The Park of a Thousand Pieces by Trey Popp Illustration by Caroline Hwang ©2011 The Pennsylvania Gazette

1. Penn Praxis has a plan for adding
500 acres of open green space to
Philadelphia in the next four years.
Their approach, informed by novel
research by Penn scholars in areas
ranging from real-estate economics
to criminology, is a new way of
imagining urban parkland.
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2. THE
PARK PIECES OF A THOUSAND
BY TREY POPP
T here are plenty of reasons to like city
parks. They give joggers a place to run,
seniors a place to walk, kids a place to cart-
responses. Replacing impervious asphalt
with rain-absorbing green space has
already saved the city water department
backed by the administration of Mayor
Michael Nutter W’79—are based in no
small part on evidence being developed by
wheel into their elders’ paths. For down- $35 million in hard infrastructure costs an eclectic constellation of Penn scholars.
town dog owners and penned-up parents, a since 2006—gains that could be multi- The analysis of urban open spaces, once
nearby patch of grass may be the difference plied. The same goes for the output of the exclusive preserve of landscape archi-
between a lasting interior paint job and community gardens, which produced an tects and city planners, has been taken up
claw marks on the walls. For a townhouse estimated 2 million pounds of fresh pro- by real-estate economists, criminologists,
dweller making do with a hundred square duce in Philadelphia in the summer of and experts in public health. Here is a
feet of sun-blasted roof deck, the shade of a 2008 alone, valued at almost $5 million. survey of some of their research, and how
sugar maple might be enough to make Then there are benefits that are harder it may inform a new take on city parkland
August a month worth living. to quantify directly, but may yield even in Philadelphia.
Penn Praxis, the student-faculty clin- bigger returns. Turning abandoned build-
ical consulting practice in the School ings into park-like amenities reduces The most noticeable aspect of Penn
of Design, makes the case for parkland crime, the Penn Praxis report claims. Praxis’s Green 2015 plan is that, to a sub-
in rather stronger terms. In a recent Adding 500 acres of green space could stantial degree, the new green spaces it
report outlining a rationale for creat- help prevent 20 asthma attacks a year as envisions are not very noticeable at all.
ing 500 acres of new public green space a result of improved air quality. The On a map of the whole city, they barely
in Philadelphia over the next four authors also cite a 2010 study that cred- show up—certainly not the way Fairmount
years, the group credits urban green- ited Philadelphia’s existing open space Park does, or the 843 acres of Central
ing projects with providing a seeming- with generating health-related cost sav- Park do on a map of New York. Instead,
ly miraculous range of benefits. ings in excess of $400 million. the plan envisions a sort of archipelago
For starters, there’s cold, hard cash. “Simply put,” the Penn Praxis plan of revitalized green spaces—mixing pub-
Converting vacant properties into tidy declares, “city parks save lives.” lic and private development—that range
lawns or community gardens, the report That is a lofty claim, and so are many of in size from the 24-acre Penn Park down
argues, can raise local property values, the others. But the declarations in Green to parcels as modest as the new one-
swell city tax revenues, and save the fire 2015: An Action Plan for the First 500 third-acre Julian Abele Park in southwest
and police departments literally millions Acres—commissioned by Philadelphia’s Center City [“Window,” Jan|Feb 2011], or
of dollars a year in averted emergency-call Department of Parks and Recreation and even as small as single vacant lots.
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3. “In an era of constrained times,” says GIS (Geographic Information Systems) Lab as 30 percent,” she wrote. “New tree
Penn Praxis director Harris Steinberg and culling data from the city tax board plantings increase surrounding hous-
C’78 GAr’82, “and difficult political ten- and the Pennsylvania Horticultural Society ing values by approximately 10 percent.
sions between [City] Council and the (PHS), Wachter and her colleagues have In the New Kensington area this trans-
[mayoral] administration … we really come up with some compelling answers. lates into a $4 million gain in value
wanted to make this as easily digestible In a 2005 paper, she investigated the through tree plantings and a $12 million
as possible.” Accordingly, they laid out a effects of a pilot program in which the gain through lot improvements.”
