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Bubbler in a city park

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The United States is not run by godless Communists. Neither is most of the rest of the world. In fact, the godless Communists that do remain are not all that Communist anymore. I bring that up because command and control economies can dictate what development happens where. Land conservation under such a system is technically easier, even if the actual results in Communist nations like the Soviet Union weren’t that inspiring. Land conservation in the free world is a trickier game, one played with carrots and sticks as opposed to edicts and directives. Here, money is your best friend.

Conservation organizations have focused on preserving big tracts of land, and rightfully so. Big buys are often more cost effective and easier to manage. But they’re also becoming trickier to execute in a world dominated by curving cul-du-sacs and one acre lots. If we want functioning ecosystems in these places, we need to focus on land conservation within the subdivision, not along its borders.

Luckily, the carrot seems to be working in those places. A study of subdivisions in Maryland between Washington, D.C., and Baltimore shows that developers have been incorporating more open space into their subdivisions. That’s not because they’re interested in land conservation. Part of it is a bit of command and control—Maryland’s Forest Conservation Act forces developers to conserve a modicum of forested land—but it’s also simple economics. Developers can sell lots and houses at higher prices if open space is nearby. Because proximity matters, that open space typically needs to be within the subdivision.

To developers, though, that open space is fungible. It can exist either as public parks or larger private lots—both raise prices. The Maryland study also found that minimum lot sizes—which governments typically use to preserve open space—can push developers away from shared open space toward larger lot sizes.

This poses a problem for maintaining healthy ecosystems. Like many laws, the way the Maryland Forest Conservation Act is interpreted matters. People can uphold the letter of the law—maintaining forest cover—without changing their usual habits—mowing their entire lot. The result is something that looks like a forest from above but doesn’t function like one.

In a perfect world, everyone would happily tend a few thousand square feet around their house and leave the rest to nature. But that’s not always the case. People will spend all Saturday mowing acres of grass and grumble about it afterwards. That’s because for many people owning a country manor is more alluring than owning a chunk of the great outdoors. You can fight that mentality by increasing minimum lot sizes to the point where mowing it all becomes completely unreasonable,¹but the closer you get to a metro area, the less tenable that becomes.

There’s also no guarantee that laws dictating minimum lot sizes will remain in place. As the city creeps closer, pressure to further subdivide will mount. Open space preserved in private lots could easily disappear.

Parks, on the other hand, tend to stick around. Unlike large lots, they’re seldom subdivided. Instead, they tend to become institutions. People like their parks and are loathe to lose them—no one wants to see their neighborhood park disappear. So let’s put that to use. Instead of—or in addition to—minimum forest cover and minimum lot sizes, let’s institute minimum park sizes. Everyone will benefit. Developers will be able to sell lots at higher prices. Kids will have playgrounds. Adults will have walking paths. And because big parks often have big natural areas, ecosystems will have a better chance at surviving. It’s a solution that’s a bit more command and control than current vague regulations, but everyone will benefit. It’s also more carrot than stick. Even if you don’t particularly like carrots, it’s better than getting hit with a stick.

¹ Though there will always be exceptions—near where I grew up, one guy mowed 18 acres. He had to buy a bonafide farm tractor so it wouldn’t take him all week.

Photo by JD Hancock.

Source:

Lichtenberg, E., Tra, C., & Hardie, I. (2007). Land use regulation and the provision of open space in suburban residential subdivisions Journal of Environmental Economics and Management, 54 (2), 199-213 DOI: 10.1016/j.jeem.2007.02.001

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Aerial view of Carrollton, Texas

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If you think American cities are sprawling now, just wait until 2025. In that time, the U.S. population will grow by 18 percent but the amount of developed land will increase 57 percent. Up to 9.2 percent of the lower 48 could be urbanized by then. And while that number includes cities and the infrastructure to support them—roads, rail, power lines, and so on—that number does not include land impacted by farming, logging, mining, or mineral extraction.

