Let's lead the paradigm shift in landscape design and bring back ecosystem services
I rode my bike the few blocks down SW 10th Street in Portland to the Pearl District to take in the excitement of First Thursday gallery openings on a warm summer evening. The Lawrence Gallery with its courtyard entrance on 10th is an oasis of green amidst densely packed buildings in this part of the Pearl. Its water features soothe the body with sound. Yet, finding not a single native plant, I was a bit distressed at the missed opportunity.
I went on to the Center for Architecture (LEED-EB Platinum), a former carriage house rehabbed by the Portland AIA chapter as its office, meeting and gallery space. There was a display on what we can learn from European building energy-efficiency technology. Largely dealing with building envelope innovations, most of the images depicted downtown commercial modernist buildings—many of which I would fight if they were proposed for my own downtown neighborhood.
But what disappointed me most—especially at the AIA site—was the landscape. While AIA is to be commended for adding any landscape at all to this historic 10,000 sf building in what was once an industrial district, and that landscape has a native plant or two, I am dismayed that AIA didn’t go further with the ecosystem services their landscape could be performing. This building is meant to be an educational center so why not educate about regenerative development?
To its credit, the landscape’s climbing vines are starting to shade the one-story, high-ceiling building from southern sun and the 2’ wide planting space at the buildings perimeter where the vines originate also sports a native rush or two. However, one of the plants that they use to climb the building’s trellises, orange jasmine, is the plant species likely implicated in the arrival of greening disease, considered the worst citrus disease in the world. The bacteria that causes greening disease makes citrus fruit inedible before it kills the tree altogether and this disease is spread by the Asian citrus psyllid, an insect that arrived on infested orange jasmine. First seen in Florida in August 2005, it had already spread to 12 counties in the state by April 2006.
By using several species of imported ornamental, rather than native plants, AIA fails to take full advantage of the opportunity to educate both their designers and the public about the need for biodiversity recovery to bring back healthy ecosystems. In his book, Bringing Nature Home, entomologist Douglas Tallamy makes the case that the major part of the food web for birds and other wildlife is native insects. And native insects need native plants to survive because only native plants are host species for their young.
This ecosystem services role played by native insects will be especially critical as the planet warms—to help us fend off invasions of destructive alien insects, pollinate plants, return nutrients tied up in dead plants and animals to the soil, aerate and enrich the soil and provide food for most other animals. I would like to make the case for any New Urbanist community and any LEED certified site to use only native species in its landscaping, no matter where it is in the transect. This would help us recover native biodiversity and the ecosystem services that diverse native plant and animal species provide. It would also leave us less vulnerable to the myriad diseases and carriers that we have imported (and continue to import) on ornamental aliens such as chestnut blight, dogwood anthracnose, pine blister rust, sudden oak death, beech scale, hemlock woolly adelgid, greening disease, soybean aphid, Japanese beetle, citrus long-horned beetle, etc.
I also believe that landscapes of native species help to give visitors and residents alike a true sense of place—to distinguish where you are on the planet. Unfortunately, most of the New Urbanist neighborhoods I have visited have failed in this respect too. In talking to a gardener at Highland Gardens Village in Denver, she told me that she had recently helped her daughter select plants to landscape the daughter’s property in Eugene, Oregon. She said she was surprised to see that the plant species she had to choose from in Oregon were the same as Colorado. Unfortunately this is true for Pennsylvania and Ohio and most anywhere in the country. The Gulf states may have a few more tropical species.
But there are now native plant nurseries in every part of the US as well. I hope that New Urbanist designers will use them. The integration of the Sustainable Sites rating system (http://www.sustainablesites.org/) into LEED and other sustainability codes like STAR will create a paradigm shift in landscape design. Let’s be at the head of that wave, rather that behind it.
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