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Ecological Succession and Plant Choice

By Wes Griffith, BSLA Student, and Chris Sass, Assistant Professor, University of Kentucky

While participating in LAF’s 2015 Case Study Investigation (CSI) program, many themes came to the surface, but one stood out to us as an area directly addressable by landscape architects. That theme is the issue of ecological succession and plant choice. Ecological succession describes how ecosystems change over time, sometimes in a predicable manner, but not always. So how do we as landscape architects begin to address ecological succession through our sustainable designs and planting plans?

One of the first goals to help landscape architects think about ecological succession should be to set a long-term management plan that dictates how a landscape will be managed, including removal of invasive plants, the addition of native seed or plants, and the social dynamic of the site. Such goals were addressed in one of the projects we studied, the Lower Howard’s Creek Corridor Management Plan, which considers ecological, social and economic integrity.

A long-term management plan is necessary because succession occurs over a long time period. How long is long-term? Well for example, the second growth forest at Lower Howard’s Creek has been re-establishing since the late 1800s and we are just now starting to see some mid-successional species as early successional species are beginning to be replaced. Species such as Eastern Red Cedar (Juniperus virginiana), Honey Locust (Gleditsia triacanthos) and foxtail (Seteria spp) are being replaced by oaks (Quercus spp), Shagbark Hickory (Carya ovata) and Riparian Wild Rye (Elymus riparius). So how long is long-term? Definitely longer than our current 25-year project lifespan. This reminds me of the Iroquois maxim stating we need to plan for the seventh generation if we are to truly achieve sustainability.

The Coefficient of Conservatism (CoC) is a tool we can use to plan for ecological succession. CoC numbers range from 1 to 10, where lower numbers indicate a wider range of plant tolerance and higher numbers indicate a much lower range of tolerance. The later successional species mentioned above exhibit a higher CoC number, meaning they require a more specific habitat and exhibit a lower tolerance range. While it may seem like the right thing to do, using higher CoC plants in our initial planting plans is probably not the best idea. Unless we are certain — or make certain through costly amendments — that the specific habitat requirements are there, the higher CoC plants will not make it very long, and we will have wasted the plants and the opportunity. We see this mistake often in our profession. For example, a planting plan may call for Shooting Star (Dodecatheon meadia), which in many areas is endangered or threatened and has a high CoC. It is tempting to plant, but will this plant not only survive, but thrive and reproduce in a new planting area? Probably not unless the habitat is within its tolerance range.

Using the CoC, we can plan plantings by assessing the stage of succession we are designing. Higher CoC numbers will require very specific tolerance ranges and habitat types, while lower CoC numbers will be much less fussy in the landscape. Looking through some of the project planting schedules for the sites we studied, we noticed that the CoC values of plant species ranged from 1 to 10, the minimum and maximum numbers. The question becomes: What have we designed for? A highly established landscape that is fairly stable? Or one that is just beginning to establish itself at the early seral stages?

Maintenance plays an important role in how we begin to plan for successional landscape designs. We have found maintenance to be an issue at two of the sites we studied. Both college campus projects, Northern Kentucky University’s Norse Commons and the University of Kentucky’s College of Agriculture Alumni Plaza, used native plants, and unfortunately some of the planted species have been outcompeted.

In all, as a profession concerned with sustainable approaches, we should think beyond the 25-year mark and aim more for the century mark and beyond. Let’s be more like the Iroquois and plan for seven generations.

Research Assistant Wes Griffith and Research Fellow Chris Sass are participating in LAF’s 2015 Case Study Investigation (CSI) program and working to evaluate the environmental, economic and social performance of three sustainable landscape projects in Kentucky.

Landscape Innovation Paving the Way... But Not Without Some Roadblocks

By Neive Tierney, MLA Candidate, University of Texas at Austin

The three projects I researched as part of LAF’s Case Study Investigation (CSI) program all share a common story: They are progressive landscapes featuring innovative components, which caused the projects to run into barriers during construction. These obstructions arose because each project was the first of its kind in its surroundings.

Houston’s Bagby Street Reconstruction is an example of a landscape architecture project that became a catalyst for political change. The project’s extensive use of rain gardens and the designers’ decision to reduce the street width and increase pedestrian area diverged from the traditional stormwater management systems accepted in Houston. Making such a radical change to something as institutional as street design did not happen without some serious push-back from various stakeholders.

