyser) with critical discourse analysis, the postmodern rehash of seventeenth-century skepticism (sic) that faulted all history as faked. In my tenth decade I find more congenial geographer Caitlin DeSilvey’s insight that “we are never ‘post’ anything but… carry our inherited (and invariably moldy [sic]) ideas with us” into how we read and react to ever-changing modes of being. The future is no freestanding novelty; rather, wrote the Russian reformer Alexander Herzen, it is “a variation improvised on a theme of the past”.

2. Values

The concept of values that people associate with places is central to this paper and discussion on thinking relating to urban places. Underpinning such a statement and approach is the understanding that the study process of, and commentary on, urban places is not concerned primarily with the old and famous. It applies equally to ordinary, everyday places as embodied, for example, in cultural landscape thinking and cultural values [26]. Regarding values, Avrami and Mason [13] contend that values-based approaches to understanding places and their cultural meanings should be context responsive and culturally specific. Underscoring concerns for values has to be guided by the question of whose value are we, or should be, addressing [22,27].

Relevant also is that over the last three decades a considerable discourse on the values of heritage has increasingly taken place among heritage professionals, in governments, and within communities. This discussion has sought to advance the relevance of heritage to dynamically changing communities and forge a shared understanding of how to conserve and manage it. Values-based heritage conservation aims to retain the cultural significance of places, typically by balancing the aesthetic, historic, scientific, spiritual, social and economic values held by past, present, and future generations. Coincidentally, within the field of cultural heritage conservation, increasing international interest and attention over the past three decades have been focused on urban areas. This is timely because the pressure for economic development and for the prioritising of engagement with the global economy have accompanied rapid urbanisation. In turn, economic development has privileged modernisation efforts leading to the loss of traditional communities. Accompanying this in the 1970s and 1980s was a concentration in the field of urban conservation on famous buildings and monuments rather than seeing cities as communities of people with values and belief systems that are reflected in a city’s overall setting: its cultural landscape9.

Changes in understanding that urban conservation involved more than a focus on famous architectural and archaeological sites gradually infiltrated urban conservation thinking to include community values in various international documents. The Washington Charter [28] was the first to focus on historic urban areas and their conservation [29] by linking these to spiritual elements that express character, stressing the need for involvement of residents. The Charter on Built Vernacular Heritage [30] saw vernacular heritage places as the fundamental expression of the culture of a community embracing not just physical form and fabric but also the ways in which they are used and understood and the traditions and intangible associations attached to them [31]. The Hoi An Declaration on Conservation of Historic Districts of Asia [32] was significant for addressing the conservation values of historic districts as living cultural heritage where inhabitants and users are key actors in conservation efforts. The seemingly little-known Seoul Declaration on Heritage and Metropolis in Asia and the Pacific [33] notably advises that:

“These heritage sites contribute to the life and memory of the metropolitan areas by the diversity of their uses. … Along with geographical features and the living social ecosystem, cultural heritage contributes strongly to the personality and character of the metropolis. It is a source of a truly sustainable development of the metropolitan areas in Asia and the Pacific in achieving their strategic and economic roles.”

Historic Urban Landscape (HUL)

In the early 2000s, the rethinking of what is urban heritage and conservation saw new approaches and new tools for urban conservation coming to the fore, not least in the concept of the Historic Urban Landscape (HUL) paradigm approach. HUL was ‘A major initiative in the field of conservation of urban areas, associated with change that is taking place in the world’s cities, is the concept of the HUL. It was first set out at a UNESCO conference in Vienna, May 2005 [34], and advocated in the Vienna Memorandum on World Heritage and Contemporary Architecture—Managing the Historic Urban Landscape’ [35].

The HUL paradigm was, in effect, a rethinking of the established approach to urban conservation and led to the drafting of the Memorandum in Vienna, May 2005 by the General Assembly of UNESCO in September 2005 [36]. Subsequently came The Recommendation on The Historic Urban Landscape (HUL) approach [37]. The HUL approach shifts an emphasis on urban heritage as buildings orientated to an approach focusing on urban communities and how they are reservoirs of human memory and identity with layers of significance through time, in effect envisaging cities as cultural landscapes [35]. Behind the development of the HUL paradigm is a series of timely historic paradigm shifts related to urban planning thinking and practice; these are discussed below.

