Data from: Denser and greener cities

Green spaces in urban areas-- like remnant habitat, parks, constructed
wetlands, and street trees-- supply multiple benefits. Many studies show
green spaces in and near urban areas play important roles harboring
biodiversity and promoting human well-being. On the other hand, evidence
suggests that greater human population density enables compact, low-carbon
cities that spare habitat conversion at the fringes of expanding urban
areas, while also allowing more walkable and livable cities. How then can
urban areas have abundant green spaces as well as density?   This
data archive contains data created as part of a scientific manuscript that
attempts to answer this question, entitled "Denser and greener
cities: Green interventions to achieve both urban density and
nature". Please see that manuscript for details on sources of data
and details of methodology. We found that there is a negative correlation
between population density and urban green spaces. For Functional Urban
Areas in the OECD, a doubling of density is associated with a 2.9% decline
in tree cover. We argue that there are competing tradeoffs between the
benefits of density for sustainability and the benefits of nature for
human well-being. Planners must decide an appropriate density by choosing
where to be on this tradeoff curve, taking into account city-specific
urban planning goals and context. However, while the negative correlation
between population density and tree cover is modest at the level of US
urbanized areas (R2=0.22), it is weak at the US Census block level
(R2=0.05), showing that there are significant brightspots, neighborhoods
that manage to have more tree canopy than would be expected based upon
their level of density. We then describe techniques for how urban planners
and designers can create more brightspots, identifying a typology of urban
forms and listing green interventions appropriate for each form. We also
analyze policies that enable these green interventions illustrating them
with the case studies of Curitiba and Singapore. We conclude that while
there are tensions between density and urban green 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.