plan they feel is capable of having a New Kensington Community Develop- In that light, it seems fitting that her
“transformative impact, but on a series ment Corporation teamed up with PHS to employer recently partnered with the city
of small scales”—rather than the sort of implement a greening strategy in that Department of Parks and Recreation to
grand vision a latter-day Robert Moses or depressed section of Philadelphia give away 300 free trees to faculty and staff
Frederick Law Olmsted might dream up. [“Gazetteer,” July|Aug 2005]. The pro- living within city limits in a pilot program
The crux of the plan is to draw from an gram focused on replacing abandoned called “Creating Canopy with Penn.”
asset that Philadelphia has in abundance: lots with tree-ringed landscapes of mowed Another new University initiative, more
vacant and abandoned land. The report grass, as well as planting sidewalk trees. symbolic in nature but a sign of the zeit-
observes that Philadelphia contains more GIS software enabled Wachter to mea- geist nonetheless, is the planting of a dif-
than 4,000 acres of vacant lots and aban- sure the precise distance of every home ferent tree species every year—one speci-
doned buildings. About one-quarter of from a stabilized lot or tree planting. men on campus and a second designated at
that total belongs to the city. Coupled with sales data from 1980 to the Morris Arboretum—to honor the gradu-
“The city is paying $21 million a year 2003, this permitted her to draw some ating class. The Class of 2011 was com-
to manage all of that, regardless of striking conclusions about the impact memorated with a sugar maple in April.
ownership,” says Steinberg, noting that of the greening pilot program (which
it costs money to seal off condemned had cleaned the trash from 18,800 lots
buildings, respond to arson, and fight between 2000 and 2003, and improved
crime in row homes that have been about 12,000 of them). “Vacant land
abandoned to drug dealers. “And if you improvements result in surrounding
can start to redirect some of that to housing values increasing by as much
actually productive landscapes that
can help increase property values,” he
adds, “you shift the whole paradigm.”
As anyone who lives across the street
from Central Park can tell you, the idea
that open green space can enhance prop-
erty values isn’t exactly novel. Nor is this
the first time Philadelphia has tried to
clean up derelict properties; former Mayor
John Street’s Neighborhood Transforma-
tion Initiative tried with mixed success to
do just that in some parts of the city in the
first few years of the last decade [“Gazet-
teer,” Sept|Oct 2010]. But until recently,
the notion that public greening could
“shift the whole paradigm” of urban
decrepitude was supported more by intu-
ition than evidence—at least when it
comes to measuring the effects of brand
new parks, particularly those built on a
much more modest scale. In the last sev-
eral years, Wharton’s Susan Wachter has
gone a long way to filling in that gap.
Wachter, who is the Richard B. Worley
Professor of Financial Management and a
specialist in real-estate economics, has
been asking questions like, How much
does cleaning up a vacant lot increase the
market value of the house next door? and
Green 2015 envisions a sort of archipelago
How much is a sidewalk tree worth? of revitalized green spaces totaling 500
Tapping into the expertise of Wharton’s acres by 2015.
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4. In a 2008 paper with assistant profes-
sor of real estate Grace Wong Bucchianeri,
Wachter argued that the property-value
increase associated with tree plantings
is largely attributable to “either social
capital creation or a signaling mecha-
nism.” In other words, tree plantings
send a signal to prospective home buyers
that the community is becoming more
actively involved in improving the neigh-
borhood. About a quarter of the increase,
they contended, stemmed from the
intrinsic value of the tree.
This underscores a related point,
which is that the payoff of public invest-
ment in greening depends on where it’s
carried out. ““It’s not just greening of
the space that does it—it’s the fact that
you’ve greened a space that previously
was depressing property values,” says
Kevin Gillen GrW’05, a research col-
league of Wachter’s. (Wachter is cur-
rently on leave.)
“If you go out to Lower Merion and
demolish someone’s home and convert
it into a little park, will that increase Part of the program calls for renovating rec
the value of the home next door?” he centers and schoolyards with things like
asks rhetorically. “Yes? By that much? tree canopies and porous pavement.
