The pruning program would target those trees in the public right-of-way that are most in need of pruning (Priority 1). The initiative is also focused on the larger of the city’s street trees – those bigger than 20 inches in diameter. Those are the trees that have the greatest impact on the mitigation of stormwater.

According to the staff memo accompanying the resolution, the city of Ann Arbor has over 46,600 street trees, counting street trees and those in parks. According to the staff memo: “Those trees intercept over 65 million gallons of stormwater annually and remove pollutants, such as fertilizer, oils, and pesticides, before they can enter local water bodies (USDA Forest Service i-Tree Streets Analysis of Ann Arbor, 2009).

Here’s where the trees targeted by the program are located:

Street trees in Ann Arbor greater than 20 inches in diameter. (Map by the city of Ann Arbor.)

From the city’s online tree inventory, The Chronicle searched for trees greater than 20 inches in diameter and designated as Priority 1 for pruning. A total of 684 trees fit those criteria. Here’s how they broke down by height, diameter and species.

Priority 1 trees by diameter. (Chart by The Chronicle with data from city of Ann Arbor.)

Priority 1 trees by height. (Chart by The Chronicle with data from the city of Ann Arbor.)

Priority 1 trees by species. Maples are the dominant species among those that will be targeted by this pruning program. (Chart by The Chronicle with data from the city of Ann Arbor.)

This brief was filed from the city council’s chambers on the second floor of city hall, located at 301 E. Huron. A more detailed report will follow: [link]