Imagine that just by viewing landscapes provides us with healing, restores our souls from tiredness, and lifts our spirits! Well, research over recent decades has established the truth of this – nature heals! This is a really important finding of research over relatively recent years.
Writer and poets, even statesmen, have long believed in the healing power of nature as is evident from the following quotes.
Natural scenery employs the mind without fatigue and yet exercises it; tranquilizes it and yet enlivens it; and thus, through the influence of the mind over the body, gives the effect of refreshing rest and reinvigoration to the whole system.
Frederick Olmstead, 1865.
Everybody needs beauty as well as bread, places to play in and pray in where nature may heal and cheer and give strength to the body and soul.
John Muir, 1912.
Beauty can enlarge man’s imagination and revive his spirit.
President Lyndon Johnson, 1965.
It may seem curious that this phenomenon, the healing power of nature, which seems to have been held as self-evident truth for generations, should have had to wait until recent years to be proved. It has been through research of landscape values that this has occurred.
Over 30 years ago in 1984, an early study by Roger Ulrich provided glimpses of this truth. It was published in the prestigious journal, Science. The study compared the recovery of patients in a Pennsylvanian hospital whose rooms faced a blank brick wall with patients who could see trees. The 46 patients had undergone similar gall bladder operations, and the records were extracted from records over a ten-year period. Those whose beds faced views of trees had shorter stays in the hospital: 7.96 days vs 8.70 days, took fewer strong and moderate pain killers, and received fewer negative evaluative comments in nurse’s notes: 1.13 per patient for those facing trees compared with 3.96 per patient for those facing a wall. The results hinted at a significant influence of viewing nature upon human health.
Figure 1 illustrates the differences over the term of the patients’ recovery. The analgesic doses did not vary significantly between the two groups for the first day or the last days but for days 2 – 5 the difference was statistically significant.
Ulrich, 1984. Figure 1 Analgesic doses per patient for wall or tree view
Ulrich went on to develop his psycho-evolutionary theory (see theme: Landscape theory) in which the positive emotional and physiological effects of experiences with nature have survival benefits. Together with colleagues, he carried out a series of studies to document and quantify the effect of viewing nature on human health.
In this theme, a non-technical summary is presented of research into the health and restorative effects of viewing nature.
Figure 2, which builds on models by Tzoulas et al, 2007 and Abraham et al, 2010, provides a framework of cause and effect; the benefits derived from exposure to nature. Han (2003) showed that the restorative influence of environments comprises emotional, physiological and cognitive aspects as well as intended behavior in the environments.
Figure 2 Framework of the health-promoting effect of landscapes
This theme summarizes the two theories that provide explanatory paradigms of the health and restoration benefits of viewing nature, and then presents the findings of research which have examined the veracity of these theories. It also examines research into several specific areas: the effect of viewing nature on violence, views of surrogates (e.g. posters), views from windows, and views along roads. The theme ends with a summary and references.
EXPLANATIONS OF WHY NATURE HEALS
There have been two main lines of inquiry, complementary but operating from differing theoretical standpoints. Roger Ulrich (1983) proposed a psycho-evolutionary in which the positive emotional and physiological effects of experiences with nature have survival benefits. The second explanation is by Stephen and Rachel Kaplan whose Attention Restoration Theory proposed that exposure to nature restores us from the fatigue of prolonged mental work.
Roger Ulrich argues that contact with nature aids recovery from all forms of stress, not just attention fatigue. Characteristics of the environment provide an early-warning signal for safety and survival that triggers positive emotional reactions. Key elements are a level ground surface, considerable spatial openness, the presence of a pattern or structure, curving sightlines and the presence of water (Health Council of The Netherlands, 2004).
In contrast to the Kaplan’s cognitive mechanisms, Ulrich argues that the response to nature is based on affect, i.e. emotions, not thought. Ulrich believes that we feel it before we think about it. Research of facial reactions to emotional triggers indicates that reactions occur far more rapidly than could be cognitively derived. For example, Dimberg et al (2000) found that subjects exposed to a 30 millisecond image of a happy, neutral or angry face reacted with the same facial expression which was entirely unconscious.
Attention Restoration Theory
The Kaplans base their Attention Restoration Theory (ART) on the insight of William James, an early psychologist, into voluntary attention, the idea that some things require effort to be focused on them in the face of distractions and are susceptible to fatigue – students swotting for exams is a good example. Directed attention requires effort to achieve focus, is under voluntary control, and controls distractions. Prolonged work leads to mental exhaustion which can be remedied by a walk in the park or other relaxing activity which restores one.
