Already we have identified areas that we might prioritize for coast live oak plantings. But given the extent of damage from the Eaton Fire, it would be easy to justify coast live oaks plantings in all parts of Altadena. Another reasonable argument, at this stage, is that it might just make sense to plant coast live oaks where our iNaturalist data tells us they were observed – assuming that they too were destroyed by the fire, and need to be replaced.
We need to narrow our candidate sites even further, which means we need to add more criteria. To do so, we look at the demographic data.
The two data points that we chose to compare were medium household income (MHHI) and racial makeup, as these two have historically been considered as key indicators of vulnerability by other institutions.
While it was easy enough to use data from Census.gov to display the percentage of either white or nonwhite residents by census tract, it was harder to create a standardized value for MHHI. To achieve this, we divide the MHHI of each census tract in Altadena by the MHHI of Altadena as a whole ($123,689). Thus, tracts that have a MHHI higher than this also have a percentage higher than one hundred.
Given that the method of standardizing MHHI necessitates that a higher percentage correlates with a higher income, we couldn't create a vulnerability index, in which a higher number was equivalent to a higher level of vulnerability. Instead, we utilized the data for the total number of white people in each census tract, found by subtracting the number of nonwhite people from the total population. When we combine this with the percentage of the MHHI for all of Altadena block census tracts, we get a map that starkly splits Altadena into a privileged East and vulnerable West.
In order to come up with suggestions of where future trees should go, we needed to not only know who was privileged in terms of socioeconomics, but also who suffered the least in terms of the recent Eaton Fire's destruction.
As such, we decided to combine the previously created socioeconomic index with two key factors that we thought would show a tract's increased resilience to fire: the number of oak trees and the number of structures that saw no damage.
The resulting index showcased an even deeper divide in the ability for certain census tracts to recover, with the neutral yellow that had previously dominated the map disappearing. Interestingly, however, certain tracts that were considered socioeconomically privileged were actually a step down in the Fire Resilience Index, likely due to being more affected by the Eaton Fire.