 www.helenair.com/ It’s that time of year again - time for crows to congregate in the most unfortunate of city parks, streets, and yards. Sinister seems invented to describe the atmosphere of hundreds of crows roosting in the darkness above you, rustling and softly calling to each other, unseen yet…sinister, a scene out of Poe appropriate to this season. And, as an author in the Michigan Daily noted during my time in grad school, “the crow sh*t falls like rain.”
Places like the University of Michigan’s campus and Forman Park and Oakwood Cemetery in Syracuse struggle with how to pull the crow welcome mat back in. Screeching recorded bird calls seem to be a favorite tactic of campuses. Other places try fireworks or gunshots. Really, not much seems to work reliably. Of interest here is that crows are recognized as being remarkably intelligent birds, with recently published research even reporting their use of tools. A memorable 2010 episode of PBS' Nature showed how crows remember the appearance of people who hassle them, and react when the same person returns. This same intelligence and responsiveness to their environment must be the key to persuading crows to roost in places we deem acceptable. In the winter months I often see flocks of crows flying overhead, high enough and dispersed enough that you don’t notice them at first glance. As you watch, though, you realize that crows continue to pass overhead, on and on, because there are a very large number in the flock. They are all going somewhere, and I speculate that when I see these flocks in the late afternoon, they are heading for roosting spots in town (an attempted murder! Sorry. There had to be at least one “murder” pun). If they are flying from out here, 15 miles away, to spots in town, the choice of those roosting spots must be intentional, because it’s obviously not proximity or convenience at play. What makes a good spot for a murder? What dictates the landscape preference of crows? I don’t know. Crows aren’t my thing. But revealing the physical environment as a key factor in life in cities is, and so I say: there are environmental characteristics that must matter here, and if we identify them, we can manipulate them, and make the crows decide to sleep somewhere else. There’s got to be somewhere else, though - like every “undesirable” in the city, crows have to be somewhere, so banishing them from one place means their arrival somewhere else. The task of research-based urban crow management might then be to eliminate those characteristics from places where we don’t want crows, and add those characteristics to places where we do want them. For a bonus point, we could draw crows to places where their abundant droppings (falling like rain!) could add needed fertility to the soil. You probably don’t want that to be any place you’re growing food for human consumption, but a degraded brownfield could be the ideal site. So what do crows like? If I list sites where I’ve personally witnessed mass roosting of crows, I list the north edge of Syracuse’s Oakwood Cemetery, Syracuse’s Forman Park, and the University of Michigan’s Diag (a central campus quad). Far from an exhaustive list, but even with just these three sites, we can compile a short list of possible crow-attracting environmental characteristics. First, most obviously: mature deciduous canopy trees. In these three sites, those canopy trees have open understory beneath them, with either lawn or low-growing perennials and shrubs. Perhaps the crows feel more secure with open space beneath the canopy and less cover for predators. All three sites also have substantial masonry buildings adjacent to them, and at least some paving - perhaps the thermal mass raises the nighttime temperature? It’s interesting that all three sites have a fair amount of human activity, including both cars and pedestrians. These aren’t isolated natural areas. The cemetery edge abuts the edge of campus, specifically a back drive serving faculty parking, a busy place at dusk in the fall and winter. Given the demonstrated attention of crows not just to human activity, but to specific humans, it seems implausible that this is a coincidence. Perhaps the crows want to be near us because we scare off more dangerous wildlife. Perhaps they know we generate tasty trash and roadkill. Perhaps they like the heat from our buildings and cars. Maybe we’re just entertaining. To you and me, a tree might just be a tree (well, really, to me a tree hasn’t just been a tree since 1992, when I took my first plant identification class), but to a crow, I very much doubt trees are all the same. Might the species matter? Is an elm better than a maple, but not as good as an oak? Crows don’t mind noise, artificial light, and urban air quality. Do these environmental characteristics actually attract roosting crows? The question here is whether crows really prefer urban sites to rural ones for winter roosting, or whether we humans only notice them in urban sites. If a murder roosts in a forest and no one is there to complain, would we know about it? Urban heat islands would seem to be a likely explanation, but surely these intelligent birds have their reasons for selecting between the many possible roosting areas available in the warm city. We have to look at the wild city through crow’s eyes to see those reasons. Written version of my August 10 talk to the English for Graduate Studies Programs for Fulbright Scholars, through the English Language Institute at Syracuse University.
