Evaluating tree canopy distribution and accessibility along sidewalks for people with disabilities in Seattle Washington
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Tree canopy coverage along accessible sidewalks is an often overlooked need for people with disabilities. Tree canopy over sidewalks provide beneficial ecosystem services through shade, reduced temperatures, and sun exposures. The objectives of this study were to evaluate potential disparity between accessibility of sidewalks and tree canopy distribution along sidewalks for people with disabilities in the city of Seattle, Washington, USA. Disability demographics were sourced from the 2020 American Community Survey while the sidewalk inventory and tree canopy data were from the Seattle GeoData Portal. Percent tree canopy cover was estimated using a 1ft buffer around sidewalks and summarized by 2020 U.S. Census Tract boundaries. Disparity in sidewalk accessibility was classified as census tracts with higher than average people with disabilities and less than average accessible sidewalks per census tract. Disparity in ecosystem benefits from tree canopy coverage was classified as less than average canopy cover area over accessible sidewalks per census tract.
Of all sidewalks in Seattle, 24% of the city blocks have unimproved surfaces with no developed sidewalks. Of developed sidewalks, 7% are in very poor or poor condition (least accessible), 40% are in fair condition (moderately accessible) and 53% are in good or excellent condition (most accessible). Of Seattle’s most accessible sidewalks, 14% had tree canopy coverage. Across census tracts, there were 32 identified with potential disparity in sidewalk accessibility representing 25% of the total disabled population of Seattle. In addition, there were 44 census tracts representing 37% of the total disabled population identified with potential disparity in sidewalk accessibility and tree canopy coverage. Census tracts identified with disparity for disabled people can be prioritized for future sidewalk installation, improvement and/or tree planting. Targeting these improvements to areas with greater than average people with disabilities can help boost accessibility and ecosystem benefits to this underserved population.