A few years ago I was visiting the west Baltimore neighborhood that inspired the American television series Homicide and The Wire. It was an urban wasteland, the brick row houses largely abandoned and boarded over. Whoever used to live here had long since gone away. Then we turned a corner onto North Carrollton Avenue, and for one city block it was a miracle: Handsome old trees formed a green canopy over the street. The houses were occupied and well tended. Someone was selling flavored ices at a stand in the shade in the middle of the block. The trees, a local woman told me, made all the difference, shading the houses, filtering the air, and making it easier to breathe. There were birds and squirrels in the branches overhead.
That visit comes to mind because I have been thinking lately about ways to make cities more livable, for people and wildlife alike. The rapid urbanization of the Earth is the dominant movement of this century, and the sprawling, unplanned growth of cities and suburbs tends to leave behind patches of greenery only by accident—a few neglected parks, some street trees here and there, and the occasional sliver of protected land. Wildlife gets crowded out and pushed toward extinction.
Plenty of studies have already demonstrated that street trees and other green spaces tend to reduce crime, improve health, build stronger neighborhoods, encourage investment in housing stock, slow stormwater runoff and lower pollution. So let’s focus on the wildlife for now. Cities are not ideal wildlife habitat, but they are increasingly the only habitat. So what do we need to do to make room for wildlife in our increasingly urbanized world?
Plan for Green Space
Add some trees along a street, and you’ve got someplace where birds can rest or roost. Add a park at the end of that street, even a small one, and now you’ve got a spot where migrating birds can stop and eat on their way to or from their breeding grounds. Even adding just 150 square meters of green space—that’s 10 parking spaces—will bring one additional bird species into a neighborhood, according to a 2013 study by urban greening specialist Paige Warren at the University of Massachusetts–Amherst. The green space can include a community garden that benefits human residents. Bees, butterflies, and other pollinators will also show up, said Warren, “even in very dense metropolitan areas like in Manhattan.”
Make those Green Spaces Connect
Multiple parks or gardens that are connected make for exponentially