They differentiate between a walk in a park which requires little mental effort, from very intense activity such as playing chess or watching a speedway race. The former provides opportunity for reflection, which is restorative, while the latter requires total commitment of attention on the matter at hand.
A park in Paris
The Kaplans consider natural settings which are aesthetically pleasing are restorative environments which hold one’s attention effortlessly. Other components of a restorative environment are:
- Being away – separation from mental activity and from the everyday environment;
- Extent – the diversity and scope of the environment to provide an alternative setting sufficient to remain engaged;
- Compatibility between “the environment and one’s purpose and inclinations.”
- Fascination containing patterns to hold one’s attention effortlessly.
In the context of natural landscapes, natural settings fulfill all four requirements of a restorative environment: they provide a compatible opportunity to be away from one’s normal environment, in a diverse setting with many objects of fascination.
Comparison of theories
The difference between the Ulrich and Kaplan models, apart from the former being based on affect and the latter on cognition, is that Ulrich focuses on the “emotional, mental and physiological components of response to taxing or threatening stimuli” (Hartig et al, 1991) whereas the Kaplan’s interest is in attention-based deficits, which result from fatigue associated with everyday activities. Ulrich believes nature promotes recovery from all forms of stress, not just attention fatigue that the Kaplans cover. Both, however, are predicated on the restorative effects of nature having an innate, evolutionary basis (Health Council of The Netherlands, 2004).
Hartig et al (2003) consider the theories are complementary with regard to the antecedent condition from which the person becomes restored, specifically stress. Both approaches and the research that has been carried out to verify them provide support for nature providing psychological health and restoration benefits to individuals.
NATURE VS URBAN ENVIRONMENTS
A great deal of research has been conducted into both Ulrich and the Kaplan’s theories and some of this is summarized below. A far more detailed account of the research click on the following: Restorative and health benefits
In his early research, Ulrich (1979) tested participants’ feelings before and after viewing images of urban and natural scenes. The results indicate that individuals who viewed scenes of cities with trees and other vegetation showed significantly reduced feelings of fear and increased positive feelings and delight, compared with individuals shown scenes of treeless city scenes (Figure 3).
Ulrich 1979 Figure 3 Affect scores before and after viewing slides for urban and nature groups
Negative feelings were lessened, and positive feelings became moreso from viewing nature scenes. Ulrich showed that the variation attributable to image content was highly significant and concluded that the importance of visual landscapes is not confined to aesthetics, but that they also give rise to emotional states, urban scenes having a negative effect and the nature scenes positive.
Ulrich and other researchers have used a battery of psycho-physiological measures, including heart rates and alpha waves (a gauge of brain electrical activity), skin conductance, pulse transit time (blood pressure), muscle tension and heart period to assess the effect of viewing slides and also the Zuckerman Inventory of Personal Reactions (ZIPERS scale) which measures fear arousal, positive affects, anger/aggression, attentiveness or concentration, and sadness.
Studies have shown participants photos of urban or industrial scenes and then scenes of nature, trees and water and measured preferences, stress, arousal and anxiety, restoration and relaxation. Studies have also monitored before and after effects of activities such as walks in a park and relaxing after studying intensively.
A typical study by Ulrich, Simons and Miles (2003) involved participants at a blood bank viewing a short stressful video and then a second video of natural and urban settings. Blood pressure and pulse were taken prior to and following blood donations and television screens showed either videos of nature or urban areas, daytime television, or a blank monitor. The television content had a significant effect on stress: the pulse rate was markedly lower for viewers of nature scenes compared with the urban scenes.
Applying his findings to interior design, particularly of hospitals and other healthcare facilities, Ulrich (1991) argued that sensory deprivation such as windowless rooms can result in anxiety and depression. Based on the evolutionary approach, he wrote that the most effective positive distractions are mainly elements that have been important to humans throughout millions of years of evolution: (1) happy, laughing, or caring faces; (2) animals, and (3) nature elements such as trees, plants and water.
Ulrich has developed a Theory of Supportive Design to improve the capability of hospitals and other healthcare facilities to enhance health outcomes through more effectively reducing stress for patients, families and visitors as well as for employees. As well as focusing on greater patient control of their situation, including privacy, and facilitating their social support, it also aims to provide access to nature via windows, health gardens and posters.
