Turning a new leaf: Social and land use drivers of urban tree canopy change in the Chicago Metropolitan Area 2010–2017

Abstract

Increasing the equitable distribution of tree canopy is a priority for many cities, and tree canopy change studies are needed to inform natural resource managers on how and for whom canopy is changing. This study examines relationships between tree canopy change, socioeconomic/demographic characteristics, and land use at the block group and county scales, in Cook County, Illinois from 2010 to 2017. At the block group level, spatial Random Forest Regression models the nonlinear relationships between six canopy metrics and socioeconomic, demographic, and land use predictors. We also tabulated canopy change across land use categories at the county scale. Tree canopy decreased by 11,634 ha—1.1 % of Cook County’s land area. Residential and transit land use types experienced the highest canopy gains and losses. Block groups with higher proportions of residential land, higher median income, home ownership rates, and lower housing densities experienced more canopy gains and losses. High housing density areas possessed less canopy, but lost less proportionally. Vacant and natural land were associated with canopy growth and persistence respectively. Diverse modeling suggests net canopy change calculations mask the presence of canopy turnover and that there is a need for a unification of canopy tabulations in the field. Protection of existing canopy as well as the investigation of vacant space for canopy growth may improve urban forest equity in a city where it could be on the rise.