Engineering Rome

Analysis of Urban Greenery in Rome

By: Sam Scherer

Introduction

Walking around Rome one immediately notices the impressive structures, the cobblestone roads, and the overall beauty of the city. Something that contributed significantly to the allure of the city was its parks. Many of the parks used to be these sprawling estates adorned with gorgeous gardens and fountains. These parks serve as so much more than just a tourist attraction though; parks are incredibly important for a healthy population, reducing stress in individuals and lowering blood pressure as well as providing an area for physical activity. In addition to the anthropogenic benefits, they also have environmental benefits by increasing water retention in cities, combating the urban heat island effect, and decreasing both air and noise pollution. Exploring all of these topics, this report will serve as an examination into the perceived benefits of parks and how the parks of Rome compare to the literature.

Background

Unlike other cities around the world, a large number of parks in Rome were not originally meant to be parks. In fact, many of the most famous parks around the city are villas that were once owned by Italian noblemen, but have since been converted- some that come to mind are Villa Doria Pamphili or Villa Borghese. Given that Rome is a city that is thousands of years old, it is difficult to retroactively put in parks as a lot of the infrastructure has historical value and is densely packed. As parks contribute positively to the mental health of an urban population as well as the environmental health of the city, converting villas around the city to serve its population of nearly three million people was a creative solution to incorporating green space in the city (World Population Review).

Urban heat island Effect

The urban heat island effect describes the discrepancy in temperatures of urban areas and the surrounding rural areas. As a result of cities and the number of paved roads and other surfaces that absorb and reflect solar radiation (EPA). It is been discovered that temperatures of urban infrastructure are about 27-50 degrees Celsius hotter than the temperature of the air. Because of this, cities remain hot even after sunset as the heat is radiating off of these surfaces (EPA). On average, the annual temperature in a city is around 1-3 degrees Celsius hotter than the surrounding rural areas, and in the evening, it can rise to nearly a 12-degree Celsius difference (EPA). Green spaces, such as parks, help to mitigate this issue as they have similar conditions to the surrounding rural areas and therefore do not experience this increase in temperature due to urban infrastructure.

Figure 1: Graph depicting the differences in temperatures in cities vs. rural areas (EPA)

Built Environments vs natural Environments

In a study that was performed to test whether or not people reacted differently to built vs. natural environments, it was no surprise to find the participants in the study preferred the natural environments. The only built environment that could hold a light to the natural environments were human’s attempts to emulate them- urban parks (Kaplan). In his study, the urban parks were preferred as much as the lowest level of natural environments. Of the scenes that were preferred the most, they usually had either a trail that wound out of view or a well-lit opening that was in part hidden by intertwined vegetation. Additionally, in this study and subsequent studies, the relationship between the complexity of the scene and the preference to it was tested, but results showed that complexity was not a sufficient indicator for preference (Kaplan). In an attempt to discover what is an indicator for preference further studies were performed showing that, as he called it, coherence played an essential role. By coherence Kaplan is referring to the “capacity to predict within the scene.” (Kaplan). Or, the effortlessness that the observed scene is able to be broken down into digestible pieces. Using the variables tested- complexity, mysteriousness, and coherence, the outcomes of understanding and exploration emerged. Understanding (coherence) describes the comprehension of the scene whereas the exploration (mystery and complexity) details the ability of the setting to draw in the viewer.

Compiling the information obtained, Kaplan created the matrix shown in figure 2 below. On one dimension of the matrix, there are the outcomes understanding and exploration and on the other axis, this is describing the availability of the information in the scene, immediate or predicted. Legibility of the scene is describing the ability to “maintain orientation” as one continues further into the setting (Kaplan).

Figure 2: Matrix Kaplan created to categorize and explain preference (Kaplan)

Summarizing the last bit of the report, the idea that human’s preference also depends on evolutionary factors was explored. In theory, people like to choose places that have an advantage, whether that is on top of hill where one can see the surrounding area, or have a place where one can observe but not be seen (Kaplan). It was discovered that the optimal place was not in a dense forest nor an open field where there is no cover, but on the tree line.

Given the above information about environmental preference, what does this say about parks? Well, my interpretation is that there is a happy medium where parks are effective. One that is well maintained that provides tree coverage but is not so densely vegetated that it becomes frightening to navigate. Additionally, there is an aesthetic aspect in that well-maintained spaces are ranked higher than over-vegetated areas that are unkempt and borderline scary.

