Peri-Urban and Urban Green Space Management and Planning: The Case of Thessaloniki, Greece

Abstract

With the increase in population and commercial development, urban development has led to a decrease in natural vegetation and an increase in solid surfaces, which negatively affect the environment. Maintaining green spaces in cities is emerging as a critical intervention for improving living conditions. This research, conducted in Thessaloniki, revealed that citizens face problems in using green space, which needs to be addressed. Through questionnaires distributed online, we examined citizens’ concerns about urban green space, including the peri-urban forest of Thessaloniki and its cities. The need for regeneration and new green networks is highlighted, as well as the importance of citizen participation in the management of these spaces at the local level. The analysis of the data results in proposals for action, including the regeneration of green spaces, their interconnection with cycle paths and pedestrian walkways, and the creation of a network of applications to inform citizens. These proposals are important for improving the environment and enhancing sustainability in urban development.

1. Introduction

Global population growth and urbanization are causing the expansion of urban areas at the expense of the countryside and natural environments such as forests and farmland [1]. Urban development constitutes both an existing and future challenge for the quantity and quality of green spaces and “green infrastructure”, in general. The growing population and the increasing demand for natural resources and space will make the management of natural capital and ecosystems increasingly critical. In addition, further difficulties and challenges that urban centers will face are expected, such as ongoing climate change and increasing energy consumption. Thus, international standards and strategies for land use are needed, and there is a need for the formulation of targets, indicators, and monitoring concepts [2].

Urban green spaces can function as means to moderate these impacts since they provide numerous benefits: aesthetic, social, recreational, ecological, and economic. They belong to the family of the so-called nature-based solutions [3,4], which express the amount of ecosystem services-based approaches in the city functionality and provide a pathway to urban sustainability. In consequence, the protection and development of urban green spaces have become highly prioritized by local authorities for cities worldwide, aiming to enhance the quality of life for residents and ensure ecological balance. Urban green spaces encompass parks, gardens, street trees, green roofs, and other vegetated areas within the city landscape. The active use of green spaces and peri-urban forests is a necessity, given that peri-urban forests provide a range of ecosystem services, such as carbon storage, raw material supply services, habitat quality, and cultural services [5,6], contributing significantly to human well-being. Also, urban expansion results not only in a change in the land use pattern of forests in urban areas but also in a reduction in the area of urban greenery [7], thus reducing the number of ecosystem services provided [8]. Therefore, studying the impact of peri-urban forest evolution and its role on human well-being is very important [9].

Spatial planning must consider the development of green spaces and their connection to existing urban infrastructure. Legislation and administrative cooperation at the metropolitan level are crucial for effective environmental protection and development [10,11]. Studies in cities such as the Mediterranean Vienna and the Baltic Stockholm, Copenhagen, and Riga [12] are representative examples of urban planning that highlight the importance of green structures in the urban environment. The urban planning of a city includes the creation of large green spaces to connect them to a network of green structures and aims to develop these spaces sustainably to maintain the city’s high standard of living. In Stockholm, green spaces cover 1/3 of the urban area and include urban forests and open spaces. Urban planning aims to expand green spaces and diversify their uses while preserving their ecological value and improving their accessibility.

The visibility of green spaces is significantly influenced by their accessibility. A study in the city of Beijing [13] highlighted the importance of the spatial distribution of parks, which is often not carried out based on environmental conservation or population convenience but rather according to accessibility by the public transport network. In areas with dense housing and low incomes, the availability of green space is limited by inefficient transport and commuting routes. Additionally, other studies [14] have shown that residential preferences in areas provided with green spaces often differ according to income. Low- and middle-income individuals usually choose to live in urban centers, while for high-income individuals, living in suburban areas with gardens and proximity to nature is also governed by age [1]. In the Warsaw urban lake area, high visitation but short duration was observed, while in large urban parks, the duration exceeded one hour despite the lower number of visitors [15]. Therefore, the perception of green quality emerges more directly, but information and education can change the ecological awareness of visitors and increase the visibility of green spaces, providing benefits to the health and well-being of city residents [15]. Additionally, the relevant literature [16] shows that the existence of green spaces contributes positively to the physical and mental health of city residents. Green spaces reduce residents’ stress and mental fatigue [17] and may improve their physical health and quality of life [18,19]. Studies highlight the importance of green spaces for the psychological and physical well-being of residents [20]. For example, regular contact with nature contributes to the improvement of respiratory and cardiovascular problems, stress, and depression [21]. Furthermore, “forest therapy” is recommended as a treatment for mental illnesses, improving patients’ quality of life [22,23]. In this context, the integration of forest environment simulation spaces into the urban fabric can be particularly beneficial for physical and mental health [17].

