Any new studio reference book needs be beautifully illustrated. In this respect, Harvard University landscape architecture professor Niall Kirkwood, FASLA, and landscape architect Kate Kennen, ASLA, don’t disappoint with Phyto: Principles and Resources for Site Remediation and Landscape Design. But while we all like to look at beautifully-crafted, well-curated imagery, that’s not the point. This book is illuminating, a careful and coherent, critical and constructive analysis of the Phytoremediation movement, which calls for using plants to remove toxic chemicals, metals, and other contaminants from the environment.
The book begins by acknowledging an accomplished group of contributors, who bring credibility to a subject critically important but too often dismissed in the “real world.” Early on, the book provides a thoughtful sequence that explains the rationale for the book’s structure and answers the question: why are we dedicating another book to this subject?
Well, the answer is clear: because no other book has provided the thoughtful and accessible bridge long needed between theory and practice. While providing justification for the book could come off as a bit self-conscious, instead it reads as an honest depiction of an emerging field. (I also feel that if more authors were forced to go through this process of self examination, we would have both far-fewer volumes, but many-more excellent books like Phyto from which to choose).
The first two chapters cover the history and fundamentals of phytoremediation. After clearly articulating the knowledge gaps that exist in the field, the book contextualizes the movement’s early failures. Phyto then provides an expansive re-branding of the discipline, empowering potential users of these plant-based technologies to think more strategically about opportunities at hand.
The text provides a clear and comprehensive vocabulary for landscape architects and designers to use in practice. From there, the book shows how to apply these technologies in real-world situations. The book delves into common contaminants of concern and how they can be targeted with precision; a summary of planting assemblages that can be deployed in concert representing best in field technologies; and typical examples of spatial designs that produce common contaminant profiles and likely site characteristics. Variation of type and scale creates flexibility, showing landscape architects and designers how to find just the right application of phytoremediation technologies.
As knowledge-based considerations continue to find their way into public landscape design and management, inventive designers and enlightened clients interested in looking at all the alternatives would do themselves a favor by adding this book to their library and its knowledge to their practice.
This guest post is by Christian Gabriel, ASLA, National Design Director of Landscape Architecture, General Services Administration (GSA).
While landscape architects, arborists, and park advocates, and an increasing number of mayors, planners, and public health officials, understand the presence of nearby nature in cities to be central to human health and well-being, the public seems to think of tree-lined streets, trails, and parks as “nice, but not necessary, add-ons,” according to a new report commissioned by the TKF Foundation and conducted by the FrameWorks Institute, a non-partisan research organization. The report shows wide gaps in understanding between members of the public and experts on the health benefits of nature, the value of daily exposure to nature, how landscape design can enhance nature’s health and social benefits, and how the presence of green space and trees can boost neighborhood and, by extension, community connections. The members of the public surveyed also don’t perceive the typical differences in the amount of trees and parks available to wealthy and poorer urban neighborhoods and so don’t see it as a major equity issue. Urban nature is simply not a top priority. As one survey respondent said, “nature doesn’t pay the bills.” FrameWorks argues the best way to increase public demand for more parks, trails, and green streets is to undertake a broad communications campaign to educate the public about the health benefits of nature.
FrameWorks interviewed 13 experts on urban nature in one-on-one sessions over multiple hours. Interviews with 52 members of the public were conducted across the country, with 20 in-depth dialogues along with 32 10-minute ones on the street. Interviewees were selected to be representative of the make-up of the country in terms of age, ethnicity, gender, residential location (inner city, outer-city, and rural areas up to three hours from the city), educational background, religious involvement, and political views. This is a small sample of the general public, but FrameWorks argues it’s enough to get a sense of the public’s “top of the mind” thinking about nature, cities, and health.
The experts and members of the public agreed on many things, and FrameWorks argues these areas of agreement are key starting points for creating a campaign that can increase public demand for more urban trees and green spaces:
First, nature is the root of human existence. Humans evolved from natural environments. Experts know this because their training is “firmly grounded in evolutionary biology,” but members of the public understand this, too.
Second, both the public and experts agree that nature sustains us. “Nature is the source of human sustenance,” said both groups, but members of the public tend to be more “consumerist in tenor and less attuned to the importance of biodiversity and linkages across ecosystems.” Consumerist because many of the respondents view nature as simply a source of food, wood and paper, etc — something to be consumed to meet human needs.