Overall, Ulrich’s research findings provide support for his theory that immediate, unconsciously triggered and initiated emotional responses – not ‘controlled’ cognitive responses – play a central role in the initial level of responding to nature (Ulrich et al, 1991). He has written extensively on the design of health facilities (Ulrich, 1997, 1999, 2000, 2001, 2002, 2008, 2009, 2010).
In a study in England, Regan & Horn (2005) found that one’s mood states – excited, happy, relaxed, upset, ill, stressed or scared – were influenced by the environment – wild nature, cultivated nature (i.e. scenes with plants and mowed lawns), and natural water. They found wild nature and cultivated nature were associated with a relaxed mood state while water was associated with relaxed and happy moods.
In studies of restoration from intensive mental activity, Korpela (1991) found the favorite places of 18-year old students were in the home (39%), restaurants and downtown (16%), sports facilities and natural settings (10% each). Korpela & Hartig (1996) found that favorite places were associated with being away, fascination, coherence and compatibility and were mostly places of greenery, water and scenic quality. Asked their favorite places, half the places listed by Californian students were beaches, lakes, the ocean, parks, forests, hills and mountains (Korpela et al, 2001). Asked about the experiential qualities of favorite and unpleasant places, the participants spoke of being relaxed, being away from everyday life, forgetting worries, and reflecting on personal matters, all indicative of a link between favorite places and a restorative experience.
Korpela & Ylén (2007) found that people with health issues were more likely to relax in a natural favorite place and gained greater emotional benefit than people without complaints. Helsinki and Tampere in Finland are cities with over 25% green space and Korpela et al, (2008) asked residents in both cities about their restorative experiences in their favorite places. They found each setting (nature areas, urban parks, water spaces, etc.) yielded different restorative experiences. The authors suggested using “favorite place prescriptions” as a supplement to “exercise prescriptions” in healthcare. In a follow-up survey 10 months later of the same respondents, Korpela et al, (2009) found that two-thirds selected the same main favorite area, with urban woodlands and waterside environments the most often selected. They also found greater stability in the repeated use of natural areas compared with urban areas.
Galindo & Rodriguez (2000) tested students in Seville, Spain with photos of urban Seville and related their general preferences for the 50 scenes with their appraisal of the photos based on affective variables – comfortable, excitement, distress, boredom, tranquillity, safety. Aesthetic preferences correlated highest with comfort and excitement, demonstrating the psychological benefits provided by attractive environments (Table 1).
Table 1 Correlation of aesthetic judgments with aesthetic responses (Pearson’s r)
Galindo & Rodriguez, 2000
Herzog et al (1997) found that natural settings had high restorative potential while urban settings had low potential and sporting and entertainment settings were intermediate.
Herzog & Chernick (2000) examined the relationship of tranquility with perceived danger in urban and natural settings. They included the degree of care shown in the settings, it being assumed that a scruffy site is more likely to attract dangerous elements and the openness and naturalness of settings were also assessed. Over 230 student viewed images and rated tranquility. The study found:
- Tranquillity rated higher in natural than in urban settings, while danger rated higher in urban settings;
- Tranquility and danger were negatively correlated across all settings;
- Openness, setting care, and nature related positively to tranquillity and related negatively to danger.
- The degree of care for the natural or urban environment was more important to the perception of danger in urban areas than in natural settings.
Using either an urban or a field/forest setting to take a break from an intense and prolonged effort, Herzog et al (2003) found that nature rated higher than the urban setting and the restorative components of being away and compatibility provided positive predictors of restorative potential.
Using Italian students in Padua and scenes of industry, housing, city streets, hills and lakes, Purcell et al (2001) assessed the extent by which their restorative effects correlated with preference and familiarity (Figure 4). They found that the order of restoration and preference was the same and correlated closely (0.81). The highest restoration and preference was for scenes of hills and lakes, much more so than for the urban scenes.
Purcell et al, 2001
Figure 4 Assessments of restoration, preference and familiarity for varying scenes
Research of how landscapes affect people
Watching nature videos significantly lowered heart rates compared with those who watched an urban video was the finding of a study in Bergen, Norway by Laumann et al (2003). The authors stated that the findings suggest that the nature video had a relaxing effect on autonomic functions.
Similar preferences for natural setting were found in the following studies.
Ulrich (1981) found that scenes of vegetation induced relaxation and low arousal while urban scenes provoked anxiety. Sadness increased markedly from viewing urban scenes but increased only slightly for vegetation and was constant for water.
Nature scenes reduced stress, and produced more rapid recovery from stress, suggesting that even momentary viewings of trees through a window can have benefit. Participants exposed to natural settings had lower scores for anger/ aggression and fear with much higher scores for positive affects (Ulrich et al, 1991).