Furthermore, the diversity of plant species, vegetation density, and distance from pollutant emission sources play crucial roles in the retention rate of harmful particulate matter [24]. Therefore, the maintenance and development of green spaces in the urban fabric should not be considered by authorities as a mere urban aesthetic or aesthetic imperative but rather as a mechanism to promote a city’s sustainability [25]. However, the use of green spaces is influenced not only by their design, availability, and accessibility but also by their cleanliness and tidiness and the sense of security they convey to users [26]. From a bioclimatic perspective [27], the presence of green roofs (bioclimatic insulation), tree walls, and “green walls” in dense urban environments provides significant benefits, such as stormwater runoff retention, a microclimate impact, noise reduction, and improved quality of life [28]. The expansion of urban centers has led to environmental degradation, with the replacement of vegetation by built surfaces causing heat islands [1]. The use of urban green development models can address this phenomenon, while active citizen participation in tree-planting programs enhances the quality of life and sustainability of cities [29].

Sustainable urban space management, which calls for the convergence of economic, environmental, and social objectives, must consider the importance of public participation in this process [10]. In addition to collecting data, the public can contribute to monitoring and supervising the quality of the environment and, further, implementing pilot urban greening programs. Awareness-raising and the active participation of citizens become crucial for the successful implementation of any action concerning urban green areas. To achieve this goal, carrying out studies of existing green spaces and their evolution over time in cities is necessary. The gained knowledge will form the basis for urban planning and the management of green spaces in the future, aiming to improve the quality of life of the inhabitants and achieve ecological balance in the urban environment.

Raising public awareness by comparing green spaces with built surfaces leads to the recognition of the adverse impacts of the built environment, whereas in densely populated areas, redevelopment by integrating green spaces is a way to improve quality of life and the urban environment [30,31]. The study of incentives for the visitation of these spaces is of paramount importance for the rational planning and management of urban greening [32]. Furthermore, the active participation of residents in tree planting and cleaning activities is an important factor for the successful management and maintenance of urban greening [33]. Moreover, the assessment and siting of informal vegetated areas contribute to improving the quality of life of citizens and regulating the microclimate in urban areas [34].

For Thessaloniki, a highly populated city, the need for open green spaces is becoming increasingly urgent within the urban sustainability context, which is the great challenge faced by humanity in the 21st century [1,35]. Urban sustainability was promoted by the United Nations’ dedicated Sustainable Development Goal for Cities (SDG Goal 11) introduced in 2015: “This goal intends to make cities and human settlements inclusive, safe, resilient, and sustainable” [1,4,36]. By relevant decisions of the Ministry of Environment and Energy (YPEN), further details and definitions are provided, forming a framework for the development, management, and maintenance of urban green spaces in Thessaloniki, aiming at sustainable development and environmental improvement. Although the city is geomorphologically advantageous, with the existence of a port and a pedestrianized coastal zone of several kilometers [35], the Thessaloniki urban area faces serious issues of green space availability in many of its municipalities. For example, the municipalities of Ambelokipi-Menemenis, Thessaloniki, and Kalamaria face a lack of sufficient green spaces and problems of vandalism in existing green spaces. Despite the decrease in the population in some municipalities, such as the Municipality of Neapolis-Sikeon and the Municipality of Pylaia-Hortiatis, the problem of a lack of green spaces remains significant. Municipalities are trying to address these challenges through various initiatives and development plans, aiming to create more green spaces and improve the quality of life of residents.

Furthermore, population growth in other municipalities, such as the Municipality of Kordelio-Evosmos and the Municipality of Pavlos Melas, exacerbates the lack of green spaces and necessitates the need for the more effective management of the available green spaces. Municipal authorities are focusing on the regeneration and improvement of existing parks and green spaces, enhancing the planting of trees and greenery and promoting the replacement of built surfaces with green surfaces, aiming to address the heat island phenomenon [1] and improve the environment.

In this context, the purpose of this paper is to identify the problems and difficulties faced by citizens in Thessaloniki regarding the use of existing urban and peri-urban green spaces. The overall approach aspires to provide a basis for the management of urban green spaces and the creation of new spaces to improve the quality of life of city residents. The questionnaires are used as a tool to collect data on the issue studied while the analysis will be based on descriptive and inferential statistical analysis methods. The analysis of primary data will be amplified by secondary data on existing green spaces in Thessaloniki derived from the relevant authorities (the seven municipalities that make up the city’s urban complex, as well as from the Forestry Department of Thessaloniki for the peri-urban forest). The questionnaires have been addressed to citizens to collect information on the use of green spaces and the problems they encounter when using them. The primary data are then analyzed using descriptive and inferential statistical methods, and, finally, the results are presented and discussed to formulate proposals for action and policy-making on urban management and planning. The contribution of this paper is threefold. First of all, it unveils the need to interconnect green spaces with one another and with peri-urban forests to create an integrated green network in a city. Secondly, it enriches the existing literature on sustainable urban management and planning with valuable insights into the management and improvement of green spaces in Thessaloniki and (generally) in other cities with similar characteristics. Finally, the research suggests a methodological framework for designing an urban policy related to participatory urban governance that has incorporated the views, needs, and suggestions of active citizens.