3. Paradigm Shifts

Discourse on cities as spaces for people rather than just a collection of buildings has its roots in, and builds on, innovative thinking and concepts on modern urban planning and urban conservation in the latter nineteenth/early twentieth centuries. Typical is the work of Camillo Sitte, Giovanonni, Riegl, Geddes, Unwin and others ‘who show[ed] a capacity to project the modern metropolis into the future, while at the same time interpreting and valuing history and continuity’ [29]. This was then continued in the late 1960s and 1970s in the work, for example, of Gordon Cullen and Kevin Lynch (discussed below). References to spaces can be controversial in that space may be regarded as an empty volume. For this reason I suggest it is advisable to refer to places because the word ‘place’ is associated with ideas of meaning for people as critically analysed by Relph [38] in his classic Place and Placelessness. Nevertheless, Relph acknowledged the existence of various types of spaces―pragmatic, perceptual, existential, architectural/planning, cognitive, and abstract―but in doing so, he cross-relates these to a sense of place. The question, therefore, is when do spaces become places? Relph advises that ‘Space is amorphous… Yet, however we feel or know or explain space, there is always some associated sense or concept of place’. Similarly, the geographer Yi-Fu Tuan [39]10 described space as a location which has no social connections; no value has been added to it and no meaning ascribed to it. It is more or less abstract. Nevertheless, he posits that spaces become places when given human connections and meaning, either through physical interaction or in indirect, associative and symbolic ways.

Relph, quoting Camus [40], cogently cites evidence supporting his claim that the places people inhabit are marked by distinctive characteristics. In effect, these are tangible, as in the physical patterns and components of our surrounds, and intangible, as in the symbolic meanings and values we attach to places and also to objects and to traditional ways of expression such as in language, art, song, and dance. In this way, physical spaces, sites and objects become places in the wider cultural landscape setting. They offer a past, are part of the present and suggest future continuity. Such places (Figure 1) with their association of meanings which give rise to local identity and sense of place of communities [18]. Place experience can therefore be associated with public or private and personal places in the sense expressed by the novelist David Malouf, that ‘…it is ourself we are making out there’11. Public places may be crowded but can still engender an intense and memorable personal experience in the same way that private and personal places do. The geographer Yi-Fu Tuan [41] applies the word ‘topophilia’ to capture an intense and long-lasting memory of the effect a particular space or place may have on someone, be it public or private12. Overall it is possible to recognise two types of spaces: doing spaces which we can publicly experience by being in the space and seeing spaces which are essentially private or semi-private, such as a golf course. The latter are visible as we move around an urban area: they add intangibly to images we may have of a city13.

Taking the construct that the past is not a foreign country in the context of how urban spaces/places play a role in being a focal point of cultural meaning and identity, a brief sojourn into influential historical figures and their contributions to the development of modern thinking on urban form and place is appropriate.

Camillo Sitte (Austrian architect and urban theorist) in his 1889 and formulating opinions that underpin various choices of solutions in the treatment of historic buildings and artefacts’ [42]. In effect, his innovative thinking, a deeply perceptive study of the allure of heritage, was the first critical analysis of a values-based approach to conservation which informs current practice. Riegl distinguishes between two categories of heritage value [29]. First is the value of memory as it applies to appreciating the antiquity of heritage places, a factor that is accessible to all people and does not need special expertise. Second is the value of the monuments in contemporary life and their use that distinguishes them from archaeological ruins. Angkor Wat, for example, provides a model in that Angkor has a meaning and use in contemporary life for local communities who live there, not just visitors (Figure 2).

Gustavo Giovannoni (1873–1947) was an architect and urban planner with an interest in architectural and art history who was highly influential in setting in place intellectual foundations for the practice of heritage conservation. In particular, he advocated the integration of historic parts of cities into contemporary planning schemes, blending new construction with historic settings. For Giovannoni, historic monuments were not to be regarded simply as museum pieces frozen in time and devoid of contemporary meaning and use. He advocated the need for conservation of the built environment of historic monuments on the understanding that urban fabric represents layers through time [29]. His ideas and practice underpin current approaches to urban conservation, including respect for the vernacular. In his ideas and practice lies the inspiration for the Historic Urban Landscape (HUL) approach.

