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The Ecology Report: A Study of Urban Tree Canopies in Seattle Neighborhoods

Photo of Seattle Academy Upper School Science Ecology Report 2021

Question: Do redlined and low-income communities have less tree canopy cover than other neighborhoods?

Each year, the 11th grade Biology course (taught by Hannah Chapin, Peter Clark, and Melinda Mueller) concludes with an ecology project. This year the class focused on urban ecology. Their final project was to analyze Seattle neighborhoods (defined by census tracts) to find out whether and how neighborhoods' demographic, historic, and environmental characteristics related to the amount of tree canopy in those neighborhoods.

Before collecting data, students read studies showing that neighborhoods historically redlined, neighborhoods with a high proportion of People of Color, and low-income communities often have less tree canopy than other neighborhoods. They learned that tree canopy can mitigate air pollution and urban heat islands, among other beneficial effects.

The students set out to discover whether these trends can be seen in Seattle, as well.  They collected tree cover data using the online data-gathering platform iTree/canopy, and found neighborhood demographic, historical, and environmental statistics on Washington State's Health Disparities mapSeattle's demographics website, and the website Mapping Inequality: Redlining in New Deal America.

The students used the science research data analysis platform GraphPad Prism to analyze and graph their results, each student choosing a particular demographic, historical, or environmental factor to compare against neighborhoods' tree canopy data, and prepared reports of their findings. Some students chose to share their findings with their Seattle City Council representatives.

The good news for Seattle is that our students found no systemic correlations between neighborhoods' economic, demographic, or historical status and the neighborhoods' tree canopy resources. However, students did find inequities in particular neighborhoods, including Seattle Academy's partner, the South Park neighborhood. South Park's tree canopy cover is among the lowest in the Seattle area, while its exposure to air pollution is among the highest. The neighborhood would benefit from added tree cover.  

Answer: Students found no systemic correlations between neighborhoods’ economic, demographic, or historical status and the neighborhoods’ tree canopy resources. 

View Supporting Documents Here