2. Methodology and Data

According to the decision of the Hellenic (Greek) Ministry of Interior (YPES), under number 28549/16-9-2019 (Hellenic Government Gazette 1327/Β/17-4-2019), the Municipal Unit of Thessaloniki is inhabited by over 820,000 citizens and consists of 14 municipalities, of which 11 municipalities make up its Metropolitan Area. Annually, Thessaloniki serves a traffic load of domestic flights of more than 660,000 passengers on average, and a traffic load of foreign flights of more than 1,000,000 passengers on average [37]. This information allows for the estimation that the annual tourism load of Thessaloniki is almost three times greater than its population; however, tourism in Thessaloniki is mainly described by city-break characteristics and consists of transit tourism [38]. Furthermore, the urban complex of Thessaloniki consists of 7 municipalities (see Table 1), whilst the peri-urban forest of the city, with an area of 30,252 acres (see Figure 1), is of public use, serving various needs of the public.

Table 1. Citizenship information and the ratio of green space area per inhabitant for the municipal complex of the city of Thessaloniki [39].

Municipality	Population		Green Area per Inhabitant (m2/Inhabitant)
	Census 2011	Census 2021
Ampelokipon–Menemenis	52.127	50.143	1.57
Thessaloniki	325.182	319.045	2.8
Kalamaria	91.518	92.248	5.2
Kordelio–Evosmos	101.753	105.352	1.6
Neapolis–Sikeon	84.714	80.888	n/a
Pavlos Melas	99.246	100.194	9.88
Pylaia–Hortiatis	70.110	72.384	2.4
Total	824.676	820.254

Table 1. Citizenship information and the ratio of green space area per inhabitant for the municipal complex of the city of Thessaloniki [39].

Municipality	Population		Green Area per Inhabitant (m2/Inhabitant)
	Census 2011	Census 2021
Ampelokipon–Menemenis	52.127	50.143	1.57
Thessaloniki	325.182	319.045	2.8
Kalamaria	91.518	92.248	5.2
Kordelio–Evosmos	101.753	105.352	1.6
Neapolis–Sikeon	84.714	80.888	n/a
Pavlos Melas	99.246	100.194	9.88
Pylaia–Hortiatis	70.110	72.384	2.4
Total	824.676	820.254

Figure 1. The peri-urban forest of Thessaloniki Seich-Su in the municipality map, including information on the sample size municipal distribution and indicative photos of the Seich-Su’s vegetation (data source: [40]; picture source: own archive).

Figure 1. The peri-urban forest of Thessaloniki Seich-Su in the municipality map, including information on the sample size municipal distribution and indicative photos of the Seich-Su’s vegetation (data source: [40]; picture source: own archive).

The peri-urban forest (Figure 1), also known as the “Seich-Su”, is an artificial forest covered with conifers (Cypress, Cupressus sempervirens), Trachea (Pinus brutia), and Hale Pine (Pinus halepensis). The peri-urban forest includes the administrative boundaries of four (4) municipalities (Figure 1), namely the Municipality of Thessaloniki (percentage of the forest: 4.30%), Neapolis–Sikeon (17.97%), Pavlos Melas (0.05%), and Pylaia–Hortiatis (77.68%). The altitude (height) ranges from 53 m to 569 m, with an average of 303 m. The Seich-Su is an important green space for Thessaloniki. The forest’s beneficial contribution involves among other things flooding protection, the regulation of the microclimate and air pollution, and a positive effect on the mental and spiritual health of residents (Figure 2). For the management, surveillance, and fire protection of the forest, forest roads with a total length of 90,848 m and a width of 4–8 m, and 90 firebreaks with a total length of 45,555 m and a width of 10–30 m, have been constructed, and a network of fire hydrants and tanks has been installed (Figure 2). Every year, as part of forest fire protection, maintenance works are carried out on both the road network and the firebreak zones. Further, in the period 1984–1986, the Forest Service constructed 14 forest recreation and sightseeing sites. To guide visitors and facilitate their transportation to the forest recreation areas, the Forest Service constructed six trails (Figure 2) with a total length of 12,474 m. Within the peri-urban forest, facilities are located serving multiple purposes, such as cultural (Forest Theatre, and Earth Theatre), religious (Holy Cathedral of the Assumption, St. Basil’s Chapel, St. Paul’s Cemeteries, and the allied cemeteries) educational (the school complex of the 11th High School of Thessaloniki, the children’s camp “Theoskepasti” belonging to the Panhellenic Parents’ Association “Christian Education”, and the Zoo Garden), recreational (the Municipal Refreshment Centre), and touristic (Hotel Philippio). The management of the forest requires continuous efforts by the forest service and the municipalities to manage it in a sustainable context and create new green spaces within their administrative boundaries. A key effort in this direction is to raise awareness of the use of green spaces by residents. Citizens must become aware of the efforts needed to preserve these spaces as well as the extent of their beneficial impact on society.