Others in the panoply of historic figures who laid foundations for modern thinking on urban planning include Patrick Geddes (1854–1932), Raymond Unwin (1863–1940), and Lewis Mumford (1895–1990). Geddes, for example, was an innovative thinker in the emergent field of urban planning who regarded ‘the city as an organism in evolution where physical and social components interact in a complex web of change and tradition’ [29]. In effect, these historic figures saw the city as a complete entity rather than as individual sections and were notably followed post-1945 by the work of Gordon Cullen and Kevin Lynch in the 1960s and 1970s (see below).

The rise of planning post-1945: cities as spaces and places advanced.

The end of WWII in 1945 saw a rising interest in the art and science of town planning in the English-speaking world. Indicative of this in the UK, for example, was The Town and Country Planning Act 1947. It came into effect on 1 July 1948 and was the foundation of modern town planning in the United Kingdom. Larkham and Adams outline how this Act was presaged by the Abercrombie, Greater London Plan of 1945 and that London, the UK’s largest city, had been extensively damaged during the Second World War as well as suffering from significant pre-war social, economic and physical problems [43]. At the time London was one of the world’s largest cities, the focus of an empire, of international trade, and a national capital. ‘Solving these problems was one of the world’s largest and most complex planning tasks’. Of particular note for considerations of green urban open space systems is the way in which the plan ‘was dominated by concepts of London as a community, a metropolis and a machine. One of the key novelties here was the concept and diagrammatic representation of ‘‘social and functional areas’’’, in other words, spaces as people places. Notably, these spaces included the concept of ‘linear green spaces, having—on a much smaller scale—similar features as the regional greenbelt; such linear spaces were indeed suggested in the Greater London Plan’ [43].

Two figures of note in the post-1945 era who focused on the structure of urban spaces as places for people were Gordon Cullen and Kevin Lynch. Relph [38] refers to such spaces and places as ‘existential space or lived space’14. He describes this as ‘the inner structure of space as it appears to us in our concrete experiences of the world as members of a cultural group’, which consists of sacred space and geographical space. In the context of geographical space―‘the significant space of a particular culture that is humanised by the naming of places [and] by its qualities’―he enrols the studies of townscape by Gordon Cullen [44,45] and Kevin Lynch [46] to illustrate human experiences and perspectives of urban spaces.

At this point, and before tracing the work and influence of Cullen and Lynch, it is notable that in the late 1980s/1990s, parallel with the developments in planning, came a renewed interest in the concept of making spaces into people places and also valuing ordinary places. This was inextricably linked to the burgeoning appreciation of the cultural landscape construct involving the meaning of cultural landscapes and, simultaneously, the understanding that ‘the landscape tells—or rather is—a story’ [47], thereby linking events, people and places through time. Furthermore, it became understood that cultural landscapes had close ties to broadening thinking on the heritagisation process. A 1999 paper focusing on an Australian experience of valuing ordinary places suggested that ‘a particular phenomenon of the Australian experience of valuing our ordinary places is that it is not centred solely on physical places or objects. It enthusiastically embraces the symbolism and meaning of places and associations that people have with place. It is where historic and cultural values’ [26]. Here, there are connections with Tuan’s (1977) [39] deliberations (see above). Related to this way of thinking is that ‘out there is a remarkable source of information on collective and personal place memory and how people make contact and feel connected with their landscapes’ [26] through memory and associated sense of place. Simon Schama [48] elegantly captures the role of memory in landscape making:

“Before it can ever be a repose for the senses, landscape is the work of the mind. Its scenery is built up as much from strata of memory as from layers of rock.”

Urban Form

Continuing thinking on urban form was the innovative thinking of Kevin Lynch (1960) [46] and Gordon Cullen (1960 and 1971) [44,45]. They made timely and ‘seminal contributions [to] present a fresh perspective on city building, emphasising questions about the meaning of a city’s form for its residents and how planners can enhance the city’s image to make it more vivid and memorable’ [49]. Lynch focused on the imageability of a city and its legibility for people. He used three cities (Boston, Jersey City, and Los Angeles) to gather information by interviewing inhabitants to review the mental images or pictures that people perceive as they move around the city, i.e., their conceptions of the city form. From interviews with inhabitants on the streets and sketch maps drawn by them, he proposed that what featured most in the images were paths, edges, nodes (centres), districts and landmarks and that these images are used by people to navigate their way through the city. He created for a central part of Boston (Figure 3) ‘a diagrammatic representation of its major visual elements derived from the field reconnaissance’ [46] where people navigate through the city mainly by spatial images, i.e., Relph’s existential/lived spaces. In a later book, Lynch [50], in understanding the central role of landscape in the story of people, events, and places through time, offering a sense of continuity, sees this process as representing a sense of the stream of time.