In order to move the project along, the Mayor of Houston and her staff became involved and played a large role in the completion of the project. At the Bagby ribbon cutting ceremony in 2013, the Mayor released a Complete Street Executive Order which called for changing the way streets are designed in all of Houston. The Bagby Street Reconstruction is a compelling example of landscape architecture’s influence on environmental progress. Both the client and design team were willing to take the difficult path to execute the design intent. Although this meant that the project took longer to implement than planned, its ultimate success resulted in widespread acceptance of this kind of stormwater management throughout the whole city. The design team is currently working on a similar project on the neighboring Brazos Street.

bagby-raingardenBagby Street rain garden (Image: Design Workshop)

The park at the George W. Bush Presidential Library (GWBPL) is a true example of designing with nature in mind. The design intent was to set up the perfect conditions where native ecologies could effectively “work” on their own. The first task was to establish a vital and living soil. Finding a sufficient amount of healthy soil for a project of this size was impossible, so the design team had to construct their own. With the assistance of a team of soil consultants, 65,000 cubic yards of soil were repurposed for the site. Each specific ecosystem and plant community required its own soil type. Constructed soil had to be treated like the brown gold that it is. Every precaution was taken to protect soil from overheating and becoming compacted before it was used on the site.

Another crucial component of the GWBPL landscape is the native plant material. The project is composed of large swaths of vegetation types native to the Dallas area, such as blackland prairie. Ironically, local plant vendors generally did not sell these types of native plants and as such, sourcing plant material for the 15-acre park was no easy task. Plants were sourced from vendors in neighboring states, and many of the grasses were planted from seed. The outcome of this initial obstacle is that the demand from the GWBPL was so great that it changed the kinds of plant material now available in the region, with vendors now selling more native plants.

belo-recycled-waterIllustration of Belo Center water system (Image: Ten Eyck Landscape Architecture)

The Belo Center for New Media is a facility on the University of Texas at Austin campus. Most of the campus is composed of more traditional plantings with turf lawns and many historic oak trees. Irrigation techniques are different depending on the section of campus, but the majority of campus is irrigated with potable water from the City of Austin. The courtyard landscape at the Belo Center uses a highly innovative water system. Air conditioning condensate is collected and run through a planted fountain that cleans water and circulates it back to the site for irrigation. In addition, all rainwater from the roof of the Belo Center is harvested and stored in on-site cisterns.

The sophisticated water system was difficult to implement and, in fact, did not work as planned until recently — years after the project’s completion. So many parties were involved in constructing this system that the design team had to make educational diagrams illustrating which group was responsible for each part of the system. These diagrams were posted at important locations around the site during construction. The delay in getting the system operational resulted in a much larger potable water demand than the design intended. However, starting this year, with all the problems corrected, the landscape will only be irrigated with recycled water, making it the first landscape on campus to not use any potable water for irrigation.

The innovative qualities of these projects required additional work from their design teams, but this extra effort led to projects with significantly higher environmental performance . By researching and documenting these projects through CSI, I have a clear example of the power behind innovative design. The inventive qualities of landscape architecture can not only result in a successful project; they can catalyze environmental improvements throughout entire systems.

Research Assistant Neive Tierney and Research Fellow Allan W. Shearer, PhD are participating in LAF’s 2015 Case Study Investigation (CSI) program and working to evaluate the environmental, economic and social performance of three innovative landscape projects in Texas.

Bumps in the Performance Evaluation Road

By Erika Roeber, Bachelor of Science in Agriculture Candidate, South Dakota State University

dashboard-600wUS Highway 16-West between Rapid City, South Dakota and Mount Rushmore

Driving across South Dakota’s never ending interstate, you are likely to hit a few bumps. Evaluating the performance of the three projects we are studying as part of the Landscape Architecture Foundation’s Case Study Investigation (CSI) program was no different: smooth sailing at first with the planning of our economic and environmental benefits. The social benefits brought our first bump when our research team decided to conduct user surveys for each of the sites.

All survey research involving human subjects requires approval from a university’s Institution Review Board. To get IRB approval at South Dakota State, each researcher needs to have a Collaborative Institutional Training Initiative (CITI) certificate. The faculty Research Fellow was already certified, but I had to complete a course with multiple readings and quizzes — in all it took about ten hours to complete. After that, the process of submitting our proposal and getting approval on our surveys only took 1.5 days. Our expert tip: use exempt status and only have adults as survey participants; this makes IRB approval a smoother process.