In Leiden, Holland, students after being attentionally fatigued strongly preferred the natural environment in which to be refreshed than an urban environment (Staats et al, 2003). The natural environment engendered a more positive attitude than in an urban environment.
After watching a frightening movie followed by videos of urban and natural environments, Van den Berg et al, (2003) found Dutch students gained greater restoration from the videos of nature. The sense of happiness was greater while depression, anger, tension and stress were lower.
Californian students at Irvine were much happier after a nature walk than a walk in an urban setting while anger decreased in the natural setting but increased in the urban environment (Hartig et al, 2003).
Over a hundred Swedish students found that following a fatiguing lecture, a more positive attitude and recovery from attentional fatigue resulted from a walk in a forest compared with a walk in a city (Hartig & Staats, 2006).
Improved cognitive function was found following a walk in a natural environment and viewing nature pictures compared with a walk in an urban environment and viewing urban pictures (Berman et al, 2008).
After engaging in a fatiguing attention test in Padova, Italy, only those participants exposed to restorative environments improved their performance in a sustained attention test (Berto, 2005).
Working on the assumption that gaining restorativeness from natural environments might also lead to ecologically friendly behavior, Hartig et al, (2001) tested the degree of restoration that students gained from a familiar freshwater wetland and compared this with their ecological behavior. They found that 23% of the variance in behavior could be explained by the fascination component of Kaplan’s theory. Hartig et al, (2007) found a similar result with adults in Norway.
Using Eye Position Detector System apparatus to measure saccades (quick eye movements) and fixations of the eye viewing scenes of nature and urban environments, Berto et al (2008) found that less effort was required to view nature than urban scenes.
A study in Ohio found that a walk in real nature provided substantially more psychological benefits than virtual nature via videos (Mayer et al, 2009). Participants were significantly more aware of their immediate environment than were the participants in the virtual-nature condition. Compared with urban videos, nature videos improved the overall positive affect by 17% while exposure to real nature improved it by 37%.
Research of people engaged in higher energy activities such as bike riding or running found that those viewing nature scenes while doing it had greater vitality than those viewing urban scenes (Ryan et al, 2010).
Viewing a nature video at the end of a work day was found to improve performance and long-term memory compared with viewing an urban video (Pilotti et al, 2015).
A study of 800 Spanish schoolchildren asked to rate their school yards in terms of it restorativeness found that perceived restoration accounted for 37% of the variance in behavior and paralleled their environmental attitudes (Collado & Corraliza, 2013).
A similar study in Australia by Bagot et al, (2015) also assessed the characteristics of the playgrounds and found that the amount of vegetation was the only significant naturalness measure of perceived restorativeness.
Gidlow et al, (2016) used randomized cross-over, field-based trials to compare psychological and physiological responses of unstressed individuals to 30 minute walks in residential, natural and natural with water environments. Mood and cortisol improved in all the walks, but restoration markedly improved after the natural walks, and cognitive function improvements persisted 30 minutes after the walk.
Children with Attention-Deficit Hyperactivity Disorder had lower symptom severity if they spent time in natural settings (Kuo & Taylor, 2004).
Tryväinen et al, (2014) compared the psychological and physiological effects of short term visits to the central city (Helsinki), an urban park and urban woodland. The park and woodland had virtually identical results with greater restorativeness reported for the woodland.
To assess whether physical activity such as walking vs siting affected well-being, Kinnafick & Thogersen-Ntoumani (2014) had subjects sit or walk in a laboratory setting or an outdoor sitting while viewing films of urban and natural environments. They found the combination of physical activity with an outdoor setting being the key for positive effects while sedentary behavior increased negative feelings, tiredness and decreased energy.
In Stanford, California, Bratman et al, (2015) found that participants in a 50-minute walk in a natural environment experienced decreased anxiety, rumination and negative affect as well as the cognitive benefit of improved performance of their working memory.
Nature and violence
Kuo & Sullivan (2001a) carried out a very closely controlled experiment among residents in multi-story public housing apartments in Chicago to ascertain whether nature (in the form of trees and grass) outside apartments reduced propensity to violence. Most of the residents were single African-American women in their 30s with several children. They had no control over which apartment they lived in or over the planting of trees and gardens in their surrounds.