What does climate change have to do with the shape of the city? Climate change is one of the defining challenges of this era - perhaps the defining challenge - and as such, it’s a good bet that it will touch or is touching every aspect of life. That includes how we live in cities, and what kinds of environments cities create for people. Since that’s my area of focus as a researcher, this post examines that aspect of climate change. Climate change is so mammoth in its impact that from a single parcel of land, that occupied by the Syracuse Center of Excellence, we can see a number of landscape elements that are important to consider. How people use land, including transportation, density, adn what happens to “used” land, is fundamental to understanding the drivers of climate change in the US, and why they are resistant to change. So if you're interested in in climate change and why it's happening and what to do about it, you should be interested in cities. Even if you live elsewhere, you should be interested in US cities with regard to climate change. We’re a disproportionate producer of greenhouse gases (GHG, but we're also a leader in how cities are shaped and run. For good or ill, other people who are involved in the shaping and running of cities in other parts of the world look at American cities as models, much in the way that American cities were largely modeled upon European cities. Most of the world's population lives in urban areas. Some of you may have heard about this: fairly recently we hit this milestone of global urbanization, where more than half of the world population lives in urban areas. This percentage is predicted to continue to rise to two-thirds of the world's population by 2050. So in that way you could say cities are our future - all of our futures. Nearly 90% of that predicted increase of urbanized people is predicted to be in Asia and Africa, most especially India, China, and Nigeria. In the US we urbanized a long time ago, back in the 1920s. Currently US cities are home to just under 63% of the US population, but our cities comprise only 3.5% of our land area. Thus a key part of dealing with climate change is to handle how people live in cities. Photo: Looking west from the Center of Excellence If we look westward from the Center of Excellence, we see a massive elevated highway. This is Interstate 81, which bisects Syracuse from north to south. Since 81 was built after the city was already established, it was built over a number of neighborhoods, displacing people, their homes, and their businesses. Syracuse right now is in the midst of a debate about the future of this highway, since it has reached the end of its designed life span. Interstate 81 exemplifies two key characteristics of American cities: the organization of the city around the private car, and sprawl. “Sprawl” here means that American cities tend not to have a defined clearly visible boundary between the city and the countryside or rural areas outside the city. Instead it's a diffused boundary, as lower density development spills into the countryside and takes up a lot of land. These characteristics are intertwined with transportation. Transportation, it turns out, is also incredibly important to climate change. Transportation accounts for about one-quarter of greenhouse gas emissions both in the US and globally. This is a lot, but it’s even more when you consider that in the US it's the number two source of greenhouse gas emissions after electricity generation, so it's not just that it's a huge chunk - it's the second largest one. Here in Syracuse it's actually even more of our total energy consumption, about 36%, so it's more than one-third of Syracuse's total energy consumption. Globally, there there there is predicted growth in the amount of greenhouse gas emissions due to transportation, mostly due to rapid growth in car use, especially in developing urbanizing countries like China. So transportation is key to climate change strategies. Here in the US, we lead the world in urban passenger transportation carbon dioxide emissions. Our carbon dioxide emissions due to transportation are actually projected to fall by 2050 in part due to redensification, or the trend of people moving back into city cores. In 2013, President Obama put forward a climate action plan, with the basic proposal of reducing greenhouse gas emissions 26 - 28% below 2005 Levels by 2020. Compare those numbers: 26-28% to 25%, and you’ll see that transportation could account for almost the entire reduction on its own. So if we all stay right where we are, and no goods or products move from place to place - that is, if all transportation ceases - we’ve got the necessary reduction solved! Since we obviously can’t do that, we need to do transportation better. How do we do this? It’s simple: we drive less. Or we drive using clean fuels that don’t create GHG emissions. So what's the problem? Let's look again at Interstate 81. This is part of the American interstate highway system, which was constructed after World War II. It is a national system, including all 50 states (even Hawaii!) and all major cities. The situation Syracuse has of the elevated freeway going