1. Introduction
Academic interest in the preservation, maintenance and restoration of historic gardens started in the 1980s, when the Florence Charter officially identified historic gardens as “living monuments” [
1]. Over the last forty years, garden management methodologies have evolved and become much more complex. According to the criteria established by the Italian Charter for the Restoration of Historic Gardens, not only is a historic garden a cultural asset and an architectural and environmental resource, but it must also be considered as “the heritage of the entire community that benefits from it”. Historic gardens located within an urban context contribute to enriching its complexity and temporal diversity. They also represent essential nodes in the plots of open-space systems and ecological networks, and must therefore be considered effective components of the landscape structures and fully integrated in the cultural and social dynamics of our cities [
2].
In this rapidly changing world, contact with nature, as well as infrastructures and green areas, has become fundamental. This represents a true resource for sustainability and the quality of city life. We are now aware of how much environmental change threatens our lives and health, and we should, therefore, be equally concerned about ecosystem services, which can be considered very important allies in the mitigation of and adaptation to climate change [
3]. Any natural space, whether large or small, has a value and widely contributes to environmental well-being. Therefore, finding the right balance between human-built environments and natural ones is currently a priority for administrations. The need is to harmoniously align, with the right strategies, the urban development process with nature to guarantee both human and environmental well-being. Rethinking the urban development not only in terms of “asphalt” (which may result in ecological and social deserts) but also through the wise management of greenery, including the restoration and maintenance of parks and gardens, can guarantee a fair access to green resources, social equity and a proper well-being [
4].
Constant and continuous population growth combined with a rapid economic and social development has made urbanization an inevitable process. Nevertheless, cities must face, today more than ever, great challenges and develop resilience to embrace the sustainability of urban sprawl [
5]. Aiming to improve quality of life, promoting and protecting urban ecosystems with their related services allow for environmental challenges to be addressed in a strategic way, with planning and competence, while improving the well-being of the inhabitants at the same time [
6].
Green areas, as a matter of fact, make us feel better in many ways. Nature is good for our health, and numerous studies have shown that, in green areas, we feel less stressed, it is possible to exercise more, positive social interactions are encouraged and it is possible to shape a better-quality environment thanks to the lower levels of air pollution. While disconnection from nature causes chronic stress, a close connection with the natural world can contribute to improvements of several aspects of health, namely behavioral, psychological and physiological aspects, and even to the strengthening of the immune system [
7].
Among green areas, parks and gardens at the heart of large cities provide a link to the natural world and emphasize an ecological rather than an anthropological vision of the world. Our landscape is characterized by an extraordinary environmental variety but, at the same time, it is strongly anthropized and marked by the great transformations that have taken place over the last century which, in most cases, have certainly not improved its appearance; on the contrary, they have contributed to making the landscape lose its identity characteristics, directing its development towards ruthless homologation. Promoting the culture of maintenance, restoration and prevention through the combination of best practices and an integrated management model, simultaneously aimed at tourism and at the sustainable development of the landscape at once, means protecting the memory of our cultural heritage and offering valuable help to the enhancement of historic parks and gardens [
8]. This may also create a virtuous combination of growth through the activation of local and human resources that also enhance and raise awareness of the community. Therefore, it has become essential to be able to pursue a balanced relationship between social needs, economic activities and cultural and environmental components that are intended to be preserved [
9].
Only by acting this way can we meet the needs imposed by contemporaneity and create a lasting and quality relationship with the landscape to protect and exploit the ecosystem services that parks and gardens offer. It is well-known, in fact, that urban parks and gardens provide a wide range of ecosystem services, including cultural ones, referring to a set of intangible benefits that people can take advantage of, such as, for example, the aesthetic, recreational activities and the socio-cultural value.
Gardens are a part of our culture; they open a window to the past and, once lost, it is hard to rehabilitate or replace the original ones. There are many historic gardens that today need maintenance, restoration and conservation, and general improvements in the skills and knowledge of their keepers are also required. Preserving this link with an enormous cultural heritage is as essential as earmarking useful funding for it. The delicate maintenance that gardens require is of vital importance for them and their conservation, since these places are resources that belong to the community and can generate income [
10]. Indeed, in recent years, the restoration of historic gardens has acquired an ever-greater importance, because the gardens themselves are beginning to also be understood by the public as a cultural and collective heritage, something precious and worthy of preservation. In fact, historic gardens are being increasingly perceived as realities that reflect a historical significance established over long periods of time. Restorations, whether large or small, however, require extensive and in-depth historical research to guarantee an authentic process. Preserving historic gardens, which means the guarantee of their survival for future generations, therefore represents a great challenge, since anthropogenic pressure and climate change have a huge impact.
Gardens, by their nature, grow, develop and change over time, and they constitute an important part of our past, which is very easy to lose and rather difficult to regain. This precise characteristic requires careful and continuous maintenance aimed at protecting them. Highly specialized workers, who know how to identify management plans with full awareness of and in harmony with the archetypes, can guarantee adequate interventions, given that gardens growth and change are permanent within a constantly evolving environment.
