Asphalt. What could be more pedestrian, literally
underfoot? Or ignored as a dull gray
ribbon somewhere beneath the floorboards as one navigates along city streets,
concentrating on one's destination? Or
still more invisibly, as the cladding along the ditches keeping parking lots
and pavement from flooding during rainstorms.
In reality, asphalt is a complex
"boundary object" that points out how cities, suburbs, and exurbs are
intricate social and ecological systems.
Asphalt as a boundary object links the consideration of social processes
and ecological phenomena across the three-dimensional spatial mosaics of urban
systems. Furthermore, as those systems
change, the role of asphalt as a boundary object can change through time as
well.
A recent paper by BES colleagues
Geoff Buckley, Chris Boone, and Morgan Grove (2016) provides an excellent
example of the changing role a boundary object may play, and it does so by
elevating the virtually ubiquitous and nearly invisible substance of asphalt to
our full attention. I recommend this paper not only for its scholarly rigor,
but for the poetic imagery and narrative power it employs in bringing the roles
and dynamics of asphalt to our attention.
This post is a teaser for that paper.
Contemporary urban residents would
hardly recognize the streets of cities in the late 19th and early 20th
centuries. There was a time when city
streets were paved with bricks, cobblestones, and even wood blocks if they were
paved at all. The expense and unstable
footing for horses were points contributing to contentious civic discussion
about these paving materials. Buckley
and colleagues show in detail how asphalt rose to primacy among a welter of available
materials, economic considerations, and networks of political influence. Asphalt achieved its familiar roles only
after it had been argued for by automobile drivers, bicyclists, and those
concerned with provision of mud-free school playgrounds.
 |
| Franklin Square school yard, asphalt partially removed. |
But as a multifaceted boundary
object, the perceptions and actions focusing on asphalt have proven to be
anything but permanent. For example, as
cities have shifted from the engineered "sanitary" focus of the last
150 or so years (Melosi 2000) to an emerging sustainability focus by looking
toward a future that is jointly motivated by ecological, social, and economic
integrity (Grove et al. 2016), so has the role of asphalt shifted. Now, city policy makers and activists promote
the removal of asphalt from school yards in an effort to reduce stormwater
runoff and lessen the heat island effects around schools. So too is asphalt reduced by replacement with
pervious pavement, or by piercing the streetside with bioswales or rain gardens. Over the century of the sanitary city and
moving into the desired sustainable city century, asphalt has illustrated an
integrative, but changing role in the social-ecological functioning of urban
areas.
As a boundary object, asphalt
focuses urban social-ecological researchers on the shifting networks of concern
and changing understanding of what constitutes an amenity or disamenity among
urban ecosystem structures. The very
factors of imperviousness and availability that led to the widespread adoption of
asphalt ultimately contributed to its disavowal by environmentally conscious
policy makers and by communities and agencies sensitive to social equity. Have a look at Buckley et al's (2016) paper
to understand this compelling history and its ecological implications more
fully.
Steward Pickett, Director Emeritus
Literature Cited
Buckley, G. L., C. G. Boone, and J.
Morgan Grove. 2016. The Greening of Baltimore’s Asphalt Schoolyards.
Geographical Review:n/a-n/a. DOI:
Grove, J. M., D. L. Childers, M.
Galvin, S. Hines, T. Muñoz-Erickson, and E. S. Svendsen. 2016. Linking science
and decision making to promote an ecology for the city: practices and
opportunities. Ecosystem Health and Sustainability 2:n/a-n/a. DOI:
Melosi, M. V. 2000. The Sanitary
City: Environmental Services in Urban America from Colonial Times to the
Present. University of Pittsburgh Press, Pittsburgh.