Third, cities are inherently stressful; they work against human well-being. Members of the public and experts agree that city life, with its fast pace, as well as “elevated levels of congestion, air pollution” and prevalence of concrete, can be “hard, cold, grey, and depressing.”
Fourth, feeling safe in nature boosts well-being. A quiet natural spot is seen by both members of the public and experts as a “respite from the stressors of modern urban life.” Places with lots of trees and water can provide “rest and positive distraction.” Nature is the opposite of our hectic urban life. Another key concept upon which to build greater understanding.
The gaps between members and the public are too numerous to list in full here, but here are main areas of divergence:
While experts view nature as central to human health and well-being, members of the public view it as a nice add-on and the absence of urban nature doesn’t rank among their top concerns. This may be because the members of the public surveyed don’t understand how time in nature reduces their stress, improves their ability to pay attention, or boosts their sense of well-being.
Experts understand that neighborhood access to trees and park space trends quite closely with income levels — wealthier neighborhoods typically have more of these natural assets than poorer ones, but members of the public are unaware of these different levels of access of nature. Experts also look to the broader return on investment these green spaces provide to tree and park-laden neighborhoods — in terms of increased safety, greater social cohesion and community connection, and improved health — while the public isn’t thinking in those terms. In particular, the community benefits of trees and green spaces are way off their radar.
Experts conceive of a whole range of innovative green infrastructure to deliver the health benefits of nature, but the members of public surveyed mostly thinks in terms of parks and walking or bike trails for recreation and exercise. According to the experts, natural infrastructure helps maximize daily exposures to nature, as exposure needs to be continuous for the benefits of small doses to accrue. But the public thinks of time in nature as a memorable one-off experience — a road trip to Yellowstone National Park, or a weekend hike on the Shenandoah Trail. Nature is a place to go to outside the city to recharge.
For experts, designed nature — realized through landscape architecture or garden design — has intrinsic value. They believe it’s still nature even if it’s managed, but the public largely sees nature “out there,” away from cities, as the most “salutary.” According to the experts, even a small urban garden can provide benefits, but members of the public don’t think these places offer a true break, only those places that truly remove them from their everyday urban life.
Lastly, the experts see the value of good design in public parks, but members of the public surveyed simply think in terms of quantity of green space. “For the public, design is largely a taken-for-granted feature.”
The question then for the many health, design, parks, and trails organizations working on these issues is: how best to communicate the health benefits of nearby urban nature to the public? How can we convince the broader public that spending time in a park, riding a bicycle on a tree-lined trail, or jogging along an urban forest path will have a “meaningful difference” in their health and this natural infrastructure can boost the broader health of the city? How can we convince them that nature in cities can be just as restorative as the nature “out there?”
The best proof may be the reality — well-designed urban parks are natural draws. But many argue that what’s needed is more research and more promotion of positive findings through the media and advocacy efforts directed at urban policymakers. ASLA created a guide to the Health Benefits of Nature, which collects the most credible research, and it has been immensely popular. But, clearly, more research studies are needed, which TKF and some universities and foundations are sponsoring, and more targeted communications campaigns are also needed to reach the urban public.
More promising small-sample research studies could also generate demand for a government-financed, large-scale, longitudinal study examining the impact of nature on all sorts of health mental and physical health issues. This kind of study, if it demonstrated positive results, could help bring the mainstream public health community on board, and, in turn, even more urban policymakers.
The good news is that many mayors and cities already get the value of access to nature, even in car-centric places like Houston, which is investing huge sums in new parks and trails. As momentum builds and more cities act, we can imagine a future where people in all of a city’s neighborhoods enjoy a daily nature outing because nature is everywhere, but this future will take lots more work to achieve.
What if what is outside a school’s windows is as critical to learning as what’s inside the building? A fascinating new study of high school students in central Illinois found that students with a view of trees were able to recover their ability to pay attention and bounce back from stress more rapidly than those who looked out on a parking lot or had no windows. The researchers, William Sullivan, ASLA, professor of landscape architecture at University of Illinois at Urbana-Champaign, and Dongying Li, a PhD student there, reported their findings in the journal Landscape and Urban Planning.