right through the center of the city, displacing neighborhoods and bisecting the city, is common. The original rationale for the interstate highway system was to aid national defense, modeled on Germany’s Autobahn (but with speed limits). However the impact that it has really was to promote suburbanization, which is building at the outside of of cities. The flip side of that is disinvestment in urban areas, like what you see around you in Syracuse. So the interstate highways moved people and money out of the cities and into the surrounding area. These consequences were in part unintentional and in part intentional consequences, because there were also a number of federal and state policies that favored suburban development for decades. These policies, with the interstate highways, set up a common dynamic where people with the economic power to choose live in the suburbs but work in city centers. Transportation between those two areas is therefore key to that way of life. The same dynamic has also created a number of challenges for urban areas in terms of being pleasant and attractive places to live. Interstate highways like 81 also work against more sustainable transportation directly. Elevated highways form a physical and psychological barrier to ground-level transportation in all forms. Imagine yourself walking down the street. From here, you can walk straight to downtown Syracuse. It’s about a mile, or 1.6 kilometers, an easy walk, flat, with a sidewalk the whole way. It’s easy to find your way to downtown, but people do not walk and do not ride bicycles because they don't want to ride or walk under 81. You can see it's forbidding. There’s no physical barrier here where we are looking, but it's inhospitable. That has to do with the way that we as humans perceive environments around us, with what we prefer and what we don't prefer. These perceptions make this feel dangerous to us, even if it's not. Interstates like 81 also work against sustainable transportation by lowering property values around them. Simply put, people would rather live, work, recreate, and invest in properties that are not right next to the structure. It’s ugly. The traffic is really loud. There's also issues with air pollution from all those cars, which leads to health problems like asthma and environmental lead (from the bad old days when gasoline included lead). As you can see, there’s quite a list of problems with this interstate and creating sustainable transportation. We know the sustainable transportation is very important to fighting climate change, so why not just get rid of the interstate? We don’t, because we already have the ring of suburbs around Syracuse, and all those people living in the suburbs and working in the city. If you eliminate the interstate, how do you get from the suburbs to the city core? This highlights an important point about land development and land use patterns: they have a lot of inertia once established, because it costs so much to change the physical landscape and it's a lot of work. Our next stop looks at that process of changing the landscape and how some kinds of construction are better than others with regard to climate change. Photo: Looking south from the Center of Excellence This construction site is what’s referred to as infill construction or brownfield redevelopment. “Infill” simply means that you are filling in an empty space within existing development. “Brownfield” means that there was a building on this site before. It’s often assumed to mean that the site is contaminated, although that’s not necessarily the case. Brownfields also include sites that are indeed contaminated, including with frightening things like dioxin. In any case, brownfield redevelopment like this is more sustainable than the alternative, which is building outside city areas. Why is it more sustainable? There's less need for transportation, and remember, transportation is about a quarter of greenhouse gas emissions. If you live and work in buildings that are adjacent to each other, you just walk next door and there's no greenhouse gas emissions. There’s also less need for new infrastructure, which is not as obvious. Infrastructure includes things like utilities and roads. When you build outside a city, you need to extend utilities - natural gas, electricity, water, sewerage - to the new development. You have to have a road to get there. In contrast, if you build on a site like this one, all those utilities are already here. Clearly the road is already here. You save all that concrete, all that pipe, all that wire and cable and conduit. All of that has an ecological footprint - it's all manufactured somewhere, so using less of it is more sustainable. Infill or brownfield redevelopment also preserves more land outside cities for natural areas, which can sequester carbon or mitigate some impacts of climate change like urban heat island. Brownfield redevelopment may also be more sustainable because it frequently involves buildings and site work that are more compact, using fewer resources. Despite all this, much construction in the US is the opposite of infill/brownfield redevelopment: greenfield development. Greenfield development