What’s the first thing that comes to mind when you think of Detroit? The auto industry? Motown music? The Tigers?
Chances are your answer wasn’t “trees.” But according to a recent New York Times article (www.nyti.ms/2VDjoot), until the 1950s Detroit was known as The City of Trees and had more of them per capita than just about any other major city in the world. Then they started dying off—more than half a million dead by 1980.
We hear often about the benefits—stormwater related and otherwise—that trees bring. They curb air pollution and sequester carbon. They alleviate the heat island effect, cooling off urban spaces during the summer. They can act as noise buffers. They reduce stormwater runoff; a significant amount of tree canopy in an otherwise largely impervious city can hold enough water to lessen peak runoff volumes. Then, of course, there are trees’ less attractive features: They shed leaves, which clog storm drains and gutters; their roots break apart sidewalks and invade pipes. On balance, though, they’re good for the urban environment. An article in Stormwater a couple of years back quantified some of the benefits of trees (“Give Me the Numbers: How trees and urban forest systems really affect stormwater runoff,” October 2016; www.bit.ly/2skLI1G), and several presentations at StormCon have addressed the topic as well. In short, trees are great if they’re well chosen and well managed, but often a nuisance or a hazard if not.
Detroit sees the value of bringing back trees, too, and it’s been trying to do so by offering to plant free ones on residents’ lots. The city would pay for and care for them, in theory. But many people—about a quarter of those to whom they were offered—turned them down, saying they didn’t trust the city to maintain them. As older trees have died or become sick enough to pose a danger, the city has been removing them, but it’s managed to get rid of only a fraction of those that need to go; some homeowners fear that new trees might also die and take power lines—or roofs—along with them when they fall.
As the NYT article notes, other cities have faced similar objections but have overcome them through successful programs, such as Philadelphia’s TreePhilly, which reassures residents the trees won’t destroy their pipes and helps them choose suitable species. Phoenix, AZ, launched a program a few years ago to affix large orange tags to city-owned trees, showing each one’s dollar value to the community in terms of stormwater management and pollution control. Both programs have been very popular, and a nonprofit group called The Greening of Detroit is now trying something similar, also linking the tree-planting effort to a youth employment program.Has your city embarked on a program to encourage trees or vegetation, at least in part for stormwater purposes? What strategies would you suggest for raising public awareness and enthusiasm? Send your comments to [email protected] or share your story on our website.