That 10 percent of the lower 48 could be crawling with people is a stark reminder that our nation—while immense—is not immune to the pressures of development. It’s also acknowledgement that despite years of hearing about the resurgence of American cities, sprawl is still king.

Today, it feels like much of what drove the suburbanization of America since World War II has changed. Incomes aren’t rising nearly as fast as they did in the 1950s and 1960s. In fact, when adjusted for inflation, incomes have stagnated or dropped in recent decades. Soaring gas prices and congested freeways have stolen some of the automobile’s glamor, too.

Yet two studies show that while the outlook in the U.S. may have changed, our desire for suburban living has not. The study’s results differ slightly—the 2004 paper says we’ll add 25.8 million hectares (64 million acres) by 2025, the 2009 manuscript says 22.4 million hectares (55 million acres) by 2030—but their conclusions are the same. American cities will continue to sprawl, adding more land per person than in the past.

In recent decades, the locus of suburbanization has shifted from the Northeast and Midwest to the South. With its warmer weather and lower costs of living, the South has grown faster than any other region in the U.S. since 1980. Development has been fueled by flat, cheap land and abundant freeways, which has pushed land demands well above the national average in some states.

That boom also meant the South was hit hard by the housing bust in 2008. But that doesn’t mean the market for suburban housing has disappeared. Living the burbs is still cheaper than the city, and since real incomes for most Americans have suffered in recent years, development will continue to chase lower land prices. The recession and housing slump may have put a damper on suburban development, but I’m guessing it’s just a temporary blip.

Another factor that should conspire against suburban development—higher gas prices—also doesn’t seem to have much of an influence. The 2009 study suggests development rates won’t take much of a hit from high fuel costs. To simulate rising gas prices, the study’s authors reduced the forecasted development rate in states where it was highest—primarily the car-centric South. Only 5 percent less land was converted from rural to urban uses.

It’s possible things could change—perhaps fuel costs will rise even higher, or maybe the home downsizing trend that’s in its infancy will mature. But I think we should prepare for a future filled with suburbs. In the South, where most of the development is happening, land continues to be cheap and easy to access. The same warm weather that drew many people there will also keep them in their cars. Nobody likes walking in the South’s sweltering summers, even if it’s just from the steamy parking lot to the over-air conditioned mall.

The question then is, how can we make the suburbs more environmentally friendly? Encouraging compactness would be a good start, even just at the subdivision level. Hopscotch development inflicts ecological damage well beyond its immediate footprint—there are many plants and animals that cannot survive surrounded by a sea of humanity. Dispersing job and commercial centers is another option, helping to reduce the number of miles people have to drive on a day-to-day basis.

In the end, though, we’ll have to push for more ecologically integrated development. We’ve seen small steps in that direction already—most new subdivisions must deal with run-off from rainstorms on-site rather than shunting it to an overburdened creek. It’s a start, but not enough to offset America’s suburban future.

Sources:

Alig, R., Kline, J., & Lichtenstein, M. (2004). Urbanization on the US landscape: looking ahead in the 21st century Landscape and Urban Planning, 69 (2-3), 219-234 DOI: 10.1016/j.landurbplan.2003.07.004

White, E., Morzillo, A., & Alig, R. (2009). Past and projected rural land conversion in the US at state, regional, and national levels Landscape and Urban Planning, 89 (1-2), 37-48 DOI: 10.1016/j.landurbplan.2008.09.004

Photo by La Citta Vita.

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Farms giving way to subdivisions in Southeastern Wisconsin

If you were a squirrel living in Southeastern Wisconsin, you’d be pleasantly surprised by the state of things. In many places, there are as many—if not more—trees than there were 200 years ago. But that rosy image doesn’t tell the entire story. Comparing the forests that cover the cities and suburbs around Milwaukee—and likely in many places around the world—is like comparing Rome before and after the fall. It’s still Rome, but it’s not quite the same as it used to be.