The significant challenge of climate change, whether it be a change in temperatures or a decrease in rainfall, has disruptive effects on our gardens, for example, the increasingly more common establishment of exotic, invasive pests mainly originating from warm climates, including insects such as (in Italy) the red palm weevil,
Rhynchophorus ferrugineus (Olivier) [
11], the box tree moth,
Cydalima perspectalis (Walker) [
12] and the brown marmorated stinkbug,
Halyomorpha halys (Stål), all originating from Asia [
13]. When it comes to restoration, we must ask ourselves how to intervene in order to preserve garden authenticity and, at the same time, how to interpret everything as an opportunity, as resolving certain issues could have a positive impact on the whole environment.
Protecting historic gardens, precious echoes of our natural and cultural heritage, is essential because they offer a range of socio-cultural, environmental and economic benefits. Unlike in the past, when they were mainly appreciated for individual pleasure, nowadays, they are perceived by society as a whole, and it is crucial for us to be able to ensure their survival through constant, qualified and long-term management. At the same time, the correct implementation and management of contemporary parks and gardens are fundamental actions that can highly engage the population and raise awareness of ecologically significant values, as modernity must support the enhancement of the “landscape system”.
In this framework, the present paper aims to emphasize the importance of historic and contemporary gardens and of the ecosystem services that they provide. These services include air purification, climate regulation, biodiversity and pollination but also cultural issues, such as aesthetic information, relaxation and stress reduction and the maintenance of cultural heritage [
14]. We mainly focus on these “cultural” ecosystem services which, taken as a whole, may be defined as the benefits that people gain from their interactions with different environments [
15,
16] (gardens and parks in our case). They can play a very important role in urban policies aimed at improving the quality of life in cities, particularly if access to their benefits is expanded to wider segments of the population.
2. Restoration Aimed at Enhancement
Gardens have now overcome the definition of decorative space characterized by the presence of ornamental plants, and their new role in modern urban reality is the provision of widespread awareness. Today, they act as a connective, offering people the opportunity to become closer to nature, and their slow and dilated rhythms, far from the urban frenzy, allow people to better perceive the world they live in [
17]. Green areas must be understood and managed, as they are fundamental components of quality of life and urban sustainability, due to their multiple services and benefits, not only environmental but also cultural, that they provide to cities.
Since 1987, with the publication of the Brundtland report [
18], the critical points and global problems of the environment have been highlighted to develop a strategy capable of integrating development needs with environmental protection. This strategy has been defined as “sustainable”, i.e., capable of “allowing the present generation to satisfy their needs without compromising the ability of future generations to satisfy their own”. The definition does not only refer to the environment but also to the well-being of people and, therefore, also to environmental quality, highlighting an ethical principle, that is, the responsibility of today’s generations to future generations for the maintenance of resources and for the environmental balance of our planet.
Urban green spaces (particularly historic or contemporary gardens and parks) are, therefore—and will increasingly be—a significant part of sustainable development, and those overseeing their management, maintenance and enhancement will increasingly have to consider “holistic”, interdisciplinary approaches, involving politics, social, cultural and economic aspects, with a view to achieve continuous improvement [
19]. If conservation and maintenance remain confined to the sphere of aesthetic taste and utility, without leading to the suppression of or alterations in natural processes, they will have a suggestive effect (a cultural ecosystem service); when these limits are instead exceeded, even when the suggestion effect remains, the damage that can be done must be considered. Questioning the “genius loci” and identifying, historicizing and understanding the multiple sensitivities that have found expression over time will allow us to orient ourselves towards the best choice to guarantee the conservation of the characteristics defining the garden’s identity, thus allowing for to enhancement of this heritage with an open eye to eco-sustainability that can embrace social, environmental and economic dimensions according to a commonly shared responsibility.
Parks and gardens assume, in the current and future contexts, a meaning that goes far beyond the “ornamental” one, since they enhance quality of life via improvements in ecosystem services (including health, psychological and cultural values), ensuring an economic return on the economic investments made [
20]. The maintenance of biodiversity for functional ecosystems, therefore, assumes primary importance also in the global agenda, given that urban parks and gardens provide a whole range of ecosystem services (including cultural ones) and economic advantages: several studies have shown that the presence of quality urban green areas (i.e., gardens) in business districts and commercial areas promotes a positive perception to buyers. Thus, the presence of plants could even be an effective way to revitalize business, bring in new customers and improve the general context of commercial areas. In fact, by reducing shopping stress and putting the visitors of these areas at ease, their total amount of time spent and their propensity to buy are very likely to increase [
21].
Moreover, botanical and historical gardens are effective tourist attractions in large and small cities and, consequently, a strategic source of revenue for the tourism sector. Tourist expenses for food, transport, accommodation, etc., increase in the presence of parks and gardens [
21]. This may result in important employment opportunities for local communities, as well as a range of related economic advantages. For example, the creation and maintenance of urban green spaces require a certain degree of manual labor that must be guaranteed throughout the year; therefore, investment in new jobs not only helps to maintain the employment of people within the community but also serves to revive the local economy through increased spending.