Being native to South Dakota, I know there is more than just one bump along the highway. The Mount Rushmore Visitor Center Redevelopment presented a huge obstacle when it came to doing user surveys. In order to do research on any federal land, including all national parks and memorials, researchers must first obtain a National Park Service (NPS) research permit. This process takes anywhere from one to six months. Once approved, the researcher can use scientific equipment to gather data (i.e. thermometers, water samples, etc.), and they can distribute up to nine surveys on-site.

If the researcher wants to disperse more than nine surveys, they must complete an additional application through the Paperwork Reduction Act (PRA) and PRA Clearance, a term used for the process of obtaining approval from the Office of Management and Budget (OMB) for federally sponsored data collections as required by the PRA. This rule was put into effect due to increasing complaints from the public about duplicate and lengthy federal government data collections. The PRA clearance process can take anywhere from six to nine months to be approved. Upon learning this, it was evident that on-site user surveys would not be feasible within the CSI timeframe.

Instead, we decided to post our surveys online through social media. A member of the Mount Rushmore staff indicated that we would not have any regulatory difficulties doing our surverys this way. However, upon further research and after the survey had been posted, I discovered that online surveys do require PRA clearance if specific questions are asked. So we should have gone through the PRA process after all. This approval is not necessary for very general invitations for public comments and suggestions.

Through all the bumps in the road, we were still able to gather valuable data and information about the Mount Rushmore Visitor Center Redevelopment. Alternative approaches had to be taken, but they were doable given the variety of information that had been collected from past research. Despite the challenges, federal land represents an exciting opportunity for landscape performance research.

Research Assistant Erika Roeber and Research Fellow Matthew James, Ed.D are participating in LAF’s 2015 Case Study Investigation (CSI) program and working to evaluate the environmental, economic and social performance of three public projects in South Dakota.

International Hurdles and Chance Relationships

By Kevin Eidick, MLA Candidate, University of Manitoba

Participating in LAF’s Case Study Investigation (CSI) program has been an extremely exciting experience so far. While I have to admit, my familiarity with the Landscape Performance Series website was little more than a quick click and overview in the past, this process has introduced me to such a vital resource that I will surely be revisiting during my remaining scholastic and professional career. This opportunity has exposed me to such a diverse breadth of projects and knowledge in landscape architecture and planning that boast some amazing environmental and socioeconomic benefits. Even more exciting is that these claims and performances are measured and backed up with some solid data.

My CSI research team is based in Winnipeg, Canada, and we are studying projects in the Riyadh Province of Saudi Arabia. Being one of few international research teams, and studying a project outside of the U.S., we were met with some unique hurdles. Firstly, many of the tools in the Landscape Performance Series Benefits Toolkit (for example, iTree, National Tree Benefit Calculator, and the National Stormwater Calculator) were developed for the U.S. They may not be appropriate to other countries or may require creative adaptations, such as using similar species or climate zones to estimate tree benefits in iTree.

We are investigating to see if we can modify variables within some of these software programs to more accurately represent the benefits in such a unique region of the world. Trying to find international equivalents to some of the software opened up the realization that most environmental agencies do not invest in similar tools. (Or perhaps they do exist but are not as readily available to the public.) It is impressive and commendable that federal agencies like the EPA and USDA offer such comprehensive resources.

wadihanifah02While faculty Research Fellow Jean Trottier was familiar with the projects and their context, going into CSI I knew very little about Saudi Arabia and even less about the city of Riyadh. I was quite concerned about pursuing measurements of our projects’ social benefits since most of the Landscape Performance Series case studies rely on questionnaires or surveys in their assessments. Given the more than 12,000km distance between our research team and the projects, as well as the social conventions in Saudi Arabia, public surveys would be impractical. This forced us to be creative and look at different social media aggregators as a way to assess the increase in project use or significance. We are also finding indirect indicators of use — the parks’ toilet blocks! However, we are not sure if we can develop a statistically solid model on this…unique… form of measurement.

I didn’t want our case studies to provide only a superficial overview of Riyadh’s social attitude towards the projects along the Wadi Hanifah. Yet we didn’t know Arabic, nor any Saudis personally who could offer opinion or insight on what some of these projects mean to them. The universe works in mysterious ways, and it seemingly threw me a bone. At the peak of my frustration with navigating the social benefits of the projects, I was fortunate enough to meet a neighbour in the apartment complex I had recently moved to. This neighbour, Farhan, had moved to Canada in 2013 after spending half a decade working at the King Saud University in Riyadh where his commute took him along the parks of Wadi Hanifah every morning.

