An article in the this morning’s Washington Post gives a new meaning to these words. Not density of people, density of trees. Turns out that in the District of Columbia and its suburbs, trees are a true marker of income. Where the tree cover rating is 82 percent, median household income is over $200,000; where the rating is 48 percent, median household income is $36, 250.

Trees aren’t cheap. At least they haven’t been for us. And even with pruning, watering and fertilizing, the trees in our yard are dying much faster than we can replace them.

I learned from the article that D.C.’s overall tree canopy has declined from 50 percent in 1950 to 36 percent today, a change due mostly to development. (In the suburbs it may be the opposite, because many neighborhoods here used to be farms with tillable fields and open meadows until the houses went in.)

After reading this article, I feel like taking off for the closest woodland path. I’d rather not think of trees in socioeconomic terms, but now, unfortunately, I will.