The protection of biodiversity guaranteed by gardens and parks is also of upmost importance. For example, planned plant biodiversity (crops and ornamental plants) and the biodiversity consequently associated with it (wild plants) provide a range of resources for the invertebrate and vertebrate populations present in the area. Plant diversity also provides support services such as pollination and conservation biological control, which consists of the implementation of practices that maintain and improve the reproduction, survival and efficiency of the natural enemies (predators, parasitoids and pathogens) of pests [
22].
Management decisions should therefore consider the biophysical processes and the benefits that can be obtained through the correct maintenance of these microcosms. Political measures should stem from evaluations of the main changes in nature, and the management of the soil should aim to ensure the safety of the territory. People involved in planning need to be aware of the fact that the value of ecosystem services is directly linked to a better quality of life. The latter may be also guaranteed by fighting off climate change (not only higher temperatures but also atmospheric or noise pollution linked to traffic noise). Urban green spaces, indeed, offer several environmental and social advantages, including the stabilization of the local climate through air filtration and cooling through the provision of shade [
23].
Moreover, the strategic positioning of treelined roads reduces energy consumption and noise, increases the storage of carbon and has positive effects on the infiltration of rainwater. Ecosystem services may thus have crucial importance for the sustainability of human development in economic, social, cultural and ecological terms since they regulate and support human natural systems. Restoring, protecting and preserving ecosystems through the use of nature-based solutions can, therefore, offer an innovative, cost-effective and responsive method of management, leading to improved sustainability [
24].
3. Green Areas and Social Equity
Natural rights are also “historical rights”, as stated by Norberto Bobbio in his book “
L’Età dei Diritti” (“
The Age of Rights”). They too, similar to positive law, are a product of history; “And on this level, history”, added the great philosopher, “has a long time to go”. Precisely, since rights have accompanied the development of history, their story has evolved painfully for generations. Civil rights came first, then political rights and finally social rights, until the flowering of a new generation, and rights have always been connected (as Bobbio observed at the end of his essay) with the goods of life, freedom and security [
25]. Among the rights linked to the goods of life, he included “the right to live in an unpolluted environment”, because the environment decides the quality of our life, regulating the degree of the possible enjoyment of some essential goods. Among these essential goods, we must certainly mention water and air, but the beauty and harmony of nature and the ecological system in which we are immersed also participate in this quality of life. All these intangible assets may not contribute to the formation of a traditionally perceived GDP, but they definitely have an impact on the degree of happiness or well-being of people. The concept of “environmental justice”, also linked to the possibility for everyone to take advantage of green spaces such as parks and gardens, is itself revolutionary, because it indicates a new dividing line between social groups, a line that it is not drawn by the power of monetary income or by the relationship with the means of production but rather by unequal “environmental opportunities”. The dividing line separates privileged people from disadvantaged people, whose drawbacks often go beyond, in terms of sustainability, low wage levels and social precariousness: from air that kills to thirst and from poisoned food to the “subtraction of creation”, be it the sea or rivers, forests or arable land [
26]. There is a question of environmental democracy that is proposed with theoretical resolve, despite the progress made by the ecological movement. This environmental democracy is proposed as a system of recognition entailing decision-making procedures aimed at reducing the specific category of environmental inequalities: it can be perceived as a new idea of democracy, reorganized around a new group of questions and urgencies and within which, in fact, the idea of justice is reformulated. Not only does environmental justice seek to identify the misdistribution of risks and deficits in terms of environmental benefits, but it also helps communities to organize based on these issues, reduce inequalities and promote positive legal and political changes that address these inequalities and that help in improving living and health conditions [
27].
Green areas, such as parks and gardens, offer a wide range of benefits that help in overcoming many urban problems and in improving the lives of city dwellers, with particular emphasis on health and well-being. Unfortunately, however, green spaces within cities are not always equally distributed, and access to green areas in the last two decades has become a matter of “environmental justice”, since the awareness of its importance for public health is now widely recognized. Therefore, among the planning priorities and planning strategies, it has become essential to seek “environmental justice” in order to transform marginal and little-used areas into green spaces, especially in places where not only environmental problems but also social problems are greater. It is precisely in these areas, in fact, that urban parks and gardens can act as places of social interaction and increase the perception of safety and belonging. Recent studies have highlighted the positive effects of the richness of species, i.e., a positive association between greater biodiversity and psychological well-being [
28]. Future planning should thus consider how green spaces are distributed among the population and how the vegetation is distributed within the green space to prevent richer neighborhoods from continuing to have greater coverage than low-income communities. Environmental justice, therefore, plays a fundamental role in promoting sustainable communities, and urban parks and gardens constitute a considerable portion of the physical environment, having numerous implications for people. Being able to incorporate these implications into the environmental justice paradigm will develop our culture, vision and hopefully our practices.
Looking to the past, we realize how historically urban green spaces were born from the need to create spaces for socializing. The creation of urban parks, as we know them today, dates back to the nineteenth century, with their aim being to improve living conditions in cities, which became overpopulated due to the industrial revolution. Although it has changed over time, the function of urban parks and public gardens has always been to improve the lifestyle of citizens, and their maintenance is the task of the local authorities in charge of promoting, preserving and maintaining them.