Scientists are increasingly finding evidence of the importance of having green space, like parks and greenways, in urban environments. But cities also need to be able to accommodate plenty of people. In a paper recently published by IRIS affiliate Andressa Mansur, alongside lead scientist for nature-based solutions, Robert McDonald, at The Nature Conservancy, and a team of experts from other organizations and universities, the researchers explored the tradeoffs between density and green space, and identified “brightspot” neighborhoods, which manage to be both dense and green.

The following summary was prepared by Robert McDonald:

How can urban neighborhoods be both dense and green?

Natural features like parks play important roles as places for flora and fauna to live. They can also be important nature-based solutions (NBS) for promoting human well-being. On the other hand, evidence suggests that more dense urban neighborhoods help spare habitat conversion at the fringes of expanding cities, while also allowing more walkable and livable neighborhoods. Is there a tradeoff between density and the use of urban NBS? And what are the ways urban neighborhoods can have abundant green spaces as well as density?

We reviewed what scientists and urbanists know about the relationships between urban density, nature, and sustainability. We also present information on the tradeoffs observed on average between density and urban nature, identifying a few “brightspot” neighborhoods that manage to be both dense and green, then learning what green interventions helped get them that way.

There is on average a tradeoff, with denser neighborhoods having less nature: each doubling of density in a neighborhood means a 3% decline in tree cover. This tradeoff is not very strong however, and we found plenty of examples of brightspots, neighborhoods that manage to have more tree canopy than would be expected based upon their level of density. We list 9 specific green interventions that help make urban neighborhoods both dense and greener, dividing them into two broad categories: land sparing interventions (where space for nature reduces the area that can be developed, as when creating a park) and land sharing interventions (where space for nature does not reduce the area that can be developed, as with a green roof). These interventions are made more tangible by discussions of their use in Curitiba and Singapore.

In summary, we found that while there are tensions between density and urban spaces, an urban world that is both green and dense is possible, if society chooses to take advantage of the available green interventions and create it.

Read the full article here.