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Professional, personal, informational, or inquiring posts written by you on a variety of topics: plant pallets, food production, design methods, planning, pollinators, client relationships, botanical excursions, or just about anything interesting.

Best Streets Policies

Posted by on Dec 15, 2015 in Planning | 0 comments

Best Streets Policies

Smart Growth America makes recommendations for policies that help create safer streets for pedestrians and bicyclists, such as this report.

Bioswales – Design and Plant Selection

Posted by on Oct 15, 2015 in Blog, Water Management | 0 comments

Bioswales – Design and Plant Selection

This post is in response to Rachel’s questions about a bioswale for a winery. The challenges for her project include high acidity and a short period of time with a high input of material into the bioswale. Plant selection is important, but so is calculating how much sediment the bioswale can handle and still function properly. There are many resources that provide simple overviews on wetland systems (bioswales, rain gardens, retention ponds) designed to treat waste water, but few go into design detail or provide thorough plant selection information. Below are a few resources I found that provide that in-depth information.

This Plant List from the Minnesota Pollution Control Agency lists plants that are suitable for the  Upper Midwest (zones 4, 5, 6) for  bioswales and rain gardens. Along with plant characteristics, it lists each plant’s tolerances (flooding, salt, nutrient load, siltation, pH), design considerations, and planting techniques. More information on plant selection is provided in this document, including properly locating plants within bioswale zones and environmental influences on plants.

The Stormwater Toolkit offers information on soil preparation, design considerations, maintenance recommendations, costs, limitations, and suggested references for grassed swales.

Understanding the limitations of bioswales is also important.  This research paper on Nutrient Removal from Wastewater by Wetland Systems presents factors that affect the ability of wastewater systems to breakdown various nutrients. These factors include temperature, inflow and outflow rates, oxygen avaiablity, pollutant and nutrient loading rates, and wetland design components, such as what type of soil it is constructed with and if it is vegetated.

 

 

 

Bio swales

Posted by on Oct 14, 2015 in Blog | 1 comment

Any tips for designing bioswales? This one I’m working on is intended to filter effluent from a winery. The peak season is in the fall “crushing.” The discharge will be acidic, some cleaning chemicals, and lots of sediment. Finding adaptable plants is a challenge…but also the sediment blocking the permeability into the ground. Resources, ideas, insights anyone?

Earthworm Invasion, White-tailed Deer and Seedling Establishment

Posted by on Sep 1, 2015 in Blog | 0 comments

Earthworm Invasion, White-tailed Deer and Seedling Establishment

Bernd Blossey presented this research on the relationship between earthworm, white-tailed deer, and native plants establishment at the New Directions in the American Landscape conference in New London, CT in February 2015. He kindly provided the article as printed in the Journal of Ecology for use on this blog.

Research in Landscape Architecture

Posted by on Sep 1, 2015 in Blog | 0 comments

Research in Landscape Architecture

How do we know what we know? Do oyster reefs really protect against storm surges? Are floating wetlands really all that great? What about biochar or hugelkultur? What plants can be used for phytoremediation?

This post is in part a response to Amy N’s recent post on the complexities of urban cleanup but also contains material I’ve been ruminating about all summer. This summer, I have been interning for the Landscape Architecture Foundation (LAF) here in DC. LAF puts out the Landscape Performance Series website (http://landscapeperformance.org/), which includes landscape “fast facts” derived from published research, case studies of sustainable projects, and benefits calculators. It’s a good resource to check out! I’ve been mostly involved with reading published, peer-reviewed research and adding to the “fast facts” section, along with editing the forthcoming guidebook and doing graphic design and general office tasks.

Landscape architecture is a profession on the edge of art and science, and historically there has been tension between the two factions. Research has not been very important in the profession, which makes sense for an art-based profession but not a science-based one. As landscape architecture plays a larger role in ecosystems and infrastructure, it makes sense for the profession to generate its own knowledge about methods and best practices and use evidence-based design.

To take a look at another profession, doctors rely on research to help them make medical decisions every day. Landscape architecture is at a stage analogous to the “leech” phase of medicine. We propose fixes and build projects but do we know they will work? We don’t always monitor and study built projects but move on and create more, still without knowing if they produce the desired results. It is very difficult for most practicing landscape architects to do research on top of running a business, thus we need a strong research arm in the profession, and we need to know how to access the significant body of research that already exists.

So, what’s the best way to find existing research?

  • Google Scholar is accessible to everyone. While it’s not the *best* search engine for scholarly journals, it’s open to the public while others (Web of Science, for example) require university access. You can really just type in “treatment wetlands” or “street design safety” and see what you get.
  • Research is *much* easier if you have access to a university library that subscribes to scholarly journals. Otherwise you’ll likely just have access to the abstract, which usually shares the paper’s conclusions but not methods.

Things to note when looking up scholarly articles:

  • These articles are written in technical scholar-speak and can be a huge pain to read!
  • Just because you find one article saying, for example, that trees reduce air pollution doesn’t mean that there aren’t 10 more articles saying trees have no effect on air pollution. Scientific articles can contradict each other. If you’re looking for a good overview on a topic, try to find a recent review paper that looks at a lot of different articles and summarizes them.
  • Each paper must contribute something new to the field, and usually the aggregation of knowledge is slow (each paper contributes a tiny amount or slightly different angle).
  • If you can sort by number of citations, that will help you find the foundational (but not necessarily most recent) contributions to the field. Google Scholar doesn’t let you do this.
  • If you find a good paper, check out their sources to see what papers they’ve cited.

Luckily, as a landscape architect you don’t have to write these papers and you can usually assume that since they are published, they are at least passable papers!