The study found that those living with nature outside their apartments had significantly lower levels of aggression and violence than those who lived without trees and grass outside (Figure 5). In addition, the study found that residents living with vegetation in their vicinity used a smaller range of types of conflicts (e.g. stomping out of room, threatening to hit or kick something, pushing, biting) than those amidst barren conditions. Clearly, the study showed that living among nature resulted in less anti-social behavior than in the absence of nature.
Kuo & Sullivan, 2001a
Figure 5 Comparisons of aggression against partner over past year in green vs barren conditions
It has been conventional wisdom that thick vegetation and trees promote crime but Kuo & Sullivan (2001b) found the opposite to be true. In a poor public housing neighborhood of Chicago, they found that the greener a building’s surrounds, the fewer property crimes and violent crimes. Buildings with high levels of vegetation had 52% fewer total crimes, 48% fewer property crimes and 56% fewer violent crimes than buildings with low levels of vegetation.
An assessment of the influence of nature on children’s self-discipline in high-rise apartments in Chicago (Taylor et al, 2002) found that the more natural the view from the girl’s home was, her self-discipline improved by about 20%; however, for boys no relationship was detected.
New Haven, Connecticut, is a mid-sized city with high crime rates. Gilstad-Hayden et al, (2015) investigated the relationship between vegetation in the city and its crime and found that independent of other compounding factors, greater tree coverage was associated with lower rates of violent, property and total crime.
Heerwagen & Orians (1986) examined the décor in 75 campus offices at the University of Washington in Seattle and found that the windowless offices had more than twice the number of posters and items on the wall as the windowed offices. The windowless offices had four times as many scenes of landscapes than windowed offices. Landscapes outnumbered cityscape posters in windowless offices six-fold whereas in windowed offices they were only twice as many. Combining the landscape and posters of other natural objects (e.g. flowers, animals), windowless offices had three times more nature materials than did the windowed offices, and they used more than twice as many nature items as non-nature items (e.g. abstract paintings, collages, crafts).
Students at Texas A&M University undertook some frustrating computer exercises in four different office environments, one with no posters, one with abstract posters, one with nature posters and one with both abstract & nature posters. The study by Kweon et al, (2008), found the highest levels of anger and stress for males was with offices without posters, whereas for females it was offices with all abstract posters. Nature posters yielded the greatest stress- and anger-reducing effects.
Views from windows
Complementing Ulrich’s 1984 study of views from hospital windows, Verderber (1986) surveyed patients and staff at six hospitals in Chicago which had rooms with windows and without windows. Among staff, nature content of windowed rooms was the most preferred. Among patients, preferences of nature views were slightly lower than views of the busy city and street life.
Kaplan et al, 1988 conducted a survey of office workers, 55 without a view and 60 with a view of natural elements and found that workers without a view averaged 3.02 ailments over the previous 6 months whereas those with a view averaged 2.45, a 19% improvement. Those with a view also claimed greater job satisfaction.
A study of the views that university students had from their dormitory windows (Tennessen & Cimprich, 1995) found that natural views enhanced the student’s capacity for directed attention compared with those with fewer natural views. Even a modest exposure to natural environment such as a window view may benefit the capacity for directed attention.
Rachel Kaplan (2001) surveyed residents in low-rise apartments in Ann Arbor, Michigan with views out to parks, streams, woods and landscaped grounds and found that the results “Provided considerable support for the premise that having natural elements or settings in the view from the window contributes substantially to residents’ satisfaction with their neighborhood and with diverse aspects of their sense of well-being.”
A study of prisoners with a view to fields and farms in the vicinity found that they had much lower use of medical services than those without such a view (Moore, 1981).
Sop Shin (2007) found that workers who had a view of nearby forests had better job satisfaction and lower stress. Individual factors such as gender, age and job category had no influence.
Classrooms with views of trees and shrubs improve student performance and behavior in terms of test scores, graduation rates, continuing on to college and less criminal behavior (Matsuoka, 2010).
A study of the view from hospital beds for coronary and pulmonary patients found that the lack of a view to natural surroundings negatively affected women’s recovery while for men, it negatively affected their mental health (Raanaas et al, 2012). Patients with a view often chose to stay in their bedroom when they wanted to be alone than those with a blocked view.
Lottrup et al (2013) found that as physical access to the outdoors and views outside increased, workplace attitudes improved and the level of individual’s stress decreased. They suggest that the workplace outdoor environment is an asset for employees’ wellbeing and level of stress.
Health and green space
Over the past decade, a number of studies have established a relationship between people’s health and the amount of greenspace such as parks and gardens in their vicinity.
