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

Published Article

Washington

Publication date: June 21, 2025

File format: URL

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Housing deficits are rising, yet strategies to meet demand differ widely in their ecological impacts. Using tree and housing data from western Washington, this study evaluates “brightening” and “dimming” pathways—how tree cover changes relative to housing density over time. Three patterns emerge: increased density with little canopy loss, modest density gains with substantial canopy loss, and tree loss without housing growth. Dimming occurred about three times more often than brightening, but most brightening happened in existing urban areas, showing that densification can occur without sacrificing tree canopy. These findings highlight policy pathways that meet housing needs while protecting ecosystems and supporting human well‑being.

Subject Tags

  • Conservation Planning
  • Policy

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.

Citation

Lambert, M. R., Des Roches, S., Auerbach, D. A., Van Deynze, B., Behrens, S., Hale, R., & Pierce, K. B. (2025). Building the neighborhood for the trees: Illuminating win–wins for housing densification and nature. Conservation Science and Practice, 7(7), e70085. https://doi.org/10.1111/csp2.70085

TNC Authors