The residents’ perception survey on the above-mentioned issues was based on an online questionnaire survey method, an effective way of collecting data (with advantages in terms of completion time and anonymity but with the prerequisite of internet skills). As part of this research, a web questionnaire was developed (through the Google Forms application) to collect information on citizens’ choices and habits regarding their views on urban and peri-urban green spaces. In addition to their contribution to the survey itself, the choice of citizens to participate voluntarily and anonymously in the completion of the questionnaire expresses their awareness and intention to contribute to the improvement of green spaces in the city of Thessaloniki. The recording of operational and accessibility problems in green spaces is expected to provide important information for rational planning toward a more “green” city, as it will provide relevant bodies with constructive guidelines for the improvement and maintenance of green spaces according to the needs and preferences of citizens. The questionnaire was anonymously distributed to the citizens of Thessaloniki, with a cover letter following the protocol of expressing gratitude for participation in the survey and the importance of the participants’ responses for the management of the city’s green spaces. The respondents were also informed of the purpose of the survey and the expected objectives and potential for policy utilization through the development of the rational management of the city’s green spaces.

From a structural point of view, the questionnaire included six thematic sections (Table 1) covering various aspects related to green spaces in the city of Thessaloniki, in particular the following: the benefits and frequency of visits to the peri-urban forest “Seich-Su”; the visitation of the forest; the benefits and visitation of the city’s parks; the information level of citizens about green spaces; the accessibility and interconnection of green spaces; and the social data of the participants. The questionnaire was constructed by closed-ended questions demonstrated in

Table 2. The questions/variables considered in the analysis.

CODE	QUESTION/VARIABLE
[Section 1] THE FOREST OF THESSALONIKI “SEICH-SU”
Q1	Most important benefit that the “Seich-Su” peri-urban forest provides to the city.
Q2	Frequency of visit to the Seich-Su peri-urban forest.
[Section 2] VISITABILITY OF THE PERI-URBAN FOREST
Q3	Periodicity of visit to the forest.
Q4	Season of most frequent visitation.
Q5	Hours of most frequent visitation.
Q6	Disincentive to visit due to dying Tomicus piniperda.
Q7	Safety of touring the forest.
Q8	Disincentive to visit due to the presence of stray dogs.
Q9	Establishment of the Forestry Department of Thessaloniki within the forest and the feeling of safety.
Q10	Disincentive to visit due to the possibility of fire in summer.
Q11	Mode of access to the peri-urban forest.
Q12	Forest recreation areas in the peri-urban forest.
Q13	Option to use existing trail network.
Q14	Reasons for not using the existing trail network.
Q15	Activities during the visit.
Q16	The responsible body for managing the peri-urban forest.
Q17	Regulations for the operation of the peri-urban forest.
Q18	Duration of the visit to the peri-urban forest.
[Section 3] PARKS
Q19	Benefits of green spaces in Thessaloniki.
Q20	Criteria for visiting a park.
Q21	Park distance from the beach as a selection criterion.
Q22	Most popular park.
Q23	Multiple uses of a park as a selection criterion.
Q24	Attractiveness of visiting parks due to events.
[Section 4] INFORMATION
Q25	Use of the Internet for information on urban and peri-urban green spaces.
Q26	Willingness to share information material from a park visit.
Q27	Evaluation of the level of personal information about green spaces in Thessaloniki.
[Section 5] ACCESSIBILITY–CONNECTIVITY
Q28	Desirable means of transport to visit a park.
Q29	Importance of easy access by public transport.
Q30	Option to commute to work via green spaces if such an option existed.
Q31	Desirability of linking city parks both to each other and to the peri-urban forest through a network.
Q32	Mode of interconnection.
[Section 6] SOCIAL INFO
Q33	Gender.
Q34	Age.
Q35	Family members.
Q36	Occupation.
Q37	Education level.

, with one possible response per question. This structure allowed quick and easy data processing while the time required for participants to complete the questionnaire was minimized.

In terms of reliability, the questionnaire was structured on a fairly reliable basis of ten (10) core questions (E2, E3, E13, E16, E17, E24a, E24c, E24d, E27, and E32) with a Cronbach’s alpha reliability coefficient equal to a = 0.58, as shown in

Table 3. The Cronbach reliability test results.

Cronbach’s Alpha	N of Items
0.580	10

. The measure is computed using the following mathematical formula [41]:

$$a={\displaystyle \frac{k}{k-1}}\cdot \left(1-{\displaystyle \frac{{\displaystyle \sum _{i=1}^k{\sigma }_i^2}}{{\sigma }_y^2}}\right)$$

(1)

where k is the number of items included in the scale; σ_i² is the variance of item (i.e., question) i; and σ_y² is the variance of total items in the scale (including pairwise covariances).

