Baltimore Ecosystem Study Cary Institute of Ecosystem Studies

2012 BES Annual Meeting Presentation and Poster Abstracts

Urban tree canopy cover and environmental justice: results from an NCEAS working group on environmental justice in cities.
Schwarz, Kirsten
Co-Authors: Kirsten Schwarz, Michail Fragkias, Weiqi Zhou, Melissa McHale, J. Morgan Grove, Jarlath O'Neil- Dunne, Chris G. Boone, Mary Cadenasso

Abstract: Environmental justice research is increasingly focused on the equitable distribution of environmental amenities. Absent from this body of work are studies addressing the distribution of amenities across cities of different sizes, age of development, climates, and histories. This study examines the distributional equity of urban tree canopy (UTC) cover for seven cities: Baltimore, MD, Los Angeles, CA, New York, NY, Philadelphia, PA, Raleigh, NC, Sacramento, CA, and Washington, D.C. using high spatial resolution land cover data and census data. Data are analyzed at the Census Block Group (CBG) and Census Tract (CT) levels using Spearmanís correlation, ordinary least squares regression (OLS), and a spatial autoregressive model (SAR). Bivariate analyses reveal negative correlations between minority communities and UTC cover in some cities. Across all cities there is a strong positive correlation between UTC cover and median household income. Negative correlations between race and UTC cover are generally not observed using multivariate regressions that include additional variables on income, education, and housing age. In some cities, relationships between race and UTC cover become slightly positive. To account for spatial dependency, we use SAR models, which result in higher r-square values compared to the OLS models across all cities, suggesting that spatial autocorrelation is an important feature of our data. In general, the scale of analyses - CBG versus CT - does not change the sign or significance of these relationships. These findings suggest that a suite of social justice variables, including income, contribute to the inequitable distribution of UTC cover.