No. Because what was there before was
pretty nice. But if you’ve got a blighted neighbors that, hey, maybe something is you have a community garden. It’s that the
abandoned factory in Kensington, happening here, it’s turning around, crime is gone, you’ve got a better view out
which is just all asphalt and soil that you’ve got another amenity.” your kitchen window, the air is cleaner,
has chemicals in it, and rusty hulking The Penn Praxis report observes that you’ve got a potential source for food.”
buildings, and you convert that to a even with Fairmount Park, the largest And unlike a lot of kitchen make-
park, you have much bigger spillover city-owned park system in the world, overs, the cost-benefit ratio of turning
effect on the nearby home values.” Philadelphia still has a need for more a vacant lot (or a cluster of them) into a
Gillen, who has pressed this research green spaces. “There are currently more pocket park can be very favorable.
forward as a vice president of Econsult, than 200,000 Philadelphians, about 1 in “Measured bang for buck, it’s quite
a Philadelphia-based economic con- 8 residents, who do not live within a positive,” says Gillen. “Because in gen-
sulting firm, says that the best areas a 10-minute walk of a public green space,” eral what we often found is that the
city can target for greening are “neigh- the report notes. “Leaving this many citi- value created would often exceed the
borhoods on the margins.” zens without access to park space is like cost of doing it. If it costs you $10,000
“That is, they’re not completely dis- leaving the entire cities of Allentown and to green a lot but it creates $15,000 in
GREEN 2015: AN ACTION PLAN FOR THE FIRST 500 ACRES / PENN PRAXIS
tressed, abandoned neighborhoods. But Erie combined without access to parks.” additional property value, then that’s a
they’re neighborhoods that are sort of Among the variables that influence a gain to taxpayers.”
at the tipping point of turning around,” house’s value—from the number of bed- The Penn Praxis report cites a study by
he explains. “Where they do the least rooms and bathrooms to the number of Gillen and Todd Baylson GCP’04 which
good are the neighborhoods that would garage bays (Wachter took 50 such found that homes near newly converted
be considered the most depressed in the variables into account in her New green spaces appreciated in value at an
city. They have the highest crime, the Kensington study)—“in general we find average rate of 13.3 percent per year dur-
highest abandonment. Those neighbor- that public amenities are somewhere ing a period when the average home
hoods need more help than just putting in the middle,” Gillen says. value appreciated at a 7.8 percent annual
in a community garden. They need bet- “Any new kitchen can increase the value rate. Over a seven-year period, this trans-
ter policing, fire, trash collection. They of your home a lot,” he adds. “[But] if you’re lated into a $22.2 million gain in incre-
need a lot more help than just convert- right next to an abandoned home being mental property-tax revenue.
ing a vacant lot. But in marginal neigh- used for criminal activity, and the next day Gillen is quick to emphasize that
borhoods, replacing an abandoned home it’s a community garden, you can expect greening is not the end-all of urban
with a community garden signals to the the effect to be pretty large. It’s not just that invigoration.
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5. “There’s a reason that we’re looking “There’s been so little done with green- Branas is currently planning to embark
at this issue” in Philadelphia, he says. ing and open green space and its impact,” on an experiment in which a large group of
“And it’s because we’re not a growing Branas says. “People have been debating vacant lots will be randomly selected to be
city … These 40,000 vacant parcels it for decades, but there’s been very little greened, and the subsequent public-health
represent dead assets on the city’s bal- actual empirical work done on this ... and crime impact compared to another
ance sheet. If something can be done We’re following on some of Susan randomly selected group of similar lots
with them, [the priority] should be to [Wachter]’s work and expanding on more that were not greened. He also hopes to
add to the tax base” via residential or than just the economic impact for spe- install time-lapse cameras in some vacant
commercial development. cific property owners. We’re really think- lots to gather finer-grained observations.
“Of course the reason Philadelphia has ing about the neighborhoods and the “In our fieldwork, going and visiting the
so many vacant parcels and abandoned health and safety impacts.” lots,” he explains, “at the middle of the
buildings, unlike, say San Francisco, is Branas and several colleagues have day, you will see a goat path beat into the
because we’ve basically been a depopu- come at it from several angles, one of middle of the lot if it’s very overgrown.
lating and contracting city,” he adds. which involves ecological studies—popula- There are a lot of places to hide. Clearly
“On top of that, our construction costs tion-scale analyses of phenomena like the people are entering and going through
are among the highest in the country, impact of smoking on lung cancer rates. them and using them in some capacity.
despite the fact that our home prices While considered less robust than cohort But it’s unclear how much and for what.
are among the lowest of large cities. So or case-control studies, ecological studies And it would be really neat to observe this
there’s economic incentive to system- can produce insights that help epidemiol- firsthand, if possible, before and after a
atically under-invest in maintaining or ogists model the effects of certain behav- greening intervention. So what happens?