In an early study, Ulrich & Addoms (1981) assessed the psychological and recreation benefits of an urban park and found it provided substantial psychological benefits to residents even though they made little or no direct use of the park. The findings implied that mere awareness of the park’s presence is beneficial.
In an experiment with runners, Bodin & Hartig (2003) found the runners preferred the park over the urban streets and perceived it as more psychologically restorative. Pretty et al (2005) found that exercise conducted in view of pleasant rural and urban scenes resulted in lower blood pressure and increased self-esteem and improved mood while the opposite resulted from unpleasant rural and urban scenes. In a study in Zurich, Hug et al, (2009) found that outdoor exercise settings were rated as more restorative than indoor settings resulting in more frequent exercise. Any walking improves one’s outlook, but walking in a park reduces concerns about time pressures to a greater extent than walking on streets according to research by Johansson et al (2011). Exercise and being outdoors during free-time was the most effective activity for recovery from work stress, and the time spent in interacting with nature was second in importance; these were the results from a survey of employees in five organizations by Korpela & Kinnunen (2010).
Grahn & Stigsdotter (2003) examined the health and use of open green spaces by 953 people living in nine urban areas in Sweden. Overall, they reported that that the more often a person visits urban open green spaces, the less often he or she will report stress-related illnesses. This occurred across all ages, gender, and socio-economic levels. While it might be expected that those who did not have a garden would compensate by greater use of open green space, the reverse was, in fact, true, they used it less and their stress levels were accordingly greater than those with a garden. Those with a garden also made greater use of open green space. The authors suggest from their findings that more green areas should be provided near apartment housing, ensuring their accessibility, to alleviate stress and improve the health of town-dwellers.
Would the benefits of contact with nature extend to elderly people in an age person’s home? To test this, Ottosson & Grahn (2005) had 15 elderly people rest in a garden or an indoor setting for an hour and then tested their concentration. They found that those who had sat outside had greater powers of concentration.
In a paper entitled “Vitamin G: effects of green space on health, well-being, and social safety”, where Vitamin G stands of the amount of greenspace near people, Groenewegen et al, (2006) outlined a country-wide study in Holland. They proposed a simple model of the relationship between people and greenspace (Figure 6).
Groenewegen et al, 2006
Figure 6 Model of relationships between green space and health, well-being and social safety
Results from de Vries et al (2003) used self-reported health data of over 10,000 Dutch people and combined this with land use data on the amount of greenspace in their living environment up to 1.9 miles (3 km). They found
- With greater greenspace, people’s health, including mental health, was better. The effect was substantial; 10% more greenspace lowers symptoms by the equivalent of 5 years’ lower age.
- All types of green were found to be effective. The difference between a “red (brick) and green environment” is the key rather than differences within green.
- Greenspace is particularly important for those at home more, “housewives,” elderly, and children.
- It is the amount of greenspace within the living environment that is relevant rather than its distance.
A country-wide study covering all of Holland (Maas et al, 2006) compared health with the greenness of an individual’s vicinity. Using a self-rated scale of health for 250,000 people, they measured the agricultural, forest, nature and urban green spaces within a 0.6 – 1.9 mile (1 – 3 km) radius. They found that those living with green space nearby were healthier than those without green space. Where 90% of the surrounding environment was green, only 10% of people felt unhealthy whereas in areas with only 10% greenness, 15.5% of residents felt unhealthy (Figure 7). In densely urban areas, proximity to green space is very important. Maas et al, claimed that the “health differences in residents of urban and rural areas are to a large degree explained by the amount of green space.”
Maas et al, 2006 Figure 7 Relation between health and green space (radius 1.9 miles or 3 km)
Van den Berg et al, (2010) using the Dutch study further examined the influence of green space in ameliorating the effects of stressful life events – events such as divorce, family death, financial and legal problems or serious illnesses or injuries over the previous 3 months. The study controlled for age, gender, income, education level and urbanity. It found that respondents with a high amount of green space in a 1.9 mile (3 km) radius were less affected by a stressful life event than those without much green space (Figure 55). A similar but lesser effect was found for mental health. Interestingly the effect was found only for green space at a distance of 1.9 mile (3 km) rather than 0.6 mile (1 km), possibly because the areas were larger. General health improved by 2% following a life event for those with green space within 1.2 mile (2 km), and improved by 7% for green space within 1.9 mile (3 km).