Parks and reduced stress levels

Stress, a feeling we humans are well-acquainted with, releases hormones such as cortisol or adrenaline. In this time, there is a release of sugar into the bloodstream that is combined with an increase in blood-pressure and heart rate to circulate the energy from the sugar quickly (Gourdarzi). As humans experience stress on a daily basis because of a variety of stimuli, this chronic stress can increase the risk of high blood pressure and adult-onset diabetes from the frequent release of sugar into the bloodstream (Gourdarzi). Green spaces such as parks however have been found to decrease stress levels and blood pressure (Hedblom). Additionally, there has been an observed reduction in noise pollution in green spaces which positively affects stress levels as noise is a stress-inducing stimulus.  

Benefits of Green Spaces in cities: Cardiovascular Health

Having green spaces in urban areas is incredibly important and is linked to a variety of benefits. One of which is positive changes to cardiovascular health; in a study done to determine the effect of green spaces on heart rate, the researchers took the participants into three different green areas in Helsinki, Finland- an urban forest, an urban park, and the city center (Lanki et. al.). During the visits they had 15 minutes of sitting time and 30 minutes of walking around; the results of their study displayed a lower heart rate in the urban forests than in the city center. Even for short visits, it was shown to have a relaxing effect. Additionally, in urban green spaces the air pollution is lessened, which contributes to the experienced lower blood pressure as particulate matter has been shown to increase systolic blood pressure.

The addition of parks in urban areas also presents the opportunity for physical activity which decreases risk of high-blood pressure related ailments and improve cardiovascular health (Braubach et al). By providing an accessible and conveniently located area to exercise, this can promote an increase in time spent outside and engaged in physical activity, which is especially beneficial for those that are have mental health issues (Braubach et al). A variety of studies that were performed found that with increased access to green spaces came increased levels of exercise. One such study in Scotland looked at the difference between exercise done in natural versus non-natural environments, and found the association of exercise in natural environments and a further decrease in the risk of poor mental health, while exercise not in these environments did not show the same advantage.

My experience

To test the benefits of parks myself, I visited the Villa Doria Pamphili, Parco Acquedotti, and others that happened to be on my walk from place to place. The Villa Doria Pamphili is park that used to be villa for an Italian nobleman back in the 17th century, and is today one of the largest parks in Rome (Villa Doria Pamphili). This park is roughly 184 hectares; if that is difficult to visualize, one hectare is roughly the size of a baseball stadium (Kleanthous). So roughly the size of 184 baseball fields, this park is massive. Many elements of this former villa contained elements that would have put it near the top of the list of preferred scenes described by Kaplan. It had large trails that wound around the corner, employing an element of mystery; it had large clearings that would be good vantage points to see all around, and tree lines to hide in.

Figure 3: Location and size of the Villa Doria Pamphili

As seen from the pictures above, the park was indeed very pretty, and included the above-mentioned elements of winding pathways. I went to the park around sunset time and during my time there, there were a number of people there that were walking around the park, and a large number of people running as well. In the research, it was predicted that access to green space would increase physical activity, but that doesn’t always translate to what actually happens. Here, however, the assumption was validated. There were other people just spending time with friends, other people, etc. sitting on the park benches or on a blanket in the clearings.

Because of the large size of this park and tree coverage, once you entered it, it felt like you exited the city. For the most part I couldn’t see the surrounding buildings or hear the noise from the cars or surrounding vehicles. In the literature, it was stated that parks could reduce noise pollution (when large enough) which helped to reduce stress levels and therefore help to reduce blood-pressure and heart rate. While I did not have the instruments used in the studies cited above to actually measure my heart rate and blood pressure, I did feel and overall sense of relaxation while walking through the area. With the same disadvantage, I did not have a thermometer to measure the temperature inside the park and compare it to the surrounding temperature, but while I was in the park it did feel cooler than the surrounding city.

One negative aspect of the park was that it wasn’t necessarily green and areas of it were a not very well-maintained. Picture below it can be observed that there were areas of the park that were over vegetated and unkempt, which detracted from the overall aesthetic quality. A large number of the paths were also lacking in lighting, making the space not as accessible closer to dark.

While walking to a different tour, we walked past this little “park” that was a playground for children. I did not physcially enter this space but walked past it. This space did not fulfill any of the items described by Kaplan. It was not maintained at all, there were weeds growing up all over the place, and it was right next to the road and surrounding buildings so the same feeeling of escaping the city that was felt at the Villa Doria Pamphii was not experienced here. Being squished in-between buildings and the road, it did not filter out the noise pollution or really cool down the space as the sun was reflecting off the side of the adjacent buildings. Also, the space was too small to really facilitate physical activity as far as running is concernced as this park didn’t even span a block in length.  

