Mitigation of the Urban Heat Island Effect via NeighborWoods Tree Program Project Manager-Clancy Taylor GIS Analyst/Web Designer-Will Johnston GIS/Remote Sensing Analyst-Michael Amaral GIS/Remote Sensing Analyst-Megan Branam

Outline 1. Introduction 2. Data 3. Methods 4. Results 5. Implications, Considerations, and Conclusions

Introduction Austin, Texas NeighborWoods Tree Planting Program Mitigation of Urban Heat Island Effect Effectiveness of Program

Urban Heat Island Effect Developed Areas are Hotter than Rural Areas Negative Impacts on City Mitigation of UHI Effect

Data The Austin Urban Forestry Department provided the NeighborWoods tree locations City of Austin provided base map information USGS Earth Explorer images from Landsat 4-5, 7, and 8.

Methods – Remote Sensing Extract the data Re-projected to Texas State Plane Central (4203) Convert digital numbers to Spectral Radiance Convert Spectral Radiance to at- satellite brightness temperature Convert to Celsius

Methods-GIS Determined how to group study areas & control areas (zip codes) Chose top 10 zip codes with most trees/ top 10 least trees (majority of zip code within AE service area) Joined zip code shapefile with tree shapefile Calculated average surface temperature for each zip code Converted raster layer to point vector Did same process for all 20 zip codes per year for all 3 years

Methods-Statistical Analysis Wilcoxon Signed Rank Test Nonparametric Test Testing differences between mean temperatures 2002, 2009, 2014 Mean Temperature per Zip Code 10 Zip Codes w/ Most Dense Tree Plantings 10 Zip Codes w/Least Dense Tree Plantings

Hypothesis Testing Null Hypothesis (H0): The median of differences between the temperature differences of the non-dense tree zip codes and the temperature differences of the dense zip codes is not statistically significant. Alternative Hypothesis (H1): The median of differences between the temperature differences of the non-dense tree zip codes and the temperature differences of the dense zip codes is statistically significant.

Methods – Tree Benefit Calculator Information gathered from the National Tree Benefit Calculator website Trees planted are 1 in. in diameter Trees grow 1 in. in diameter every year Trees from one year are multiplied many times Disregard 2002 year, no species information

Results– Remote Sensing Not real land surface temperature Light travels through the atmosphere, along with “noise” Cloud coverage Not the highest quality images For two images, the pixel size was 50 feet One image 100 foot pixel size

Results-GIS Base map Established study/ control areas Average surface temperatures per zip code Prepared data for statistical analysis Final maps

Results-Statistical Analysis Significant Temperature Differences ; No Temperature Differences

Results– Tree Benefit Calculator Trees are awesome! Many assumptions involved Keep planting trees!

Considerations Health of Trees At Satellite Brightness Temperature Climatology Other Cooling or Mitigation Factors

Conclusions NeighborWoods-Urban Heat Island Mitigation Energy and CO₂ Savings and Reduction Neighborhood Level Temperature Reduction As Austin continues growing, so should NeighborWoods