Dr. Warren was one of 5 experts invited to testify at a hearing before the Boston City Council on June 18. The hearing was called to discuss and assess current and future tree coverage in the City of Boston. Dr. Warren testified on the topic of equity in tree canopy cover distribution in Boston and other cities around the country.

Boston exhibits considerable variation in levels of tree canopy across the city, with some neighborhoods supporting lush, shady streets, and others virtually treeless. Studies are divided, however, on the question of equity (systematic disparities in access to tree canopy). A 2014 study from the Warren lab found income disparities, with higher canopy cover in wealthier areas, but another 2014 study found no income relationship. Both studies agree that there are not significant racial disparities in access to tree canopy cover across the city. Dr. Warren pointed out, however, that even when current canopy coverage is not inequitably distributed, there can still be issues with equity in the process of tree planting.