The stump of an ash tree lost to EAB.Photo by Mary Mumbrue

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After the mild winter and unseasonably early spring weather, the emerald ash borer (EAB) has been spreading at a rapid pace, leading to the removal of a large number of Evanston’s parkway trees. In July 2006, the Illinois Department of Agriculture confirmed the EAB was located in the far northern edge of Evanston. When the insect was first detected, Evanston had more than 4,000 ash trees on its parkways and in its parks, comprising about 12 percent of the City’s 33,000 public trees.

The EAB has now spread to nearly every corner of Evanston. While efforts to find a control measure to stop the spread of the invasive insect continue, nothing has yet proved to be effective enough for the City to consider widespread use. The Forestry Division’s only real option at this time is to quickly remove any ash trees that Forestry staff has confirmed as infested. As a result, the number of parkway ash trees removed over the past year,  nearly 500, has outpaced the funds to replace them. Staff anticipates that this insect will continue to spread at a rapid pace.

In some cases, when the infestation has not been severe, the Forestry Division has allowed residents to treat their ash trees on the parkway. It requires their contractor to use Tree-Age (which cannot be applied by a homeowner because it is a restricted-use product) and to get a permit to do so. Forestry Division staff will inspect the ash to be sure it is a good candidate for injection, and then issue the permit accordingly.

Ash trees were widely planted in the City and in much of Northeast Illinois because they were fairly inexpensive and generally quite tolerant of soils and climate in this area. In the early 1970s, a master tree-planting plan was implemented that assigned each separate block of the City with one specific tree species. The unintended consequence of this plan is that those blocks designated to be planted with only ash trees are now being stripped of nearly all their trees. Some blocks have even been entirely cleared of all parkway trees.

Specific examples of blocks that recently have been severely affected by ash removals include the 100, 500 and 600 blocks of Asbury Avenue, the 2100 block of Ashland Avenue, the 2900 block of Colfax Street, the 1700, 1800 and 1900 blocks of Darrow Avenue, the 600, 700 and 800 blocks of Dempster Street, the 1100, 1200, 1700 and 1800 blocks of Dodge Avenue, the 900 block of Elmwood Avenue, the 2200 block of Ewing Avenue, the 2700 block of Hartzell Street, the 1900 block of Jackson Avenue, the 1500 and 1600 blocks of McDaniel Avenue, the 700 and 800 blocks of Oakton Street, the 2200 and 2300 blocks of Ridge Avenue, the 300, 400 and 500 blocks of Sherman Avenue, and the 3000 block of Simpson Street.

The plan, especially for those blocks that have been hit particularly hard, is to replace one-third of the trees either this spring or fall, and then continue replacing one-third in 2013 and 2014.

A reforestation fund was established in 2011 following a series of severe storms that destroyed many of Evanston’s public trees. Donations to this fund will be used to replace more quickly Evanston’s urban forest. Forms to donate to this fund, as well as additional information are available at www.cityofevanston.org/forestry. More information is available at that website or by calling 311.