The family of core questions included items from all the thematic categories of the questionnaire, except for demographic characteristics, which is a differentiated addition. Given that the research team constructed the questionnaire on a novel basis (without following the structure of an existing questionnaire as a template), the numerical reliability coefficient is considered satisfactory. However, due to the abundance of thematic axes drawn from the relevant literature, the remaining questions in Table 2 were added to the questionnaire (thus reaching a total of 37), resulting in the overall reliability being reduced by almost half. In this context, the research is conducted with the awareness, on the one hand, of the reliability of the core questions tested by Cronbach’s test and, on the other hand, of the informative character that the remaining questions on urban sustainable planning may have.

The questionnaire was distributed from February to April 2023 via email and social media to residents of Thessaloniki. A special effort was made to distribute it to people of different genders, ages, education levels, employment levels, and marital statuses to ensure the representation of all categories of visitors and to comply with the requirements of representativeness and social inclusion. A total of 399 questionnaires were completed. The calculation of the sample size was based on the formula for estimating the percentage p of a population N, with a margin of error e and significance level z², according to the following formula [41,42]:

$$n=\left({\displaystyle \frac{z^2\cdot p\cdot (1-p)}{e^2}}\right)/\left(1+\left({\displaystyle \frac{z^2\cdot p\cdot (1-p)}{e^2\cdot N}}\right)\right)$$

(2)

Applying Relation (2) for a population of 4 million inhabitants (including city population and average tourism load), a 5% margin of error, and a 95% confidence level leads to a desired sample size of 385 persons. In this survey, a total of 399 questionnaires were completed, which is a sufficient number to provide representative results for the case of Thessaloniki.

To analyze the questionnaire variables, we used descriptive statistics (e.g., means, medians, frequencies, and percentages) and then inferential statistical analysis, based on the nonparametric Spearman rho correlation coefficient [41], to examine pairwise relationships between the variables. In particular, the Spearman rho correlation coefficient is computed on the standard formula of Pearson’s correlation coefficient, where the rank variables rnk(x) and rnk(y) with the rank of the magnitude of each element are used instead of the values of the variables x and y, as shown in Relation (3):

$$r_{XY}={\displaystyle \frac{\mathrm{cov}(\mathrm{rnk}\left(x\right),\mathrm{rnk}\left(y\right))}{\sqrt{\mathrm{var}(\mathrm{rnk}\left(x\right))}\cdot \sqrt{\mathrm{var}(\mathrm{rnk}\left(y\right))}}}$$

(3)

The coefficient ranges within the interval [−1, 1], describing a perfect linear relation (positive or negative) when it is equal to one. This process allows researchers to better understand their data, draw conclusions, and understand trends or differences that may exist between questions.

Finally, to detect correlation patterns among the items of the questionnaire, we applied a community detection analysis to the correlation matrix [43,44], including Pearson’s correlation coefficients between the variables defined by the questionnaire questions. The community detection analysis builds on the modularity optimization algorithm [45]. The modularity function (Q) is defined as the sum of the differences between the actual and expected connections within a network community. When Q = 0, the network is concrete and thus not modular (such as a star graph); when Q→1, the network is highly divisible [46], whereas an entirely disconnected network has Q→∞ (infinite modularity). The algorithm [45] of modularity optimization involves greedy targeting of the intra-connectivity (within communities) maximization and the consequent interconnectivity (between communities) minimization. The algorithm is applicable in two stages [45,46]. First, each node belongs to a single community, and, sequentially, nodes are placed in collective communities provided that the gain in the weighted modularity function (Q_w) increases. Second, the resulting communities are considered nodes, and the procedure is repeated until a convergence point is reached. This process generates communities with dense connectivity within and sparse connectivity between communities [45,46]. Due to the heuristic setting of this algorithm [46], the analysis is repeated several times (30 iterations), keeping the most frequent modularity classification membership. In this paper, the state of membership in a correlation network community generated by this algorithm indicates a greater degree of relevance for a community’s members than for other communities. This allows us to consider the items (questions) included in each community as attributes describing the overall profile of visitors that a community has.

3. Results

3.1. Descriptive Analysis

The survey initially involved information on the characteristics and social data of the respondents. In terms of gender, 61% of the participants were female, and 39% were male. In terms of age, 37% of the respondents were aged 41–54 years, while 26% were aged 26–40 years. In terms of family size, families of four members made up the largest proportion (40.05%), while large families consisted of more than five persons corresponding to 16.11% of the total. In terms of employment, the participants were public and private employees, freelancers, students, retired individuals, unemployed individuals, and housewives. In terms of education, the majority of the respondents were university graduates and holders of postgraduate degrees.