Cullen coined and introduced the concept of townscape on the basis that a city is more than the sum of its parts… which is one reason people like to live in communities’ and behoves us to try to understand ‘the visual impact which a city has on those who live in it or visit it’ [45]. He focused on how ‘townscape grounds itself in individual visual perception, treating the town as an object perceived by its inhabitants, fostering an art of relationship through concepts like serial vision, place, and content’ [49]. In effect Cullen saw the city as a series of urban spaces―Relph’s existential spaces―and ‘analyses the experiences we have of urban spaces from the perspective of the person in the street [in order] to establish the fundamental components of that experience, noting particularly the importance of serial vision, of places or centres, and of the content of those places’ [51]. To illustrate his ideas of serial vision and sequence of experiences, Cullen sketched a series of these spatial experiences―such as enclosure, precincts, and focal points―based on a plan with eight sequential movements from one space to another (Figure 4) in the direction marked by the arrows on the plan, thereby representing different human experiences of places. He then enlarges on this concept of spatial experience in an engaging series of examples highlighting aspects such as closed vistas, punctuation, narrowing, definition, and accessible outdoor rooms. Notably, the reader is presented with extensive examples of urban green landscape treatment at various scales from intimate to public. In this context Cullen can be seen as one of the planners, amongst others, who paved the way for developing worldwide scholarly interest in the critical role of urban open space systems and the need for a diversity of urban green spaces (UGS) which has taken place over the last two or three decades.

4. Urban Open Space Systems: Role of Urban Green Spaces (UGS)

Since the 1990s, international attention on urban open space systems as a fundamental element of urban morphology involving an inextricable link to the character and form of urban green spaces (UGS) has occurred. Although here again there are examples of similar ideas taking shape in the 1960s, i.e., sixty years ago. The following part of this paper presents an overview of the what and why of this phenomenon, starting first with thinking from the 1990s onwards and then reflecting back to earlier in the twentieth century.

Palpably critical to such an overview are the following questions and related themes to guide ideas for action [52]:

Questions:

“What should we be demanding from urban open space in the 21st century? What are the social and spatial implications of new lifestyles, value systems, and attitudes toward nature and sustainability? What models for future city life will accommodate these?”

Themes:

• Variations on green networks where, for example, urban parks are not necessarily wild, but neither are they deserts of mown grass and a few standard trees;
• Protecting natural resources and systems;
• Urban recreational use;
• The importance of the street as a public space;
• Varying urban densities;
• Varying needs of people and those who need more access to public parks;
• Fundamental human need for access to some form of nature;
• Create new patterns of urban open space networks to celebrate cultural diversity and which offer a place to meet other people or where people can transcend the crowd and be anonymous or alone.
• The concept of urban green spaces (UGS) and their management dovetails neatly into an overview of urban open space planning and design as urbanisation unrelentingly grows at unprecedented rates. This has led to research on UGS at an international scale since the early 1990s, with a focus on the USA, Canada, Australia, New Zealand, China, Hong Kong, and Europe [53]. Paudel and States [54] suggest that UGS comprising ‘forests, meadows, residential yards, parks, grassy lawns and engineered green roofs and rain gardens provide multiple ecosystem services to humans and the environment’. They also point to studies from Europe, North America, Australia and recently China as highly relevant and suggest that the ecosystem services and ecological services provided by UGS include the following:
  • reducing elevated urban heat,
  • pollution,
  • flood mitigation,
  • offsetting greenhouse gas emissions,
  • providing habitats for urban wildlife and biodiversity conservation,
  • social and human health benefits.

Notably, Paudel and States [54] draw attention to the overwhelming occurrence ‘of intensively managed manicured grassy lawns… as the dominant feature of UGS globally’, which has spread from western cultures around the world. Whilst acknowledging the benefits of lawns (Figure 5), such as visual aesthetics, health benefits (recreation and physical activity), urban heat regulation, flood and pollution control, and possible CO₂ sequestration, alternative treatments are suggested. These include, for example, native floral meadows with a mixture of perennial grasses and forbs that are infrequently mowed, thereby mimicking natural or semi-natural vegetation (e.g., American prairie or Eurasian steppes), and xeriscape meadows with drought-resistant planting for drier climatic zones. Paudel and States [54] acknowledge that there is limited research that offers comparisons between traditional lawns and meadows. This points to the need for more inquiry into exploring ‘urban green space management options for ecosystem multi-functionality’, thereby offering options for a diversity of treatments of public open green space in urban settings.

