This week, I delved through the historic taxlot data, joining it by location to the 2010 block groups in order to arrive at a median value of land per square foot for each block group. This data provides visual confirmation of what I knew from delving through PortlandMaps.com—the entire city, east of I-205, has seen a pretty dramatic increase in inflation-adjusted land values, with the percent increase most stunning in historically black North Portland. Beyond this, it allowed me to systematically examine the effects of major rail expansions on nearby land values, which I think will be a centerpiece of my outcome for this independent study (assuming a full spatial and statistical analysis of that data can say anything). I haven’t yet had time to go through each of the six rail projects I intend to examine (MAX Westside expansion, airport extension, Yellow Line, and Green Line, and the Portland streetcar and its later eastside expansion) and their effects on land value by year, though I have looked into the MAX Yellow Line and the original Portland streetcar. The Yellow Line had a completely insignificant effect on land prices over the when viewed at the block group level. At the taxlot level, one can see some very localized effects, especially right along the street itself, but I doubt the relationship is statistically significant. The streetcar, meanwhile, seemed to have a rather significant impact.
In just a week and half, I’ll be presenting a poster of my project at Lewis & Clark’s Festival of Scholars. With this in mind, I’ve started thinking about what exactly I’ve found and will be presenting, in addition to outlining the content of the poster. A rough, text-based outline is:
- Introduction
- Gentrification theory
- Supply-side factors (Smith)
- A rent gap (realized rents well below potential rents) is opened up by historic disinvestment, suburban flight, and industrial restructuring, creating relatively cheap land near the city center.
- The rent gap then opens up the opportunity for profitable redevelopment
- Transit can be theoretically linked to the rent gap—expansion of transit could intensify the rent gap by allowing for even higher potential land rents
- Demand-side factors
- Combination of strong, professional-oriented economic growth in a city and the attractiveness of urban living/amenities to the creative class (Florida)
- Transit can also be linked in this theory as increasing access to downtown professional jobs, being an urban amenity itself, and being an indicator of where those amenities are.
- Typology of Gentrification (Morrill)
- A: characterized by mass scale public and private partnerships to densify, replace structures, and perhaps institutions and infrastructure, typically occuring in the city core
- B: more the result of individual decisions (though with municipal influence via zoning designations, expansion of mortage lending, or transit routing) to live near the city center, characterized by rehabilitation of vacant structures and displacement of existing, lower-socioeconomic status residents
- Supply-side factors (Smith)
- Brief, bulleted literature review of the relationship between transit and gentrification, drawing mainly on Revington (2015).
- Methodology
- I chose to focus on land values as the purest expression of gentrification drivers. Census-based socioeconomic or housing value data does a poor job of distinguishing “gentrification A”—namely, in Portland, the Pearl District and South Waterfront don’t appear as gentrified landscapes, since they were industrial brownfields before.
- Results
- Map of the relationship of land value and transit in Portland, at the taxlot level
- Scatterplot of the two variables, with the strong correlation noted
- Tabular results of variegated analysis of change in land value before and after rail extensions. This is measured as the difference in change in median land value between the two years proceeding and proceeding the opening of major rail extensions, for block groups within half a mile of new stations.
- Selected quotes from Portland renewal documents linking transit to development.
- Discussion
- There is a strong and clear relationship between proximity to transit and land values (in terms of present day values and their change over the last twenty years), though determining causality is messy, considering the confounding variables. Proximity to downtown is a key contributing factor to both transit provision and land value. Historical development patterns, urban form, transit, and gentrification are all intimately connected in the context of Portland. Most of the inner neighborhoods which have experienced recent gentrification were constructed around streetcar lines in the late 19th and early 20th century; it may be the urban form of those areas which attracts gentrifiers, rather than the transit itself.
- Rail transit is explicitly seen and promoted by the City of Portland as prompting “reinvestment” and development, as can be seen in the Portland Mall Impact study, the Albina Community Plan, the Gateway Document, and the city’s justification of streetcar projects.
- Broader Implications
- Gentrification creates a contradiction between the utility of transit as an equitable form of mobility and its effects on land prices. Transit investment carries the potential to displace those who can benefit the most from that investment.
- Further research
- Study the relationship between zoning, zoning changes, land value, and gentrification. There is an apparent relationship between zoning and land value, as commercially zoned blocks adjacent to arterials frequently have higher land values per square foot.
- Applicability of results elsewhere? Portland is far from unique in facing gentrification pressures in neighborhoods well served by public transit—indeed, gentrification is a phenomenon most widespread in older metro areas with relatively high transit use. Despite a civic pride in being different/weird, Portland’s urban history and layout (specifically the prevalence of streetcar suburbs) is substantially similar to many other North American cities, and is thus potentially generalizable on those counts. The robustness of the theoretical linkages between transit and gentrification also provide an indication of the broad applicability of these findings.
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