developing real estate. iors or interventions on things like neigh- What’s the foot traffic like when the lot’s
“Insofar as the city is willing to take borhood crime levels. That’s how vacant overgrown and trash strewn, versus after
those steps to really turn it around and land rose to Branas’ attention. you green it? Does it really change? I don’t
make it a competitive city, it’s going to “What was striking about these mod- know. Maybe it doesn’t.”
have this problem with vacant and els [that came out of our study] is that, Depending on the results, Branas
abandoned parcels. So the question in the laundry list of different things points out, greening could turn out to
becomes: What’s the next best thing that could have affected crime—eco- be an unusually cost-effective crime-
you can do with them? And in that case, nomic conditions, poverty, racial con- reduction mechanism.
since you can’t develop them at market ditions, segregation, all these things— “Public health has really, over the past
rate and do so profitably, then you may vacant properties rose to the top as the 40 years or so, concentrated more on deal-
as well use some public moneys to con- strongest effect in terms of correlating ing with individuals and a biomedical
vert them to some other use, to elimi- with crime. And so that was really tell- model or a bio-behavioral model, where
nate blight and enhance your tax base ing. I was very surprised by it.” you’re really seeking to either treat people
by improving local property values in This line of inquiry is still in prog- medically and try to get them more treat-
the neighborhood.” ress, but it has yielded some more spe- ment, or you’re seeking to treat them one
Penn Praxis’s Steinberg echoes that cific observations. by one as individuals and try to change
sentiment. “I think that really helps “What we’re finding in this is that there their behavior with some psychological
shape the economic argument for are certain crimes that seem to have been campaign,” he observes. “Those are won-
transforming vacant land,” he says. highly affected by the greening,” Branas derful. In fact, many of them have been
“Now that doesn’t mean it all has to be says. “For instance, we think gun assault shown to be incredibly successful. The
green space. We want people to move is something that’s been highly affected. problem is, scaling it up isn’t so easy and
into the city, we want the tax base to And maybe gun robbery at some level. is immensely costly. Millions of dollars to
rise, we want the school system to get “We think that’s the case because treat a handful of high-risk kids in one
better … All those things are important. there’s been some early anthropologic neighborhood is wonderful, because those
But we have found that there is a direct ethnographic work in places like New kids do reap the benefit of that. But it’s not
impact between quality green space Haven and Detroit where they will fol- sustainable because you can’t keep spend-
and property values, social cohesion, low criminals with illegal firearms. And ing millions of dollars year after year for a
and then we get into public health and most of them don’t carry their weapons handful of kids.
then all those other reasons.” with them. This is one theory, right. “So in thinking about greening,” he
Most of them don’t carry their weapons goes on, “it’s sort of a long shot—or it was.
P ublic health and “all those other reasons”
have a burgeoning champion in the
person of Charles Branas, an associate
with them because it’s illegal to have
them. You have other arrests, you’re a
felon: you’re not going to carry your
But if it works, it’s incredibly inexpen-
sive, relative to an army of psychologists
or public health workers going into the
professor of epidemiology as well as emer- weapon, but you need it because you’re neighborhood. And everyone may get the
gency medicine at the Raymond and Ruth part of this illegal drug trade, let’s say, benefit of the greening: people who are
Perelman School of Medicine, whose aca- for instance. You need that protection. high-risk and coming through the area,
demic portfolio ranges from cartographic So they will often, apparently, store the and people who live there and so forth
modeling to criminology research. weapons on vacant lots.” whether they’re high-risk or not.”
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6. Like much of the research it draws from, garden and why we need urban agricul- It’s good environmental policy. It’s the
the Green 2015 plan focuses broadly on ture changed when Susan Wachter did sort of thing that gets regular resi-
green space without delving too deeply her studies of greening—which were not dents—as opposed to city departments
into the finer details of what specific very much about urban agriculture—in spending tax dollars—to invest in clean-
functions it should serve. Community the Fishtown area,” he says. “Then some ing up cities and make them more won-
gardening and urban agriculture sur- scholars at NYU knocked off Susan’s derful in many ways. So it’s a very effi-
face here and there, but in such general methodology, but just for community gar- cient sort of investment.”