In the descriptive analysis, the first question (that involved the benefits of the peri-urban forest) showed that the majority of respondents recognized its contribution in terms of the environment and climate. The next questions (2nd–5th) indicated that the majority of respondents visited the forest with moderate frequency (mostly 2–4 times a year), with visits increasing in spring and decreasing in winter and with a preference for evening (47%) and late morning hours (30%). The fact that the pine trees were infested by a phlox-eating insect (question 6) did not seem to have affected people’s planned visits (at 78%). Regarding the feeling of safety (question 7), the majority of responses were divided between feeling quite safe (47%) and somewhat safe (33%) when browsing the forest. The presence of stray dogs (question 8) within the forest appears to be a concern for a significant proportion of visitors (65%) to the extent that they consider it a deterrent to visiting the site. However, the presence of the Forest Service (question 9) seems to inspire a sense of security in a significant proportion of visitors (79%). During fire protection periods (question 10), visitors mainly prefer other activities (53%), either visiting the beach (34%) or staying at home (4%). In terms of visitability, journey to the forest (question 11) is mainly by car (68%), but there is also a notable proportion of pedestrians (17%). In terms of information, visitors’ knowledge of forest recreation areas (question 12) appears limited, with 42% stating that they have little or no knowledge. Despite the creation of trails (13th and 14th questions) by the Forest Service, 32% of visitors did not use them during their tour, while in terms of preferred activity during the visit (15th question), in descending order, hiking (52%), walking and taking photos (30%), picnicking (12%), sports activities (4%), and cycling (2%) were selected. Eighty-one percent of participants were aware of the body responsible for the management of the peri-urban forest (question 16), while fifty-one percent were aware that the operation of the forest is governed by regulation (question 17). The duration of the visit (question 18) for 57% did not exceed two hours; for 41%, it ranged from two to four hours; and for 2%, it was more than four hours.

In general, 48% considered that parks (question 19) contributed to the peace of mind of residents, 39% considered the large shaded areas (question 20) by trees or shelters highly important, 29% considered the existence of parking spaces valuable (question 21), and 31% preferred a park on the city beach (question 22). In addition, the distance of a park from the beach (23rd question) was not an important selection criterion for the majority of respondents (62%), while, concerning events in parks (24th question), the majority believed that these could increase their visitation while also boosting local businesses and helping to improve the mental health of citizens. However, there was also concern about increased noise levels (47%). In terms of information and communication, the internet (question 25) emerged as a popular (64%) source of information for Thessaloniki residents (as expected, given the familiarity suggested by their online participation in the survey), while the greatest percentage of respondents (73%) stated that they would share photos and information from the green spaces they visited online (question 26) to share the beauty of the city with other citizens. However, the majority of respondents (51%) described their information as incomplete to insufficient (question 27), while only 15% described it as satisfactory, highlighting directions for improvement in the area of information about the city’s green spaces. Finally, in terms of accessibility, the majority of respondents (55%) expressed a preference for the use of nonmotorized means to visit green spaces (question 28), recognized (70%) the supportive role of public transport in accessing green spaces (question 29), and overwhelmingly (91%) preferred transit through green spaces (question 30) when traveling to work, school, or other activities, as well as linking the city’s parks (questions 31 and 32) with each other and with the peri-urban forest through a network (93%).

3.2. Correlation and Community Analysis

This section applies correlation analysis between the questionnaire variables, where only statistically significant results are shown in Figure 3. There is a weak negative correlation (−0.287) between the feeling of safety (Q₇) while touring the peri-urban forest and the gender of the respondents (Q₃₃). This result indicates that women may feel less safe than men. There is also a weak positive correlation (0.125) between the mode of walking in the peri-urban forest (Q₁₁) and the gender of respondents (Q₃₃), which reflects differences in preferences between men and women. The weak positive correlation between the use of the existing trail network (Q₁₃) and respondents’ gender (Q₃₃) reflects the potential for gender differences in use. In addition, the positive correlation between variables (Q_24b, Q₃₃) and (Q_24c, Q₃₃) indicates that the positive view of the enhancing role of events in the area is a more male-dominated issue. The gender correlations highlight that women and men differ in their views, with women tending to value park activities more and expressing more positive views on the interconnectivity of these activities. These findings highlight the importance of the social dimension in views and preferences regarding parks and their associated infrastructure, providing insights into the design and implementation of policies and programs that better reflect social needs.

Next, the significant negative correlations between the age of respondents (Q₃₄) and (i) the level of information citizens received about green spaces in Thessaloniki (Q₂₇) and (ii) the desired way of approaching (Q₂₈) a park highlight the importance of age as a factor in designing policies and programs that better respond to social needs. The correlation analysis in terms of (the participants’) family members and (i) the way of accessing the peri-urban forest (Q₂₇), (ii) its distance from the beach (Q₂₁), and (iii) the choice of a multifunctional park (Q₂₁) provides important information regarding their families’ criteria for choosing recreational and green spaces, which are characterized by accessibility, the availability of ample space, and the conduct of alternative activities. These findings can be used to better design and adapt parks and related infrastructures, taking into account the needs and preferences of families with different numbers of members.