Urban Open Spaces: Variations

Reflective of the various characteristics of urban open spaces are two diverse but highly creative examples: (i) the rehabilitation in the UK of Manchester’s inner-city canals (Figure 6) and (ii) High Line New York (Figure 7a,b). The Manchester example is the work of The Canal and River Trust on the Rochdale Canal in the city centre. Figure 6 shows a section of the Rochdale Canal in central Manchester where waterside cafés, bars, restaurants, incidental tree planting, small parks and greening schemes have taken shape along the canal in a scheme dubbed ‘Manchester—Venice of the North helped make our city and are key to its booming future’15.

High Line (Figure 7a) is a 1.45-mile-long (2.33 km) elevated linear park, greenway, and rail trail created on a former New York Central Railroad spur on the west side of Manhattan in New York City. The abandoned spur has been redesigned as a “living system” drawing from multiple disciplines which include landscape architecture, urban design, and ecology. The park is built on an abandoned southern viaduct section of the New York Central Railroad’s West Side Line. Originating in the Meatpacking District, the park runs from Gansevoort Street—three blocks below 14th Street—through Chelsea to the northern edge of the West Side Yard on 34th Street near the Javits Centre.

A nonprofit organisation called Friends of the High Line was formed in 1999, advocating its preservation and reuse as public open space, an elevated park or greenway. Plans for a High Line Park were announced in 2003. Repurposing the railway into an urban park began in 2006 and opened in phases during 2009, 2011, and 2014. The Spur, an extension of the High Line that originally connected with the Morgan General Mail Facility at Tenth Avenue and 30th Street, opened in 2019. The Moynihan Connector, extending east from the Spur to Moynihan Train Hall, opened in 2023.

Since opening in June 2009, the High Line has become a prominent landmark of American contemporary landscape architecture. The High Line’s success has inspired cities throughout the United States to redevelop obsolete infrastructure as public space. The park became a tourist attraction and spurred real estate development in adjacent neighbourhoods, increasing real-estate values and prices along the route. By September 2014, the park had nearly five million visitors annually, and by 2019, it had eight million visitors per year (https://en.wikipedia.org/wiki/High_Line, accessed on 5 March 2025). One of the attractions of this elevated park as a linear roof garden is the varying views it affords out across the city and its setting (Figure 7b).

5. Greenways: Systems Approach

5.1. Boston, USA

In addition to specific examples of UGS, there is the systems approach to planning city-wide, linked greenway spaces. An eminent example is the Emerald Necklace in Boston. It was first envisaged by Frederick Law Olmstead in the 1870s, including a system of six park units―Back Bay Fens, The Riverway, Olmsted Park, Jamaica Pond, Arnold Arboretum and Franklin Park―interconnected by linear parkways to become known as the ‘Emerald Necklace’ in the 1920s [55]. As a result of the work of Charles Eliot, what was known as the Boston Metropolitan Park System expanded across 38 municipalities. Over time the system succumbed to increasing car use and encroachment by development. Nevertheless, as O’Connell explains, by the 1980s the system was coming back into favour, and in 2024 further improvement work was carried out on the parkway system. It now consists of 4.5 kms² of parks linked by parkways and waterways in Boston and Brookline, Massachusetts, giving continuous footpaths and cycleways along the system. In essence, the Emerald Necklace is a textbook example of incorporating a linked green open space system through an urban area, acting essentially as a skeleton for the body of a city. Such a system of greenways includes large major parks, small parks, natural elements such as creek and river valleys, and streets with street trees, all linked and, in many cases, forming a connection to the surrounding landscape setting of a city.

