tree_equity_score_austin (FeatureServer)

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Service Description: This layer includes the variables used to calculate Tree Equity Scores for Austin, Texas. Created by American Forests 2021.

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tree_equity_score_austin (0)

Description: Date of Publication: 07/21/2021

Name of Person Responsible: Alan Halter

Date to be removed/updated: Ongoing updates. Last updated on 07/21/2021.

This map includes the variables used to calculate Tree Equity Scores for Austin, Texas. For more information, contact the original data author, American Forests. Layer colors are HEX F99D3E (orange) to 6CC396 (green).

A Tree Equity Score is a metric that helps cities assess how well they are delivering equitable tree canopy cover to all residents. The score combines measures of tree canopy cover need and priority for trees in urban neighborhoods (defined as Census Block Groups). It is derived from tree canopy cover, climate, demographic and socioeconomic data. Geographies represent selected Census blockgroups for Caldwell, Hays, Travis, and Williamson counties. They cover the Census "urbanized area" for Austin and might not represent the full City of Austin jurisdiction.

The score is calculated at the neighborhood (block group) level.

Methodology (For more information about methodology, visit https://treeequityscore.org/methodology/ )

Step 1: A Neighborhood Goal

Density Adjusted Canopy Target

The canopy target – which is meant to be equitable, aspirational and achievable – requires the following data:

Tree canopy cover. High resolution tree canopy where available, the National Land Cover Database where it is not.
Census American Community Survey (ACS) 2018 5-year Block Group population estimates
Census ACS 2018 5-year city and block group Median Income estimates

To identify a baseline canopy target, we use generalized natural biome baseline targets selected in conjunction with the USDA Forest Service. We select the baseline target based on the location of the municipality.

Forest: 40%
Grassland: 20%
Desert: 15%

This target is then adjusted based on population density to estimate a neighborhood goal. Based on research completed by The Nature Conservancy, adjustments are made using the following table:

Adjusting for population density makes for more achievable targets, while recognizing differences in plantable areas suitable for tree canopy. Note: Neighborhood goals are capped at 150% of the natural biome baseline target.

The formula for each neighborhood goal, GOAL, is as follows:

GOAL = Baseline target * Density adjustment factor

Step 2: The Canopy Gap

The neighborhood canopy gap, GAP, is calculated by subtracting the existing neighborhood canopy from the density adjusted target, that is: GAP = GOAL – EC, where EC is % existing canopy for that neighborhood

The canopy Gap is then normalized to a score from 0-100.

GAPScore = 100 * GAP / GAPmax , where:

GAPmax is the maximum GAP value citywide for that indicator; and

Notes: If the GAP is negative (i.e. Existing canopy is greater than the neighborhood goal), it is adjusted to 0 before normalizing to create the gap score. Also, if Gapmax = 0, then GapScore is set to 0 as well.

Step 3: The Priority Index

The Priority Index is developed to help prioritize the need for planting to achieve Tree Equity. The priority index includes the following equally-weighted characteristics:

Income: Percentage of population below 200% of poverty
Employment: Unemployment rate
Race: Percentage of people who are not white non-Hispanic
Age: Ratio of seniors and children to working-age adults
Climate: Urban Heat Island severity
Health: Prevalence of poor mental, physical, respiratory, and cardiac health (composite index)

These measures are normalized and combined to create a simple priority index from 0 to 1, where 1 indicates a greater amount of inequity. The indices, N, are calculated as follows:

Ni = (xi - xi,min ) / (xi,max - xi,min) , where, for each indicator, Ni,

xi is the value for that neighborhood for that indicator, i;

xi,max is the maximum value citywide for that indicator, i; and

xi,min is the minimum value citywide for that indicator, i.

The Priority index, E, is then calculated as follows: E = (N1 + N2 + N3 + N4 + N5 + N6) / 6 , where Ni refers to each indicator value (income, employment, race, age, or climate)

Step 4: Tree Equity Score

Tree Equity Score, TES, is calculated by multiplying the Baseline Gap Score by the Priority Index, simply:

TES = 100 (1 - GAPScore E)

A lower Tree Equity Score indicates a greater priority for closing the tree canopy gap.

Tree equity scores of 100 indicate tree equity has been achieved.

Data Dictionary

geoid: the blockgroup id

total_pop: the total population of the block group

state: the state the blockgroup is in

county: the county the blockgroup is in

pctpov: the percent of people in poverty inside the blockgroup

pctpoc: the percent of people of color inside the block group

unemplrate: the unemployment rate inside of the block group

medhhinc: the median household income of the block group

dep_ratio: the dependency ratio (childrens + seniors / 18-64 adults)

child_perc: the percent of children inside of the blockgroup

seniorperc: the percent of seniors inside of the blockgroup

treecanopy: the tree canopy percentage of the blockgroup (set to negative 1 if the source is 'ED')

area: the area of the blockgroup in square kilometers

source: the source of the tree canopy of the block group

avg_temp: the average temperature of the blockgroup on a hot summer's day

ua_name: the urbanized area the block group is located inside

incorpname: the incorporated place the block group is located inside

congressio: the congressional district of the block group

biome: the biome of the blockgroup

bgpopdense: the density of the blockgroup (total population over area)

popadjust: the population adjustment factor (based on the population density)

tc_gap: the tree canopy gap of the block group (goal minus canopy)

tc_goal: the tree canopy goal of the block group (set to negative 1 if the source is 'ED')

phys_hlth: the self reported physical health challenges of the people in the block group (a percentage)

ment_hlth: the self reported mental health challenges of people in the block group (a percentage)

asthma: the self reported asthma challenges of people in the block group (a percentage)

core_m: the self reported male coronary heart challenges of people in the block group (a percentage)

core_w: the self reported female coronary heart challenges of people in the block group (a percentage)

core_norm: the normalized total coronary challenges of people in the block group

healthnorm: the normalized health index of the block group

priority: the priority index of the block group

tes: the tree equity score of the block group

tesctyscor: the tree equity score of the incorporated place/municipality of the block group

geometry: the geometry of the block group

Copyright Text: Original Data Author: American Forests City of Austin Contact: Alan Halter, City of Austin, Development Services Department, Community Tree Preservation Division

Spatial Reference: 102739 (2277)

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