Mitchell & Popham (2007) examined the relationship between green space and “not good health” covering all residents of England. Using the 32,482 statistical areas, they calculated the percentage of greenspace in each and then related this to the answers in a question in the 2001 Census, whether the person’s health had been ‘‘good’’, ‘‘fairly good’’ or ‘‘not good’’, over the previous 12 months. They used the “not good” responses and as well as greenspace, related it to the levels of employment deprivation, education skills and training deprivation, barriers to housing and service, crime and income deprivation in each of the statistical areas. The study found that only greenspace and urbanity were positive factors, but minor compared with employment deprivation and income deprivation which were the major factors. They derived a graph relating poor health with the amount of greenspace (Figure 8). Clearly, large proportions of greenspace have a positive effect on health.
Mitchell & Popham, 2007 Figure 8 Relationship between poor health and greenspace
Mitchell & Popham (2008) then took their research further by examining the relationship between green space and mortality in England. Using data covering 40 million people of below retirement age, they looked at mortality from all causes (366,348 deaths) as well as specific mortalities (circulatory disease, lung cancer and intentional self-harm) for 5 years, 2001-2005, and compared the mortality with green space exposure measured in 2001. This covered areas as small as 10 square meters and covered parks, open spaces and agricultural land, but excluded domestic gardens. The study also included area-based income deprivation levels. After controlling for confounding factors and income deprivation levels, the study found mortality rates reduced as green space increased. Compared with the group with the least green space (i.e. green space 1):
- Green space 2 mortality increased by 1.6%
- Green space 3 mortality decreased 1.8%
- Green space 4 mortality decreased by 5%
- Green space 5 (most) mortality decreased by 5.5%
The authors estimated that the highest exposure to green space saved 1328 lives annually. The study found the mortality from circulatory diseases similarly decreased with exposure to green space but that no relationships were detected for deaths from lung cancer or suicide.
A study by Nordh et al, (2009) that compared the restorative effect of parks with their detailed attributes found that the variables most predictive of restoration were the percentage of ground surface covered by grass, the amount of trees and bushes visible from the given viewing point, and apparent park size. They suggested the results be used to guide park design. The authors further refined their method (Nordh et al, 2011) and found that the amount of grass, trees and other people had the most influence on their choices of parks, these being more important than flowers and water features.
Paquet et al, (2013) in a study in Adelaide, South Australia measured the relationship between cardio-metabolic health and availability of public open space (POS). They found the number and proportion of POS were not found to be statistically significantly related to cardio-metabolic health; however, greenness, size, and type (active) of available POS were inversely related to cardio-metabolic risk. Physical activity was important in the association. The results suggest that it is the characteristics of public open space rather than their number that is important and that improving their quality rather than their accessibility would be more beneficial.
Lachowycz & Jones (2013) proposed a theoretical framework to better understand the relationships between green space and health, involving five components:
- Exposure – access to greenspace;
- Potential moderating factors – demographic, living context, greenspace characteristics, climate;
- Mechanism of moderation – opportunity to use, personal drivers and motivation to use, ease of use;
- Potential mediators – improved perceptions of living environment, aesthetic pleasure and relaxation from viewing greenspace, use of greenspace;
- Outcomes – physical health benefits and psychological health benefits.
Street trees are an important aspect of exposure to nature in cities and Taylor et al, (2015) examined the link between the density of street trees in London’s boroughs and rates of antidepressant (AD) prescriptions. After adjusting for possible confounders, they found that for every unit increase in tree density (e.g. from 30 to 31 trees/km), that AD scripts fell by 1.18 per 1000 population/annum (Figure 9). Areas of higher rates of AD had lower densities of street trees and also higher rates of smoking.
Taylor et al, 2015. Figure 9 Street density vs rate of antidepressant prescriptions, London
Champs Elysees, Paris – one of the most famous streets in the world –
imagine this street without the trees
Do the benefits of planting more street trees increase with every tree or does it taper off? To answer this question, Jiang et al, (2015) measured the density of tree cover in 121 community streets in four towns in the US and had these rated by over 300 people. They found that at low tree cover densities, a slight increase resulted in a considerable increase in preference but this fell off as tree cover increased (Figure 10). Although preferences still increased, diminishing returns set in so there was less increase for each additional tree. The priority should therefore be to plant trees where there are none rather than increasing the density of well-planted areas.