5.2. Sheffield, UK

In the UK, the city of Sheffield was regarded as the UK’s greenest city in a Green City Report by NatWest in 2021 (see Colin Drury Independent 30 October 2021 www.independent.co.uk, accessed on 5 March 2025) The lead expert behind the NatWest report, William Powrie, reflected that ‘[T]he message from the report… is that we can and must all contribute to making our towns and cities as green as possible… It’s great to see Sheffield scooping the accolade of the UK’s greenest city, with schemes like their Grey to Green campaign creating high-quality green recreational areas and active transport corridors, helping people behave more sustainably… and benefitting the city’s environmental trajectory’ (Demi Olutunmogun https://hellorayo.co.uk/hallam/local/news/sheffield-greenest-city-uk/ accessed on 3 November 2021). In a review of Sheffield’s symbiotic relationship between green networks and ecological networks, Ersoy et al. [56] outline how the city has a coherent and connected system of green spaces and other open spaces founded on creating connections between habitats and human actions. Parallel is the concept of spatial planning of green space that can deliver benefits for people and the environment. ‘Subsequently, the green and ecological network approaches in Sheffield have been developed and supported both by governmental bodies and non-governmental organisations: the green network (GN) developed by the Sheffield City Council (SCC) and the Living Don ecological network (LDEN) developed by the Sheffield and Rotherham Wildlife Trust (SRWT) [56]. The result is a city-wide linear green network which joins the city to the Peak District National Park to the east, allowing a seamless interchange between the rural setting and city (Figure 8).

5.3. Philadelphia, USA

The systems approach to greenways has long been a fundamental key element behind the thinking for Philadelphia’s planning dating back to when Ed Bacon served as Executive Director of the Philadelphia City Planning Commission from 1949 to 1970 [57]. Bacon envisaged a new golden age for Philadelphia in the postwar years that would reinvigorate community investment and development. In 1947 the Better Philadelphia Exhibition was staged in 1947 with a model of the city. The exhibition showed a future vision for the city, which included open space, planning for pedestrians, and efforts to work within the original landscape. In 1960 this initiative led to the formulation of the Comprehensive Plan: The Physical Development Plan for the City of Philadelphia, which included a section, ‘The Plan for Recreation and Community Facilities. The linking of recreation and community facilities was a notable move.

Philadelphia sits on the western approaches of the Delaware River. It was first set out in William Penn’s c1800 Plan in which he ‘dreamt of building a new kind of city… a vibrant urban place connected by grand and intimate parks… lush open spaces that would create a distinct sense of place while sustaining the city’s natural resources [21]. The recreation section of the 1960 Development Plan for Philadelphia, a Park Plan (p. 62), highlights existing and proposed parks. These included (i) 20 district (large) parks with other existing large parks extended and (ii) two extensive new regional parks. In addition, neighbourhood (local) parks were included. Notably, the Delaware River was slated to house new marinas and parks, whilst two tributaries―Poquessing Creek and Schuylkill River―were the focus for extensions to existing large parks. Of particular note is that here can be seen the beginnings of a linked open green system of parks for the city, which has become a hallmark of the city as embraced in the 2010 GreenPlan Philadelphia [58]. It is ‘a massive, city-wide, inter-agency effort… to identify the city’s natural resources, and to develop, with community input, a plan to preserve and protect open green spaces throughout the city’. An existing open space plan (pp. 20/21) shows the distribution of parks and recreation centres, trails, wetlands along the Delaware River and meadows, green streets, private open spaces, and cemeteries. Distinctive in the plan is the linear significance of the tributaries―Schuylkill River, Takony Creek, and Pennypack Creek―to the Delaware River as green fingers. Subsequent plans for Philadelphia have continued to stress a green plan approach, with the largest of the city’s parks and natural areas remaining concentrated around waterways linked to surrounding urban development by parks and tree-lined green streets. For the 2010 GreenPlan, engaging the community in forum discussions was stressed. Points raised included, for example, the following priority actions:

• Provide new green space;
• Provide new greenways;
• Plant more trees;
• Improve river fronts and access;
• Enhance bicycle access;
• Change planning policies on new development to promote provision of open space and use of green development strategies;
• Change planning policies on open space to provide for equitable access, ecological function and future open space needs.