With the Wadi Hanifah as the initial catalyst for conversation, this chance relationship has grown into a budding friendship. Farhan explained to me his experiences in the parks, how these experiences differ when he is there with his young family. He also gave me great insight on some of the social and cultural norms that exist in Saudi Arabia. It is interesting to see how the design of these projects responds to the cultural context of Riyadh. While there were some striking similarities between car-oriented North American cities and Riyadh (apparently their morning commutes have gruesomely endless bumper to bumper traffic that could give Los Angeles a run for its money), the Saudis are a much more private society with much less exuberance and flare in their public domain.

wadihanifah01It has been quite interesting to hear what are some of the most successful spaces in the Wadi Hanifah public parks from a citizen’s point of view. For example, the semi-circular seating areas with large limestone slab walls delineating more private areas offer families more intimate and comfortable spaces to enjoy the park and are heavily used on a daily basis. Similar to us Canadians and to our American neighbours, the Saudis also love to barbecue and use the public cooking areas in the parks to break the ice with strangers — inviting random passersby for a bite to eat and subsequent conversation.

Farhan has helped me navigate some interesting information (all in Arabic of course) that may inform our team as we delve further into the research process. Through this opportunity with CSI, I have been fortunate to meet a new friend, learn about a vibrant Saudi culture, learn more about Islam, and better inform myself on a part of the world I would otherwise not have been so thoroughly exposed to.

Research Assistant Kevin Eidick and Research Fellow Jean Trottier are participating in LAF’s 2015 Case Study Investigation (CSI) program and working to evaluate the environmental, economic and social performance of three projects that are part of the Wadi Hanifah Civic Parks and Comprehensive Development Plan in the Riyadh Province of central Saudi Arabia.

P is for Process

By Sadie L. Walters, MLA Candidate, North Carolina State University

The writings of Richard Louv, Rachel Carson, and Aldo Leopold have long served to guide me in my work and, ultimately, were responsible for leading me to landscape architecture. Since entering this circle, I have been inspired by the artful and environmentally sensitive work of historical and current landscape architects, including my teachers at North Carolina State University.

In my two years as a graduate student, I have come to the realization that evidence-based design is the direction in which I am headed — I want to know how landscape can be a bridge between human health and quality outdoor experience, how it can provide a corridor for the sweet song of the wood thrush, and how built environments can respond to and integrate with natural systems. To that end, landscape research has captured my focus. In the fall of 2014, Andy Fox approached me with an opportunity to participate in LAF’s Case Study Investigation (CSI) program. In this program, I saw an opportunity to frame and begin to answer some of these questions within three landscapes in the North Carolina Piedmont.

While the chill of winter still clung to the dry air, Andy and I began the process of gathering information about our three projects, meeting with the design firms and respective project stakeholders. There was excitement in every meeting as we explained the value of landscape research and the forthcoming recognition of each site’s commitment to sustainability. As our discussions gained momentum, lists of sustainable features and potential areas of study grew long — certified North Carolina native landscape, innovative stormwater treatment trains, native bee habitat, increases in garden membership and volunteerism, reduction in mower time, and on and on. Following the meetings, we were rich in the currency of performance criteria, and so began our (re)quest for records and data.

01-researchprocess

We collected data and had follow-up meetings well into late May; it was then that the research limitations became clear. The façade of mountains of information opened up to reveal key missing links, holes in data collection, and absent records. The month and a half of deep digging showed us that there were far fewer suitable research topics than our initial meetings had indicated. It was to no one’s fault, but was simply a necessary reality of research.

Out of this experience, I offer the following lessons learned: take time early on to define your own method(s) of sorting through piles of information and develop a process to know when you will let go of a potential research topic and when you will push for more information.

As the heat of summer’s arrival pressed at the windows, Andy and I convened in his office for a conference call with LAF. As Andy described our current plans for measuring stormwater benefits, my eyes wandered to three books on his shelf — Louv, Carson, and Leopold. Even with our slimmed down list of measurable performance benefits, it was clear that we were still on the path, and the future of our study, though quite full, was bright.

Research Assistant Sadie Walters and Research Fellow Andrew Fox are participating in LAF’s 2015 Case Study Investigation (CSI) program. They are working to evaluate and document the environmental, social, and economic performance of three exemplary landscape projects in North Carolina’s Research Triangle.