Southern Wisconsin is a case study of the changes that were affecting much of the country in the 20th century. Most of the forests had been cleared in the 1800s by farmers, resulting in a landscape that little resembled what came before. The woodlots that remained were small and scattered. In one famous study, only 4.8 percent of the original forests remained by 1935. Milwaukee and its surrounding cities grew steadily in the run-up to World War II, but positively boomed thereafter. They needed room to grow, and since cleared land is easy to build on, farm after farm was subdivided.

The path from forest to front yard seems clear cut. A woods is cleared to make way for farmland, which is later subdivided into lots and sold off to make way for homes. But the reality is much more complex than that. Though a neighborhood may maintain its wooded appearance, it’s original character is gone.

In Wisconsin, subdivisions are invariably preceded by farms. Farming is a tough life. There’s not much money to be made with a small family farm, and an farmer’s property often doubles as his retirement fund. To maximize the investment, he’ll usually subdivide it for housing. It usually works out well for him, because land that’s good for growing crops is also good for building houses—it’s not too steep and most of it doesn’t need to be cleared.

That’s not to say farms are entirely devoid of trees. Most contain small woodlots and extensive fencerows that separated fields of corn, wheat, and soybeans. They’re relics of bygone forests, and in many places that’s all that’s left. Though the relationship is a bit one-sided, relic trees and farms have existed side-by-side for decades.

Maintaining that landscape during subdivision isn’t difficult. Building houses around trees is easy if you don’t take a cookie cutter approach, and houses with big trees in their yards tend to sell for more. But conservation rarely happens. That’s the conclusion of one study of Southeastern Wisconsin. It looked at the fate of extant vegetation as farms gave way to subdivisions between 1937 and 1975. Though the sum total of forested land didn’t drop as much as anticipated, very little of the original vegetation that made it through the transition. By 1975, the trees that dotted subdivisions and roadsides were almost entirely new.

That study reminds us that sum totals seldom tell an entire story. The relationship between forests, farms, and yards is complex and multidirectional. Forests are often cleared for farms, but abandoned farms can return to their forested state over time—much of New England underwent this process. However, urbanization can intervene along the way, removing the little remaining vegetation and replacing it with landscaped yards. But that’s not all the forest loss development is responsible for. Though many subdivisions are carved from land cleared previously for farms, they can be indirectly responsible for the loss of even more forests. Street and yard trees can’t offset this entirely. Similar patterns are well documented in developing nations. In Brazil, for example, expanding soy production has pushed cattle ranchers to clear land further into the frontier. It’s easy to forget these same processes are at work here in the United States.

Even when subdivisions spring fully formed from forested land—skipping the intermediate farm stage—their lots are often cleared of existing vegetation. Some of my research in graduate school documented the stark changes forest edges undergo when houses move in. In old black-and-white aerial photographs, the bare earth of cleared building sites stood out in stark contrast to the dark gray of the surrounding woodlands. Straight, sharp lines separated the two. In time, the edge bled back into the yards, but it wasn’t quite the same.

Suburban development isn’t going away anytime soon, but some of the structure and function of the old woodlands they replaced can be recovered. Homeowners can plant native trees. People can lobby their cities to plant native trees as well, rather than the whatever low-maintenance tree is in fashion among city foresters this year. The result won’t be the same as an intact woodland, but at least it will be similar.

Source:

Sharpe, D., Stearns, F., Leitner, L., & Dorney, J. (1986). Fate of natural vegetation during urban development of rural landscapes in Southeastern Wisconsin Urban Ecology, 9 (3-4), 267-287 DOI: 10.1016/0304-4009(86)90004-5

Photo by sierraromeo.

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Chicago streets at night

Pushing high density living may seem like a good way to get people out of their cars—saving them money, curbing emissions, and reducing oil dependence—but densification may not be a silver bullet, according to one recent study. The authors dug into the National Household Transportation Survey to examine per household vehicle ownership rates, vehicle miles traveled (VMT), and fuel consumption. While the results are by no means comprehensive or conclusive, they suggest that only the steepest increases in density could reduce car usage.

