Addressing Social and Environmental Needs through Community Tree Planting Keep Indianapolis Beautiful, Inc. & The Department of Geography Indiana University Purdue University Indianapolis
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Tree Planting Site Selection Model

Purpose

A site selection model is a decision making tool for identifying locations in a landscape where multiple criteria overlap in geographic space.  The purpose of the site selection model used in this project was to identify specific Center Township residential neighborhoods in which to focus tree planting efforts.  The site selection model was developed and implemented using geographic information system (GIS) and remote sensing technologies.  The goal of the model is to distribute plantings in a way that maximizes environmental, social, and health benefits to communities that need them most. 

Model Variables

Nine socio-economic and environmental criteria were selected for input into the model:

• Income
• Crime
• Zoning
• Industrial Emission Sites
• Pediatric Asthma Rates
• Major Streets
• Surface Temperatures
• Tree Canopy Density
• Impervious Surface Density
  

Model Variable	Description	Source	Maps
Income	Median household income by census block group in 2000.  Census block groups with median household incomes below the township average were coded with a value of 1, while those above the average were coded with a value of 0.	2000 US Census of Population and Housing
Crime	Adult and juvenile crimes by census block group in 2004.  Density of juvenile and adult crimes was calculated by dividing the total number of crimes in the census block group by the block group area.  Census block groups with crime density values greater than the township average were coded with a value of 1, while those below the average were coded with a value of 0.	SAVI Community Information System
Zoning	Residential zoning in Center Township was delineated using the Indianapolis Department of Metropolitan Development's zoning GIS layer.  All residential zoning was coded with a value of 1.  All other zoning types were given a value of 0.	Indianapolis Mapping and Geographic Infrastructure System (IMAGIS)
Industrial Emissions	Locations in Center Township with Title V industrial emission permits were buffered at a distance of 1/4 mile.  Areas within 1/4 mile of a Title V locations were coded with a value of 1.  All other areas were given a value of 0.	Indianapolis Mapping and Geographic Infrastructure System (IMAGIS)
Pediatric Asthma	Pediatric asthma rates by zip code in 2000 based on hospital discharge data for children ages 5 to 14.  Zip code polygons with higher than average rates for the township were given a value of 1.  All other areas were given a value of 0.	Health and Hospital Corporation of Marion County
Major Roads	Emissions from vehicles are among the major contributors to air pollution in cities.  Areas within 500 feet of major road center lines were coded with a value of 1.  All other areas were given a value of 0.  Major roads include expressways, freeways, primary and secondary arteries, and selected collector streets with heavy traffic.	Indianapolis Mapping and Geographic Infrastructure System (IMAGIS)
Surface Temperatures	Radiant surface temperatures in Center Township were measured by the Enhanced Thematic Mapper Plus (ETM+) sensor on board the Landsat 7 satellite.  The thermal band of the ETM+ has a spatial resolution of 60 m.  Areas with radiant surface temperatures above the township average were coded with a value of 1, while those below the township average were coded with a value of 0.	Department of Geography Indiana University Purdue University Indianapolis
Tree Canopy Density	Tree canopy density within an 800 foot buffer was derived from the data described in the tree canopy mapping section of this report.  Percent area covered by tree canopy within the buffer was computed.  Areas below the township average canopy density were coded with a value of 1, while those above the township average were coded with a value of 0.	Department of Geography Indiana University Purdue University Indianapolis
Impervious Surface Density	Estimates of impervious surface coverage were derived from GIS data that combined building footprints, road center line buffers, and impervious surface areas delineated in the IMAGIS database.  Percent impervious cover within an 500 foot buffer was calculated.  Areas above the township average impervious density were coded with a value of 1, while those below the township average were coded with a value of 0.	Indianapolis Mapping and Geographic Infrastructure System (IMAGIS)

Each of the binary layers for the variables describe above were added together in a GIS to produce the final site selection map.  The values in the map range between 0 (no criteria met) to 9 (all criteria met).  The final map is shown in the following image (Figure 1).  Clicking on the image links to a higher resolution version of the map in PDF format.

Figure 1.  Site Selection Model Results Areas shown in warmer tones (orange and red) meet more of the site selection criteria.  Click on the image to access a higher resolution version of the map with legend in PDF format.

Eight "hot spots" (areas where most or all of the model criteria occurred) emerged from the modeling process (Figure 2).  These hot spots serve as target neighborhoods for residential tree planting efforts.  Figure 3 shows an example of the site selection model output overlaid on an aerial photograph for the hot spot identified as number 3 in Figure 2.  Areas tinted red on the photo meet at least 8 criteria in the site selection model.  

Figure 2.  Hot Spots Hot spots are areas identified as meeting most or all of the criteria in the site selection model.  Eight residential hot spots were selected for targeted tree planting efforts.		Figure 3.  Hot Spot Close Up Example This image illustrates the results of the site selection model overlaid on a high resolution aerial photograph for the hot spot identified as number 3 in Figure 2 at left.  Areas with red shading meet at least 8 model criteria.

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