An article by Eric Jaffe included in today’s newsletter from the Alliance for Community Trees is titled, “US Cities are Losing 4 Million Trees a Year.” Citing a study by David Nowak and Eric Greenfield from the journal Urban Forestry and Urban Greening, mentioned in an earlier article about tree cover and impervious surfaces, the article paints a rather bleak picture of our national urban landscape.
Starting with a study of 1,000 random points in 20 large American cities, and comparing current digital images with images from 5 years ago, Nowak and Greenfield found “clear trends away from tree coverage and toward impervious coverage.” In 17 out of the 20 cities studies, tree coverage went down statistically. Impervious cover (roads, buildings, and other surfaces where water cannot be absorbed) rose in 16 of the cities. Our own Tacoma, Washington, had the largest increase in impervious surfaces in the entire study. To get an even more random sample of the whole country, they then selected 1,000 points in urban areas across the U.S. and compared those as well to come up with their estimate of an average net loss of 4 million trees from U.S. cities every year. What does this all mean? Fewer trees. More concrete. Lower air and water quality. Higher need for tree protection and environmental health programs in general.
Remaining end-of-season planting projects need all the helping hands they can get in the next month or two, so head to your nearest Green City and find a volunteer opportunity to get your hands dirty. As the days get longer and we start to think of drier weather (not that we’re complaining!), planting season is coming to an end. But, invasive weed removal and other projects going on in spring and summer help prepare the natural corners of our cities for more planting starting next fall. Hope to see you out there in Seattle, Tacoma, Kirkland, Redmond, or Kent. Let’s turn this trend around!