This post was chosen as an Editor's Selection for ResearchBlogging.orgDespite a correlation between density and car usage, other factors seem to play more important roles. Density is responsible for a fraction of annual VMT; increasing density by 1,000 housing units per square mile—a titanic leap, given that the average household is 2.6 people—reduces VMT by just 1,171 miles, all else being equal. Since that the average one-driver household in the study tacks on 10,100 miles per year, that represents just over an 11 percent drop in annual mileage.

housing density and Vehicle Miles Traveled

If you look at the numbers another way, the case for density reducing car usage looks even more tenuous. VMT only really declines substantially at the highest housing density—over 5,000 units per square mile, or about the same as Chicago. To halve VMT of the highest mileage households, you would need to increase housing density in those areas by 20- to 100- fold.

The inflexibility of our automobile usage boils down to a few factors, with work being the most important. The more workers in a household, the more drivers, and the more drivers, the more miles. A one-driver household, as noted above, tallies 10,100 miles per year; a two-driver household racks up 18,800 miles; three drivers, 33,900; four drivers, 47,700.¹ We are, by and large, beholden to our cars because we are beholden to our jobs. After that, driving increases as a result of income (richer people drive more), number of children (more and larger cars), education (higher education means more cars), and people’s life stage (households with older children have more cars).

While higher housing density doesn’t seem to reduce VMT, it does drive down fuel consumption. Households in the 50 to 250 houses per square mile range use 1,650 gallons of fuel annually, the most of any group. Every other group uses far less fuel. In the big cities, fuel usage drops to 690 gallons per household per year.² The reason? People with the space to use pickup trucks, SUVs, and vans tend to buy them more than people who live and drive on tighter city streets—they typically drive smaller, more fuel efficient vehicles. Yet this trend could be changing as we speak. Small car purchases have been increasing across the country, and anecdotally at least, I can confirm that large pickup trucks are harder than ever to sell these days.

fuel consumption and Vehicle Miles Traveled

One of the main arguments behind higher density living is that it will reduce our carbon footprint. While density may be a better long term solution, right now the most expeditious approach is to increase fuel economy. Rebuilding neighborhoods will take decades. In that time, most people will buy at least a handful of new cars, primarily for commuting to work. It would be great if everyone had access to mass transit, but for many, mass transit isn’t just a poor option, it isn’t an option at all. Those who do travel by bus or train today may only be a job change away from having to drive. Modern life demands mobility, and few things are better at providing that than the automobile.

¹ The increase from one to two drivers probably reflects some combining of trips by couples or roommates. The sharp increase from two to three drivers is probably the result of a family’s children driving to school or work.

² The lone outlier is areas below 50 houses per square mile, where households use 1,200 gallons per year. They probably have fewer nearby destinations, and so stay home more often.

Source:

Brownstone, D., & Golob, T. (2009). The impact of residential density on vehicle usage and energy consumption Journal of Urban Economics, 65 (1), 91-98 DOI: 10.1016/j.jue.2008.09.002

Photo by dsearls.

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Accessory dwelling unit

Sprawl, in many cases, is in the past tense. It’s already happened. Though it continues in plenty of places, it’s most problematic where it already exists. For booming regions, sprawlish suburban rings threaten to choke the central city with snarled traffic and lean tax rolls. Rather than throw their hands up in disgust and move on to a city that “gets” it, a group of planners and architects have focused on retrofitting diffuse neighborhoods and intensifying four lane boulevards. In the process, there are myriad problems to tackle, but I’d like to tackle one right now: What to do with suburban housing.

Density is suburbia’s saving grace and Achille’s heal. Who wouldn’t want to be ensconced in their own private garden? But that same dispersed living isolates people and causes many of the headaches of daily life. Sprawl retrofit really means higher density living, which also means more shops close at hand and less time behind the wheel. It’s no secret that many suburban lots would easily support another house. Slapping another behind the existing one is a simple way to double the density. It’s a common approach to sprawl retrofit, and one raised at the 19th Congress for the New Urbanism. But if erecting backyard residences solves one set of headaches, it risks inflicting more in the process.