Sullivan and Li argue that “context impacts learning. It is well-documented, for instance, that physical characteristics of school environments, such as lighting, noise, indoor air quality and thermal comfort, building age and conditions all impact learning.” However, schools’ surrounding landscapes have been too long overlooked for their impact on learning, and it’s time to understand what campus greenery — or lack thereof — means for student performance. Research studies to date have had relatively small sample sizes. While these studies point to encouraging correlations or associations between improved student performance and access to nature on campus, Sullivan and Li argue that up until their study, no causal connections have been proven.
Looking at the effect of views of nature on both cognition and stress recovery, they test two theories: attention restoration theory and stress reduction theory. According to their report, attention restoration theory posits that “people use voluntary control to inhibit distractions and remain focused, and this capacity to remain focused fatigues over time.” But the theory also contends that even just a short period of time in nature (10 minutes or so) can renew our cognitive capacity to pay attention. Nature does this through its ability to engender “soft fascination” that doesn’t demand all of our attention, just enough to enliven us. Stress reduction theory looks at how nature supports psychological and physiological recovery, including lower blood pressure and levels of stress hormones.
In Sullivan and Li’s study, a third of the 94 students, equally male and female, were each randomly assigned to a classroom with either no windows, a window view looking out on a barren landscape, or a window view looking out over greenery. They were all put through about 30 minutes of classroom exercises. Their stress and cognitive states were tested in the beginning to set a baseline, at the end of the classroom activities, and then again after a 10 minute break after the activities. Researchers used both standard questionnaires to test stress and attention levels and various tools to measure their physiological responses to stress, including heart rates, body temperatures, and skin conductance.
After the students had completed 30 minutes of classroom activities, the researchers found the window views of greenery had no impact on students’ ability to pay attention or their stress levels. However, at the end of a 10 minute break after the activities, the researchers discovered those who had a green view bounced back, attention-wise, and became less stressed — this group “performed significantly better on standard tests of attention and showed significantly greater stress recovery than their peers who were assigned to classrooms without a green view.” They think this is because during the classroom activities the students were too busy focused on what they were learning. Only when students with green views had a chance to take a break was their “involuntary attention” engaged while looking out the window. Only then did they receive the restorative benefits of looking at the trees.
Sullivan and Li say they found a causal relationship: “green views produced better attentional functioning and stress recovery.” Furthermore, viewing nature helps both cognition and stress recovery, but through separate mental pathways. In other words, nature’s ability to help us recover our ability to pay attention has nothing to do with whether we are stressed out or not, but nature, separately, also helps us recover from stress. (To learn more about this aspect of their research, read the study).
What’s important for designers, school principals, and educational policymakers is that this is yet another promising study that points to the direct benefits of exposure to nature for students. Sullivan and Li argue that new schools, which are often placed at the “urban-rural fringe” need to be sited where there are a lot of existing trees, and, if that’s not possible, trees and shrubs need to be added. New schools should also be designed so they maximize views of trees and greenery from the inside; and existing schools retrofitted to improve the connection to nature. As Sullivan and Li argue, “architects should work to ensure every classroom has views of green space. Landscape architects should consider the location of classrooms, cafeteria, and hallway windows in the development of their campus design.”
These changes to schools could be more cost-effective than “most interventions aimed at relieving stress (e.g., emotional skill building, anger management, positive behavior programs). Placing trees and shrubs on the school ground is a modest, low-cost intervention that is likely to have long-lasting effects on generations of students.” Lots of schools encourage student environmental groups to engage in volunteer community service. Why not involve these students in the greening of their own campuses and teach them about the value of nature at the same time?
As with any study on the health benefits of nature with a relatively small sample size like this, there are priming issues. And Sullivan and Li acknowledge this: “one limitation is that we could not take into account students’ interactions, physical activities, and their immersive experiences out on the school ground during break, or their exposure to green space during physical education classes or after school. This limits the ecological validity of the findings.”
What’s needed is a large-scale, longitudinal, government-financed study that looks at the benefits of nature across all critical dimensions, but, until then, here is another study that points to the positive effects of nature on cognition and stress recovery, this time in an educational environment.