The urban forest of trees that grow in our cities and suburbs needs protection and nurturing so we can harness its many benefits. But first, we need to understand it. To that end, The Morton Arboretum, in cooperation with the U.S. Forest Service, has conducted a tree census, or urban forestry assessment, in the seven-county Chicago region.
The results, analyzed in a report, “Urban Trees and Forests of the Chicago Region,” show that there are about 157 million trees in Cook, Du Page, Kane, Kendall, Lake, McHenry, and Will counties; the tree canopy covers about 21 percent of the land area in the region; and the most common trees are European buckthorn, green ash, boxelder, black cherry and American elm.
The results will support the development of the Regional Trees Initiative, an urban forest strategy envisioned in the Chicago Metropolitan Agency for Planning's GOTO2040 plan, and ultimately help improve the health and well-being of people in the region.
The study also showed:
- Trees in the seven-county Chicago region currently store about 16.9 million tons of carbon.
- These trees remove about 677,000 ton of carbon per year (absorbing 2.5 million tons of CO2).
- These trees remove about 18,080 tons of pollution from the air each year.
- The trees of the Chicago region reduce residential energy costs by about $44 million per year.
- Each year, these trees provide services valued at about $51.2 billion.
Data were collected from the 4,000-square-mile study area in 2010. Arboretum teams studied 1,400 randomly selected plots in the seven counties. The plots included all kinds of land—residential, commercial, public, and private. They included a variety of land uses, such as open fields, forest preserves, parking lots, front lawns, and work sites.
Depending on the terrain, the teams traveled by car, foot, and canoe to count, measure, and catalogue trees.
The data were analyzed by the US Forest Service using a software tool called i-Tree.
Download the executive summary Regional Tree Census Executive Summary (PDF)