Suburban homes were built with very specific ideals in mind. The front of the house is the public side, presenting its widest part to the street, shielding the backyard and creating a private area where people can relax in relative peace. While many early car-centric suburban houses reacted tepidly to the backyard—the best they offered were a few more windows and a back door—we soon became practiced in the art of suburbia. Large picture windows, sliding doors, four-season rooms, and covered porches quickly festooned the private side. The backyard became more than an outdoor amenity—it was a private garden to be enjoyed from the indoors, too.

Hacking a lot in two and adding a second residence could destroy one of the few things many suburban homes have going for them—a sense of privacy. The attractiveness of this feature should not be underestimated. Research suggests that open views are help ensure a feeling of privacy, even more so than actual proximity. The bad of suburbia—houses turning their backs on the street—was driven by a noble aspiration—homes embracing the yard. No one wants their view to embrace another home, no matter how beautifully designed.

And so a lynchpin of sprawl retrofit—boosting the number of houses—may be the most difficult to achieve. That’s not to say it cannot be done, but it will require careful consideration to do properly. Suburbia may be, in many ways, a consequence of bad planning, but it got one thing right—the yard. We crave green, open space, and suburban lots with suburban houses have it in spades. It may have given us too much, but we shouldn’t take it away in too much haste lest we compound the mistakes of the past.

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Cabrini-Green, Chicago

If you ask any big city mayor what is one of the most pressing problems facing his or her city, I’m guessing poverty will be high on the list. Cities across the United States are filled with pockets of hardship, and while rural poverty is widespread, too, impoverishment within metropolitan areas tends to be strikingly concentrated near downtown. Did the rich flee or the poor converge? One study says transit provides the answer.

The article begins with pages of hypotheses, formulae, and tables, but the real history of the trend is buried at the end, just before the conclusion. The key to it all is the fact that public transportation is a distinctly modern invention, and before its advent, most people lived within walking distance of their jobs, regardless of income.

It is in the late 18th and early 19th centuries that we get a geographic glimpse, uninfluenced by modern public transit, at where the rich and poor lived. Proximity to employment dictated where people lived, and people, then as now, worked everywhere. Even the most successful hedge fund’s offices are cleaned by janitors who make little more than minimum wage, and this maxim held true back in the 18th and 19th centuries as well. The difference then was that the middle-class, the well-to-do, and even some of the wealthy walked to work. Only the fabulously wealthy had hansom cabs and carriages to take them about.

When mass transit started catching on, it was mostly enjoyed by those with money, like most new technologies. Affluent types began fleeing the city for “streetcar suburbs.” But as transit prices started dropping, a new technology burst onto the scene—the automobile. For the rich, cars were far better than cramped street cars. They could travel from home to work in relative privacy (though comfort was not a given due to the poor condition of most roads in those days). Plus, cars doubled as a status symbol.

Again, the poor were stuck in the city, and many remain stuck there today. The cost of owning and operating a car is simply beyond reach for a chunk of society. And given the limited reach or slow speed of many American mass transit systems, people without cars need to live closer to their jobs, which are typically in the city.

It’s a tidy narrative, and one that the study backs up with both anecdotal snapshots,¹ statistical models, and data-driven time points from the modern day. The modern observations paint a convincing picture, and one that backs up the narrative. In cities with extensive subway systems, the study found that incomes dip slightly within a one-mile ring of downtown—where land values drop but remain accessible by transit—and then rise and hold steady from three to seven miles out. Transit usage also rises after that first mile, peaking two miles out, where incomes begin to rise. This peak exists in those cities because rail systems—they move far more quickly—appeal to more than just the poor. Wealthier people are more willing to forsake their car for a train and a simpler commute. But in newer American cities without subway systems, buses rule. In those places, most people with sufficient means pay for the shorter commute by car.² The final piece of evidence lies in the geographic distribution of jobs. In “old” American cities with extensive transit, 55 percent of the jobs in the metro area are within five miles of downtown. In “new” cities, 81 percent of jobs are more than five miles out.