Jiang et al, 2015. Figure 10 Landscape preference vs tree cover
Preference for nature scenes over urban scenes
Table 2 lists the 21 studies that compared the preferences for nature and urban scenes and indicates the percentage increase of preference for the nature scene over the urban scene. The basis of each study varied and included measures of affect, vitality and restoration, and the use of photos, posters, views from windows, and walks. They include physiological measures such as heart beat and pulse, brain alpha waves, and taking analgesics, all of which can provide direct evidence of the calming effect of nature. The overall mean is 168% (SD 61%) which means that the preference for nature is more than two-thirds higher that for urban scenes.
Table 2 Preferences for nature scenes over urban scenes
Restorative power of nature
Applying Attention Restoration Theory, several studies measured the restorative effect of urban and nature scenes using the four components: being away, fascination, extent or coherence, and compatibility. Restoration in natural environments from “being away” is over three times that of urban environments, followed by “compatibility” (i.e. compatibility of the environment with one’s purposes) and fascination at over twice the urban environment (Table 3).
Table 3 Restorative power of nature – Percentage increase over urban scenes
Note: PRS = Perceived Restorativeness Scale; FU = Favorite sites % cf unpleasant sites; EEG = electrocephalography, EMG = electromyography. Korpela et al studies compared favorite & unpleasant places. Felsten compared no view with views of murals of land and water.
Health Council of The Netherlands Report findings
In 2004, the Health Council of The Netherlands published an extensive review of the literature on nature and health from which they issued the following conclusions:
“There is strong evidence that nature has a positive effect on recovery from stress and attention fatigue. Exposure to nature evidently has a positive impact on such factors as mood, concentration, self-discipline and physiological stress. This applies both to experimental and quasi-experimental research, performed under laboratory and field conditions with healthy adults and, in some cases, with children.
It is notable that beneficial effects occur even in connection with brief exposure to a view of nature. We know little, however, about what impact the duration of the exposure has on recovery from stress and attention fatigue and about the knock-on effect of that impact on the prevention of illness and on well-being in the long term. It is not inconceivable that a permanent view may lessen the stress-relieving effect.
Little is known about the influence of different types of nature. Subjects were always exposed to nature either via a view of one type of predominantly urban nature (whether simulated or real) or by walking or playing in urban nature. Only in a few studies did the researchers look into the influence of wild nature.
(It) is plausible that there could be a genetic component (i.e. evolutionary influence). This does not, however, rule out the possibility that all manner of individual and cultural factors may play a moderating role. Research indicates, for example, that people tend to seek out nature when they feel stressed or tired because they presume nature to have a restorative effect. It is not known whether people who do not believe nature to have restorative powers – or are perhaps even afraid of nature – can also recover as a result of contact with nature.”
The past several decades have seen much research on the healing and restorative effects of viewing nature. Over 150 studies were reviewed, and the universal conclusion is that viewing and experiencing nature provides substantial emotional and physiological benefits. The preference for nature scenes is more than two-third greater than that of urban scenes, while the restorative benefits of nature are at least three times as much as viewing urban scenes. Exposure to green space in cities is vitally important, improving health and even reducing morbidity.
The research findings should be applied in the design of hospitals, offices, schools and homes to ensure views and access to greenery, to the design of cities to integrate green spaces more into their fabric and ensure their access by residents. No one should be without nearby open green space. The research shows the importance of introducing greenery into cities with street trees, back yards with trees and greenery and green parks and gardens with extensive trees and grass. With increasing higher-density living in cities, the research shows how essential it is that people have windows to view greenery, not blank walls. This calls for care in designing living spaces at a micro level, ensuring views together with proximity and access to greenspace.
The research also encourages us as individuals to make greater use of nature, by visiting green spaces more often, by ensuring our houses look out at greenery in our private space, by taking children to parks and gardens and natural areas so that they become accustomed to them, by ensuring that the elderly is still able to enjoy a view over gardens with flowers and trees. All of these will promote better health for the individual and may even prolong our lives!
There have been five special issues of key journals with extensive papers on restorative environments:
- Environment & Behavior, 33:4, 2001;
- Journal of Environmental Psychology, 23:2, 2003;
- Landscape & Urban Planning, 118, 2013; 148, 2016;
- Landscape Research, 41:6, 2016.
In addition, there have been the following reviews of the health/nature literature:
- Maller, C., M. Townsend, A. Pryor, P. Brown & L. St Leger, 2000;
- Health Council of The Netherlands, 2004;
- Tzoulas, K., K. Korpela, S. Venn, V. Ylipelkonen, A. Kazmierczak, J. Niemela & P. James, 2007;
- Ulrich, R. S., Zimring, C. M., Zhu, X., DuBose, J., Seo, H., Choi, Y. et al,
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