Building the neighborhood for the trees: Illuminating win–wins for housing densification and nature

Abstract

Housing deficits are pervasive because of multiple factors including insufficient new construction, rising costs, restrictive zoning, and income inequality. Policies to address housing deficits—both through housing densification or sprawl—have varied implications for ecosystem processes, biodiversity, and human well-being. Communities that achieve a given housing density while minimizing ecosystem degradation have been termed “brightspots.” Building on the brightspot concept, we use tree and housing data for western Washington, USA to assess tree:housing “brightening” and “dimming” relationships through time. Our analysis highlights three brightening or dimming pathways: (1) housing density increases with little or no tree cover loss, (2) modest housing density increases with modest or large tree cover losses, and (3) little to no change in housing with tree cover losses. Most neighborhoods show small changes in the tree:housing relationship. While dimming was about three times as common as brightening, most brightening occurred in existing urban areas, emphasizing that housing densification can and does occur while maintaining tree canopy. Our work illustrates policies and pathways to meet housing needs while reducing harm to natural systems and improving human well-being.