Considering the small size of this space, the added benefits of reduced heart rate and blood pressure stemming from the reduction in noise pollution and being in a green space were not achieved. Because the space was also not maintained this added to the lackluster appeal and visual. There were no winding paths that were partially hidden from view, getting rid of the mystery factor described by Kaplan, nor was part of it hidden by vegetation. This would have fallen low on the list of preferred spaces according the list of variables Kaplan outlined.

From the pictures, one can see also that this space isn’t being used, or at least at the time these pictures were taken. The literature outlining that green spaces can be used as a place for physical activity did not hold here, reinforcing the idea that in order for that to be achieved, there needs to be a larger area.

Environmental benefits

Not only do urban green spaces improve human health, but they also improve the health of the city. Within my first few days in Rome, there was a large thunderstorm that brought heavy rainfall leaving many pools of water around the city. Urban green spaces, such as parks, help to combat this issue as they are able to increase water retention by allowing the water to infiltrate the soil instead of sitting on top of an impermeable surface (International Network for Capacity Building in Integrated Water Resources Management). Shown in figure 4 below, the day following a large rain event there was a large pool of water that collected on top of the stones of the road. This type of surfaces in theory could be a good drainage system, allowing the water to go in-between the stones; however, on one of the tours in the program, it was said that many of them have been filled with asphalt making them unable to drain to the earth underneath.

Figure 4: Large pool of standing water outside a piazza in Trastevere

Not only is the runoff concerning from a standing water perspective, but also from a water quality one as well. The streets of Rome are not the cleanest, as one may imagine, from the cars driving on them to the large number of people trafficking the streets as well. In addition to increased water retention, the water is also filtered somewhat as it moves through the layers of soil. This is important considering the below figure illuminating the poor quality of the Tiber river- where the water would drain to. Water health is important for a city; apart from the obvious reasons, it is also important for tourism. Along the bank of the river there is a space where little booths and restaurants were set up; this could be a really neat attraction for the city, but not when it is next to a smelly, dirty river.

Figure 5: Poor water quality of the Tiber River

Future and climate change and why parks are important

With the threat of climate change ever increasing, it is more and more important that measures are taken to combat this. Parks and other urban green spaces can be important tools that can be used to help fight this issue. With climate change, the frequency of large storm events is going increase and in an area like Rome that has such historic and delicate infrastructure, the flooding that can be seen because of climate change could have a serious impact. Not that parks are a cure-all for climate change, but with the added benefits of increased water retention and cooler temperatures they can play a role in the preservation of Rome and the fight against climate change.

References

Braubach, M., Egorov, A., Mudu, P., Wolf, T., Thompson C., Martuzzi, M. (2017). Effects of Urban Green Spaces on Environmental Health, Equity and Resilience. Retrieved from https://link.springer.com/chapter/10.1007/978-3-319-56091-5_11

Environmental Protection Agency (EPA). (2019). Learn About Heat Islands. Retrieved from https://www.epa.gov/heat-islands/learn-about-heat-islands

Goudarzi, S. (2007). Why Humans (and Baboons) Stress so Much. Retrieved from https://www.livescience.com/4380-humans-baboons-stress.html

Hedblom, M., Gunnarsson, B., Iravani, B., Knez, I., Schaefer, M., Thorsson, P., & Lundström, J. N. (2019). Reduction of physiological stress by urban green space in a multisensory virtual experiment. Retrieved from https://www.nature.com/articles/s41598-019-46099-7

Kaplan, S. (1987). Aesthetics, Affect, and Cognition Environmental Preference from an Evolutionary Perspective (Environment and Behavior Vol. 19).

Kleanthous, B. (2019). How Big is a Hectare. Calculator Site. Retrieved from https://www.thecalculatorsite.com/articles/units/how-big-is-a-hectare.php

Lanki, T., Siponen, T., Ojala, A., Korpela, K., Pennanen, A., Tittanen, P., Tsunetsugu, Y., Kagawa, T., Tyrväinen, L. (2017). Acute Effects of visits to urban green environments on cardiovascular physiology in women: a field experiment. Retrieved from https://www.sciencedirect.com/science/article/pii/S0013935116309100#bib20

International Network for Capacity Building in Integrated Water Resources Management. (2018). Urban Green Spaces. Retrieved from https://www.ctc-n.org/sites/www.ctc-n.org/files/resources/urban_green_spaces.pdf

Villa Doria Pamphili. History. Retrieved from https://www.villapamphili.it/la-storia.html

World Population Review. (2019). Rome Population 2019. Retrieved from http://worldpopulationreview.com/world-cities/rome-population/

Sam Scherer

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