Plans have developed over time from the 2010 GreenPlan and have kept a green open space and community involvement focus. Additionally, innovations such as a green roof garden featured in the Fall 2022 issue of Living Architecture MONITOR (https://livingarchitecturemonitor.com/ accessed on 5 March 2025) Case Study: Philadelphia’s Cira Green Project: Innovation in Urban Placemaking. It sits over a 12-storey (sic) parking garage with sweeping views of Philadelphia’s skyline and Schuylkill River. Here, on this one-block site, developer Brandywine Realty Trust created the elevated park as a unifying space within a vertical neighbourhood (sic). Overlooked by two mixed-use high-rise towers, the park offers a novel setting for group gatherings, concerts and picnics, yoga, outdoor movies, and just plain old hanging out. It is an example of how privately managed open space that is consistently open to the public is a relatively novel approach in urban thinking. In the case of Cira Green, the convenience and accessibility of the elevated park are bolstered by a restaurant, a direct connection to adjacent residential high-rise, active ‘pop-up’ programming, and a dedicated website. Cira Green has become a cherished destination in the Philadelphia community, similar to New York’s High Line, which effectively is a linear roof garden (see above). In such roof gardens a fundamental design aspect is handling stormwater runoff and storage, which has to be assessed in each individual garden (see also ‘On every roof something is possible: how sponge cities could change the way we handle rain’, The Guardian, 2 May 2024).

6. An Asian Perspective

The section on the role of UGS and urban open space systems (see above) refers to the attention raised on this topic in China. It is appropriate to view this within a wider Asian setting, and it has become the focus of scholarly and professional attention. Naydenov and Atanasov [51], in acknowledging that whilst the concept of the green city originated in Europe and North America, nevertheless, claim the concept in Asian countries is very different on the grounds of climate, people’s backgrounds, culture, goals, and history of development without any real evidence to support this assertion. In contrast, Kanasan and Hassan [59] address the topic of urban green growth and its importance to cities in Asia. They approach this in the context of how governments worldwide are seeking to implement policies to address green growth from the perspectives of actions that will also facilitate and support economic growth.

Further, and in contrast to Naydenov and Atanasov’s claim that the green city concept is different in Asia, Ian Mell [60] presents an informative and comprehensive overview of urban green infrastructure in East and Southeast Asia. He establishes that questions on what green infrastructure is and what place it has in urban planning debates are not unique to East and Southeast Asia. Rather, they have been levelled in all areas of the world. It is critical to understand that the nuances of green infrastructure planning in East and Southeast Asia require a reflection of the influence asserted by cultural preference for diverse urban spaces, historic/contemporary landscape architectural motifs, the economics of development and land value, as well as the politicisation of nature within urban development debates. Again, these issues are not unique to East and Southeast Asia. He further articulates, through his examination of China, Hong Kong, Japan, Singapore and South Korea, how green infrastructure in Asia is subject to complex socio-cultural, economic, and ecological pressures.

As Asian cities expand to become denser, the role of green infrastructure as a facilitator of liveability will become more explicit. In effect, whilst understanding that internationally cultural differences exist in perceiving green spaces and associated sense of place, they also exist between countries in the same region and between different communities in any urban location. In this discourse, which inevitably must consider heritage associations as discussed in earlier sections of this paper, it is helpful to encourage appreciation of different ways of seeing that inform the idea of heritage values.

7. Conclusions

International discourse on urban green spaces (UGS) is timely and welcome. Thompson [52] unambiguously states why in her perceptive and succinct summary of urban open space in the 21st century:

“I see open space in cities as places to celebrate cultural diversity, to engage with natural processes and to conserve memories. Urban open space must provide a place for the meeting of strangers and a place where one can transcend the crowd and be anonymous or alone. And in all of this, the urban park will continue to serve a central function in society’s self-definition.”

This means not just protecting/conserving existing UGS and seeing them as a critical element in urban morphology. It also means engaging with the political and governmental reviews and action taking place in cities and towns worldwide to combat urban sprawl by increasing densities. As urban areas densify, green spaces integral to the layouts will be needed not only for their value as breathing spaces but also as spaces that are attractive to and for people and for urban wildlife and encouraging nature in our cities to thrive [61].

This paper has outlined the extensive thinking and practice in UGS as crucial aspects of urban open spaces and green cities. From this stems the need for serious interaction with urban planners and government agencies for cross-disciplinary discussions to review the meaning and importance of existing green open spaces in urban settings for communities. Further, such discussions have to address new ideas on open space and effects of changing demographics. How do we adapt existing spaces and networks to new and changing needs? No matter what, we have to be able to underscore the social and economic benefits of green open space systems as the skeleton for defining overall city, which is similar to the green fingers model. A model for measuring economic benefits is the 2022 report on New York by the Trust for Public Land, ‘Parks Provide Billions of Dollars in Benefits to NYC Residents Every Year’ (https://www.tpl.org/ accessed on 3 March 2025). Underscoring such considerations are how local communities’ views are being taken into account―or not―in governmental decision-making.