Urban Trees and Forests of the Chicago Region. To determine the vegetation structure, functions, and values of the trees that currently constitute the Chicago region’s urban forest, a tree census was conducted by The Morton Arboretum and the U.S. Forest Service in 2010. The findings provide a basis for regional leadership to build a platform for urban forest management that will inspire the region’s stakeholders to plant and protect trees and improve the vigor of the urban forest. The following is a brief summary of its findings.
- As of 2010, the Chicago region had approximately 157,142,000 trees, providing a canopy that covers 21% of the region. The most common tree species are European buckthorn, green ash, box elder, black cherry, and American elm.
- Trees in the Chicago region currently provide a number of important environmental and economic services. They store 16.9 million tons of carbon (61.9 million tons CO2) valued at $349 million. In addition, these trees remove about 677,000 tons of carbon per year (2.5 million tons CO2/year; $14.0 million per year) and 18,080 tons of air pollution per year ($137 million per year). Chicago’s regional forest is estimated to reduce annual residential energy costs by $44.0 million per year. The compensatory value of the trees is estimated at $51.2 billion.
- 21% of the region's street trees in residential areas are ash species (Fraxinus). The emerald ash borer is an invasive species currently devastating ash populations across the region. As ash trees die, removal and replacement costs are crippling the budgets of municipalities and other stakeholders. An effective strategy to plant a diverse number of species across areas of different land uses is necessary to avoid devastating losses like these in the future.