Dear Reader readers:
In response to Ben Joravsky's July 15 article regarding recent concerns of some residents that isolated cases of tree leaf browning are occurring as a result of the City's street resurfacing program, the Chicago Department of Transportation sought the expertise of one of the top tree specialists in the country to make a conclusive evaluation.
After carefully inspecting trees on the blocks specified in the article (on N. Sacramento and W. Eastwood), Dr. George Ware, tree specialist with the Morton Arboretum in Lisle, Illinois, found that "no long-term damage has occurred as a result of the City's street resurfacing program. At all the trees inspected, the leaf browning is short-term and there is, universally, almost immediate regrowth of leaves, indicating that tree health is not in jeopardy." He added that the new foliage should obscure the browning within a few weeks. Dr. Ware concluded that "all trees will return in a normal state the following growing season." He also examined trees that were browned during last year's resurfacing program and observed all of them to be healthy and thriving. Dr. Ware determined that the trees affected during the resurfacing process are generally those that have branches overhanging the street below a 12-foot height.
Dr. Ware's conclusions are consistent with those of the City's Bureau of Forestry, which continually monitors the condition of trees through the construction season. In a follow-up to the reference of a damaged maple in the July 29 Reader, Forestry also checked out all trees on the 2700 block of W. Agatite (misidentified as the nonexistent 2800 block in the July 15 Reader article) and found no resurfacing-related tree damage.
During the three years prior to 1994 in which the "heater scarification" process has been utilized for City resurfacing programs, totaling 200 miles of street resurfacing, not one tree has been lost. "Heater scarification" refers to a process in which existing street pavement is heated, dug up, and recycled for use as new asphalt. The City of Chicago utilizes this process because it is more environmentally responsible, by eliminating the need for asphalt disposal; faster; and 30 percent less expensive than previous methods, allowing the City to increase the size of resurfacing programs without additional revenue.
Involved City departments, including Transportation, Streets and Sanitation, and Environment, have taken, at the insistence of Mayor Richard M. Daley, a number of precautions in the scarification process to insure that no long-term tree damage results. These precautions include:
Heat shields installed on the top and sides of scarifier machines.
Strict City supervision of all crews to make sure that machines keep moving to avoid sustained heat exposure, and are turned off immediately when in down periods, such as lunch breaks, and materials delivery.
Modification of the machine's heat level to achieve the lowest temperature possible to adequately heat the pavement.
Coordinated consultation with the Bureau of Forestry to continually monitor the condition of trees through the construction season.
Residents are urged to water tree roots and branches prior to the arrival of the resurfacing crews. This will minimize any heat-related leaf browning. Residents should look for special doorhangers and No Parking signs, which indicate when the resurfacing crews will arrive.
The City's 1994 resurfacing program is the largest in its history. It consists of 2000 blocks of residential streets, 30 miles of arterial streets, 1000 alleys, and thousands of feet of sidewalks and curb and gutter. The program is currently more than half complete.
J. F. Boyle, Commissioner Chicago Department of Transportation