The Illinois Tollway Authority is undertaking a three-year initiative to plant 58,000 trees along their 292-mile right-of-way to increase the regional forest canopy in the Chicagoland area. However, trees are notoriously difficult to grow in poor-quality roadside soils. Furthermore, the Tollway seeks to not only increase the number of trees, but also the diversity of trees in the region.

To overcome these challenges, the Tollway Authority and The Morton Arboretum are collaborating to learn more about the factors, conditions, and practices that enable the successful establishment and growth of trees planted in highway right-of-ways. Specifically, Arboretum researchers are assessing tree performance in existing Tollway right-of-way plantings and have established experiments in Tollway sites to test the effects of soil organic amendments, site design, species selection, and stock size on tree establishment, growth, and ecosystem service provision. The goals of this project are to establish the value of proper site preparation and set the standards for roadside tree planting.