means building on new land, kind of a ridiculous idea, because of course there is no “new” land. All land was used for something else before. In this case, it’s usually agricultural land or natural vegetation like forests. Greenfield development is seen as far easier, cheaper, and often more desirable than building on lots within the city. It tends to be more predictable, and unpredictable delays in construction are costly. Urban sites tend to have surprise environmental issues, when you dig into the soil and discover it is contaminated with something. There can also be delays when historical artifacts are uncovered, since construction has to halt while the artifacts are evaluated for historic significance. There's also the more basic requirement of the need to work around and preserve existing structures, in contrast to building in an open field. On this site, there’s several valuable elements immediately adjacent to the construction: the wall of the Center of Excellence, the pavement around it, the trees along the street, even the street itself. Because greenfield development is more popular, there are a number of federal and state grants and various incentives to redevelop brownfields. However they tend to focus on very large brownfield sites like old factories, landfills, or shipyards, and omit small sites like gas stations and dry cleaners. This site adjacent to CoE actually included an old gas station. Finally there is a consumer preference in the US for suburban or exurban housing. People in the business of developing land are aware of those preferences and they cater to them. We tend to think that new is always better, perhaps due to some bias in American culture toward seeing ourselves as breaking new ground and taming the wilderness. Our final stop on our walk around the CoE site looks at what happens to sites like this when they're not redeveloped. Photo: Looking north from the Center of Excellence Looking at this view is somewhat tricky, because the element I want to discuss here is actually what’s not there: the land just across the street. People who study cities refer to this as vacant or underused land. This is one of the outcomes of what we talked about previously, including transportation, lack of investment in urban areas, and the difficulty of infill or brownfield redevelopment. Sites like the one across the street are not really used for anything. They tend to sit like this for a long time. These same dynamics also produce abandoned buildings, and abandoned buildings tend to become sites like this in our litigious society. It’s far easier for people to hurt themselves in an abandoned building then it is on a vacant site. People also tend to tear down buildings because they see it as as being cleared for a new use or to be more attractive to new investors. It makes “used” urban land a little bit more like that greenfield. If you look carefully, you’ll see that the vacant parcel across the street has a bit of asphalt on it, and that asphalt has some yellow stripes. If you look at an aerial photo of the site, you can see that those stripes are parking spaces. Underused urban parcels often are nominally used as parking lots, even if no one parks there. There's some possibility of income from parking in urban areas. More than anything, however, this parking lot is merely a placeholder. It’s what this land will be until it becomes something else. Vacant and underused land like this site indicate that infill development isn’t happening. They also increase the perception of urban neighborhoods as undesirable, dangerous places, full of contaminated land and other health hazards. If this was a valuable parcel, wouldn’t someone be living on it, or build a business on it, or turn it into a park? Regardless of the facts, the perception of parcels like this one can be quite negative, and in turn they influence the perception of the entire urban neighborhood. People on foot or on a bike may be reluctant to pass vacant lots like this one, especially at night, so they also act to suppress more sustainable modes of transportation. In these three views from one parcel of land, we’ve seen a number of major factors in why land use in the US is a driver of climate change. We’ve also seen some reasons why our use of land resists change to more sustainable practices. Climate change is such a gigantic challenge that it’s sometimes difficult to grasp - it is, after all, *global* warming. It helps to realize that some important aspects of it are not exotic or huge in scale - that they are actually just across the street. --------------------------------------------- Facts and sources:
From Stephanie
Milwaukee’s Menomonee Valley: A Sustainable Re-Industrialization Best Practice By Christopher De Sousa UIC Institute for Environmental Science and Policy Full story in pdf 
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AboutAssorted drafts, previews, and outtakes from the book I'm currently writing about the impact of vegetation and neglect on urban life. I also take other thoughts for a test drive here, including nascent design and research ideas. Archives
September 2020
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