By Doug Boucher
In 1987, a wonderful field guide to the trees of Washington, D.C. was published by local author and naturalist Melanie Choukas-Bradley. It was called City of Trees, and a recent article in the Washington Post showed just how apt that title was and still is today.
Using data assembled by the U.S. Forest Service, the Arbor Day Foundation, and the consulting company PlanIT Geo, Post columnist Niko Kommenda showed that the Washington area (including D.C. and its suburbs in Maryland and Northern Virginia) has one of the largest “urban forests” in the country. Just a fraction under 40% of the region is covered by trees. Even more encouraging is the fact that the tree cover has been increasing in recent years, growing by 1.1% during the last five-year period. Its tree cover figure puts the D.C. area slightly ahead of other local towns and cities, such as Frederick (31%),
Poolesville (36%), Hagerstown (38%) and Baltimore (also 38%). For the state of Maryland as a whole (including rural areas), the figure is just under 46%. As Kommenda’s article points out, people can’t claim all the credit for Maryland’s numbers; one of the reasons that we have more trees is simply that we live in the eastern half of North America. Our region has a relatively moist climate, with an annual average of about forty inches of rain or snow distributed fairly evenly across all the months of the year. This makes forests the natural kind of vegetation for our region. As you go westwards, the climate gradually
gets drier, and forests are replaced by grassland in the Great Plains region and then by desert in much of the West (the Pacific Northwest is the major exception to this pattern).
It’s particularly impressive to find such large percentages of land with tree cover over them, even in our cities, because of the history of land use in the U.S. Roughly three fourths of our eastern forest had been cleared for farmland by the Civil War, but then the forests began to recover as farming moved westward into the Great Plains, and by the mid-twentieth-century they covered three fourths of the land east of the Mississippi. Since then, there hasn’t been much change in either direction. The recovery of the eastern forest has been good for humans as well as other animal species. People have long appreciated many of the benefits of trees in the city, including their shade, their beauty, and the habitats they create for wildlife, but in recent years, science has begun to realize some of their contributions to
human health as well.
As our forests grew back, they took up carbon from the atmosphere (about half of the weight of a tree is carbon) and thus helped slow down climate change. The effect of reforestation wasn’t strong enough to completely prevent heat waves, droughts, and floods, but it did make them less harmful than they would have been if the land had remained clear. Urban trees both reduced deaths from heat
waves and cut down the electricity we use (and the dollars we spend) for air conditioning. There are also psychological benefits: People tend to feel happier if they can see trees from where they live.
Research published last year estimated that an ambitious urban reforestation program in the U.S. would produce an additional $9.6 billion in benefits, mainly from better health and less need for electricity. Of course, it would take time for the trees to grow up and give their full benefits—which is all the more reason to start today.
Published in Monocacy Monocle May 2025 Issue