terms that they essentially come off as dens in New York, and found some really
placeholders awaiting a more compre-
hensive treatment. They have a strong
advocate in another member of Penn’s
interesting things: that they raise adja-
cent property values. And it’s maybe unfair
to say that’s all certain policymakers in
L ike all of these sorts of plans, Green
2015 is more a vision than a shovel-
ready project, as they say. But there are
faculty, though. Philadelphia care about, but for the most signs that it’s gaining traction. Since the
Domenic Vitiello, an assistant professor part, that’s what they care about.” beginning of the Nutter administration,
of city and regional planning in the School He worries that this perspective has 100 acres have already been greened or
of Design, has spent the last several sum- pushed policymakers’ views about com- are under way. Another 105 have been
mers investigating, with urban-studies munity gardening in the wrong direction. identified for future work. The Penn
lecturer Michael Nairn, Philadelphia and Praxis report is chock full of GIS maps
Camden’s community gardens in an up- designed to shed light on where new
close and personal way. (It becomes clear “I believe that it’s a way parks might provide the most bang for
that there’s no other way to put it when he out of the post-industrial the buck—highlighting areas where resi-
wakes up his desktop monitor to reveal a dents are under-served, where heat-relat-
wallpaper photo of the Camden Men’s landscape that we have ed fatalities are highest, where tree cano-
Garden, and says, “That’s where Michael —the literal landscape, pies are insufficient, and so on.
and I want to retire.”) Meanwhile, the city’s Department of
“It’s very well established,” says which is blighted in Licenses and Inspections (L&I) has be-
Vitiello, that community gardens “are many places, inequitable gun a pilot project to ramp up enforce-
very effective tools for stabilizing ment on 143 properties in the North-
neighborhoods, helping them be safer, in many places.” east, taking a harder line on property
more attractive, helping to encourage owners who fail to bring their derelict
people to pick up trash more and invest “[Some people have the idea] that properties up to code. Other sections of
in them … But its economic returns are urban farming could be a really won- the city have also seen an uptick in the
very indirect. And that’s one of the rea- derful interim use for land that the ticketing of derelict buildings by L&I,
sons we went around and tried to count, RDA [Philadelphia Redevelopment sometimes instructing owners to either
and put some dollar signs on the pro- Authority] holds, as a way to improve rehab or demolish them. Perhaps that
duce of community gardens.” properties and sell them in three to will be a first step toward reclaiming
The Penn Praxis plan mentions one five years,” he says. “That’s a great idea Philadelphia’s vacant and abandoned
of their findings: that community and for the RDA. But I don’t know any land for something better and greener.
squatter gardens yielded an estimated farmer or gardener in Philadelphia, or “I believe that it’s a way out of the
2 million pounds of food, valued at any other city, who would really want post-industrial landscape that we
almost $5 million, in a single summer. that. Because what farmers and gar- have—the literal landscape, which is
For Vitiello, though, the dollar signs deners build is not really visible—it’s blighted in many places, inequitable in
don’t tell the whole story. Gardeners soil, and relationships with one anoth- many places,” says Harris Steinberg of
don’t just produce a lot of food; they er and their neighbors.” the Green 2015 plan.
give a lot away. Sometimes nearly For that reason, he hopes Philadelphia “These small doses—in this case of
everything they grow, whether to neigh- will think again about policies like the green—I think can have a big effect in
bors or food banks. They also get exer- city’s new lease agreement for garden- the aggregate,” he adds. “Perhaps as
cise (a big benefit, since so many gar- ers on public land, which would require much as the creation of Fairmount
deners tend to be older), help nourish gardeners to carry insurance on those Park initially did. I wouldn’t go so far
cultural traditions (by growing hard-to- currently vacant lots at the level of as to say that ultimately it’s going to
buy crops like pigeon peas and creole fully developed properties. have that kind of sweeping effect, but
corn), and in many cases provide oppor- The capacity of community gardens in the end, when we’ve pieced together
tunities for kids on summer break to to raise property values and therefore this kind of network of trails and green-
help with something productive. the tax base is all well and good, he ways and access routes, we can really
So for Vitiello, the strongest case for hastens to add. But that shouldn’t be begin to think: Can we take these little
urban agriculture isn’t really the econom- the only goal, or even the ultimate one. archipelagos of parks, and really make
ic one. “The impacts go well beyond food. “Urban agriculture—farming and gar- them into one big system?”
They’re mostly social impacts,” he says. dening—is great social policy,” Vitiello A question, perhaps, to be posed when
“The whole conversation about why we says. “It’s great public health policy. 2020 appears on the horizon.◆
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