Data on house prices are available at the neighborhood level for central Brooklyn and offer a window into the process. Overall, what we see in central Brooklyn are steeply rising housing prices (figure 3.5). To be sure, they fell in response to the mortgage crisis, but they had more than recovered by 2015—increasing threefold from 2000 (a little less in Bed-Stuy, a little more in North Crown Heights/Prospect Heights).
 
FIGURE 3.5 Index of housing price appreciation, all types, by community district in central Brooklyn, 2000–2015
To provide a sense of the pressures on homeowners in the area, we can look at the likely impact of rising house prices on property taxes. Property is assessed annually in New York City, and property tax rates increased from 2000 to 2015 (from 11.6 percent to 19.6 percent for residential properties up to three units, and from 10.8 percent to 13.4 percent, but then back down to 12.9 percent, for larger residential properties).56 There are exemptions for part of the property value for veterans, but it is safe to assume that property tax bills more than tripled in the same period that property prices tripled because rates were increasing as assessments were also increasing. To the degree that many residents of central Brooklyn in 2000 were lower-income (a safe assumption for Bed-Stuy given what we saw about college education in the neighborhood), these changes are likely to have created pressure—both negative and positive—to leave.
The rent data at the subborough level reflect similar pressures on renters (figure 3.6). It is notable that rents in these central Brooklyn neighborhoods remain below average for the borough, indicating that these gentrifying neighborhoods are still catching up to Brooklyn Heights, Park Slope, Cobble Hill, etcetera. Nevertheless, the change is stark. It is not surprising that the increases are steepest for Bed-Stuy, but the trend for North Crown Heights/Prospect Heights is less clear (some increase, but unstable). This may be a feature of the data, which are only available in the subborough aggregate. Anecdotally there is reason to believe that rents in Prospect Heights are the highest of all the neighborhoods under consideration.
 
FIGURE 3.6 Median rent in central Brooklyn, 2005–2014
One way of measuring the likely effect of such increases in rent on neighborhood change is to create an affordability measure for each neighborhood. It is simple to calculate such a measure by dividing the median rent by median household income (MHI). Housing experts generally agree that rent should constitute no more than 30 percent of household income. Beyond this point, households confront “shelter poverty,” an inability to pay for necessary goods and services because of the fixed cost of rent. (This is less of a concern for higher-income households because they have more disposable income in absolute terms.)
By this measure, the Brooklyn subborough areas decisively crossed the threshold into shelter poverty around 2009. The volatility in figure 3.7 reflects the volatility of income as measured in these neighborhoods (median rents climb more consistently), but the trend lines indicate a distinct and increasing rent affordability concern. Although volatile, income in these neighborhoods is effectively flat but is much higher in North Crown Heights/Prospect Height (about 14 percent). Medians conceal a great deal, and the income median is distorted by inclusion of all of the homeowners in each neighborhood, some of whom are likely to have higher incomes, thus skewing the measure in a way that underestimates the rent affordability problem. Despite all of these caveats, this remains clear evidence of direct displacement pressure.57
 
FIGURE 3.7 Rent affordability in central Brooklyn
Conclusion
In Baltimore I puzzled through a variety of hypotheses about the relationship between historic district designation and neighborhood change, observing a range of neighborhood conditions and periodization. In Brooklyn, neighborhood change was already well underway, and landmark district designation was coming afterward. Rather than asking if one caused the other, in Brooklyn I ask why landmarking is the strategy neighborhood residents chose, how it is facilitated or frustrated by the city government, and how it does or does not mitigate the effects of gentrification.
First, and perhaps most important, landmarking is the primary apparatus available to residents to intervene in a process of gentrification that they perceive is changing their neighborhoods. This is true from the perspectives of both local laypeople and preservation professionals inside and outside government. Furthermore, none of my informants are aware of alternative political approaches to managing gentrification. It is not so much that landmark district designation is the strategy of choice but that it is the only tool available.
Although my informants’ concerns were primarily about the demographic change they see affecting their neighborhoods, their orientation to preservation is not simply instrumental, or desperate, but also aesthetic. They are driven to undertake the districting effort because they are admirers of these historic designs and turn to landmarking to defend those designs in extremis. They uniformly recognize the limitations of landmarking: It can preserve the physical environment of a historic neighborhood but cannot prevent an increase in property prices or prevent new kinds of people with new magnitudes of wealth from moving into the neighborhood. Some of my informants also recognize that they are part of this process of neighborhood change, acknowledging that they are racially distinct from the longtime majority of the neighborhood and perhaps implicitly acting to take some responsibility for the undesirable and indirect effects of their own presence.
My Baltimore story was mostly about variation from neighborhood to neighborhood, recognizing the interaction effects of historic district designation as they varied from place to place. But my central Brooklyn story is about commonality across continuous neighborhoods. This commonality inspired the model in figure 3.8.
FIGURE 3.8 Conceptual model of landmark districting dynamics
My reason for introducing this model is to foreground the group-building process my informants described. The prominent causal connection may be between a perceived threat to the neighborhood and the designation of a landmark district, but the mediating mechanism is a social process of building collective action that, as Bankoff notes, may be at the foundation of the effect landmark districting has on neighborhoods in New York City. This process has repercussions for many other neighborhood concerns—predatory lending, foreclosure, eviction—and points to the possibility that landmark districting is not just the only approach available but is an appropriate response to gentrification.
Taken together, my Baltimore and Brooklyn inquiries clearly show that historic preservation regulation is one of the few policy avenues available to residents to influence change in their neighborhoods. In Baltimore, designation can consolidate status or facilitate changes. In Brooklyn, designation mitigates change. These two examples at either end of a spectrum of development and affordability encourage us to explore other neighborhoods that might further complicate our understanding of historic preservation and neighborhood change.