 

Phragmites australis

Photo: by Andreas Trepte (Own work) [CC BY-SA 2.5 (http://creativecommons.org/licenses/by-sa/2.5)], via Wikimedia Commons

Amy N. was trying to find articles about native plants in phytoremediation, and she asks some great questions (potentially great Master’s/PhD thesis questions if they haven’t been answered…) Finding articles on native plants in phytoremediation is a bit tricky. It is very easy to find scholarly articles with “phytoremediation” in the title, but these articles come from all over the world and native plants of course vary by location.

I don’t have time right now to search through every article on “phytoremediation wetlands”, but here are a few highly-cited ones:

  • Phragmites australis, an invasive species in the northeast U.S. sequesters more metals belowground than the native Spartina alterniflora, which also releases more via leaf excretion (Weis, 2004))
  • Four wetland plant species (Scirpus validus, Carex lacustris, Phalaris arundinacea, and Typha latifolia) were grown in monoculture and as a four-species mixture to compare effectiveness of nutrient removal in controlled… outdoor subsurface treatment wetland microcosms. S. validus was most effective and P. arundinacea was generally least effective at reducing N and P in monocultures, with treatment capabilities similar to unvegetated microcosms. The four-species mixture was generally highly effective at nutrient removal, however the results were not significantly different from the monocultures (Fraser, 2004).

Scholars spend a significant amount of time reading all the articles they can find on a specific topic in order to form a basis of knowledge and to keep up on new developments, which is pretty hard to do as a working person. Luckily for us, two landscape architects have already written a big book on phytoremediation. I just got “Phyto: Principles and Resources for Site Remediation and Landscape Design” by Kennen and Kirkwood (2015) out through interlibrary loan from my university. So far, it’s a good, realistic look at phytoremediation. It’s not a silver bullet, they say, and they carefully outline its limitations. The book doesn’t cover remediation through wetlands, as that topic has been covered elsewhere, but it would be a very useful reference for anyone doing projects that involve phytoremedation.

Have at it, researchers!

… and stay tuned for a critique of Oyster-techure and a report on the ability of oyster reefs to mitigate storm surges (if I have time…)

– Renee

 

Fraser, L. H., Carty, S. M., & Steer, D. (2004). A test of four plant species to reduce total nitrogen and total phosphorus from soil leachate in subsurface wetland microcosms. Bioresource technology, 94(2), 185-192.

Weis, J. S., & Weis, P. (2004). Metal uptake, transport and release by wetland plants: implications for phytoremediation and restoration. Environment international, 30(5), 685-700.

 

Complexities of Urban Cleanup

Posted by on Jul 9, 2015 in Blog, Planning | 0 comments

Complexities of Urban Cleanup

I know that Becca has been doing some work on the Gowanis Canal as a personal project.  I found this article that provides some in-depth analysis on waste removal in the Gowanus Canal. This article suggests a couple of options for treatment, including the use of Chrysopogon Zizanioides or Vetiveria zizanioides also known as vitivegrass. This grass has considerably high potential to become invasive.

The use of native plants for cleanup is underway, but funding is limited for this type of research, it is difficult to find useful results, and it will take some time to develop strategies using native plants for different ecoregions. This article on the use of prickly pear cactus species in the San Joaquin Valley in CA discusses some of the problems with introducing non-native species – and the common problem that native species are often not even considered in research. And this research form UMass is already fourteen years old, and I couldn’t find the results.

I’d like to ask if you consider it an acceptable risk to treat a highly polluted area by planting this grass, despite the potential for the plant to escape.

  • What are the longterm ramifications of plant invasions versus longterm pollution of this magnitude?
  • Are there native plant options with the same cleanup characteristics?
  • Should we always assume that native plants are the best or only option for remediation efforts based on our current understanding of ecology?
  • Is it reasonable to expect science to be able to quantify the benefits and risks of using native and non-native plants? How long would this research take and is it feasible to wait for the results?
  • What criteria would you use to decide if a certain treatment plan is acceptable or not (whether native or non-native plant, or technology-based)?

If you have found useful information on using native plants for remediation, especially practical methodology, please share it!

 

 

Tree Protection Plans During Construction

Posted by on Jun 4, 2015 in Blog, Construction | 0 comments

Tree Protection Plans During Construction

It might take seven years for a tree to start showing dieback from root disturbance, and by then it is probably too late. Following some simple measures can help identify which trees are at the most risk and protect them from damage in the first place.

1. Take a tree inventory before any work starts or materials get delivered to the site.

2. Identify which trees are at risk during the construction process – this includes trenching, driving over, and storing materials on the root zone.

3. Identify the best circumference for protecting each tree type. Some trees are more sensitive than others and require more space.

4. Create a barrier around each tree – some arborists recommend a chainlink fence because orange construction fences often get moved by contractors. Monitor the fences for displacement.

5. Place tree protection signs on each barrier.

6. Educate the contractors and utility installers.

The North Carolina State University Co-op Extension and University of Minnesota Extension both have excellent information and practical guidelines about tree protection during construction or utility work.

Brooklyn Gardens

Posted by on May 18, 2015 in Blog, Design | 0 comments

Hey all! Here is a small collection of photos of places I’ve been gardening this season… thought you’d enjoy them!

The New CO2 Epoch

Posted by on May 15, 2015 in Blog, Planning | 0 comments

Horticultural Myths Exposed

Posted by on Mar 27, 2015 in Blog | 0 comments

Please visit the Horticulture Myths page at Washington State University’s Extension Urban Horticulture site for science-based information that corrects horticulture myths. The pdfs on this site offer insight on a wide range of topics using review of current research, in order to offer a better alternative to out-of-date practices.