Since the significant correlations in Figure 3 are abundant (202 in number), commenting on the individual relationships they describe for all pairs of variables is not feasible for this purpose. To macroscopically manage and interpret this large amount of information available in the correlation analysis, a meta-analysis is performed, which aims at grouping the relevant correlations in Figure 3 and the subsequent profiling of green space visitors in the city of Thessaloniki (according to the relevance of their responses to the questionnaires). The grouping occurs by applying community detection analysis from network science [43,45,46], which (as mentioned above) divides the nodes of a network into communities with strong connectivity within and sparse connectivity between the communities. That is, within the framework of this paper, the correlation analysis matrix in Figure 3 can be read as a graph [41], whose nodes represent each of the 38 questions (35 of which contain 4 sub-questions), while the links in the graph express the correlation coefficient per pair of questions. In this context, community detection can reveal the profiles of the relevant behavior of visitors to green spaces in the city of Thessaloniki, which will define the characteristics of the related properties of the questions contained in each community. Therefore, the results of the community detection analysis are shown diagrammatically in Figure 4 and are descriptively shown in

Table 4. Community membership of the correlation network.

	Profile	Membership (Items)
Community A	Safe, versatile, and socialized long-term visitors	Q7: Safety of touring the peri-urban forest. Q12: Forest recreation areas in the peri-urban forest. Q14: Reasons for not using the existing trail network. Q18: Duration of the visit to the peri-urban forest. Q19: Benefits of green spaces in Thessaloniki. Q23: Multiple uses of a park as a selection criterion. Q24b: Attractiveness (negative due to noise increase) of visiting parks due to events. Q28: Desirable means of transport to visit a park. Q34: Age. Q36: Occupation.
Community B	Seasonal and selective visitors	Q4: Season of most frequent visitation. Q5: Hours of most frequent visitation. Q6: Disincentive to visit due to dying Tomicus piniperda. Q8: Disincentive to visit due to the presence of stray dogs. Q11: Mode of access to the peri-urban forest. Q21: Park distance from the beach as a selection criterion. Q 24a,c,d: Attractiveness (positive for visitability; positive for public health; positive for entrepreneurship) of visiting Q32: Mode of interconnection. Q33: Gender.
Community C	Regular and informed visitors	Q1: Most important benefit that the “Seich-Su” peri-urban forest provides to the city. Q2: Frequency of visit to the Seich-Su peri-urban forest. Q3: Periodicity of visits to the peri-urban forest. Q9: Establishment of the Forestry Department of Thessaloniki within the peri-urban forest and the feeling of safety. Q10: Disincentive to visit due to the possibility of fire in summer. Q13: Option to use existing trail network. Q15: Activities during the visit. Q16: Responsible body for managing the peri-urban forest. Q17: Regulations for the operation of the peri-urban forest. Q20: Criteria for visiting a park. Q22: Most popular park. Q25: Use of the internet for information on urban and peri-urban green spaces. Q26: Willingness to share information material from a park visit. Q27: Evaluation of the level of personal information about green spaces in Thessaloniki. Q29: Importance of easy access by public transport. Q30: Option to commute to work via green spaces if such an option existed. Q31: Desirability of linking city parks both to each other and to the peri-urban forest through a network. Q35: Family members. Q37: Education level.

.

The analysis led to the configuration of three communities (groups) with 10, 9, and 19 nodes (content questions) each. The first group seems to be related to safety, versatility, and social engagement. Visitors in this group need to feel safe while walking in the forest, make long visits, and are driven by a desire to participate in recreational activities. They prefer multi-usage parks that attract large numbers of people and have high regard for the cultural life and social interaction offered by public spaces. They value the environmental and social benefits of green spaces and have a heightened environmental awareness and interest in improving the quality of life. Additionally, they have specific preferences for how to approach parks, showing sensitivity to sustainable mobility issues.

The second group seems to be related to seasonality and is distinguished by selectivity when visiting parks. Visitors in this group are selected based on the time of year and the time of day at which they visit the park. Their selectivity is also expressed through the inclusion of environmental problems (e.g., dying due to Tomicus piniperda) and the presence of stray dogs, which are inhibiting factors for their visit. They appreciate cultural events in parks and prefer ways to facilitate easy access to the forest, while distance (from the beach of Thessaloniki) is a selection criterion related to easy access and a combination of activities.