The evidence in this paper led me to a few conclusions of my own. First, since the poor are less likely to use roads and highways, government highway subsidies are regressive, that economic term that describes a policy that benefits the rich more than the poor. That makes transit subsidies progressive, but even that is an oversimplification. Transit gives the poor greater access to employment, which will hopefully make them not poor in the future. It also boosts property values in the near vicinity. Since the better-off can afford pricier houses, they clearly benefit, too. Still, some communities fail to understand transit’s merits, instead equating it with an influx of poverty. These rich communities³ will eventually need more viable transit options, though, because they employ poorer people to do the things they’d prefer not to do. And as gas prices rise, no one will want to pay through the nose for that privilege.

¹ “…in New York, 52 percent of workers earning less than $10 per week walked to work in 1907. Only 12 percent of workers earning $20 per day used that form of transportation, and instead used streetcars. Just as the car today favored the non-poor, the streetcar did in the past, and it helps to explain why the poor lived close to the city center 100 years ago.”

² This in turn gives the non-poor in those cities a negative opinion of transit. As in, “Only the poor take the bus.”

³ Parts of Orange County, I’m looking at you.

Source:

Glaeser, E., Kahn, M., & Rappaport, J. (2008). Why do the poor live in cities The role of public transportation Journal of Urban Economics, 63 (1), 1-24 DOI: 10.1016/j.jue.2006.12.004

Photo by reallyboring.

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I-80 and M2

Travel can be revealing. In many cases, “where” can answer as much about a person as “who.” Much of who we are is tied up in what sorts of stores we frequent, where we work, and where we go for fun. While that sounds creepy—especially given the recent furor over smartphones storing location information—city-wide travel trends can help explain a lot about where we live.

A study comparing British and American travel habits discovered that trip distances in the United States predictably lengthen as the population thins out. In Great Britain, though, that relationship isn’t as strong, in part due to its greater population density. But when the researchers filtered out differences in income and density between Great Britain and the U.S., the British still traveled less.

The reason behind the travel discrepancy, the researchers suspect, lies in the strict separation of space for living, working, and shopping that is common in the U.S. To arrive at that conclusion, they had to use a bit of mathematical cleverness to make an apples-to-apples comparison. The model compared British and American cities of similar population and density, but shuffled the contents of the American ones until their general urban form resembled their ale-swilling counterparts. This meant that shops were now next to houses, grocery stores located just down the street, and pubs scattered about town. The results suggest that the jumbled urban land uses in England, Scotland, and Wales keep the lid on travel distances.

The British also get out from behind the wheel more often, using their feet for something other than operating gas and brake pedals. Whereas under 7 percent of trips in the U.S. are taken on foot, nearly one-third are in Great Britain. And while almost 90 percent of trips in the U.S. are made by car; only 58 percent are in Britain. More people in Britain take buses and trains, too. This modal flexibility could help explain why British of different incomes tend to take similar numbers of trips, unlike in the U.S. where wealthier people step out more often. In both countries, though, wealth is still tightly correlated with mobility, which is partially reflective of people’s ability to own, maintain, and fuel automobiles for such trips.

The one odd bit the researchers discovered was that people in smaller metropolitan areas—with populations between 250,000 to 500,000—traveled more frequently than larger ones. In theory, residents of large metro areas should have more available destinations and ways to get there, which left them stumped as to why big city people made fewer trips. My suspicion? Smaller metro areas may be a sweet spot in the spectrum, with just enough destinations and modes of transportation without the congestion present in big cities.

Source:

Giuliano, G., & Narayan, D. (2003). Another look at travel patterns and urban form: The US and Great Britain Urban Studies, 40 (11), 2295-2312 DOI: 10.1080/0042098032000123303

Photos by Minesweeper and Loganberry.

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