Finally, the third group seems to be related to the frequency of visits and awareness of the possibilities and regulations for visiting parks and green spaces. Visitors in this group appreciate the environmental and social contributions of green spaces in the city; they regularly visit the forest, prefer to use the existing network of paths during their tour, and are interested in organized activities. They know and follow the regulatory framework of operation in the forest, acknowledge the contribution of the Forestry Department of Thessaloniki in providing safety during the visit, understand fire protection measures, and comply with curfew decisions made when needed. They also consider location and give importance to easy access by public transport, preferring to pass through green spaces and supporting the possibility of linking city parks with each other and with the peripheral forest through a network. Finally, they use the internet to obtain information about green spaces and are willing to share photos and information from their visits.

4. Discussion

Urban planning and sustainable development are critical components for the prosperity of cities and their inhabitants. The survey in this paper, conducted through an online questionnaire on the Seich-Su peri-urban forest in Thessaloniki, highlights the need for the sustainable management and utilization of green spaces and provides important information on their planning and management. First, to the extent that it was found that citizens’ knowledge of recreational areas and the trail network in the peri-urban forest is limited, this paper demonstrates the need for more social awareness and participation for the optimal design of a greener city. In terms of urban policy, it highlights the need to design programs that promote social interaction and integration through activities in green spaces, to stimulate the environmental awareness of the citizens of Thessaloniki. For example, the organization regularly in the peri-urban forest of cultural and sporting events, such as concerts, theater performances, or sporting activities (e.g., open yoga classes, team sports, etc.), could communicate more widely to different age and social groups in Thessaloniki the existence and benefits (e.g., flood protection, microclimate regulation, reduction in air pollution, sports and recreational opportunities, and more) of the peri-urban forest and green spaces in the city. On the education side, the development of educational programs in schools and local communities (including activities related to tree planting, recycling, and biodiversity conservation) and the organization of guided tours and walks in the Seich-Su forest to educate citizens about the area’s flora and fauna, should further promote this objective. The community analysis applied in this paper suggests a method that may facilitate (through its resulting grouping) the management and program development direction, as the knowledge of the particular characteristics and preferences of the resulting visitor groups provides a “market fragmentation” that may lead to measures promoting and communicating the peri-urban forest to citizens in a more personalized and targeted manner.

Also, the survey in this paper showed that most residents visit the forest with moderate frequency (2–4 times a year, mainly in spring and less in winter), with preferences for visits in the afternoon and morning hours and the main means of transport being the car. This result highlights the importance of easy access to green urban spaces and the need to develop a network of green corridors connecting the city parks with the peri-urban forest. For example, the development of cycle and pedestrian paths linking green spaces to the main nodes of the public transport system, and the provision of free or discounted public transport to the peri-urban forest and green spaces, could enhance sustainable mobility and promote environmental awareness among citizens. Here, the implementation of measures to increase security in green spaces (e.g., the extension of the electric lighting network and security cameras, strengthening of the presence of police and rangers, the creation of a mobile app that allows citizens to report problems and receive security updates, etc.) also plays an important role, and is expected to enhance the citizens’ intention to visit. In addition, the creation of digital information platforms and applications to provide information on forest activities and infrastructure, as well as information campaigns to raise awareness of the possibilities and rules of visitation, will improve the information of residents.

In general, the analysis showed that the peri-urban forest in Thessaloniki provides an excellent spot for outdoor activities such as hiking, jogging, picnicking, and mountain biking, though further infrastructure development is necessary to adequately serve the related recreational and educational purposes. Its proximity to the city makes it an accessible escape for residents and visitors, though non-motorized access to the visitors would be preferable to secure a greater number of visitors annually. Another direction of improvement relates to the expansion of green spaces throughout the city to provide commuters with a pleasant green space on their way to work, improving the citizens’ route to work. Within this context, the development of an integrated strategic management plan that takes into account the findings of research and the needs of the urban community, while implementing innovative solutions in forest management and protection proposed by scientific research, opens up horizons for ensuring more effective urban green management and promoting sustainable development.

5. Conclusions

The management of urban and peri-urban green space in Thessaloniki highlights essential issues for the life of residents and urban sustainability. The analysis in this paper highlighted the need to improve the urban environment and enhance the quality of life through active citizen participation in the management of green spaces, which can be proven essential in leading to the creation of sustainable bottom-up green space management practices. In this vein, the interconnection of parks through a coherent “green” network of paths is expected to provide added value and contribute to improving the city’s quality of life. In this context, the digital transition of information related to urban green spaces is expected to bring about increasing returns to scale. Furthermore, the visitor profiles of the peripheral forest and green spaces identified for the city of Thessaloniki can contribute to a more rational management of urban and peri-urban green spaces both for this case study and for any city interested in replicating the proposed methodological approach. The preceding analysis can propose a framework of active participatory planning for the management of urban green areas, realizing an important step toward the creation of a greener, more united, and sustainable urban environment. Overall, this research underlines the importance of citizen participation, awareness rising, and infrastructure improvement to promote sustainable urban development in Thessaloniki. By implementing these strategies, the city can improve the quality of life of its inhabitants and enhance its natural environment, creating a more sustainable and prosperous urban community.